Hey guys,
I've been searching all over for information on how to swap in a 1992 GSXR1100 USD fork into a 1989 FJ. I see its been done via the following website: http://www.fjmods.btinternet.co.uk/MarkAlva.htm.
Does anyone have any additional details?
I am committed now. I just purchased a parts bike to do the swap.
I'll keep you all updated on progress.
The GSXRs that will be donating parts (One is a 90, the other a 91...all parts are there, pictures are taken while they were getting pulled apart)
(http://s1174.beta.photobucket.com/user/Jason_Penney/media/152.jpg.html)
(http://s1174.beta.photobucket.com/user/Jason_Penney/media/151.jpg.html)
The fork length is just 2 inches off of the FJ length. This will be compensated by using handlebar mounts and a superbike bar. Both bikes use a mechanical speedo so I'll be able to retain the FJ speedometer. The FJ and GSXRs share the same steering stem diameter and have the same specs for the upper and lower bearings....the only problem is the stem length. So I'm in the middle of pressing the FJ stem into the GSXR lower triple.
Some pix of the USDs compared against the FJ forks:
(http://s1174.beta.photobucket.com/user/Jason_Penney/media/150.jpg.html)
(http://s1174.beta.photobucket.com/user/Jason_Penney/media/149.jpg.html)
I know all this has been done before but I thought I would share anyway.
All the best and more to come
I'll try this again!
The GSXRs that will be donating parts (One is a 90, the other a 91...all parts are there, pictures are taken while they were getting pulled apart)
(https://lh3.googleusercontent.com/-wfXO2CQaqCU/USV7HtZXvoI/AAAAAAAAAtI/lp0eUAiaSes/s640/151.JPG)
(https://lh6.googleusercontent.com/-UvYIHUPRWg0/USV7IGT8ufI/AAAAAAAAAtQ/pnPOHa-HUoA/s640/152.JPG)
(https://lh3.googleusercontent.com/-btAW6FmRvf4/USV7Irr7kSI/AAAAAAAAAtc/vz-yepTRV6o/s512/154.JPG)
(https://lh6.googleusercontent.com/-3Gj_73qx23A/USV7IUADrCI/AAAAAAAAAtY/xtB8Rw9a7uA/s640/153.JPG)
The fork length is just 2 inches off of the FJ length. This will be compensated by using handlebar mounts and a superbike bar. Both bikes use a mechanical speedo so I'll be able to retain the FJ speedometer. The FJ and GSXRs share the same steering stem diameter and have the same specs for the upper and lower bearings....the only problem is the stem length. So I'm in the middle of pressing the FJ stem into the GSXR lower triple. I'll also be using the ignition switch from the GSXR.
.
Some pix of the USDs compared against the FJ forks:
(https://lh4.googleusercontent.com/-BTwh6__fuvU/USV7HrJIKrI/AAAAAAAAAtE/qmNUnyWU2rY/s512/150.JPG)
(https://lh5.googleusercontent.com/-h58tn5pytg0/USV7HLRrfbI/AAAAAAAAAs0/Q6AVyMCncF4/s512/149.JPG)
(https://lh6.googleusercontent.com/-YKSS1hSs20c/USV7Kp8i09I/AAAAAAAAAuU/5tw1sE2ttBg/s512/159.JPG)
I know all this has been done before but I thought I would share anyway.
Doesn't matter whats been done before. I learn something from every project, even from the ones I have done before. There is always more than one way to do things. Keep the pictures coming. :good2: You can use the rear end stuff on your bike also.
George
Yup already well on the way...
(https://lh5.googleusercontent.com/-czsZyLFVpBs/USV7EF1bhmI/AAAAAAAAArs/5E8QtwrUX7s/s640/140.JPG)
(https://lh6.googleusercontent.com/-fVRb2KGnif8/USV7Emv66uI/AAAAAAAAAr0/7WkKruSSh_w/s640/141.JPG)
(https://picasaweb.google.com/101856546688647667533/FJ1200#5847215016882017314)
FJ rear sitting beside the 190 GSXR rear
(https://lh6.googleusercontent.com/-7h7zbM6AbX4/USV7I-a1pWI/AAAAAAAAAtk/CF5zucQ3ySA/s640/155.JPG)
That's about the stage mine is in. Start making new "dog bones" tomorrow. Hope to be done with the rear by the end of the month. Next month new wheel and tire. The forks are going to have to wait until later. Keep the photo's and progress reports coming.
George
Hey George,
Will you be adding the Honda F4 shock as well? I just picked one up and will be modifying over the next couple of weeks.
(https://lh5.googleusercontent.com/-6ByWMZZLZBY/USV7FMt3rdI/AAAAAAAAAsI/qMojJ_WPzdQ/s640/143.JPG)
Your timing on this is perfect for me.
I have been looking at buying a 1994 gsxr1100 and doing the same swap. Do you think the rear swing arm would swap in to?
Scott
The watercooled GSXR1100s (1993 - 1998) have a different swing arm then the oil cooled ones I have so I couldn't say. The swing arm on the oil cooled looks very similar to the FJ. So I didn't see the benefit of the swap.
