HELP! - Dominator Gearbox Problem
 

Dominators gearbox problem - stuck in forth gear, engine/clutch fine, did still run but obviously had very limited useability! No gearbox problems or grinding/jumping-out-of-gear prior to current problem.

Removed clutch in the hope that it might have been the gear shift cam (located under clutch), but sadly this is not the problem. My main questions therefore, before I remove the engine and split the cases, are:

Anyone had/heard of similar problems?
Possible cause(s)?
Any possible remedy without splitting cases? (Already know the answer!)
What to look for once cases are apart?

Any thoughts, ideas or general observations greatfully received.

Cheers

Boyd

Mini-Thumper,

It may not look like the shifter cam is mal-fuctioning, but it could be the spring on the shift follower does nor have enough tension and and just slips off the cam...

Rotate the engine forward while you attempt to turn the gear selector tumbler and see if it will shift that way. The engine must be turning somewhat as the gears have "dogs" and in order for them to locate and engage there has to be some rotation. If that works you are saved from splitting the cases.

If not, I can't imagine what in the case would leave you in 4th and everything else work right.... Even if a shifter fork broke, it would still shift into another gear (at the same time!) There is no "interlock" system except the shift forks staing in the tumbler...

Another possibility is that there are wear grooves in the clutch basket and it is not really disengaging, therefore making it difficult to shift, but that usually comes on little by little.....

Boyd,

What have you found? I can't sleep at night for wondering! I guess it's the Mechanical Engineer in me that has to "figure everything out" !
:(

Rather than spend time and money on stripping and repairing the broken one I managed to get a decent priced replacement engine. Not as straightforward as I'd hoped but easy enough given that they were five years apart in manufacture (original 1997, replacement 1992). After some mucking about with 'plumbing' the carburetor (the original the had over-engineered, California inspired, oil breather recycling system - usually recommended to be dumped!!) the new motor works very well. Had thought I might need to replace the CDI unit but again this was unfounded.

Hope this is of use to someone?

Cheers
Boyd