Rebuilt Topend 2006 crf250x

[wagz112]

After being the 3rd owner and a couple of years riding under my belt, the original valves finally went south. After a couple of shim jobs I decided to rebuild the top-end of this bike I've grown to appreciate. I researched a bunch on this site and others and decided on a brand new head 2007 crf250r with Kibble White SS intake and exhaust valves from CRFs Only. I figured for $200 more than a rebuild of my current stock head, it'd be worth the added performance of the '07 R. Additionally, I settled on keeping my stock cylinder that was in good shape with original cross-hatching. I planned on getting a HC piston, like 13.5-1, but couldn't purchase one in time for the build and settled on a new stock '08 crf250R piston. Not sure if the '08 piston is spec at 13.1-1 compression ratio due to decreased volume of the '08 head vs. the '07 head 12.9-1 ratio, but I went with it anyway. Along with the '08 piston, I went with a '08 R cam. Per Rick Ramsey's site information I went with stock '06 crf250x head and cylinder base gaskets for thinner measures in hopes of increased or maintained compression ratios. I also replaced the cam chain and tensioner.

 

I tore down by myself (easy part). Rebuild done by Paul at Powertoys in Montclair, CA, for 3 hours of labor.

 

I was already running 4x4 open air box, FMF Q4 muffler, stock X header, 42 pilot 2 turns out, 158 main, and stock gearing.

 

After a few complete warm-ups and baby runs at no more than 1/3 throttle and complete cool downs, I took her for her first ride yesterday. Nice nice dirt after Thursday's rain at Silver Wood Lake OHV area to SW Arrowhead  ! Perhaps it felt so great being a fresh top-end in general, but I am happy with the '07R head and '08 R cam. Maybe a tad bit of lost bottom-end, but coming off the stock '06 California X cam, anything is better! It seemed to stall a bit easier a couple times in slow rocky areas that I hadn't before, but I was still trying to baby the new top-end so not the best momentum. This fresh bike definitely rips and tears up the trails. I can't wait to really open her up next ride!

 

Here's some pics of my tear down, new head from CRFs Only, and yesterday's ride. Let me know what you think or if you have questions on my rebuild. Cheers!

[wagz112]

Does anyone think my old head and cam would be desired on the resale market? I'd like to get a bit of scratch back after some healthy coin put into the rebuild? Any thoughts on the post, resale or experience with my new setup to share? Thanks!

[adamsavage]

regards your tickover just run it slightly higher i had to when i fitted an 05 r cam

[Brendantherider]

Ya I'm interested in the cylinder head for a good price.

Edited August 21, 2014 by Brendantherider

[Qqqqqqqqqqqq]

I think Fastheads supply the Heads to CRF 's only .

[hondalife1700]

I noticed your rear shock is red is it an aftermarket part?

[wagz112]

It was on when I bought the bike from a guy weighing about 180 lbs, but recently the guys at the suspension shop who revalved said their paper work show stock spring rates and that they change out for red color stock rate as a personal touch of their shop. They bike seems to ride good for my 155 lbs and I can get close to required sag specs. So I guess I'm good. Maybe one of these days I'll look for the markings on shock to verify???

[ollydog30]

I rebuilt my bike the same way you did but with 13.5:1 piston. Runs great had to go with the quickshot to help get a little bog out after jetting. I have rod it hard for a year now and the valves are still right where I set them. The only big difference I noticed was the topend had more valve train noise than before.

[Griffy-]

After being the 3rd owner and a couple of years riding under my belt, the original valves finally went south. After a couple of shim jobs I decided to rebuild the top-end of this bike I've grown to appreciate. I researched a bunch on this site and others and decided on a brand new head 2007 crf250r with Kibble White SS intake and exhaust valves from CRFs Only. I figured for $200 more than a rebuild of my current stock head, it'd be worth the added performance of the '07 R. Additionally, I settled on keeping my stock cylinder that was in good shape with original cross-hatching. I planned on getting a HC piston, like 13.5-1, but couldn't purchase one in time for the build and settled on a new stock '08 crf250R piston. Not sure if the '08 piston is spec at 13.1-1 compression ratio due to decreased volume of the '08 head vs. the '07 head 12.9-1 ratio, but I went with it anyway. Along with the '08 piston, I went with a '08 R cam. Per Rick Ramsey's site information I went with stock '06 crf250x head and cylinder base gaskets for thinner measures in hopes of increased or maintained compression ratios. I also replaced the cam chain and tensioner.

I tore down by myself (easy part). Rebuild done by Paul at Powertoys in Montclair, CA, for 3 hours of labor.

I was already running 4x4 open air box, FMF Q4 muffler, stock X header, 42 pilot 2 turns out, 158 main, and stock gearing.

After a few complete warm-ups and baby runs at no more than 1/3 throttle and complete cool downs, I took her for her first ride yesterday. Nice nice dirt after Thursday's rain at Silver Wood Lake OHV area to SW Arrowhead ! Perhaps it felt so great being a fresh top-end in general, but I am happy with the '07R head and '08 R cam. Maybe a tad bit of lost bottom-end, but coming off the stock '06 California X cam, anything is better! It seemed to stall a bit easier a couple times in slow rocky areas that I hadn't before, but I was still trying to baby the new top-end so not the best momentum. This fresh bike definitely rips and tears up the trails. I can't wait to really open her up next ride!

Here's some pics of my tear down, new head from CRFs Only, and yesterday's ride. Let me know what you think or if you have questions on my rebuild. Cheers!