Quote from: FJNovaScotia on February 21, 2013, 06:27:59 AM
Hey George,
Will you be adding the Honda F4 shock as well? I just picked one up and will be modifying over the next couple of weeks.
(https://lh5.googleusercontent.com/-6ByWMZZLZBY/USV7FMt3rdI/AAAAAAAAAsI/qMojJ_WPzdQ/s640/143.JPG)
My FJ is a 1990. As soon as the dog bones are made and the canister is mounted then the f4i shock conversion is in and done... I am going to mount the canister after the brake stay is in place. Not the best picture but you get the idea :).
George
(http://fjowners.com/gallery/4/1651_08_02_13_6_12_31.jpeg)
Quote from: movenon on February 21, 2013, 10:17:06 AM
(http://fjowners.com/gallery/4/1651_08_02_13_6_12_31.jpeg)
George,
Every time I look at that photo I see the shock mounted upside down. Is that the way everyone is mounting this shock?
Randy - RPM
Aint trying to tell anyone what to do but I agree with Randy.... looks upside down to me too.
KOokaloo!
Frank
Yea, its a grand experiment in futility... I am doing it "just because" I can. I know there are about a million reasons not to do this. It is just in my nature so said the fox to the chicken ......... I am doing no harm to the bike mounting points (other than the rider, me) so I can later install a better shock when I give up and surrender.
No, the shock is only upside down mounted in the later FJ's (89 and newer?).
The early ones are mounted right side up and easier to deal with. I am just going to the 5.5 rear wheel and had a shock on hand and said what the hell, I am here.
Back in the old days I had a two stroke and decided that with a grinder and a ruler I should port it, great ran better, more porting, great power band about 200 RPM wide !, ported some more and you know that damn thing can run backwards...... Its just in my nature....
George
Quote from: racerman_27410 on February 21, 2013, 05:07:21 PM
Aint trying to tell anyone what to do but I agree with Randy.... looks upside down to me too.
Frank
It IS upside down. Who cares? There's a bladder between the oil and the nitrogen.
It would have been near on impossible to modify the stock lower mount and keep it upright.
Arnie
Is there anything wrong with mounting a shock upside down? Compression and rebound are still compression and rebound.
Does the nitrogen leak out when upside down? :-)
Just curious. We used to have this discussion when setting up the Sprint Car years ago. Some would mount the shock with the body on the bottom so they could easily/quickly read the shock settings. Others would mount the body on top for less unsprung weight. AFAIK the shock performed the same.
Either mounting geometry would leak when he crashed the car. :-(
DavidR.
Quote from: SlowOldGuy on February 21, 2013, 06:40:25 PM
Is there anything wrong with mounting a shock upside down? Compression and rebound are still compression and rebound.
Does the nitrogen leak out when upside down? :-)
Quote from: Arnie on February 21, 2013, 06:39:36 PM
It IS upside down. Who cares? There's a bladder between the oil and the nitrogen.
It would have been near on impossible to modify the stock lower mount and keep it upright.
+2 I wondered the same thing...
Dan
Quote from: movenon on February 21, 2013, 06:10:30 PM
Back in the old days I had a two stroke and decided that with a grinder and a ruler I should port it, great ran better, more porting, great power band about 200 RPM wide !, ported some more and you know that damn thing can run backwards...... Its just in my nature....
George
Had a friend with a Husky that would run backwards if you didn't kick it hard enough, thanks to a home porting job..... We used to have contests to see who could ride it the farthest, backwards. Great fun!!
Quote from: RichBaker on February 21, 2013, 11:02:37 PM
Quote from: movenon on February 21, 2013, 06:10:30 PM
Back in the old days I had a two stroke and decided that with a grinder and a ruler I should port it, great ran better, more porting, great power band about 200 RPM wide !, ported some more and you know that damn thing can run backwards...... Its just in my nature....
George
Had a friend with a Husky that would run backwards if you didn't kick it hard enough, thanks to a home porting job..... We used to have contests to see who could ride it the farthest, backwards. Great fun!!
Yes and it would sound a little different when it happened. It was kinda fun to play with but ultimately it was off to the Yamaha dealer for a new barrel :)..... Back when bikes were easy to work on. High tech was a reed valve.....
George
Back to the Honda F4 shock upside down discussion....
Arnie, how long have you been riding with your current setup? As I understand it you are the one that first modified the F4 shock to fit a post 89 FJ.
Hey if the front forks work best upside down....why not the rear shock! :i_am_so_happy:
Good afternoon,
Well, at the risk of this looking like another discussion about oil...
As they pertain to FJ's SPECIFICALLY the upside down forks are not better, however they may be comparable to the Fork Valves (& the Fork Brace to tie it all together). That being said, based on how the vaunted usd's have performed on other non-FJ motorcycles that I have come across, any advantage was inconsequential.
And back to FJ's, the main problem was the front wheel "pushing" when cornering (regardless of speed). Also front tire "cupping" was a problem & premature wear as well. The Fork Valves, at least in may individual case, eliminated the negative aspects of tire wear while allowing for enhanced cornering. Just to keep the focus [not to mention the peace] this has been my individual & most enjoyable experience....
