I have a 1992 3TJ the rev counter when I was riding home last night decided to be abit hit and miss, and not reading accuratly when riding. When the clutch is pulled in it stops working completely. I have cleaned the wires at the back of the rev counter hoping it was a bad connection, but this hasn't seemed to work.

From what I have read on the forum im led to believe the clutch needle bearing could be worn aswel, could this be part of the problem? i.e clutch pulled in not much engine noise, when let out it sounds almost industrial When accelerating from low revs (under load) there is a constant whirring noise coming from the engine.

Any help would be appreciated cheers!
Mike

I think they're probably separate things.
The rev counter is electric and counts the number of pulses to the coils ... probably from the CDI unit. It could be water causing a short in the system or a loose earth, check the battery terminals are tight and the battery is ok. You might also have put to much load on the battery ... with an accesseory or over rated headlight bulbs.

I could well be the clutch bearing but befor that take off the front sprocket cover and clean it inside especially the clutch mechanism. Use some parraffin and add a drop of gear oil so the mechanism isn't dry before putting the cover on again.
Use semi-sythetic oil not fully sythetic.

thanks alot for getting back, im off tomorrow so i'll get the tool box wacked out and see if I can get it sorted. No doubt something will go wrong!

It sounds straight forward

Got the rev counter working again, cleaned all the earths its all good however...

I removed the sproket cover and cleaned it, checked for play in the gear lever shaft, its all ok. I inspected the chain and there seems to be a number of stiff links which won't free up, cant way up wether this is the cause of the whirring noise?

I was also thinking it could be the timing chain, but the noise only happens when its under load, should the timing chain tighten up when accelerating?

any thoughts enlighten me please cheers!

The timing chain has a tensioner so it stays at the right tension. if it was the timing chain it would rattle like a can of nuts in a shaking thing.

Probably the clutch then :)