Raise comp. on mo' power port for '01 CR250?

[TRC]

I already had Eric port my '01 CR250 for mo' power all over but I was using pump gas. I want to raise the compression. I can have it done at a local machine shop, but I was wondering if Eric needs to do work on the ports to make it right. Also how much should I take off .030? And does this come off of the cylinder base?

Thanks for any and all help.

 

[parkerCR]

TRC,

I was considering having Eric port my 01 CR250 for mo better. How do you like it? What did you notice? Do the jetting issues cure themselves with this modification? Info would be greatly appreciated.

Thanks

 

[bclapham]

i want to do the same with my EG yz250, eric is real busy right now but i am sure he will see this thread. Eric, to adjust the head for race gas, is it as simple as just taking some material of the head surface in the lathe or do we need to readjust squish angles and stuff. Also, to mount the head in the lathe, i see that you can do this via the spark plug hole. Can you get away with some steel rod of the same thread, or does it need a special tool to mount?

ive got a machine shop at work, so if its simple i may have them do it, otherwise i will wait to you are less busy, it costs $80-100 around here for the mod., and its not like my arms arnt stretched enough annyway!:)

cheers

BC

 

[marcusgunby]

You can lathe off some from the face of the cylinder but only if the squish gap isnt too small.1mm is the smallest i go on a 125-im not sure on a 250

 

[TRC]

REPLY TO parkerCR : My jetting was already on so that wasn't an issue. But it took away some of the hit and gave it more bottom and a much smoother transition between the low end and top. Overall probably more power everywhere but most noticeable the low and mid range. The '01 already is a screamer on the top end!

I weight around 235 w/ gear and I am 4 for 5 holeshotting my races with this mod. w/ second gear starts (14/52 gear, V Force Reed cage, stock pipe and shorty silencer. The reason I didn't get the one was I thought I clicked it up to second for the start but I was in neutral.

I still don't have an answer to my question at the top of the thread. Anybody?

 

[EricGorr]

TRC you could use a Cometic high compression gasket kit, I set the squish clearance on the thick side for pump gas.

Bruce, Goodson is an automotive tool and supply company that makes a threaded mandrel for centered plug heads for $25 so a home machinist can turndown a head with a small bench lathe that uses a 3 jaw chuck.

 

[TRC]

Thanks Eric.

I want everyone to know that I read a post by Eric saying that he has been getting over 300 tech. calls a day and he may not be answering the phone due to that. But he had the time to help me and my cousin out with an issue the other day. Eric is the man I highly recommend him.

TRC