Michael Hall
Active Member
- Joined
- Feb 24, 2009
- Messages
- 29
Does anyone know what model cmb 21 this power head is and what type of pipe?
I wouldn’t even bother to fire up that engine without replacing the bearings. Also check the conrod and wristpin. A good running 21 engine will need perfect bearings and wristpin. When bearings are worn it starts to eat plugs very quick.Wasn't very successful, o-rings in the carb have gone hard.
Also what glo plugs should I be running in it?
When I got it I replaced the bearings and then never ran it, they are still like new, ill pull it apart and check the rod.I wouldn’t even bother to fire up that engine without replacing the bearings. Also check the conrod and wristpin. A good running 21 engine will need perfect bearings and wristpin. When bearings are worn it starts to eat plugs very quick.
MCCoy #9 or KB HP 7300 is very good plugs. 50-60% nitro
If I were you I would ask Stu Barr if he can provide you some parts. If Stu can’t help you may contact Mauro Braghieri directly and ask if there is any parts left for this engine. I guess Andy Brown would know a lot about this engine as well. As for the nitro I would not go any lower than 40%, you will loose too much torque. That Irwine pipe is good, don’t know which one would be the best option, both should be okWhen I got it I replaced the bearings and then never ran it, they are still like new, ill pull it apart and check the rod.
Will it need 50%?
Also where can I buy parts for it like a new con rod, piston and liner?
And ive found another pipe, which would be the better one to run?
View attachment 98898
Ive just stripped it down, the big end rod bush has a bit of play.If I were you I would ask Stu Barr if he can provide you some parts. If Stu can’t help you may contact Mauro Braghieri directly and ask if there is any parts left for this engine. I guess Andy Brown would know a lot about this engine as well. As for the nitro I would not go any lower than 40%, you will loose too much torque. That Irwine pipe is good, don’t know which one would be the best option, both should be ok
Are you in US?Ive just stripped it down, the big end rod bush has a bit of play.
How do I contact Stu Barr or Andy Brown? I dont know who they are.
ThanksAre you in US?
Stu Barr - [email protected]
Andy Brown , look for contact info bottom left http://cmdracing.com/updated/main.htm
Sorry, I thought you were in US.Thanks
Im in New Zealand
That will work, but it will require very accurate machining.Joern...
How about take the con rod to a local machine shop and have a new bearing made and pressed in... Not a big deal..
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