CMB67 Greenhead

[ReidCuddy]

I've only had one other .67 motor and it was a K&B. I was taking apart my new CMB 67 greenhead to make sure there were no flashings in it before I started it. After I removed the water jacket, it seemed very difficult to remove the engine head. On my old K&B, the head just came off once the water jacket was removed. The CMB seems to be held in pretty tight. What is the best way to remove the head? Thanks guys

 

[steve wood]

I've only had one other .67 motor and it was a K&B. I was taking apart my new CMB 67 greenhead to make sure there were no flashings in it before I started it. After I removed the water jacket, it seemed very difficult to remove the engine head. On my old K&B, the head just came off once the water jacket was removed. The CMB seems to be held in pretty tight. What is the best way to remove the head? Thanks guys

a couple ideas: screw in an old glow plug and pull with a pair of pliars. or pull liner and head as an assembly, then tap out the head button with a soft wooden or plastic dowell, with care.

 

[John Knight]

Unless you NEED to remove the head button from the liner/sleeve - DON'T. It has a good fit together and if you separate them, you will be removing the very good fit and seal for that engine. You can clean it out without removing the head button.

 

[TERMINATOR]

Unless you NEED to remove the head button from the liner/sleeve - DON'T. It has a good fit together and if you separate them, you will be removing the very good fit and seal for that engine. You can clean it out without removing the head button.

he said he was taking it apart to check for shavings in a new engine..how can you get them out without taking the head button off?

tk

 

[Ken Hildreth]

You can pull the head button up, the sleeve will come out with it if the button is tight. What John is saying is there is no need to pull it out unless your head clearance is off. The tighter the head button fits, the better the seal. My 2 cents,

Ken

 

[Chris Wood]

there is a reason the head don't come off.. usually there is a small birr on the very edge of the head for what ever reason.

it is very suttle.. a nice smooth stone will take car of it.

chris

 

[ReidCuddy]

ok thanks guys. I got it off by putting the glow plug in, then putting the glow plug in a vice. Thanks again

 

[PakMan]

Unless you NEED to remove the head button from the liner/sleeve - DON'T. It has a good fit together and if you separate them, you will be removing the very good fit and seal for that engine. You can clean it out without removing the head button.

Sometimes you have to ask yourself, is this a machining mistake??? Let's think about this for a moment. The Bearing press fits, the crank seal, the drum clearance, all the other stuff, why is this head button so frickin' tight, so much so that it sticks and/or shaves on re-insertion.... I'm not sure it's an accident. Even though it is a PIA, MAYBE these guys are trying to tell us something.... anyone think of that.... It looks like John did. I don't know that I'm 100% sold, but I'm listening... Let me know your thoughts.

David Jensen

 

[Chris Wood]

so don't tare it apart.. don't clean out the shavings in the motor from the factory.. and don't clean up the burrs in the slots in the rod. see what happens

and i am sure they thought about it when they put a tiny radius on some of the pistons on a different motor and it totally screwed up the timing and had to be fixed

trust me pull the motor apart and dbl check EVERYTHING.

 

[steve wood]

just worked on a brand new motor, which i won't name , that had a total of .001 head clearance, from the factory, with shims installed, spose they did that on purpose too. had another motor with multiple shavings in the oil slots in the rod. almost instant destruction would have occured, had they not been inspected before running. by the way some head buttons fall out instead of being too tight. there is almost no consistency in any of their tolerances

 

[mark voorhies]

just worked on a brand new motor, which i won't name , that had a total of .001 head clearance, from the factory, with shims installed, spose they did that on purpose too. had another motor with multiple shavings in the oil slots in the rod. almost instant destruction would have occured, had they not been inspected before running. by the way some head buttons fall out instead of being too tight. there is almost no consistency in any of their tolerances

Yea, And that being said, I would not trust any motor without looking inside!!

After taking many apart, there is always something inside you wouldn't want to race .

 

[PakMan]

so don't tare it apart.. don't clean out the shavings in the motor from the factory.. and don't clean up the burrs in the slots in the rod. see what happens
and i am sure they thought about it when they put a tiny radius on some of the pistons on a different motor and it totally screwed up the timing and had to be fixed

trust me pull the motor apart and dbl check EVERYTHING.

My comment was in regard to the Head Button being a very tight fit to the sleeve. I said I wasn't sure it was an accident, but was open to the fact that maybe it was. OF COURSE you need to go through a motor thoroughly before 1st Firing.... Gotta love computers.... <_<

DJ

 

[Chris Wood]

and my comment wasn't toward you either.

good luck