Refitting fork tubes!!

R

RichRoberts44

New Member
Hi guys. Got a cb900fz and I'm struggling. I got the bike in pieces and im mocking up some stuff. Trying to get the forks back into the triple trees and they just wont go! Ive tried prying the trees open, oiling them but theres no way. Am I missing something? Are they supposed to be so tight? Same applies to both top and bottom triples!
 
If you have a deep freeze big enough, throw your forks in there overnight and put your triple trees somewhere warm, or MILDLY heat them before trying to fit them in!! This is a rough method, but sometimes it's all it takes!! Good luck!!
 
I dont have room in the freezer for forks, but will a heat gun on the trees work? Are they supposed to be this tight? I only wanted to mock them up before paint!
 
I've had some pretty sticky ones in the rear, but nothing a lil spit or oil couldn't cure!!! I wouldn't recommend a heat gun, might be a lil much! Maybe a lil bit of heat from the heat gun on just the collars so you can pry them apart a lil bit!
 
Ok so on further inspection, i seriously believe they are cb750 triple trees and cb900 forks! I can only measure with a ruler as my vernier is at work, but the diameter of the trees looks around 35mm and the forks closer to 39mm. I did also recieve some cb750 carbs so it wouldnt be a shock! I guess I'll have to do the gsxr front end after all!
 
Well that sounds like your problem.... It shouldn't take more than a flathead and maybe a couple washers to open the trees if the forks are right.
 
Ok so the forks measure at 35mm and the triples at 35mm. What should they measure? Is that correct or should the triples be 56mm? Heres the top triple to see if anyone can identify it!

 
You should never need to freeze, heat or pry to fit fork tubes. They're either a match for the trees or they're not.

If your rough measuring shows a 4mm difference then the forks and trees are mismatched and don't belong together.
 
Sorry my rough measuring shows no difference, both seem to be 35mm. Measured with a vernier though so cant get much more accurate. Most accurate measures are Forks=34.95 Trees=35.02
 
Did you really crank on the fork tube caps? Perhaps enough to distort the tubes a bit? Try backing them off and inserting the tubes in the triples without the caps. Use a little lube too.
 
I just looked at a schematic for the 900fz...those forks don't seem to match. http://www.cmsnl.com/honda-cb900fz-bol-dor_model14511/partslist/F08.html#results
 
Yes I no I think they are cb750. But I cant find the triple trees I have. Was hoping someone recognized them. Cant match them up anywhere. ???
 
Those aren't from a cb750. Not sure what they are from. By the picture, I would guess the cap and retaining ring need to come off then slide thru the trees and reinstall. Just a guess, but I would see if the caps can be unscrewed. GENTLY...or see if it is possible to remove that retaining don't without distorting it. Since you can't identify how these are put together, take your time and be patient. They have to come apart somehow....you will figure it out if you can resist the urge to force things along.
 
Ok, unscrewed the top, came open easy. Was then very slowly opening it whilst crapping myself that the spring was putting preload on the end and this thing was going to take off, but it didnt, and, viola...



Still unsure what they are from, but they have a honda steering stem.
 
As would be my luck, the other side is seized! Any suggestions? I dont want to clamp the fork tube and damage it. Benind the screw cap at the top is a valve that is the same as a tyre valve. Is this used to pressurize the tubes?
 
Yes, the valves are to add a couple psi (between 2 and 7 depending on the bike, but since that is unknown...i would not jump to add any air). Will probably ride fine without. Soak with some penetrating fluid. You can also use what is called a strap clamp to hold the tube without damaging while you unscrew the cap. Don't use heat...you will damage the o-ring. And maybe a few GENTLE taps on the cap and around the internal threads of the fork tube with a very small hammer may help once the penetrating fluid has soaked.
 
Cheers for the advice. As they are smaller than what I'd like, I will most likely sort these out then move them on. Im on the hunt for a gsxr front end now. Obviously with these being smaller id assume they wouldn't perform as well as standard cb900 forks are 39mm I believe. The last thing I want to do id downgrade. So gsxr front end and possibly rear here I come!
 
They are probably off a DOHC custom.
Take the wire clip off and they should slide in easy
I looked them up on CSML, 1982 CB750c is real similar but had a balance pipe between the two legs
 
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