What cmb engine are these?

[BlueBlaster]

What type of cmb motors are these I know there 21,but any specific kind.I'm wanting to get bearings for them and want to be sure which kind. Thank you.

 

[moparbarn]

One is a Greenhead LS (long stroke) with what looks to be a Mac carb. The other is a RS "red head" with a CMB carb. There were a couple different versions of both in the crank induction style. The green head is easy to distinguish, original has a silver case, evo2 has a black case. The red head I'm not sure how to tell among the variations, but I believe there was a RS & a RS07. RS07/second gen has a black case also, but not positive if that is a guaranteed identifier. Both versions of the green head & the RS were also available in valvola style also. Greenhead came out before the Redhead.

 

[Grimracer]

Gold, LS Red, LS Green, (in that order) then to the RS line... all 14mm rear bearing I THINK..

The LS Red head did not last long on the market.

Grim

 

[moparbarn]

So the LS red head preceded the green heads? Never knew that, thought green was before any red's. Learned something, thanx Grimmie (-;! LS red were silver case & RS were black case? Was the LS red a 3 port exhaust like the RS? The green head evo2/black case was very short lived also, but an excellent power plant.

 

[Grimracer]

Same as the green head.. I can not remember the numbers or number of ports.

case volume was too large making the motor hard to tune.. I did win a number of times with one in a sport 20 but it was a challenge..

Grim

 

[BlueBlaster]

So are these engine worth keeping or should I try something better?

 

[moparbarn]

No experience with the redhead, but I like & still run the greenies (-;

 

[bsmtboy2]

I run a redhead and it is a challenge to keep it from burning up plugs no matter what adjustment with fuel intake or water cooling. Gonna move on to a Novarossi later this season. Robin call Carl he is the guru on these little daemons he helped me get mine at least to run consistently for awhile.

 

[moparbarn]

Carl is & has been my CMB guru for a while, Charles. Got my first CMB's from him (-;

 

[shoboat]

Charles,

If you are still burning up plugs, look in two different areas.

1.) Bowl Volume Of The Head Button And The Head Clearance .008" is great.

2.) Open Up Your Intake on the opening side 5 more degrees on the crank.

These will help your problem.

Thanks,

Mark Sholund