Now, Mr. Conlon please do not execute , I mean excommunicate me & Flynt, remember, it is not nice to shoot a midget (especially a pudgy one)...
Gentlemen, keep smiling & ride safe,
Midget Ramos.
Quote from: Mike Ramos on February 22, 2013, 04:35:31 PM
Now, Mr. Conlon please do not execute , I mean excommunicate me & Flynt, remember, it is not nice to shoot a midget (especially a pudgy one)...
Midget Ramos.
Mike, if you would just grow a grey beard, we could bestow the the honor of "FJ Gnome" to you.
FJNovaScotia asked, "Arnie, how long have you been riding with your current setup? As I understand it you are the one that first modified the F4 shock to fit a post 89 FJ."
I answered this last night, but it isn't here. ????? I wonder if I was so tired I never actually posted. ?????
Anyhow, 20-January-2009 and 20,000 kms ago is when I fitted the F4i shock. I chose the F4i shock because the spring rate was about right, it had lots of adjustabliity, and it was cheap. If I was unable to get it to work, I'd have just tossed it. To fit it to my '91 B FJ, I had to have a clevis on one end, and the top eye was much easier to cut and weld a clevis bracket to then the bottom (almost impossible since some of the damping adjustment is there). Gas filled shocks have a bladder separating the Nitrogen and the oil, so orientation doesn't matter. There is nothing magic about "upside down" suspension IMO.
Upside down forks are a bit different, in that as well as being cartridge type forks (as opposed to damper rod forks), the legs that are now in the triple clamps are much larger in diameter. This makes the whole front end stiffer. I question whether this can be felt on the street.
BTW my other bike has upside down forks.
Lets see if this time it makes the list :-)
Arnie
Ho Hum, nothing new from Mike here...same old same old....However, I do wonder specifically what FJ Mike has ridden that has USD forks...?
He would not be speaking hypothetically would he...? Naaa...He must be speaking from experience... (I added my signature line just for you Mike)
Note to others: I really do enjoy Mike and Mike's company at the rallies. He is a good guy...just a wee bit misguided.... Cheers!
Performance of RPM valves against USD forks put aside, I know which setup looks the best. Pete. :lol:
Quote from: oldktmdude on February 22, 2013, 10:06:20 PM
Performance of RPM valves against USD forks put aside, I know which setup looks the best. Pete. :lol:
Yep, the USD's gets the chicks......
The shock does not know or care which way it its mounted, works the same either way.
Kurt
Quote from: yamaha fj rider on February 23, 2013, 10:36:48 PM
The shock does not know or care which way it its mounted, works the same either way.
Kurt
So I got a drink and went out in the cold dark garage and ask my shock "if it minded being upside down" ? After a pause and another drink it answered "nope".....
Then I asked it if USD forks really do get the chicks ? Again after a long pause it said "YEP , but when you get them you won't have any money left to spend on them"........ I said "OH" and went back inside the warm house. :dash2: :wacko1:
George
I have always understood the main reason for USD forks. Besides being stiffer. Was to drastically reduse unsprung weight. Witch would allow any suspension, cartridge or rod. To get and keep the wheel/tire back to the pavement quicker/easier. Improving traction. I know with my limited skill set that I would never feel the difference. But I need any advantage in traction I can get. Just might be the difference. That I didn't know. Kept me from feeling the pavement against my person (again)
And they get the chicks
All that being said If I didn't have the Mod Problem. I would have already installed Randy's valves in my original forks. I've (even though I have USDs on my86 and adding them to my 87)already spent over $1000 @ rpm and have a list for the future that will probably be in the thousands before I can stop... Help Me..
Nothing better than an FJ debate...other than more pictures of FJ stuff:
Here are "side by side" pics of the 88 and newer FJ rear shock and the F4:
(https://lh3.googleusercontent.com/-jpSfRVujLE4/USqVVOIoUQI/AAAAAAAAAxY/yfzEtJd9az8/s640/fj1200%2520001.JPG)
(https://lh5.googleusercontent.com/-rzGN2KsNLgg/USqVVINC1tI/AAAAAAAAAxY/lbw3eUtPgxo/s512/fj1200%2520002.JPG)
You can see the bolt on the top left that will have to be turned down to fit both the FJ Chassis and the F4 shock.
A match made in heaven.... Unless you have the RPM shock.... Randy!!!! Where the hell are you with your shock????
