1st Gear Problem

As others have suggested, I think you are on the right track by looking at the clutch first.

1: is the cable working, engaging/ disengaging correctly. Is it adjusted correcty? With the oil filler cap removed, can you see those visible plates working? Can't see all of them this way but it gives some idea of how its working.

2: Over the years, I have had a couple of those cable attachment arms break or bend with use. (this is the weak link in the clutch cable system) Down on the L.H. side of the eng.

3: On any multi wet-plate clutch that has sat idle for years, like the carbs, the clutch can have one or more fused plates. This can create a host of problems.

4: The factory shop manual covers a thorough clutch inspection, with photos.

5: Interesting you mentioned the surface rust on the shafts. As a last resort, if it is in the transmission? I have seen corrosion built up to the point that the gear will not slide on the input or output shaft. New NOS shafts appear from time to time on ebay.

6: On any engine that has sat idle for a long period, frequent oil changes can be a cheap solution to getting parts lubricated, that have not had oil on them in a long time. Like oil changes in two to three cycles @ 50 mile intervals. That is, if it's not in the clutch.

Best of luck in finding the cure to this problem.

Hello Pete,
The problem with my first gear is still raising it's ugly head! I have checked the clutch and cleaned up the basket with grit paper etc. and have also modified the clutch arm. I had a new one machined from 4mm Stainless steel plate and a new, modified cable attachment machined. As per my previous post, all selectors, slides, shift drum etc. are in perfect condition, however, looking underneath with the sump off, I notice the dogs engaging into the first gear are only barely locating (ball hair!), obviously causing it to jump out when under load. looking at the dog teeth and recesses I would assume that the dogs should locate in by a minimum of 4 - 5 mm. What surprises me is that the selectors are perfect and not bent in any way at all! What am I missing here. Could the shimming of the driven shaft and/or the driven shaft cam damper and/or the driven shaft collar have anything to do with the problem. In other words, causing the 1st gear to run further away from the 4th gear dogs? As I said in an earlier post, this bike was running perfectly prior to be parked and stored for a number of years. Any help or suggestions will be greatly appreciated. Thanks

Todd, all the gears are sliding freely on the input and output shafts with no snagging at all.

Say Craig:

While the bike was together, did you have an opportunity to start off in 2nd, thru 5th gear?

Was curious if you were able to verify that this engagement problem is contained to 1st gear only.

T.

Craig:

As for other suggestions, here is what the manual says for "Jumps out of Gear." I understand in your earlier posts you have inspected and checked some of these items.

Shift fork(s) worn
Gear groves worn
Gear dogs, dog holes, and/ or dog recesses worn
Shift drum groove(s) worn
Shift drum positioning pin spring weak and/ or broken
Shift fork pin(s) worn
Drive shaft, driven shaft, and/ or gear splines worn

Hope this helps.

T.

My apologies for not updating you guys sooner on my first gear issue, but here is a brief of what I found and how we sorted the problem, unorthodox as it may appear!

We took the motor out and turned it upside down at a friends engineering shop to get a better view into the box. As mentioned in an earlier post, all dogs, shifter forks etc. appeared perfect. On closer inspection we noticed that the 1st gear dog had only been engaging by approximately 0.015" and the very fine edges of the dogs had rounded. We replaced the fork with a new one and had exactly the same result. the shift drum grooves etc. were all well within spec!! The only thought we could come up with was that the recess in the casing that holds the shift drum bearing was probably not machined deep enough allowing the shift drum to move across slightly more aiding the better engagement of the first gear dogs. All the other gears, operating off the other selectors and in the opposite direction had excellent engagement depth and we didn't see there being any issue if the drum was moved across slightly (would anyone know what a good engagement depth is as I can't find any reference to that?) Having said that, a decision was made to modify the selector to avoid stripping the motor. We ground off the selector nipple that slides in the shift drum and drilled a hole in the selector 2.5mm across to the left (looking at the motor upside down)and sweated in a high tensile pin the same diameter and finished length as the previous nipple. Reassembled all and now have covered +/- 4000 miles a few wheelies and no problems. As I said, an unorthodox fix, but one that has worked for me so far (touching wood).