Honda CB125RS/D 1985

hi everyone,

just completed complete motor rebuild on the 125, including rebuilt
crank, piston kit, geabox bearings and complete top end.

Motor still sounds like the big-end has gone, even though it's
brand-new........HELP!!!!!, this is the 3rd time it's been apart, I'm
obviously missing something (like a clue), but have now drawn a blank.

Any suggestions (other than the crusher)?

Thanks,

Rick

 

When you say complete top end , did that include Cam Chain?
Also Cam Chain tension ,as if its not tensioned right the chain flaps around
to much and can rub in places causing noises like you describe.
I've had a few of these bikes and the Cam chain has been a problem on all of
them .
I dont know if they had automatic tensioners on any of these bikes but mine
was a manual tensioner .And if you rebiult the top end you had to retension
the cam chain every 200kay's or so early on then after the chain seated into
the new tensioners you could leave it for every oil change or a couple
thousand kay's or so.
I hope that helps.
Cheers;
Brian

 

thanks for the reply Brian, unfortunately, virtually the whole of the
top-end is brand new apart from, literally, the casings. All cam chain and
valve gear, including the cam are brand new.

I still think it sounds like big-end, it was the one thing I didn't check
when assembling the motor, simply due to the fact that the crank was rebuilt
by local Honda dealer, so I expected it to be right.

Might turn out to be an expensive oversight on my part!