Honda CB125RS 1985 Rev Counter Drive

Tedwood · Two Stroke Sniffer Joined: 08 May 2014 Karma :

Hi,

I'm looking to getting my rev counter working.

The drive in the r/h/s crankcase cover is not turning to drive the cable, if I turn it gently with a screwdriver it clicks!

So, I'm thinking that one of the two parts for the rev counter drive is something like nylon/plastic which has been damaged somehow (perhaps seized tacho in the past).

Does anyone know if this is the case and if it's Part #1 or #2? So I can order the part without removing the cover just to find out.

Many thanks, Ted

WD Forte · World Chat Champion Joined: 17 Jun 2010 Karma :

Not sure its got plastic innards
We recently refurbed a Kymco 125 with a similar clone engine and the
tacho cable drive shaft (1) was steel
As I recall the shaft off the oil pump was steel too
best whip the cover off and inspect it

here's a pic of what I reckon you'll find
https://oi61.tinypic.com/jufupg.jpg
____________________
bikers smell of wee

Tedwood · Two Stroke Sniffer Joined: 08 May 2014 Karma :

Thanks for the info WD Forte.

Yes, without knowledge of the tacho drive parts in this engine, the only way to find what's wrong is to take a look inside.

Probably leave it until I have to clean the centrifugal oil filter though.

Cheers

Ryder666 · Two Stroke Sniffer Joined: 22 Feb 2015 Karma :

out of interest, as i have a practically the same engine in my new bike do you know the drive ratio of the speedo, i would like to fit 1 but finding 4/1 and 7/1 ration "universal" honda units

cheers

tom

Tedwood · Two Stroke Sniffer Joined: 08 May 2014 Karma :

Sorry, I don't know the drive ratios of the speedo or rev counter.

Ed Case · World Chat Champion Joined: 01 Mar 2009 Karma :

If the 'output' cable drive of the rev. counter gearbox is not turning when the engine is running, remove it from the cam cover (one bolt) and see if the roll pin is in good order in the cam, if not you'll have to replace it with a new one,. If it is OK check the forked end of the gearbox shaft that engages with it and if it looks alright, turn the g/box input shaft and see if the output cable connector turns and if not, it's bolloxed and it's Hello Ebay, there's several of these units going for a few quid. Best of luck.

Casper · World Chat Champion Joined: 12 Jul 2010 Karma :

But it will click as it should only spin when running. Start bike and look at it to see if moving before wasting money on parts you dont need.