honda f4i rear shock

[giantkiller]

I'm about 280lbs and I had mine set at 7 and it was way too stif. I think I'm at 3. Still trying to sort out the carbs. Then I'll set the suspension.

[chocker]

I was at 2 at the beginning and when I sat on the bike it felt really droopy. Once it was at 7 it held up. I set the dampening and rebound to stock settings and it drives great. Very smooth on the bumps. We've definately got a lot of bumps on our roads in Quebec. It's a big improvement compared to the stock shock.

Mark

[movenon]

Yes, it WILL work on an '89.
You have to cut the "upper" eye to make a mount for a clevis that needs to be welded on.
You then mount the shock upside down.  You also have to modify the OEM Yamaha upper mount bolt and make new dogbones to control the ride height from the longer shock.

Arnie

Since im new here im gonna ask
Ive yet to dig in to the suspension
This mod will or wont work on an 89fj?

OK, winter is coming and I am giving some thought to cleaning and modifying my 1990 FJ 1200. I am considering going to a GSXR rear wheel and while back there I will pull apart the swing arm and shock to clean and inspect (bike has 32,000 miles). The F4 shock mod looks interesting. Are there any photo's of one that has had a clevis mount welded on it? Do you have to cut the eye off down flush? And how much were the dog bones modified. Just looking for "heads up" info. I know all this will probably come to light when it is pulled apart. Sometimes it's better to ask first. Being retired I keep the costs down and in 65 years have learned to fabricate decently.
Also as I notice that you can pick up entire swing arm Assembly's pretty cheap. Would it be of any benefit to get an older swing arm assembly and use that rather than modding the shock ? I suppose there was a reason Yamaha changed the swing arm in 1988. Things to ponder.... Nice thread to read.
"if you are lost, go faster" "never ask for directions" " always smile"

[Arnie]

Last Q first:  I think the main reason Yam went to a steel swingarm was cost. 
So, an older Aluminum swingarm may be a good change to make.

I'll take some pics (if I can get visual access) and post them.
I cut the upper eye at about the centerline and welded the clevis to that.
This provided a large wide support and kept the weld a bit further away
from the body of the shock and the gas enclosed within.

The dogbones need to be made shorter to raise the ride height. 
Exactly how short they need to be will be dependent on tire/wheel
used, OA length of your shock, and your choice of ride height.
I assembled the whole rear end, put the bike on the centerstand,
and then determined my dogbone length, and made new dogbones.

Arnie

[movenon]

Thanks for the info.! I would like to do the conversion and trying to also feed idea's out for the later model FJ's. I will do a little digging now for an early swing arm. I see them advertised and the demand has to be between a negative number and zero....
In contributing information on the f4i shock, this site is interesting   http://cbrforum.com/forum/how-mechanical-40/how-rear-spring-change-66943/. More to follow I hope. 

[RichBaker]

Thanks for the info.! I would like to do the conversion and trying to also feed idea's out for the later model FJ's. I will do a little digging now for an early swing arm. I see them advertised and the demand has to be between a negative number and zero....
In contributing information on the f4i shock, this site is interesting   http://cbrforum.com/forum/how-mechanical-40/how-rear-spring-change-66943/. More to follow I hope. 

They changed to a steel swingarm in '91.... The 1st 3 gens are Al.

[movenon]

You are correct. My 1990 is AL.. I like the idea of keeping it so it would be back to welding a clevis adapter on the shock. Think I can handle that, now I am looking into spring rates. I don't weigh 150 lbs... . The bike is heavier than the Honda. Also I plan on more "touring" than sport riding. I notice the F4i's stroke is 60mm (2.36") , I can't locate the FJ rear shock stroke yet. That stroke number is from Olin so it might not be the stock number, its just the best info I have right now. Lots to consider.

[jscgdunn]

Some help here:

http://www.bulkky.com/honda-motorcycle-information/cbr600/cbr600f4i-01-03/cbr600f4i-01-02-03-rear-suspension-compression-rebound-damping

[movenon]

Thanks for the info.. It will help in the set up. Today I bought a F4i shock off flea bay with 6000 miles of time on it for 69.00 to the front door. This winter I will get into the conversion on my 1990 FJ. I am now looking for some GSXR "bits" for a rear wheel conversion as I will probably be due a new rear tire next year anyhow.  just never ends and that's the good news...... The bad is I will probably have to get a job.

