brucey Posted December 13, 2011 Report Share Posted December 13, 2011 I've just aquired the above bike to use for local club trials. (I also have just finished building a Cub for pre 65 stuff) For a 2000 bike it is pretty good condition but needs water pump seals (judging my the mayo in the gearbox) and fork seals. I have the following questions: Fork Seals: I have removed the fork legs and seal cartridges. I drained the oil by removing the bolt at the bottom (about 350ml oil came out of each leg). I have tried removing the big nuts(with the damper adjusters in) at the top of the stancions, but they don't come out (they just click). I understand I put 300ml of 5 wt oil in, but am not sure how to do this and bleed the air. As I weigh over 100kg, I would like to add say 10mm spacers to the spring preload. How do I do this? I have 1lt fully sythetic 7.5 wt fork oil in the shed. Would this be o.k. considering my weight? Before I stripped the fork legs, I tried altering the adjusters on the top of each leg but they seem to make little or no difference to the dampening (in either direction) are they broken? I know the adjusters turn because I made new stainless tops! Water Pump Seals: I have ordered a shaft and seal kit from John Shirt. I have removed the small cover (to expose the impellor) but it looks like I need to remove the RH engine Cover to access the seal and shaft. Is this assumption correct? Any advice would be appreciated. Bruce. Quote Link to comment Share on other sites More sharing options...
jse Posted December 13, 2011 Report Share Posted December 13, 2011 I've just aquired the above bike to use for local club trials. (I also have just finished building a Cub for pre 65 stuff) For a 2000 bike it is pretty good condition but needs water pump seals (judging my the mayo in the gearbox) and fork seals. I have the following questions: Fork Seals: I have removed the fork legs and seal cartridges. I drained the oil by removing the bolt at the bottom (about 350ml oil came out of each leg). I have tried removing the big nuts(with the damper adjusters in) at the top of the stancions, but they don't come out (they just click). I understand I put 300ml of 5 wt oil in, but am not sure how to do this and bleed the air. As I weigh over 100kg, I would like to add say 10mm spacers to the spring preload. How do I do this? I have 1lt fully sythetic 7.5 wt fork oil in the shed. Would this be o.k. considering my weight? Before I stripped the fork legs, I tried altering the adjusters on the top of each leg but they seem to make little or no difference to the dampening (in either direction) are they broken? I know the adjusters turn because I made new stainless tops! Water Pump Seals: I have ordered a shaft and seal kit from John Shirt. I have removed the small cover (to expose the impellor) but it looks like I need to remove the RH engine Cover to access the seal and shaft. Is this assumption correct? Any advice would be appreciated. Bruce. Bruce, http://www.trialspartsusa.com/tech.html has a lot of good information and also a video for replacing the fork seals on your bike. You don't need to bleed the forks when replacing the oil. There is a "jam nut" under the spacer that locks the top cap on. The adjusters do work to "fine tune" the damping (if you are just pushing on the forks, you can't tell) and try setting the compression all the way out and the rebound all the way in, which seems to work well for most riders with the GG forks. For your weight, I'd try the 7.5 weight oil (300 cc's) and the 10mm longer spacers, which you can make from schedule-40 (thick wall) PVC. Just take the old spacer to the hardware shop to match the OD of the tubing. You will need to take the cover off to replace the seal (use a new gasket). Jon Quote Link to comment Share on other sites More sharing options...
brucey Posted December 13, 2011 Author Report Share Posted December 13, 2011 Jon, Many thanks for your quick and concise reply. That's a really useful website. Looks like I'll be busy down the shed tonight! Bruce. Quote Link to comment Share on other sites More sharing options...
brucey Posted December 15, 2011 Author Report Share Posted December 15, 2011 O.k. water pump seal replaced and new seals and dust caps in fork cartridges ready for reassembly. I even turned down a location bush to press the new fork seals in! I have a couple of questions: How do you remove the front fork springs to put a longer pre tension spacer on? existing one is 63mm long, I intend to make 2 new plastic sleeves 75mm long. I think you pull the spring down from the top (maybe compress it using strong cable ties) then hold the top nut (the one with the adjuster in) and undo the exposed hex nut under the spring near the top. Is this correct? I'm also a little unclear how I fill it up with oil on reassembly. I was going to reassemble everything apart from the M8 cap head screw that goes in the very bottom. Turn the forks up side down and pour the oil in there. The trouble is I think the solid ally bush at the bottom (that the M8 cap head screw goes into) will stop me filling it from here. Am I missing something obvious? Bruce. Quote Link to comment Share on other sites More sharing options...
jse Posted December 15, 2011 Report Share Posted December 15, 2011 O.k. water pump seal replaced and new seals and dust caps in fork cartridges ready for reassembly. I even turned down a location bush to press the new fork seals in! I have a couple of questions: How do you remove the front fork springs to put a longer pre tension spacer on? existing one is 63mm long, I intend to make 2 new plastic sleeves 75mm long. I think you pull the spring down from the top (maybe compress it using strong cable ties) then hold the top nut (the one with the adjuster in) and undo the exposed hex nut under the spring near the top. Is this correct? I'm also a little unclear how I fill it up with oil on reassembly. I was going to reassemble everything apart from the M8 cap head screw that goes in the very bottom. Turn the forks up side down and pour the oil in there. The trouble is I think the solid ally bush at the bottom (that the M8 cap head screw goes into) will stop me filling it from here. Am I missing something obvious? Bruce. You can make a small plate with a slot in it (the width of the damper rod) to slide under the jam nut when you pull down the spring/spacer. Assemble the fork and leave the upper tube unscrewed from the top cap, tilt the fork over slightly and slowly pour the oil through the spring coils into the lower leg. Jon Quote Link to comment Share on other sites More sharing options...
brucey Posted December 15, 2011 Author Report Share Posted December 15, 2011 Jon, Once again, many thanks. That's pretty clear now! Bruce. Quote Link to comment Share on other sites More sharing options...
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