Pictures of the front end work this weekend:
This is the FJ stem pressed into the GSXR1100 lower triple:
(https://lh6.googleusercontent.com/-6YEc99Cmm4Y/USqVWNdfpLI/AAAAAAAAAxY/WOtNjGl6nyU/s512/fj1200%2520004.JPG)
This may be overkill but below are pictures of the FJ top triple compared against the GSXR1100 top triple:
(https://lh3.googleusercontent.com/-O2DONGINObQ/USqVY9JJR_I/AAAAAAAAAxY/UZr-2561kU8/s640/fj1200%2520012.JPG)
(https://lh4.googleusercontent.com/-i54ZIheHLVs/USqVYtzjJrI/AAAAAAAAAxY/iFlzED4WIos/s640/fj1200%2520011.JPG)
(https://lh5.googleusercontent.com/-UM8X9yTdcA8/USqVYss8cpI/AAAAAAAAAxY/ptlns6pscPQ/s640/fj1200%2520010.JPG)
(https://lh3.googleusercontent.com/-XXmYS1YQb_8/USqVXdwDqaI/AAAAAAAAAxY/u3Q497GB1EE/s640/fj1200%2520009.JPG)
(https://lh4.googleusercontent.com/-e4axnBEKCZw/USqVXAqx-uI/AAAAAAAAAxY/ujhjGC4Lzzg/s640/fj1200%2520008.JPG)
(https://lh5.googleusercontent.com/--VPDTUW8CgQ/USqVWl64rUI/AAAAAAAAAxY/zpVPRZUb5n0/s640/fj1200%2520007.JPG)
(https://lh4.googleusercontent.com/-aEYzhSUmlnY/USqVWUX0XuI/AAAAAAAAAxY/b9EvArDa2xE/s512/fj1200%2520006.JPG)
(https://lh4.googleusercontent.com/-naAQquO6GfA/USqVZdmA5hI/AAAAAAAAAxY/8Ivj_yWq_tQ/s640/fj1200%2520013.JPG)
(https://lh3.googleusercontent.com/-S8AFbM39RzI/USqVaMe8YII/AAAAAAAAAxY/1-iJazlH7IE/s512/fj1200%2520018.JPG)
(https://lh6.googleusercontent.com/-WzEf-d9FAMs/USqVbfIKrBI/AAAAAAAAAxY/qHvByGYqmFA/s640/fj1200%2520022.JPG)
(https://lh4.googleusercontent.com/-9SxkYCxUHJo/USqVbdTQdwI/AAAAAAAAAxY/pnqTmvnx6tU/s512/fj1200%2520023.JPG)
(https://lh6.googleusercontent.com/-A_fZ4FdJWac/USqVa9coWrI/AAAAAAAAAxY/0RK2nfajtz0/s640/fj1200%2520021.JPG)
(https://lh4.googleusercontent.com/-6LUaTc8PW0g/USqVZ6rSEVI/AAAAAAAAAxY/rrPyiVIwAjc/s640/fj1200%2520014.JPG)
Keep the pic's and info coming :). Are the forks shorter/longer or same length as the FJ forks ?
Giantkiller: I feel your pain.... Let me know if you find the answer. I keep saying "just this last one thing". It might help when riding season gets here...
George
Quote from: FJNovaScotia on February 20, 2013, 08:06:44 PM
(https://lh5.googleusercontent.com/-czsZyLFVpBs/USV7EF1bhmI/AAAAAAAAArs/5E8QtwrUX7s/s640/140.JPG)
Not to stray off topic, but just a piece of advice...........Very soon, you will want to shorten your mid-pipe, and move the muffler can forward enough to put a strap around it, and use that to hang it from the rear footpeg bracket..........Otherwise, it will exit the motorcycle when you least expect it to............Most likely during a spirited ride in a canyon, where it will go tumbling over the edge, never to be found again.........Despite Andy F's best efforts to locate it.........DAMHIK.
Nice job on the suspension upgrades though!
Need more pictures
Have you finished this yet?
Scott
Pictures coming soon, I finished rebuilding the front forks (needed to building lots of special tools for the USD forks!), modifying the rear shock and painting the upper tripple tree and rims.
Just a bunch of pics....new bearings in the rims, the ignition is the GSXR one grafted to the fj wiring harness and the cbr f3 shock is on as well...next up, mounting rear fork reservoir to bike, building 130MM dogbones, brake installation.
USD Fork rebuild:
(https://lh3.googleusercontent.com/-NAjzHhb3pAQ/UXFqZfrkm9I/AAAAAAAAAzg/9jY1jxDfoW0/s640/IMG-20130316-00344.jpg)
Rims refinished:
(https://lh5.googleusercontent.com/-qBUfJvYdQOk/UXFqY_K8moI/AAAAAAAAAzg/PRreOTQgcDQ/s640/IMG-20130316-00341.jpg)
(https://lh3.googleusercontent.com/-fPzWGRoTSJU/UXFqaJEpQaI/AAAAAAAAAzg/uIkmw_9Bjc0/s640/IMG-20130412-00357.jpg)
(https://lh6.googleusercontent.com/-A5BBifIuxVI/UXFqZ1KRG4I/AAAAAAAAAzg/bDoFicNfX8M/s640/IMG-20130412-00356.jpg)
Upper triple refinished:
(https://lh5.googleusercontent.com/-vxOh72UT30A/UXFqaxiELcI/AAAAAAAAAzg/Ca3vGM89sbg/s640/IMG-20130412-00359.jpg)
Pics of Bike still being put together:
(https://lh6.googleusercontent.com/-Idj1eWy0Ncc/UXFOOrlCjbI/AAAAAAAAAyU/XpxqJqiNgBg/s512/009.JPG)
(https://lh6.googleusercontent.com/-hOvd9igJgKA/UXFOOdiPr-I/AAAAAAAAAyY/VRxf2YCJa9Q/s640/008.JPG)
(https://lh6.googleusercontent.com/--wFvgAV_wuk/UXFOOJdAJfI/AAAAAAAAAyQ/4RDz5d2mxWQ/s640/007.JPG)
(https://lh5.googleusercontent.com/-NmoJaOp_isk/UXFONLtb4ZI/AAAAAAAAAx4/EOAUdnx_Mng/s512/006.JPG)
(https://lh5.googleusercontent.com/-66LN9Tc2XdI/UXFONazCxFI/AAAAAAAAAx8/vwpTG0zr4h4/s512/005.JPG)
(https://lh5.googleusercontent.com/-1nsgxT_utJA/UXFONWtqz5I/AAAAAAAAAyA/TYzZt4bCBYI/s640/004.JPG)
Here is what I did.
