GT 500 fork re-assembly.

jackyman · Posted: Fri Jan 29, 2010 4:55 pm Post subject: GT 500 fork re-assembly.

Having taken the forks apart some time ago and re-chromed the inner tube I'm looking to rebuild. The main point I'd like some help on is the spring seating... the bolts holding them in place have been loosened and I'm concerned that I need to make sure they are correctly placed before continuing with the re-build.
Any help with this point or points connected with putting the legs back together would be much appreciated.

dorT500 · Posted: Fri Jan 29, 2010 6:39 pm Post subject:

Well, this is at least the second or third post on GT models about worries that bolt at the bottom of the outer tube that is suppose to be for centering the spring seat at bottom of the inner fork tube and is not supposed to be loosened acccording to manuals. (may cause rattling or chattering during fork operation). However, member 'Russell' s interpretation of that warning was that the writers probably meant ' in usual operation or other exterior maintenence,etc'. ( I am just paraphrasing here on his original comments). I think I tend to agree about the meaning of the warning now. Last question was on a GT250 by member 'Horsmann'. He was having a bad time getting the tubes separated and finally took the forks to a dealer and they removed the bolt on each leg and pulled the forks apart. I believe he has them back together now but do not know if he has the bike running and done any road tests to see there are any noticeable problems. Sorry I can't be more help, but the GT forks are a different animal from what I am use to. Hopefully. member 'Horsmann' can add some input about the results he has had since putting his back together.. Member 'Bikegeezer' also has a GT500 and perhaps he can help on the fork question. I sure would like to find a pic of the inside of these forks somewhere. Is the bottom seat like a cone?. Seems like they would center themselves on complete reassembly and then you would tighten the bolt? Speculation is, I am afraid, all I have to offer. Rolling Eyes

Good luck.

bobbyjim · Posted: Sat Jan 30, 2010 7:50 am Post subject:

[b][i]Don't know if this will help but I have exploded diagrams of the '72-'75 GT550's. Maybe they would help you.

jackyman · Posted: Sat Jan 30, 2010 9:58 am Post subject:

Thanks for the input guys....as you stated dorT500 the manual says you shouldn't release the end bolts but goes no further ( nothing to help us over zealous types who did). My plan is to knock up a tool that will fit within the fork outer tube with a cross hair to match the spring seating point , this should tell me that it is central or not. As I only slackened 1 of the bolts I don't think it should be much of an issue, just don't fancy stripping them down later.

dorT500 · Posted: Sat Jan 30, 2010 2:38 pm Post subject:

Oohhhhh....I see now how it is made. (page 14) Just now found this.....

Bikegeezer · Posted: Sun Jan 31, 2010 9:26 am Post subject:

dorT500 · Posted: Sun Jan 31, 2010 12:00 pm Post subject:

That is great, another foggy subject cleared up by 'Da Man'. Thanks Stu. Though they were not my forks, the elusiveness of the procedure was bugging me. I only had a faint idea of how it was configured in there. Details rule. Hope everything works out for you member' jackyman' and post some pics if you can. Maybe one of these days I will run across a used GT500 fork and cut the lower leg for a cross section pic of the components and their arrangement.....think it would make a neat picture. Wink

Here is the fork page pulled from the download I had posted...

Russell · Posted: Sun Jan 31, 2010 2:43 pm Post subject:

With reference to Stu's very clear and helpful outline of procedure above.What is it that allows some manual's to be so obscure in their descriptions while some experienced practicioners like Stu have the ability to be so clear and straightforward in their explanations?Stu your concise and pragmatic ability to clearly describe process in lay terms is of enormous value to all of us.

I've dismantled and eventually re-assembled several different forks, older and newer, from Honda, Suzuki and Yamaha,plus a number of bicycle examples and have been amazed by the variety of ways they are put together.I haven't had any problem getting any with a bolt through from the outside/underside of the fork lower back together as everything always seems to have 'centred' itself to allow the bolt to go back in properly. There was however one fork,I think on a Yamaha, where the bolt was an Allen head and it was fitted on the inside at the end of the damper mechanism.There would have been a factory special tool.We made our own by finding a nut that we knew would fit and act as an Allen key and welding it to a metre rod.We welded a short T piece on top to make T handle.The tool is still lying under the bench but the bike concerned is long gone.I think it was the XT550. It sits alongside a once broken kick-starter shaft for the same bike. The splined section where the lever clamps on had some-how been stuffed. We couldn't get a new shaft, nor the clamp end of the lever , at that time so a friend built the splined section up with weld,ground it into a square section,which neatly fitted a piece of square section steel tube he'd welded onto the kick start where the splined clamp should be.Worked brilliantly for a couple of years till the right parts were eventually found and fitted.

It's re-assuring when these artifacts catch my eye in the shed and I remember the story.It's somewhat less pleasant when I have no idea what the piece came off and why we removed/modified or discarded it.

jackyman · Posted: Thu Feb 04, 2010 5:26 pm Post subject: Fork re-assembly

Thanks for all the help guys. Have taken the parts into work to give them a good clean down and check over before re-biulding . Taking snaps along the way, thank goodness for the digital revolution, will post what I have along the way...any requests before they go back together ? I'm happy to oblige!!! Just leave the wife out!! One thing of note..... the shuttle valve ...how does that work? I have shims ..are they part of that assembly or have I just got some parts mixed up?

Bikegeezer · Posted: Thu Feb 04, 2010 6:36 pm Post subject: Re: Fork re-assembly

dorT500 · Posted: Thu Feb 04, 2010 7:16 pm Post subject:

'jackyman', I was going to suggest looking for any wear marks that might have been left on the tubes from the shims but then I remembered you had the forks re-chromed. Might they have left a wear mark on any other related parts? Might check before any further cleaning. Good luck.

jackyman · Posted: Sun Mar 07, 2010 12:10 pm Post subject:

Finally got a slot in the workshop to spend some time looking at the fit of the chromed tubes and the aluminium cones. When I fitted the tubes into their outers it became clear that one travelled further than the other, as a result I bit the bullet and removed the offending article. Taking a closer look at the cone and the tube sizes it became apparent that good alignment is essential (only .2mm differance between the I.D and O.D,). Bikegeezers advice for refitting is spot on!

dorT500 · Posted: Sun Mar 07, 2010 12:54 pm Post subject:

Thanks for the pics. I am afraid I am still a little lost. Embarassed

Where are the shims mentioned earlier. Location? Are those shim wear marks on the cone in the first pic or do they go somewhere else? It is not a shim you removed is it?

dorT500 · Posted: Sun Mar 07, 2010 4:33 pm Post subject:

Oh...OK...sorry. After rereading Stu's reply, I see the shims go on the tube first and then the valve.

jackyman · Posted: Sun Mar 14, 2010 3:24 pm Post subject:

Pics I forgot to take .... not sure they will be of any help. Shims (2) can,just about be seen !