'96 RMX 250 head gasket swap w/ RM part?

[PAMXC200]

I remember reading about swapping the head gasket on RMXs with an RM part to raise the compression (and therefore power). My question is twofold....is this a valid tuning option on the '96 RMX? If so, what year RM head gasket is needed for this change? Thanks for any help.

 

[PAMXC200]

*bump*

 

[Layton]

Yes you can do that. I can't give you a year for the replacement gasket. Your best bet would be to just take the old one with you and compare them.

 

[89rmx250]

Not sure about the 96, but for the 89-95 you use the 89 RM 250 head gasket. I have an 89 RMX. Rebuilt the top end with the stock gasket and I had 160 lbs of compression. The next winter rebuilt with the 89 RM gasket and had 200 lbs of compression.

 

[placelast]

PAMXC200: I have a '97 & a '90 RMX. The '89 RM250 head gasket is the one you want to use, or you can buy the Cometic High-Performance top-end gasket kit if you are doing a top end.

If you get the former, don't tell the pimply kid behind the counter what you have, only what you want.

I bought the latter to use on my son's '90 when I do the piston later this fall.

 

[PAMXC200]

All,

Thanks for the replies. Placelast, I know what you mean when you say to tell the pimply kid what you want, not what you have ;) The bike already has an FMF pipe and silencer and the airbox lid removed....It was rejetted as well. How much more power will it have with the RM head gasket? What does it do to the power delivery?? Again, thanks for the responses.

 

[placelast]

Originally posted by PAMXC200
. How much more power will it have with the RM head gasket? What does it do to the power delivery??

Sorry: I can't quantify the answer, nor even address it as I did the swap before firing mine up & my son's came that way.

For $10 + coolant + your time wrenching, just do it. Don't forget to torque the head properly.

One last thing (feel free to e-mail me @ [email protected] for more): be sure to clean the exhaust valve once a year; unbeknownst to me, mine came clogged up with the junky (premix) spooge the previous owner used, and after beating my head trying to get the jetting right I came to find this as the real source of the return-to-idle run on & off-idle jetting woes. Thereafter it ran much better.

 

[PAMXC200]

Thanks very much for the info. I hadn't thought to check the power valve either - good tip. And you're right....for 10 bucks, what the heck - I'll try it! :D

 

[Stew312]

Defintiely a good idea to clean the exhaust valves.. I bought my 88 RM 250 a month ago, and it wouldn't get more than 3/4 up in the RPM's, and wasn't getting as much compression in the low end as it needed. All because the exhaust valves were carbon-welded in place, stuck half way open. They probably hadn't been touched in 10 years. Definitely check yours out.

 

[DEANSFASTWAY]

you should buy gorrs book because it tells you different hop ups on the rmx. I think the bike has a throttle limiter and a powervalve limiter also . good luck