CR125M conrod info

[cyclegod]

Hello all, I need some info on CR125M 74/75 rods, rod kits, or alternative models that will do the job. Local (Aus) suppliers are prefered but if you have a discount O.S source all info will be gratefully received.

[Noel]

Hi ,
When I had mine done I think they used an 81 model rod and had a new stepped crank pin made to adapt to the new big end bearing
Had mine done at MMT in Sydney
Cheers
Noel

[Lozza]

Why the stepped pin? If the crank pin is 20mm and 100mm centre to centre with a 14mm gudgeon a KT100J/KSI rod will be available from kart shops for $70 approx. Then there is the great unknown to ponder, if a Yamaha kart rod will 'work' in a CR engine

[cyclegod]

Why the stepped pin? If the crank pin is 20mm and 100mm centre to centre with a 14mm gudgeon a KT100J/KSI rod will be available from kart shops for $70 approx. Then there is the great unknown to ponder, if a Yamaha kart rod will 'work' in a CR engine

When you consider how hard a kart is raced compared to how slow I race I think the chances are good, do the rods come as a kit with crank pin bigend and thrust washers?

[Lozza]

Measure the length of the crank pin there will be a Wiseco long enough, kart crank pins will be shorter(the Yamaha is solid to), the kart rods take a smaller OD little end bearing , last time I got rod, thrust washers and small end was about $90.I know a 56mm piston has run on the KSI rod.

[bigk]

The 100j rod fits and is a good strong option, but works out quite expensive and they can be a little hard to get sometimes. We use them and I can give you the part numbers of what you need if you want to go that option. The other one we do is to use the later Honda rod, but have the crank webs bored to take the bigger pin. The initial cost is a little more, but you only have to do it once whereas with the steppeed pin way, you have to do it every time you replace the rod. We do lots of Elsinore engines and I have a fair few engine spares.
Cheers,
K

[cyclegod]

The other one we do is to use the later Honda rod, but have the crank webs bored to take the bigger pin. The initial cost is a little more, but you only have to do it once whereas with the steppeed pin way, you have to do it every time you replace the rod. We do lots of Elsinore engines and I have a fair few engine spares.
Cheers,
K

That sounds like the best option as I have 2 spare cranks to rebuild that are already apart, thanks.

[Freakshow]

I found a pair of cases with a crank and rod still in it ( tranny gone) at the wreckers today, the cranks look like shovels on the sides, weird looking rotors, rod didnt seem to loose, not sure if thats  any use to you ,  but if ya get stuck 

stop press - correction it was a 250m now i think about it.