(http://fjowners.com/gallery/4/1651_16_04_13_7_35_38.jpeg)
(http://fjowners.com/gallery/4/1651_16_04_13_7_38_55.jpeg)
(http://fjowners.com/gallery/4/1651_09_04_13_8_20_37.jpeg)
If I like the shock after riding it a while I will think about installing a longer air line and mount it up where the FJ shock adjuster was.
George
Never thought about mounting to the brake arm. Good idea! But George...why is your bike so clean???
Quote from: FJNovaScotia on April 19, 2013, 04:15:23 PM
Never thought about mounting to the brake arm. Good idea! But George...why is your bike so clean???
Same problem you have, to *(^*#^*#@ cold to ride it :yahoo: It's been on the center stand for maint. since last January. I was just going to put new tires on and clean it up a bit and somehow it got out way of control. :dash2: I need to do some engine work but that's going to put on hold until next winter. It will just have to smoke. I am trying to get it ready for the WCR.
I tried the swing arm mount but wasn't happy with the exhaust pipe to hose clearance, engineered some brackets and wasn't happy with that. Then it dawned on me that there was no reason not to mount it on the brake stay/tension rod. Also the brake hose was a new hose (NOS) off a GSXR 750 and was a bit short plus the fitting's were not at the best angles, and as it turned out it fit a lot better by running it up the stay also. Anyhow that's where it is for now.
George
Quote from: FJNovaScotia on April 19, 2013, 04:15:23 PM
But George...why is your bike so clean???
Disgusting!
Derek
Hey George,
What settings are you using on the F3?
Quote from: FJNovaScotia on April 22, 2013, 07:11:44 PM
Hey George,
What settings are you using on the F3?
Right now I have it on 4 I think. I haven't had it out yet to check everything but right now the static sag is within spec.. This sounds simple but make sure you are using the correct reference point for setting the number... It's not the casting mark on the rear or front of the shock. Look at it from the side and peek though the "windows" and look at the ramp as you adjust it, count the notch's.
George
What is your sag without a rider? I have my shock set to the top of the adjustment ramp and it feels really soft and though I haven't measured yet too much sag.
Quote from: FJNovaScotia on April 23, 2013, 09:17:56 AM
What is your sag without a rider? I have my shock set to the top of the adjustment ramp and it feels really soft and though I haven't measured yet too much sag.
Our projects are about neck and neck here. here is a pretty good video to watch on setting sag.
setting suspension sag (http://www.youtube.com/watch?v=FjGgq1z9zbo#ws)
My top out is close to 10mm. I need to get a helper to get accurate measurements on the total sag but just sitting on it as close as I can eye ball it settles about an inch or possably a little more. Just for details I weigh 217 lb. at present (working on that problem also :rofl:).
All the numbers aside I need to just get it out on the road and get a "butt" feel for whats going on. My old FJ shock felt stiff and clunky for the lack of another term (POS) the F4i feels a lot better. While looking at the video notice the softness and rate of return on the bike he is using.
My neighbor just took delivery on a new custom ZX 14R. I should go over and do a bounce test on his machine :). He is a nice guy into having the best and the fastest
I just smile and make it a point to sit out front on my patio area with a cup of coffee every morning waving him good bye as he trod's off to work every morning :lol:......
I keep tell him to get an old FJ, retire and be happy. "Money or your life" I guess. You trade one for the other. Less I digress....
He did at one time own an FJ 1200 and still looks out the corner of his eye longing at mine......... Especially the comfortable seat.
George
I'll take a look at the video for sure...thanks!
Another question, how long did you make your new dogbones? Mine are 130MM from center to center.
OK George,
Just watched the video and a buddy of mine happened to just drop by so these are my measurements:
With the highest spring rate setting: 10MM static and 60MM with a rider (185 lbs). That is double what is recommended in the video.
This is also throwing off my USD fork measurements. When I get on the bike the front doesn't drop evenly with the rear.
Summary: Rear is way to soft for my liking.
I would like to put a stiffer spring on my honda f4i shock. Haven't had the time to search one out. (Im not too good @ it) If you find one let us know.
Quote from: giantkiller on April 23, 2013, 04:23:48 PM
I would like to put a stiffer spring on my honda f4i shock. Haven't had the time to search one out. (Im not too good @ it) If you find one let us know.
