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Pro Design Cool Head
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Posted by: chris46250r

I've always ran my 250r's with a stock head milled down to where the flat gasket surface has no edge before going into the dome and a CR head gasket. I have a Cool Head with a 19cc and 20cc dome. Does anyone know if either one of these two domes is close to what I've been using. I got the Cool Head with my last '88 250r and I've got mixed reviews from people about it. Some love it and some say it works best when installed in the trashcan.

Posted by: beerock

to be honest the shaved head is the ticket, you can vary your compression with the 3 piece gasket or a cr250 gasket

the 3 compression setting are kind of like this

highest comp: thin piece of 3 piece gasket

mid comp: cr 250 gasket

low comp: center peice of 3 piece.

all of them should be sprayed with a permatex orange gasket aerosal for a even coat on both sides

the only thing thats cool about the cool head is interchangeable domes, but at 20+ a pop you can go get another stock r head or cr250 head for 30-35 and not have to worry about new orings etc

Posted by: chris46250r

Actually the thin piece of a three piece is whats on it now. I didn't know there was much difference in it and a CR gasket. I have never sprayed any gasket maker on them though, never had any reason too. I was just wondering what cc dome was compareable to my current set-up. I'm not going to buy any domes, I just had a 19 and a 20 laying there.

Posted by: mxduner

with the 19cc i get around 210 psi compression do you have an oring head or gasket head? i got a gasket head and am sorry i do.

Posted by: chris46250r

Gasket head.

Posted by: 86 Quad R

quote:
Originally posted by mxduner
i got a gasket head and am sorry i do.

en why is that?

Posted by: KFX400 RACER

Where can I get my stock head shaved. Anyone know any good places? How much or what amount should I have shaved off?

Thanks,
Jake

Posted by: mxduner

quote:
Originally posted by 86 Quad R
en why is that?

i've heard a ton of threads of others having troubles keeping them sealed, I've gone round and round with different gaskets and sealants/sprays to end up with only temporary results.o yea and put a straight edge on the head and cylinder after 2 tries and 2 different gaskets and found a minor warp, had it milled flat at the machine shop...that was a tease

called the guy at pro design,yea he claims he puts a "step" in the sealing surface and says he's never had a problem what so ever and he also recomends to "listen to no one on the internet and theres a lot of BAD people on the net" and "bogus unskilled people wrenching on these machines" was another famous qoute from him, unlless you have o-rings i'd stick with beerock on this topic, i'd go with the stock head and gasket configuration.
p.s. the 5 extra head gaskets that came with the machine when i bought it should be a good indication

Posted by: 86 Quad R

quote:
Originally posted by KFX400 RACER
Where can I get my stock head shaved. Anyone know any good places? How much or what amount should I have shaved off?

Thanks,
Jake

how much compression are ya looking to run on your engine?

Posted by: 86 Quad R

quote:
Originally posted by mxduner
I've gone round and round with different gaskets and sealants/sprays to end up with only temporary results.o yea and put a straight edge on the head and cylinder after 2 tries and 2 different gaskets and found a minor warp

developed a warped head after truing it and a short while of running? what compression were you running at the time? i personally havent havent had the problems you describe.

Posted by: KFX400 RACER

I wanna run race gas or av gas. Not sure on compression. What do you think is best? I have no idea what to run. I wanna get a 265 big bore kit later on down the road.

Thanks

Posted by: 86 Quad R

quote:
Originally posted by KFX400 RACER
I wanna run race gas or av gas. Not sure on compression. What do you think is best? I have no idea what to run. I wanna get a 265 big bore kit later on down the road.

Thanks

in that case. i would check and see what the squish is with the thinnest of the 3 layer gasket (should be .010 thick). i'd also check what the compression is with that gasket. it's easy to acheive 185 to 190 psi(which is a good running compression) with this set up but, if you want more then i'd take about .010 from the head (check the squish afterwards). this should put you up to or over 200 psi and if you want more. take another .010 off(check squish) you want to keep the squish above .035. good luck

Posted by: mxduner

quote:
Originally posted by 86 Quad R
developed a warped head after truing it and a short while of running? what compression were you running at the time? i personally havent havent had the problems you describe.

the head was warped when i checked it then i had it milled it was this way when i bought the quad