Rev counter problem TS 150 *** Help?!

[edward1987uk]

Hi, i have recently bought a 1979 TS 150cc and it has a problem with the rev counter - think it may be the drive gear in the gearbox but i hope i'm wrong;

It works intermittently dropping to zero if the engine is idling/not under load and the engine makes a nasty rattle.. but i you rev it up it sometimes springs back to life??

I havent got a manual for it yet so am pretty clueless as to what it could be/ease of fix/parts availability so if anyone could give some advice?

Many Thanks

Edd

[djsbriscoe]

Hi,
The cable has a piece of metal on the end that engages with a slot on the engine drive gear. Maybe this is slipping so best to check this by reving the engine with the cable removed at the engine end and then at the tacho end.

David.

[edward1987uk]

Thanks David,

i have checked this as you said and it seems the problem lies within the geabox itself.
The slotted drive that protrudes from the gearbox casing intermittently stops turning at the correct speed which coincides with the nasty rattling from the casing.

Will this require me to dismantle and rebuild the gearbox to ascertain the problem?

cheers

Edd

[Adrian]

May be not so drastic as the tacho is driven from a worm drive via a gearwheel behind the clutch. The gearwheel is the same one the kick strat operates on to turn the engine. If you take of the left hand cover, once you have drained the gearbox oil you can remove and replace the worm gear easily. It is all held on with a circlip If your kickstrat works ok it cant be a problem with the gear itself.

Adrian

[ts125drummer]

Did you sort this out in the end?

My TS 125 is doing the exact same thing, haven't had a chance to remove the cable and take a look yet but it only seems to do it when the bike is hot after about 10 miles or so.