Fork Seal Change (on Yam Tyz250)

[motopat]

haven't looked at the manual yet , but was wondering how much of a job replacing fork seals was going to be on my TYZ?

Do you undo the caps at the top of the yolks, drop the forks, empty oil and pull apart? I guess you prize (sp?) out the old items and insert new?

Is there any special tool I may need, or could a mechanical numpty like me do it with basic tool kit of spanners, screwdrivers and sockets, hack saw etc.

I think previously someone (could have been Woody) suggested I leave well alone unless somethings the matter, but that time has come....

Cheers,

Pat

[woody]

It's not so bad to do, just a bit time-consuming that's all. Manual covers it well, but basically;

Loosen the top nut of each leg whilst the leg is still in the bike but undo the top yolk pinch bolts before trying to loosen.

Put the leg in a vice or whatever to hold it. Loosen the allen bolt in the bottom of the fork leg that holds the damper rod in place. Don't remove it at this stage or oil will pour out, just crack the thread. Use an air wrench if you have one to do this but if not it should undo ok. The compressed spring should stop the damper rod turning. To get an allen key into the allen head you will need to screw the damper adjustment screw right in otherwise the allen key won't fit properly into the allen bolt head. Count the number of turns you screw the adjuster in so you can reset it afterwards.

Once you've cracked the allen bolt, put the leg vertically in the vice (remember it's still full of oil at this stage) unscrew the top nut from the stanchion. The stanchion can then be pulled down showing the damper rod and spring. The top nut is still attached to the damper rod at this stage so hold the locknut that is underneath the top nut, you'll need to pull the spacer and spring down to see it, then unscrew and remove the top nut, followed by the spacer and spring. Make sure you note the order of these components as they come off for reassembly.

You can now drain the oil by pouring it out of the stanchion. You'll also have to pump the stanchion and also the damper rod (not both at the same time) to remove all or at least most of the oil. Then remove the allen bolt from the bottom of the leg. Prise up the dust seal out of the leg and remove the circlip (I am pretty sure there is one) that holds the seal in. You then have to clamp the leg in the vice and pull hard and sharply on the stanchion to yank it out of the leg. At this stage only the tight fit of the bush is holding the stanchion in the leg. It may take a few good pulls but it will come out (cue the inuendos) Expect to fly backwards accross your garage when it does so make sure you have an clear path for your journey just in case..... When the stanchion comes out it will have the seal, bush and a spacer on it and it will also spew a bit more oil out. Note their order. You may as well put new bushes in whilst you're doing the seals.

Reassemble the new bush and seal on the leg with the spacer and push the stanchion back into the leg. You should coat the seal with grease as per the manual. You will need to drift the seal and bush into the leg until they are seated correctly. You can't just push them in. There is a special tool but you can improvise. I use an old tube spanner large enough to slide over the stanchion. Whatever you use be careful not to damage the seal.

Replace the damper rod allen bolt and ensure it is properly tightened. Then follow the procedure for filling with oil. Leave a final gap of 95mm from oil to top of stanchion. Refit the spring, spacer and top nut. Readjust damper adjustment screw and job done.

Please note that this is from memory and just to give you an idea of the procedure. It's not the definitive procedure and I may have overlooked something as it's been a while since I did the job. Give yourself a couple of hours as it's the first time you've done it. It's not too hard, just a bit time consuming but follow the manual and you will be ok.

[motopat]

thanks Woody. You make it sound easy(ish). Don't know that I'm tempted to do it alone, so will try and enlist the help of a friend who's a bit handier on a motorcycle and has done fork seals before. Along with the manual and your notes I'm sure the jobs a goodun . Hopefully he'll assist and I'll be more confident the next time

Incidentally, my clutch drag dissappeared after an oil change - but strangely not on the first run of the bike, but the second. I guess there was stil some old oil between the clutch plates sticking them until 1 good heat cycle. now