Check this out. Its good info on the spring http://cbrforum.com/forum/how-mechanical-40/how-rear-spring-change-66943/ (http://cbrforum.com/forum/how-mechanical-40/how-rear-spring-change-66943/)
http://www.eshocks.com/hyp_make.asp (http://www.eshocks.com/hyp_make.asp)
George
Quote from: FJNovaScotia on April 23, 2013, 03:22:01 PM
I'll take a look at the video for sure...thanks!
Another question, how long did you make your new dogbones? Mine are 130MM from center to center.
My bones are 125mm c to c.. With the center stand on a 2 X 8 (1.5" thick) broad my rear wheel has 1/4 clearance off the concrete floor. I estimate the bike now sits 1.5 inch's higher than stock in the rear. I put a 3/4 " "shoe" under the side stand, now sits at approx the same angle as a stock FJ. I will have to remove the center stand before I take it out to ride. I plan on redesigning the center stand if I decide to keep the shock on.
I thought about a heaver spring but again, I want to see how it works before ordering a spring. I need a valid reference point. Other wise you are just shooting in the dark. The Honda spring rate on paper is lower than the FJ but there are other things like the links, ratio's etc that come in to play. Plus factory claims and numbers are debatable. I thought I would educate myself on the subject, let me save you some time. Don't bother, it will give you a severe head ache. :yahoo:
If you order new springs make sure you get those collars from race tech. The Honda spring is tapered and the aftermarket ones are straight, you will need the race tech collars. They are cheap.
Another coil site http://www.hrpworld.com/index.cfm?tpc=Hyperco-Coil-Over-Spring-6-Inch-Free-Length-2.25-Inch-ID-2&form_prod_id=926&action=product (http://www.hrpworld.com/index.cfm?tpc=Hyperco-Coil-Over-Spring-6-Inch-Free-Length-2.25-Inch-ID-2&form_prod_id=926&action=product)
George
I can not remember where I got the information but the spec's I have for a 1990 stock FJ shock is:
Stock 1990, 3CV-10 FJ Shock:
Coil turns= 6 Coil dia. Bottom =85.60mm Coil dia top= 87.60mm Coil thickness= 13.8mm Coil length on shock= 5 13/16
1989 Stock Rear Suspension
Shock Absorber Travel 40mm(1.57in)
Spring Free Length 163.5 mm(6.44in)
<Limit> 159mm (6.26 in)
Fitting Length 151.5mm (5.96 in)
Spring Rate 196 N/mm (20kg/mm 1,120lb/in)
Stroke 0-40mm (0-1.57in)
Optional Spring No
George
Any thoughts on taking the fj coil and putting it on the f4 shock? They look close, both are tapered and are close to the same inside diameter on both the tapered and non tapered end (I'll have to use a caliper to be sure)?
Anyone remove the spring from their FJ rear shock?
George,
I don't know where you got those numbers for the OEM stock shock, but they are definitely NOT what Clymer (yeah, I'm cautious about this as a facts source too) lists as specs for that spring.
They list 174.5mm as free length (new) and 170mm for the 'wear' limit for the 84-90 bikes.
The 91on bikes are 181mm (new) and 174mm 'wear' limit.
This IS pretty close to what I measured after removing a few springs a number of years ago when we had some springs made.
The spring rate is also not anywhere near the 1120 lbs/in you list. Much closer to 6-700 lbs/in.
We had 2 spring rates 'ordered' of 900 and 1100 lbs/in. Unfortunately, the springs delivered were a bit long so the preload was higher than desired when installed, even with the ring at minimum setting.
Removing and installing these springs was a difficult and dangerous operation. Using 2 screw type coil spring compressors with modified jaws, we stripped one of the compressors after about 8 spring changes, and broke the jaw of the other. Luckily none of us was in the path of the flying metal. :-/
If you don't have proper tools and some experience be VERY careful. There is a LOT of energy just waiting to be released when you have the spring compressed enough to get the keeper out.
I haven't measured the F4 shock spring rate, but it is probably in the 900 lb/in range (by feel). Certainly stiffer than the OEM '91 or '89 springs.
I'm about 105kg (too fat) and find the F4 shock and spring suit me very well for the road solo or with luggage. A bit soft with a big passenger added.
Arnie
The Honda shock on mine is way too soft for a fat guy like me. The guy @ Traxxion told me the spring on the Honda f4i shock was around 780. The guy on the cbr forum switch to 900 eibach and thought it was alittle too stiff. And thought he might go down to a 850. So the original must be less than that.
I just got done ordering an eibach 900 and the bushings to fit it to the f4i. Might be a few weeks to get the spring.
Just wanted to say thanks to everybody that led the way on the Honda shock.
Quote from: Arnie on April 24, 2013, 11:36:29 AM
George,
I don't know where you got those numbers for the OEM stock shock, but they are definitely NOT what Clymer (yeah, I'm cautious about this as a facts source too) lists as specs for that spring.
They list 174.5mm as free length (new) and 170mm for the 'wear' limit for the 84-90 bikes.
The 91on bikes are 181mm (new) and 174mm 'wear' limit.
This IS pretty close to what I measured after removing a few springs a number of years ago when we had some springs made.
The spring rate is also not anywhere near the 1120 lbs/in you list. Much closer to 6-700 lbs/in.
