Cool head question

[wykyd z400]

I just bought a 250R...It has an 88 bottom end, and an 86 top end with spacer plate. It has a cool head head on it. The guy said he just had a new gasket put on it, when they put new studs in. I noticed the gasket is leaking between the cool head, and cylinder. Its seeping out. I am curious as to which gasket to use. Can a regular gasket be used with a cool head?? Thanks.

[punker69q]

with a cool head you are better to use stock gaskets, as thin gaskets tend to create problems. If you want lower compression, change the dome size.

[MossboysRacing]

Cool Heads should use an O-ring instead of a typical gasket.

[wykyd z400]

Being that it has a new gasket.....Whats the chances of me pulling it out, wiping it off real good, and spraying it with copper spray, and it sealing up??

[deathman53]

a head and base gasket is only good once. when you pull the head off, check to see if its warped, it may be, thats why its leaking. was it torque to 20lb's? Not all coolheads are o-ring, mine isn't. As a rule I use copper coat on head gaskets.

[wykyd z400]

I dont know what it was torqued to, as the previous owner done it. :( If it matters, I believe he said it was a cometic gasket.

[deathman53]

use oem honda gaskets, if you want a higher compression gasket use a 85 atc250r head gasket, real high compression use a 89 cr250r gasket

[wykyd z400]

I dont wanna up the compression at the moment. I have no way to test it, and I wouldnt know if race fuel would be needed. Do I just buy an 86 gasket from my dealer?

[Scott-300ex]

I have a Cool Head on mine, I used a 89 CR250 gasket for more compression.

I called Pro Design and I asked about head to piston clearence and they said it would be fine.

[wykyd z400]

I wanted to contact PD, but couldnt find a site, or number. If ya can help me, it'd be much appreciated. Thanks.

[86 Quad R]

as suggested. i would stay with OEM gaskets, preferribly the metal ie the three layer trx or the thin CR one.

regardless of which you decide to go with i suggest that you get a compression gage so that ya can take a reading so you'll know what fuel you will need to run. otherwise your asking for trouble. juss my .02 worth

[wykyd z400]

I just pulled the head on it. It has a "19" stamped onto the dome, so I assume thats a 19 cc dome. Does that mean I will be looking at race fuel when I put a new gasket on?? I will try to borrow a tester until I can obtain one. Thanks.

[kiesta00]

get a compression tester and if its over 200psi you'll need to run 100+ octane

[86 Quad R]

Originally posted by kiesta00
get a compression tester and if its over 200psi you'll need to run 100+ octane


IMO! anything over 190 is pushing it on pump gas

[Scott-300ex]

I heard 180.

Yes its a 19cc.

I gaurentee you you will be fine runnin 93. Not race gas.

I got Pro Design # in my cell phone. LoL.

1-714-534-0620

[86 Quad R]

190 is absolute max cranking compression for 93/94 oct

[fireburns99]

Originally posted by 86 Quad R
190 is absolute max cranking compression for 93/94 oct

Not true. I run 210 on pump gas, NO PROBLEMS. It's been at 210 for over 7 years now, always ran 91 octane. The squish makes a difference and can help determine what type of fuel to run.

[wykyd z400]

I plan to do a check real soon. Maybe this weekend if I get it together. I ordered a stock trx gasket, and I am debating on using three bond, or copper spray.....I dunno what I should do.:(

[fireburns99]

the copper spray has always worked good for me.

[86 Quad R]

Originally posted by fireburns99
Not true. I run 210 on pump gas, NO PROBLEMS. It's been at 210 for over 7 years now, always ran 91 octane. The squish makes a difference and can help determine what type of fuel to run.

190 is the max that i've been able to get away with. i'm sure it varies from setup to setup but, ofcourse we all know that in the end its the running c/r (affected by port timing, squish and ect)that determines the oct. of fuel to run. what the engine likes so to speak.

btw what squish are ya running versus chamber size?



Originally posted by wykyd z400
and I am debating on using three bond, or copper spray.....I dunno what I should do.


believe it or not i've had tremendous luck with Krylon fast dry paint. color choice is yours lmao

[wykyd z400]

LOL...Hard to believe, but I can kind of see it working. :p I may try the copper spray still tho. Thanks for all the input everyone.

[fireburns99]

to be honest, i'm not sure what squish i am running exactly. I bought the R from a guy who used to race arena cross, and he said that it was good to go on 91, so thats been what i've used ever sense. I've rebuilt it, but i've always put the CR gasket back on to keep things consistent.