mcman56

I have a slow leak in the rear tire so want to replace the schrader valve with the tire. I see that bike shops sell them in different diameters. What does the back rim of an '02 2.9 take?

I'm assembling a C15 and see that the drive chain hits the inside of the engine cases. By inside, I mean the clutch side. This is a 428 chain with the smallest (13 tooth?) sprocket. I know you can run a 520 chain so something must not be correct. Can someone tell me what a notmal or expected clearance should be? A couple of pictures are attached.

These are the shocks. I can get a closer picture if needed. I can see what looks like a removable nut/ seal head around the shaft but am concerned about parts. I also have a lathe. Thanks, Dan

I have a set of shocks from a 1971 Alpina. They are red with chrome springs but I do not see any markings on them so am not sure they are Betors. (I could post a picture.) Are these rebuildable? Can I get a manual or procedure somewhere? I saw seals for sale on a web site but that is it. Thanks, Dan

I'm in the process of fitting the '71 Alpina rear wheel to the C15. It looks like all it needs is some appropriately sized spacers. However, I'm not sure what to use for reference. Sighting down the sprockets makes it look close but I suspect there is a better way. Measuring the wheels...center of tire to sprocket looks similar on both. Any suggestions? Thanks!!

I have an 02 and it has the taller low gears. Going down one tooth on the front sprocket gets it a 1st gear near the GG.

In addition to what others have said, the 2002 280 Pro Gas Gas has an aggressive power delivery. By comparison the 02 2.9 has a much smoother power delivery...not less power just a less abrupt delivery. The GG clutch also seems to need frequent attention. The 02 Sherco has taller than normal 1st and second gears. This requires lower overall gearing to get a first similar to the GG. The Sherco has a 5 speed and a big gap between 3rd and 4th. For trials, it does not seem to matter but if you trail ride the bike, it can be annoying and leave you wanting for a 3 1/2 gear. By comparison the GG 6 speed has a gear for everything.

I have seen recommendations and replacement swing arms 1" longer than stock for Cubs and C15s. The only description is that they work better. Could someone elaborate on exactly what this improves and how this may help on specific obstacles? Does it help the back wheel get over sharp objects like a vertical 12 or 18" step? Is it a significant difference or a subtle change? Thanks, dan

Are the 4 bushes that engage the rear wheel and sprocket still available somewhere? (Bikebandit shows them as obsolete.) Or...is there another option? I have heard of filling the area with weld to tap for studs but I'm no great aluminum welder. Has anyone tried press fitting solid metal bushes? Thanks!

My M85 fork tubes are rusted a little where the taper meets the top fork clamp. Can grease or something similar be applied to the taper during reassembly to slow down the corrosion process? or would this make the forks move? Thanks!!

Well...I pressed out the stem and saw that it was not a press fit for the first 1/8" below the bearing. I shaved off 1/8 from the top surface of the bottom clamp and reinstalled the stem. I then shaved about 1/16" off of the top of the top clamp and everything fits nicely.

I installed an 18 tooth sprocket and used a 40 x 52 x 5 seal. This is 2 mm thinner than the original so 2mm was removed from the case. Basically it was that little lip that stood out on the 1960 cases. Mine was in pieces so I just set it up on a mill to remove the metal.

Yes, mine has play too. But..I have my links off so thought I would share a picture of the bushings with grease fittings. Rather than experiment with the originals, I made up a pair to play with. There is nothing special about them. The only tricky part is to get the angle of the front grease fitting correct so that it can be filled from the bottom. I also did a pair of these for an 02 GG. The GG did not have space for the angled grease fittings so I used a needle type fitting facing down. To eliminate play, has anyone tried the GG links on a Sherco? I don't know about length but GG deals with the offset in the link casting where Sherco uses those top hat inner bushes. http://i103.photobucket.com/albums/m137/mc...rco/linkpic.jpg

Yes, I still have the originals. Who sells the one you mention? Thanks, Dan

I have a TLR Reflex and a Sherco 2.9. Certainly, there are many differences but one particular has me wondering. Even relatively speaking, the rear end of the TLR has a much harder time on "abrupt" type rocks...like 12" to 18" squarish rocks. Is it just the weight or is a lot of it due to the short swingarm and twin shocks? Has anyone made improvements in this area?