We had 2 spring rates 'ordered' of 900 and 1100 lbs/in. Unfortunately, the springs delivered were a bit long so the preload was higher than desired when installed, even with the ring at minimum setting.
Removing and installing these springs was a difficult and dangerous operation. Using 2 screw type coil spring compressors with modified jaws, we stripped one of the compressors after about 8 spring changes, and broke the jaw of the other. Luckily none of us was in the path of the flying metal. :-/
If you don't have proper tools and some experience be VERY careful. There is a LOT of energy just waiting to be released when you have the spring compressed enough to get the keeper out.
I haven't measured the F4 shock spring rate, but it is probably in the 900 lb/in range (by feel). Certainly stiffer than the OEM '91 or '89 springs.
I'm about 105kg (too fat) and find the F4 shock and spring suit me very well for the road solo or with luggage. A bit soft with a big passenger added.
Arnie
Arnie,
On these projects you gather up all the data you can find but there is no substatute for seat of the pants. I don't trust any of the numbers that are published at least to a point. I also think the 1120 lb figure was high. But having no real data you just start digging for answers.
My spring is stock right now and after I ride it I might change the spring, but I need to know where I am before I go changing springs. I have changed motorcycle shock springs in the past. They can be intimidating. I have never had a close call but,,, I was keenly aware of what I was doing. :rofl2: Ever changed a garage door spring ? :biggrin: It will get your attention..
Good point on the aftermarket spring being longer thus adding some built in preload.
I am a shade under 98kg and trying to hit 90-91kg. I started the "bio engineered suspension improvements" in Nov. at 116 kg.
The last post from "giantkiller" he mentioned someone going to a 900 lb spring and thought it was a little to stiff. That comes into alignment with what you discovered at 900 lbs of spring. He mentioned going to 850lb spring. He didn't mention the guys weight and preffered riding style. I lean more toward touring with a little power to play with..... :lol:
Thanks for the input Arnie.
giantkiller:
If you can, keep us posted on the spring change. Its all good information. Another member in Utah is also doing the same shock conversion and I am sure he is following this post also.
George
The guy that said he thought the 900 was maybe too stiff, was on a Honda f4i( lighter bike). And I believe he said he was 180lbs. The guy @Traxxion that I talked to on the phone said I should go to 1000-1100lbs. But he wouldn't even sell me a 900 without him doing a revalve. Even after I told him I would send him the shock if it didn't work.
Hey Arnie,
You mention that the stock f4 shock works for you. Would you be able to measure static sag? Perhaps the nitrogen charge is low or non existent on mine.
I'm going to have mine looked at by a local bike suspension guy but that won't be for another couple weeks (he is on vacation).
Jason
Just measured static sag at 12mm and rider sag at close to 50mm. Not exact on rider sag doing it myself. I'll crank in another notch or two of preload to see how that feels.
Note: I ride torn up roads and not smooth racetracks, I don't want it too stiff for my old bones :-)
Arnie
Quote from: FJNovaScotia on April 24, 2013, 06:20:35 PM
Hey Arnie,
You mention that the stock f4 shock works for you. Would you be able to measure static sag? Perhaps the nitrogen charge is low or non existent on mine.
I'm going to have mine looked at by a local bike suspension guy but that won't be for another couple weeks (he is on vacation).
Jason
Thanks Arnie that is close to my measurements 10MM/60MM. I'm going to swap the fj coil into the f4. Can you describe how to seperate the fj rear shock? The top part of the shock screws off, is that part under load? Do I have to remove that first, then compress the spring and remove a clip inside the shock to allow the bushing and spring to be removed?
Jason
IIRC
I compressed the spring until I could slip the upper keeper/seat out.
The spring then just slips over the upper mount eye.
Arnie
Hey guys,
Still researching to see what I can learn about the f4 shock. Based on my research thus far I believe that the shock needs a stiffer spring to handle the heavier FJ. I have been researching VFR forums as this is an option for that bike as well. Even using the VFR as a platform the consensus is the same: the f4 shock spring isn't enough to handle the load. Here are the sites I have been reviewing:
http://www.vfrdiscussion.com/forum/index.php/topic/32986-cbr-f4-shock-in-place-of-vfr-shock/ (http://www.vfrdiscussion.com/forum/index.php/topic/32986-cbr-f4-shock-in-place-of-vfr-shock/)
http://www.vfrdiscussion.com/forum/index.php/topic/73424-shock-option-vfr1200-rear-shock-on-vfr800/ (http://www.vfrdiscussion.com/forum/index.php/topic/73424-shock-option-vfr1200-rear-shock-on-vfr800/)
http://www.vfrdiscussion.com/forum/index.php/topic/19712-vtec-shock-options/ (http://www.vfrdiscussion.com/forum/index.php/topic/19712-vtec-shock-options/)
I still think the best option right now is to replace the f4 spring with the fj spring and see if the dampening can handle the heavier shock, if not then will I revalve or buy a new shock? I'll be on vacation for the next 2 weeks. I'll post my updates when I get back.