[bigbore2]

Looks like the top mount of the F4i shock can be fitted with the bushing/spacer from the original shock.  Mine [84-1100].  The original shock top mount has a bushing of 50 mm length and 12mm ID which will work perfect if cut to fit to take up space on either side of the F4i shock top mount. The bushing on my 06 F4i top mount measured at 28.5 mm. 50 mm total space to fill means one 10 mm spacer and one 11 mm spacer made from the original shock bushing with 1/2 mm play leftover. This bushing is hardened steel so a precision cut is needed here, this is not a hack saw in the garage type cut. Should have this done on Fri. so if anything changes I will let you know.

[giantkiller]

Looks like the top mount of the F4i shock can be fitted with the bushing/spacer from the original shock.  Mine [84-1100].  The original shock top mount has a bushing of 50 mm length and 12mm ID which will work perfect if cut to fit to take up space on either side of the F4i shock top mount. The bushing on my 06 F4i top mount measured at 28.5 mm. 50 mm total space to fill means one 10 mm spacer and one 11 mm spacer made from the original shock bushing with 1/2 mm play leftover. This bushing is hardened steel so a precision cut is needed here, this is not a hack saw in the garage type cut. Should have this done on Fri. so if anything changes I will let you know.

I used the fj bushing also worked great.

[bigbore2]

Thanx for the info, Giantkiller.  I would add that the two bushings/spacers need to be the same length, so instead of one at 10 mm and one at 11 mm like I posted before , I would change that to 2 at 10.5 and that they need to be a loose fit so the top shock mount can rotate the couple of degrees it needs to as the rear wheel moves up and down.

[jscgdunn]

Looks like the top mount of the F4i shock can be fitted with the bushing/spacer from the original shock.  Mine [84-1100].  The original shock top mount has a bushing of 50 mm length and 12mm ID which will work perfect if cut to fit to take up space on either side of the F4i shock top mount. The bushing on my 06 F4i top mount measured at 28.5 mm. 50 mm total space to fill means one 10 mm spacer and one 11 mm spacer made from the original shock bushing with 1/2 mm play leftover. This bushing is hardened steel so a precision cut is needed here, this is not a hack saw in the garage type cut. Should have this done on Fri. so if anything changes I will let you know.

I used the fj bushing also worked great.

The no-cutting-or-purchasingparts method:
I heated the top original F4 bushing from the inside using a propane torch; just hot enough to break the bonds of the rubber.  Then using the FJ bushing I pressed out the f4 bushing in a vise.  The FJ bushing is slightly larger than the F4 bushing.  Final fit is very tight. 

The same method can be used on the bottom mount.  Using heat as above, press out the original FJ bushing and clean off with wire wheel.  Then drill out the bottom mount of the F4 shock and press in the original FJ bushing.  You will need a pretty good drill press to drill this large hole, which is just under 1 inch.

[Brian]

Ok you guys have convinced me , I have my 05 f4i shock coming $112.00 from the U S of A to Sydney so pretty happy with that ,think ill go with the upside version like Arnie says to get to the adjustments easier , but decide that upon fittment i guess ?.
I weigh about 85k withgear on so 3 on preload and 1 on dampning sounds like the starting point from what ive been reading here
Sent my forks to a local guy called Shock Treatment $600.00 & feels real nice although ive Still got original 16" wheels on mine & running with Battlax's & think i do alright ,starting to question my ability now,
So maybe im not havin a go after all ,? 
Cant wait to put rear shock in 

Cheers to all info provided ,great site , great people go hand in hand with great Bike !!

[Goetz]

Shock= $40 shipped (some retard had spraypainted it black, on ONE side... sigh. it works great tho)
2 bearings for the lower mount- $18 shipped
butane torch
assorted wrenches, drivers, etc.
two hours of my life.

and now i have a bike that doesn't wallow like a fat lazy pig.
Took her for a short ride and WOW what a difference.
found out the PO had CUT the oem spring down, it was like riding a hardtail. felt EVERY little bump. Now much less so.
She sits RIGHT now!! and way more fun to ride. Blue ridge parkway this weekend!!!! maybe deals gap on the way back home, might as well i guess.
BTW, i highly suggest using a piece of thin spring steel, something real thin and flexible, to work in between the f4I top mount bushing and its rubber sleeve in between blasts from the torch.. then try to get some lube in there before you press the f4 bushing out with the oem fj one and PRESTO instant spacers. Iforgot to take pics till i was done, kinda got in the zone.
before

DSC00238 by goetzjordan, on Flickr

after


DSC00253 by goetzjordan, on Flickr

btw im about 5'9" 230lbs, and it feels pretty good.