Anyone with a PRO-X 350 Cylindr....NEED HELP FAST

[LT250Racer609]

Ok well, I had my cases machined, Installed my CT- racing/Pro-X 350 cylinder...and everything was going fine...but once I installed the head and put the coolant in, It poured out of the head all the way around....

I took the head off, and the Compression Dome, when compressed all the way into the head, it stick out too much...so when you torque the head down, the inside O-ring seals, but the outside doesnt seal enough and thats why the coolant is leaking on the outside O-ring...

Is this normal?? The Head Says Procross on it...I got the cylinder from a buddy who never installed it since he got it from the guy before him...What do I need to do?? Would like to have this together by wensday for my first supercross race this season.

[number5]

With the head off look at it across and see if its level. I had to sand my pro design down on a piece of glass because of that.

[LT250Racer609]

no thats not it....the dome sticks out too much that it doesnt seal the back O-ring on the head tight enough to hold the coolant.

[LT250Racer609]

Does anyone know if the Cool head dome is supposed to be flush with the Head on the Procross head for the CT 350??

[86 Quad R]

i maybe waaaay off here when i say this but, it sounds as tho you may have a dome that is for a non o-ring head. meaning it should be used on a gasket type application.

i have limited experience with those heads so, i maybe wrong about this. :confused:

[C-LEIGH RACING]

If that is a CT cylinder kit, be sure the little divit up in the outside schell is lined up with the divit hole machined into the dome.
It a thing machined into the inside mateing surface inside the head to keep the dome from spinning in the outter part of the head.

Sometimes the dome itself will have a pop up of around 0.0001 to 0.0002 just to be sure the inner o ring will have a good seal. Normally though, both pieces of the head will be flat.

Check that divit thing out, its real easy to get it out of aline when placing the dome in the head.
Neil

[LT250Racer609]

Yah thanks alot....I knew about the divit thing. I called CT racing and talked to a Mechanic about it...said exactly what you said. It Had a Pop Up of .0005 or something when it was supposed to be .0001-.0002 like you said....Soo we machined the dome, and made it .0002, put it on, torqued it down and now theres no leaks...Had it running and took it for a ride, and runs good...now just gotta jet it right.

[C-LEIGH RACING]

Sence you cut the dome surface, need to check the squish clearance, be sure thats not to tight.
Neil

[86 Quad R]

juss curious.... are the o-ring grooves on the big bore cylinders cut into the head or into the top of the cylinder?

[LT250Racer609]

cylinder...head is flat

[86 Quad R]

Originally posted by LT250Racer609
cylinder...head is flat

ok thanks :cool:

btw neil... why is it that they cut the grooves in the cylinder rather than in the head?

[LT250Racer609]

Originally posted by C-LEIGH RACING
Sence you cut the dome surface, need to check the squish clearance, be sure thats not to tight.
Neil

what would happen if it was too tight???