thats_a_five Posted February 16, 2012 Report Share Posted February 16, 2012 (edited) I am hoping for some help with my Gasser. Bit of history: Bike runs good, did have an extra neutral between 2nd and 3rd sometimes. In a recent event I rode between sections, stopped to walk one so shut off the bike. When I restarted I had nothing but neutral. Foot lever moved up and down freely. Got the bike home and pulled the clutch side cover and found broken shift claw. I figure it got damaged in a practice crash (If I keep practicing I should get good at crashing, right?) and finally failed during the event. Replaced the claw and rivet. Tested by hand with the clutch off and it shifted up and down OK. Put it all together and test rode. Shifts good first to 2nd, and 3rd to 4th. Big problem is shifting from 2nd to 3rd. Sometimes it shifts, sometimes the foot lever moves up but does not shift. By fiddling with the lever with my foot, it sometimes shifts. It acts like the shift claw is not reaching the pins on the drum. It shifts down through the gears perfectly. I took the clutch cover and clutch apart again and checked for any interference. None found. Soooo Edited February 16, 2012 by Thats_a_Five Quote Link to comment Share on other sites More sharing options...
gasgas249uk Posted February 16, 2012 Report Share Posted February 16, 2012 I know these gearboxes fairly well. All i would bear in mind is that the selector drum should rotate easily , changing gear as you move the drive shaft round simulating the engine moving. Ive recently had a partially seized bearing on the end of the selector drum which gave the same symptoms.Where the drum pushed its head through the inner casing from the gearbox to the clutch it was also binding tightly causing the same problem as yours. All id advise is whether it involves stripping the engine make sure the selector drum rotates easily without snagging Good luck Quote Link to comment Share on other sites More sharing options...
thats_a_five Posted February 16, 2012 Author Report Share Posted February 16, 2012 (edited) Thanks for the input. I will keep that in mind. I have never split the cases. Does it sound like I will need to? I know these gearboxes fairly well. All i would bear in mind is that the selector drum should rotate easily , changing gear as you move the drive shaft round simulating the engine moving. Ive recently had a partially seized bearing on the end of the selector drum which gave the same symptoms.Where the drum pushed its head through the inner casing from the gearbox to the clutch it was also binding tightly causing the same problem as yours. All id advise is whether it involves stripping the engine make sure the selector drum rotates easily without snagging Good luck Edited February 16, 2012 by Thats_a_Five Quote Link to comment Share on other sites More sharing options...
peterb Posted February 18, 2012 Report Share Posted February 18, 2012 It does seem you will have to split the cases, don't lose the ball bearing inbetween the clutch pushrod and the "mushroom". I had a similar problem with a new 1993 bike years ago. This one was because there was too much end float on the shift drum and needed shimming out to reduce the endfloat to approx 10 thou. The selector forks and the rest of the gearbox are built quite strong, should have no problems there. I got the shims during a factory visit while chatting with the guy who was building up the motors, there was no part number for the shim. From memory, I think the gear shafts stay in the right side casing when splitting. Bye, Peter. Quote Link to comment Share on other sites More sharing options...
thats_a_five Posted March 5, 2012 Author Report Share Posted March 5, 2012 I fixed it! Solution below. Thanks again to those who contributed. I checked your suggestions and everything was good. I tore the bike pretty well down, planning to split the cases. I do not have the correct flywheel puller and could not get the flywheel off (turned out to be a good thing!). I had ordered all 3 springs that are involved with the shifting system. The new ones are thicker springs and definitely have a lot more tension. The one for the neutral roller was really challenging to install. I ended up intalling it unhooked from the lever and then prying and pushing and using some "encouraging words" to get it hooked then fully tightening the screw. Put everything else back together and went riding today. The shifting definitely takes more force and it shifts firmly up and down through the gears perfectly. I really feel very confident that it is fully in gear with no chace of it popping out like it has occasionally in the past. WooHoo, I don't have to tear it all down and split the cases now! If anyone has an old bike and has to replace the shifting claw I strongly engourage you to replace a 3 springs while you are in there. It must be beer thirty right about now! Keep the rubber side down guys! Quote Link to comment Share on other sites More sharing options...
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