FJ Fork Swap 1100 to 1200

[movenon]

That is pretty clever Krusty.  Here is mine.  From memory it is an 18mm bolt, welded a 3/8 socket jambed on the end (yard sale socket).

George

[krusty]

I've got'em out now how do I get these suckers back in. I've got the preload wound to softest and I know that the rod has to line up somewhere down inside, and a couple of times I've managed to get the cap into the tube but missed getting the threads to take up and when I try again I can't get back to that point.
Am I missing something?

[movenon]

There is something wrong there. That short top spring shouldn't be there.  A question, did you install the small spring on the dampener tube ?  Someone has either added that extra small spring on top or that spring is the one that is suppose to be on the dampener tube. If all is done correctly with the bikes forks fully extended the threads of the cap should be close to touching internal threads of the tube.  It is possable that someone added that spring in an attempt to increase the spring capcity instead of buying a new spring with the correct spring rate for there weight.  Seems that with that added spring it would be hard to compress and align the "D" rod with it's slot all at the same time?

Not the best picture but the spring I am referring to is on the dampener.

George

[jscgdunn]

Check to se that the washers on top of the spring fit down past the threads. As I recall, the 92 3xw washers are slightly different than the 89 3cv.  Maybe same issue in your case?

Jeff

[krusty]

I've just had a look at the service manual for these 1200 forks. They are pre 1991 and I have measured the spring length as 484mm which is well within spec. I have no idea why these extra springs have been fitted, and, when I first removed the fork caps the spring adjuster was on max preload. WTF? No wonder I was having trouble getting the caps back on. I'll be back in the grage tomorrow and I'll try again without the extra springs. I'll measure the oil level while I'm at it.

[IceFJ]

Hold on....
If my bad memory serves me right these "extra" springs were also inside my forks when I opened them a while ago, so is it possible that there is a difference between years of manufacture and they may be supposed to be there?
This is not my territory so I will let someone that knows better chime in....
And by the way, mine is '86

[IceFJ]

I just checked the parts catalog for my '86 found here http://www.fjowners.com/index.php?topic=692.0
and I see that the little "extra"spring is there (see item 31 & 70)

Brgds.
Magnus

[krusty]

Mine are later forks, without the antidive,  to the ones in the .pdf which I did see while I was researching this. This is the pdf I found http://www.fjowners.com/index.php?topic=695.0
The internals are much the same but, as far as I can determine,  the parts diagram only shows 2 springs whereas my forks contain 3 springs (each). Am I making sense or am I looking at this wrong.

[Firehawk068]

That extra spring (between the 2 washers) is not supposed to be there.

As was stated already, someone probably added it to gain a little more pre-load, or spring-rate to the forks.
I would remove it, and ride it for awhile to see how you like the setting.

Most people use a solid spacer (section of PVC, or metal pipe) to gain some more preload. Or step up to a stiffer-rate spring.

[Pat Conlon]

...Or step up to a stiffer-rate spring.

+1 The '89/90 stock spring rate at .644 kg/mm has proved to be weak sauce for our heavy FJ's although probably the maximum rate the damper rod design can handle (without cartridge emulators)

Still, the '89/90 oem rates are better than the oem '91-93 oem springs @ .475 kg/mm.....
Aoogah, aoogah, aoogah, dive, dive dive..( I threw that in for Commander Frank)

[Mark Olson]

Silly question, but do you have the bike jacked up so the front wheel is off the ground and forks fully extended ?

[krusty]

Today I removed the extra spring and washer and the fork caps went back in as they should. I've done dozens of fork overhauls in years past and never had the trouble that these gave me. The forks are now back on the bike but I can't test ride it yet until the new rotors arrive from China. Will report back.

[FJ_Hooligan]

As was stated already, someone probably added it to gain a little more pre-load, or spring-rate to the forks.

Stacking 2 (or more) springs on top of each other actually results in a spring rate that is less than the smallest rate.  At least until the weaker spring is totally collapsed.  Then it acts as a spacer and the rate changes to the rate of the spring that's not coil bound.

[krusty]

Happy to report that the new brake rotors arrived from China today. Purchased off ebay 23/5 arrived 28/5, that must be some sort of record out of China. Most impressed with how they were packed and they appear to be good quality, well made. So what did I do today, yep, fitted them. Front end is all back together now. Only have to fill engine with oil and test ride.

[krusty]

After about 300klm these new rotors are working just fine. Very happy with them. Went on a VJMC ride last Sunday of about 250klm, with wifey on the back, and brakes are excellent. The new fork seals I put in are not leaking either.