jr's brain picking

[jr1349]

g'day all,
              man there are some nice fj's on this site, I especially like the bikes that have had the 17" wheel, brake and swing arm conversions, is there a particular model of bike in which the parts for these conversions are taken from, some of them resemble the parts on my xjr a lot, brakes especially, the swing arms look the same also except for mine being a twin shock setup?

straight up, im just looking to gather a bit more info on the potential interchangability of certain parts, mostly out of curiosity, but its all fuel for thought, I might like to go for some lighter wheels one day as that should help at both the drags and with handling, but compatibility is still a bit of a mystery to me as I haven't done much of that level of mucking about with road bikes, in the past id prolly just modify and make stuff as I needed them, but not working in the trade anymore I don't really have access to the equipment now days, and factory made parts generally work better anyway.

any info on the parts u use will be greatly appreciated, hope im not stepping over a line here.

cheers

kris

[Arnie]

Hi Kris,

Most of the 17" rear wheel mods are GSXR rear wheel assemblies including brake and hanger, as well as cush drive.
Reason for that is that it works well, and is dead easy to do.  NO machining at all.
The biggest, most helpful parts supplier used is RPMracingca.com, aka Racerrad8 who is a regular on this site.  He's developed and had a number of pieces made for FJs and is a great guy to boot.  He (and his wife) even attended the 30th anniversary FJ rally held last March in Jindabyne, NSW.

Being an XJR owner, and in Perth, you will probably want to make acquaintance with Victor Drummond, also a good guy and local to you (when he's in country).  He has a parts supply business servicing both FJ and XJRs and also knows his way around bikes.  His website is:        http://yamaha-parts.victordrummond.net/

Take a look around, look through the files section here, and feel free to ask any Q's you may have.

Arnie

[jr1349]

cheers Arnie, so did the fj's originally have 16's front and rear, or just rear.

those balloon tyres are starting to grow on me, well maybe not the front.

now that ive had a bit more of a look around there seems to be swing arms, forks and wheels from all over, gixxer, t/ace, fz's, r1's, etc, and some of em look like they need a fair bit of work to fit.

but do the blue spot callipers bolt straight on?

k

[Bones]

but do the blue spot callipers bolt straight on?

k

Yep, from 89 I think onwards they bolt straight on.

[Bill_Rockoff]

1984-1987 FJs had the 16" fronts.  1988 and later had 17x3 front wheels.  They do okay with modern radial tires, but they're a bit heavy.  The 1987-1988 EXUP FZR1000 front wheel fits right in in its place, and it's a lighter 17x3.5 wheel.

YZF600R 17x5 rear wheel can be fitted in back as well, with a modified FJ brake torque arm and some machining of the spacers / cush drive hub.  You can run the factory FJ rear caliper, but it's meant for the wider (internally vented) FJ rear rotor.  So, in theory, if you use up the full depth of rear pad material on the thinner solid YZF rotor, you could wind up with the pads too close toward the caliper center, where the caliper would fail to hold them in place.

[JMR]

I have a Kosman 17" X 5" rear wheel conversion. It makes everything easy and I have to say the work has held up perfectly (after 5 years). I like using all FJ stuff (though I do have a bunch of GSXR wheels in my shop).

[jr1349]

are the fj clutches exactly the same as xjr's?

I've rebuilt the clutch on mine twice in the nearly 100k that I've owned it, I bought it at 36k and had to rebuilt the clutch at 40k because of roll on type excessive slippage, on this occasion the problem was a couple of warped steels, but the fibre plates were fine and I have reused them after the second rebuild.

the second rebuild was due to some cold slippage that went away after the engine had warmed up, at about 80k on the odo (the mechanic I spoke to when I rebuilt it the first time said that they need rebuilding about every 40k, so this seemed pretty accurate) this time the steels were fine but the aftermarket fibre plates I fitted at the first rebuild were worn down to bottom tolerance, I refitted the original fibres and an extra clutch spring at this point.

its been 50k since then and the clutch is fine, although the lever is maybe seeming a little longer on take up, at my last stint at the drags, which was about 20k ago, I worked out that I was getting a little top end slip via my gearing chart (about 500rpm from memory), so I changed the oil and that sorted it (I was in the middle of an oil experiment at the time, but that's another story), and its still fine for street use with no noticeable slip and good take up, but obviously I am going to have to rebuild it again some day, and most likely due to my hammering it at the drags, which is something that will be coming up again this southern summer.

