Hi
My bike has covered nearly 400 miles since it was repatriated from the States with few problems. However although all the other gears select perfectly it will not go into top. I select that gear and it is as if I am in neutral.
Any ideas, clutch or gearbox ?
John
First question is: how have you managed to cover 400 miles without being able to get into 4th gear?
If you can't select 4th gear with the engine not running then it is almost certainly a gearbox problem rather than a clutch problem. If you are not getting 4th, I would have thought that as you try to change up from 3rd to 4th gear you do not hear the distinctive clunk you get in the lower gear changes as the camplate slots into the next detent position and the gear lever movement may also seem different? Unfortunately, whatever the cause, it is likely that you will need to dismantle the gearbox to find out what the problem is. It could be anything from a damaged camplate to damaged selector forks to a problem caused by someone not putting the gear clusters back on the shafts properly after an overhaul.
I had the same problem with my SS90, 4th wouldn't engage just a false neutral. This happened after a rebuild and after a couple of test runs during which all gears were able to be selected. Eventually traced to burrs on the thrust washer between gears on the main shaft which stopped the gear dogs engaging. The burrs on the outside diameter were caused by friction of the adjacent gears during clutch use which produces side loads. I had to take inner timing cover off and deburr washer, not easy, but easier than taking gearbox out.
Hope this helps and good luck.
Just looked at parts book for B44 and unfortunately you can't access the gearbox internals without taking the gearbox out.
Hi
Thanks for replies. The first 400 or so miles were problem free it has only just occurred. Yes unable to select fourth when engine not running all other gears ok. Yes it does not give the usual click when trying to select fourth. Its just like its slipping into neutral.
John
All that should happen when you try to change from 3rd to 4th is that the 2nd gear pinion should move along the mainshaft splines so that its dogs lock it to the output (4th gear) sleeve gear. In doing so it will lock the sleeve gear on which the engine sprocket is mounted to the mainshaft giving a gear ratio of 1:1 with the engine sprocket and clutch then revolving at the same speed.
At face value, it looks as though something is preventing the 2nd gear pinion from moving into engagement with the sleeve gear which, in turn, is stopping the camshaft from rotating sufficiently for the 4th gear detent notch on the camplate to be latched by the spring. Inevitably, this will leave the gearbox in a false neutral.
Whatever, the reason for the problem, it will be necessary to remove the inner and outer timing covers along with the gearbox internals so they can be examined for damage or any mis-assembly. Quite a bit of work but at least this can be done without removing the clutch from the other end of the mainshaft.
Thanks Spaceman the exploratory work will begin in conjunction with the Rupert Ratio bible!
I agree that it is something preventing the 2nd gear pinion from moving into engagement with the sleeve gear and removal of the gearbox is necessary.
I may be wrong (and welcome correction) but I believe that when you remove the inner timing cover on a B44 side points engine the whole gear cluster is attached to the cover, so to remove it you have to take the clutch off. This is different to dizzy models where the inner timing cover can be removed, leaving the gear cluster in place.
Thanks Colin
Hopefully all will be revealed in due course.
There's no problem in removing the inner timing cover with the clutch in place - the only thing that will stop it being removed is the nut on the end of the mainshaft holding the kickstart ratchet mechanism on. The ideal way of dealing with the gearbox internals is to take off the clutch first allowing everything to be removed while still attached to the inner cover and to also enable it all to be re-assembled on to the cover again before everything is put back into the gearbox. However, it can all be done without touching the clutch and it just makes it all a bit trickier but perfectly doable.