Jason
I've been using an f4i shock on my 1100 with no issues of a soft spring, preload at 3 rebound and compression both about quarter turn from lowest set, but I'm maximum 75kg depending on the week :biggrin: , , randy at rpm is working on having his shocks out soooon, if your going to buy new, these are made especially for the fj,s
Jason,
I don't believe anyone said the F4i shock was ideal to use in the FJ.
However, it is not a $600-1000 spend item either.
The spring on mine could stand to be a bit stiffer than it is, but as is it is MUCH, MUCH better than the OEM FJ spring and the damping of the shock is better and more adjustable than the OEM FJ shock ever was.
The '89+ FJs were sporTOURING bikes, and were given very soft springs.
The Honda F4i 600s were a "proddie racer" that was street legal, and given (almost) race suspension. As such, they were much stiffer, relatively, than the FJs so just looking at the bike weight does not tell a full story.
I'm certain that a purpose built shock from Ohlins, WP, Penske, Bitubo, Sachs, RPM, and other manufacturers would be 'better' than the kludge of swapping in a F4i shock. In fact, you will almost certainly be able to find another "take-off" shock from some other bike that will work better in the FJ.
But, YOU've got to buy and try all those other bike shocks and then do the swap and report back here.
I've swapped springs and had springs made for the OEM shock and changed preload spacers. I've also bought and tried a GSXR1100 shock before buying and trying this Honda F4i shock.
Please let us know when you come up with either a cheaper or better choice.
Arnie
Thanks Arnie,
Will do!
Jason
I got the 1990 FJ up and running today after a winter of mods including a F4i shock. On a short "safety of flight" run, I have to say the shock works great for me. Intially it seems is a lot better than the old FJ shock. I will admit that I did not push it hard or run it over 50 - 70 mph. I was looking for big issues not tuning the suspension. Also I wasn't wearing my helmet or gear, I was listening and looking for problems.
For the lack of terms it seemed to track better, take the road irregularities better. I also ran it down an "Idaho freeway / cow trail " unimproved dirt road with 4 to 6 inch deep "chuck holes" about 1 1/2 to 2 feet in diameter and it seemed to work right through them with out pitching , banging or lost of control. :good2: :good2:
It felt a hell of a lot better than my stock rear shock and my current front end......... That's another issue on the horizon. :good2:
Tomorrow I will take it on more of an extensive run and will play with the suspension settings.
As far as the F4i shock. I weigh 216 lb (97.7 kg), the bike has a rear rack with an empty top box and tank bag with approximately 1/2 tank of non alcohol laced fuel :lol:... Dogbones are at present are about 125 mm C to C and the rear end sits about 1 1/2 inches (38.1mm) taller. On the center stand with a 2 X 8 (1 1/2 inch thick) under it the rear wheel the tire clears the floor about 1/4 inch. I have the preload set on the 4th or 5th position.
That's all I have at present. For the 75.00 dollars total I have in the shock I am pleased with it at least in a touring mode. With more seat time I will be able to evaluate the conversion more but I am not a track or street racer. I had the opportunity to ride a full up track only bike once (I used it to take the MSF course as my bike was down for repairs) and suspension settings in that range are a different animal, for long distance street riding I don't think I would enjoy it.
George
I'm 280lbs. So I needed a stiffer spring. Would have liked to go heavier than 900lbs on the spring. But that seems to be the limit of what the honda guys think the stock rebound can handle without a revalve. I'm going to have $115 into the spring(including bushes and motorcycle spring compression tools) So $170 total into the shock.
That will be a sh.tload better than an fj shock.
Yes, you have to consider that the dampers have limits and given enough spring it will over whelm it.
I just took some measurements on my bike with the F4i shock. Got a helper to give me a hand and measure.
static (unloaded pulling up on the bike with the rear wheels of the ground) 8mm
bike vertical with no rider my measuring point was 480mm
bike with me on it in riding position 440mm
sag measurement 40mm plus 8mm = 48mm with spring on the number 5 slot/ramp.
Rider weight 216 1/2 tank fuel, rear rack and top box.
I am not suspension guru so please forgive any errors and correct me. Just a guy in the garage..
George
In researching information on another problem I stumbled into a 1991 Factory FJ manual (its online here in the "files section) and they gave the FJ rear shock spec's as:
Shock travel..........................48mm (1.89in)
Spring free length...................181mm (7.13 in)
<limit>..................................174mm (6.85 in)
Fitting length.........................164mm (6.46 in)
Spring Rate...........................132 N/m (13.5 kg/mm, 756 lb/in.... model K1
stroke..................................Zero 48 mm (Zero 1.89in)
Optional Spring......................No
Enclosed Gas Pressure............1200 kPa (12 kg/cm2, 171 psi)
Note the spring rate, 756 lb/in. But there is a lot more to it than rate, length, rate at which it gets to max etc. But it interesting that it isn't far off the f4i shock.
Just information to throw into the pot. :good2:
George
Shameless plug/example...
I saw that information, and thought it'd be a nice thing to have on reference. I went ahead and typed in
fjowners.wikidot.com/rear-shock
clicked 'create page'
signed in (you will have to register the first time)
and added some basic information and then the stats listed.
It's small and incomplete... But hopefully you guys will add info to it and links to other things when you notice it now or in the future.
Slowly but surely...