I have fat bars on my 2002 and like the little bit of flex they provide. With Protaper adapters and the Suzuki Factory/ KTM bar bend, the bar height is almost exactly the same as the originals. The big bar pad coves the adapters and total price was about $100.

I have some 1971 Alpina forks and notice that the fork caps are vented so that they will breath in and out as the forks work. I have never seen caps like this. Would it make the fork more progressive if they were sealed..with maybe a valve to relieve pressure? Would it then blow seals?

Well....I tried to assemble the fork clamps to the frame but the stem is about .275 short. The nut under the top clamp has a tube on top that fits up into the top clamp. The top clamp has a pinch bolt that grabs this nut and then there is a simple flat nut on top. I have come up with a few ideas. Does anyone have a recommendation. Need about 0.275 big nut under top clamp is .158 top clamp is .640 with .270 cross hole so wall is .185 above and below cross hole lower clamp is .635, the bearing sits on a .210 step on the lower clamp Option 1 press stem further up in bottom clamp. Engagement will go to .36 - not much Option 2 Thread inside of steering stem and use bolt above top clamp instead of nut - maybe..is stem hard?..part of bearing will ride on threads Option 3 use top nut under top clamp and make a nut similar to C15 nut for top - not easy to make nut (Did Bultaco do this somewhere so I could buy the nut) Option 4 shave .125 off of top of lower clamp, .06 from top and bottom of top clamp - a lot of work and weakens assembly Option 5 Make new stem - a lot of work

Does an undercut log on a slope (10 to 20 degrees) require a different technique than one on the flat? I struggle with one maybe 18" diameter several inches off the ground. Timing seems difficult and there is a tendency to touch the front wheel and get the bike very vertical. This just results in the bash plate sitting on the log. The odd thing is that bigger more undercut logs on the flat are not so difficult. Other people do not seem to have this same problem. I understand a Jap Zap may be the technique to use but am not that accurate with front wheel placement and stand a good chance of just stuffing the wheel into the bottom of the log. For that reason, the wheel hits the log on it's way up.

Mr. Woody, I followed your advice and it worked out well. thanks, Dan <a href="http://s103.photobucket.com/albums/m137/mcman56/?action=view&current=IMG_0040.jpg" target="_blank"><img src="http://i103.photobucket.com/albums/m137/mcman56/IMG_0040.jpg" border="0" alt="Photobucket"></a> http://i103.photobucket.com/albums/m137/mcman56/IMG_0040.jpg

I have a leaky shock on my 2002 2.9. Does anyone in the US rebuild these? Thanks!

On the subject of swingarms....removing the swingarm pivot (7/8" round thing) on this bike requires a hydraulic press. It is very tight and makes nasty groaning sounds as it is pressed in and out. I thought maybe something was bent but it is tight all of the way through and the pressure marks around the pivot are fairly symmetric. I'm thinking of using a brake cylinder hone or reamer to open the hole but how loose is too loose. Are there any recommendations on this? Thanks

Thanks. It sounds like I should give the C15 arm a try. However, it does have some cross holes approximately in the middle of the arm. It looks like someone had used them to mount passenger pegs. Should the arm be strong enough to tolerate the extra holes? The Bultaco parts I have are from a '71 Alpina. I thought for sure the arm would be lighter but it is not.

I'm planning to put a Bultaco rear wheel on a C15. I also have the swingarm and am wondering if it may be a better idea to install that also. From what I read, the C15 arm has limited tire clearance and is improved if made longer by an inch. C15 type mounts could be welded to the front of the Bultaco arm to accomplish both. Has anyone done this? Are there other recommendations?

Thanks for the reply. Did you make the sleeve a slip fit or a real tight fit? What material did you use..steel...aluminium..or? Thanks for your help with this. Dan