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cub base gaskets


dutch350

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The 4 mill 68 bore is supposed to have a .012 base gasket to get to a .01 in the hole deck thats what calvin designed them for.

 

I have everything you need give me a call 877-301-1700 or go to http://www.mmatvonline.com

 

Andy

 

I would advise you set the squish by base gasket thickness. I've been around a lot of cubs, cheetahs, etc. and not once have I read anyone, including Calvin, mention .01 hole deck.

 

Squish...however, comes up all the time... My 4 mil needed about .024 or .030 worth of base gasket to set the squish right (two base gaskets, no one at the time had a single thick enough...)

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I would advise you set the squish by base gasket thickness. I've been around a lot of cubs, cheetahs, etc. and not once have I read anyone, including Calvin, mention .01 hole deck.

 

Squish...however, comes up all the time... My 4 mil needed about .024 or .030 worth of base gasket to set the squish right (two base gaskets, no one at the time had a single thick enough...)

 

 

On a 68x58 cub, based off of Calvins blueprints which I have right in front of me, is set up for a .012 base gaskets which leaves the piston in the hole .01 => 10 thousandths in the hole. I have set up probably 20 4 mill cubs all with a .03 step in the dome which is the way i set up all my 4 mill cubs and its always .04 squish. I personally set up the motor with the gasket Calvin recommends then have the domes cut to fit the motor. Setting the motor up is a personal preference but just my $.02

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i set up all my 4 mill cubs and its always .04 squish. I personally set up the motor with the gasket Calvin recommends then have the domes cut to fit the motor. Setting the motor up is a personal preference but just my $.02

 

I agree with you on both points... I always say .040 to .050 squish, good to go on the 68mm pistons. Super Cubs and Cheetahs like a little tighter squish... .035 to .045.

 

Dutch, to answer your question...

I had the head surfaced and the deck height surfaced to get them flat. Not sure if the head needed it or not, but because I snapped two head studs on the bike while running (leaking coolant due to the dip in the center of it) I wanted to be sure the mating surfaces on the head was flat as well...

 

Now...since it was basically put on a surface plate till it was flat, I really can't tell you how much was taken off. I'd venture to say .001 to .004 off the block, probably minimal on the head.

 

So...if I said I milled it, which I may have...I mispoke... It was merely sanded on a plate to get flat then sealed.

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Don't mean to worry you at all...what Andy is saying is correct, just different preferences from different people...

 

I just don't want you to think it's a simple, throw together motor....it's not. Just check the normal things, squish, compression and leak down before you go out and rip it...

 

My 10 mil this year was brand new as well, I put it on a surface plate and it was flat...but I checked it anyways to be sure.

Just use common sense and safe practices, you'll be fine.

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