I've read of some blokes replacing the both the anti judder ring and the thinner end fibre rings all with the other thicker fibre rings, can anyone confirm whether this is the case and if it works, as id look into doing this at the next rebuild if its a good thing?

cheers

k

[movenon]

I would assume they are closely related here is a thread of what an FJ clutch looks like and some info on springs and modding the pack.
http://www.fjowners.com/index.php?topic=1808.0
George

[oldktmdude]

I've read of some blokes replacing the both the anti judder ring and the thinner end fibre rings all with the other thicker fibre rings, can anyone confirm whether this is the case and if it works, as id look into doing this at the next rebuild if its a good thing?

cheers

k

This is a common practice with FJ's. Another popular mod (and keep this to yourself) is to double up the diaphragm spring. I did this about four years ago when I had a badly slipping clutch and have never had to touch the clutch since. Clutch lever pull is somewhat harder but this is easily overcome by the use of a 14mm master cylinder. I used an FJR spring because it's the same as the FJ but half the price.   Pete.

[ribbert]

I've read of some blokes replacing the both the anti judder ring and the thinner end fibre rings all with the other thicker fibre rings, can anyone confirm whether this is the case and if it works, as id look into doing this at the next rebuild if its a good thing?

cheers

k

This is a common practice with FJ's.
Pete.

Recent posts suggest this also gives rise to chatter when engaging the clutch.

Noel

[jr1349]

I would assume they are closely related here is a thread of what an FJ clutch looks like and some info on springs and modding the pack.
http://www.fjowners.com/index.php?topic=1808.0
George

this is awesome you blokes, a really well put together write up, well done, especially to Pat Conlon by the looks, for putting it together

so just to clarify, we don't remove the anti judder plate (or is this just another steel that's held behind the wire ring with the second thin fibre), just remove the wire ring and replace the last thin fibre plate in the pack with a thick one.
and you cant change the first thin fibre with a thick one unless you have it bored to fit the pressure plate, I think that's it right, I've already got the piggy backed diaphragm springs and I've found this to be an excellent mod.

on a separate note, I fitted new front braided brake lines today, my bike has the blue spot callipers set up that a lot of you guys fit to your fj's, the lines and callipers themselves seem to have gravity bled fine through the master cyl, and I've tried pressure bleeding them from there, and all though I'm getting flow and no more bubbles at the bleed nipples, the lever simply wont build up any pressure and pulls straight back to the bar, the master cyl has remained filled and has not drawn air, but it just seems that the master cyl itself (as in the piston and cylinder volume) wont fill and pressurise.

any advice?

k

[oldktmdude]

   Kris, I've had a similar issue to this in the past. I overcame it by removing the m/c lid (cover with a towel or rag) and levering the calliper pistons back to their fully relaxed position. Take care not to damage the brake pads as you do this. I found that the air trapped behind the pistons was very hard to bleed but by forcing the pistons back , it helped remove most of it. After doing this, perform bleeding as normal.  Regards, Pete.

[FJ_Hooligan]

The best tool for bleeding the brakes or clutch is PATIENCE.  Wait for the bubbles to rise rather than trying to force them down.

Tapping the lever seems to work best rather than full pulls.  Let is sit awhile, drink a beer, then resume.  Should complete the bleeding before you finish the 6-pack.

[jr1349]

good advice you blokes, cheers.

yeah the pushing the calliper pistons back in sounds like a good idea to me, I've already tied back the brake lever over night, the hel (brake line suppliers) website reckons this is a good method, but if this doesn't work, then ill try the calliper pistons idea, the clutch (new line there as well) bleed up fairly easily, well comparatively anyway, but yeah, hopefully just try a few things and some patience and bob will, by rights, be my uncle. 

bit wet today though, so ill leave it till the weekend I reckon.

back on crutches and gears though, is the rpm shift detent kit easy to install, like the type of thing that can be done alongside a clutch rebuild?

k.

[oldktmdude]

is the rpm shift detent kit easy to install, like the type of thing that can be done alongside a clutch rebuild?

k.

If you're doing a clutch rebuild, it's the ideal time to fit the RPM shift kit. Did mine a couple of weeks ago, simple job and the difference is unbelievable.   
Pete.