History:I’ve had this engine 39 years – never any issues with the transmission (slipping out of gear, hard shifting etc). I destroyed the original engine in 1978 on a freeway crash. Deb at Jacks Go Shop in San Bruno CA rebuilt the engine for me.
I’ve split the casing a few times over the years, broken kicker shaft, seals, rebuilt crank etc.
Always checking wear on gears, dogs, shift forks etc. Other than one of the dogs showing slight wear nothing amiss. I had the engine open about 5 years ago when I installed the rebuilt crank from Charlie. Maybe 2500-3000 miles on it since then and no problems at all anywhere.
I’m very much aware of case pin dowels ((question on dowels below)) – this might be the problem. Thanks John Schlumberger for pointing this out along with the new circlip types).
I always checking case fitment, shifting and all matting surfaces before buttoning the cases.
Problem: 1. This summer I was doing some riding in Texas and as I was riding the transmission shift was stuck – would not change into any gear up or down. There was play on the shifter but not enough to change gear position.
2. With some semi-aggressive movement on the shift lever and rocking the bike managed neutral.
3. I split the casing and found the circlip between 4th and 2nd broken. I found part of the circlip in the case (I think I got it all). There were no serious marks or scaring where a piece of the circlip or any other matter was flying around…. The only thing I did not take out was the shift-drum. Read below….
4. Replaced the circlip with the newer types, everything dry shifted fine, buttoned it up and did a couple of different (short) test rides, everything seemed fine.
5. Fired it up to take out for a ride (third one since buttoned back up). Made it down the street and it locked up again – same problem – would not shift.
6. Opened it up and nothing wrong except the damn same circlip (between 4th and 2nd) had jumped out of the groove but was not broken. (could have been my error over-stressing these new clips – I hate them – I do have a nice circlip pier set). Everything dry-shifts fine – again with the case off – and pretty sure will with the case on too – like last time.
7. This time I took extra special care looking for something wrong – nothing….. And I pulled the shift drum this time – nothing wrong there either – a very fine mark where something “might have” rubbed in the drum but no metal anywhere in any of the oil, in the case, anywhere….
I have a H1 transmission in good shape I’m thinking about using. Other than a different ratio it fits and dry shifts fine.
Dowel Question: I notice the two dowels on the transmission shaft locators are slightly lower than the clutch push rod bushing. I’ve seen a few other pictures of cases like this too – maybe it’s normal?
Looking for anything that would cause this Lock Up problem I took a hard look at this (thanks again John Schlumberger). I’ve attached some close-ups of the bearing caps and cases. I cannot see where the caps would have spun off the dowel pins and not left a serious mark. You can see some slight marks on the cases around the dowel pins and on the bearing caps but again nothing that I think would indicate the caps have spun under load – just my normal assembly and checking – maybe I’m wrong. The H1 bearing caps look identical. If this is not normal please someone chime in.
Note - I certainly would have noticed something wrong if they were NOT aligned properly during assembly.
First time opened it up – originally thought circlip breakage from age…. Second time opened it up, could have been just me over-stressing the new circlip type. Case pictures and caps.You can see the holes in the caps don't appear to be rounded where they would have slipped off the dowel.
This is putting the cap over the dowel for the clutch rod pusher (pusher dowel is higher compared to the other pin dowels).
Just getting a high/low inside look comparison.