2007 valve ?

[klx450junkie]

Long story short. My son has an 07 crf250r. He said when it's cold there is like no compression. When its warmed up it feels normal. So took it apart and checked the valves. The exhaust valves are .009 and looking forward the left intake is .005 and the right one I can't even put a .002 in. Do you think I can just shim all of them to spec and be good? Should I replace the intake valves and piston rings? Why does Kibblewhite only sell an intake valve and spring kit? Are the intake and exhaust valves both titanium? Thanks

[1down4up]

exh are stainless stock. int are titanium stock. dont waste time shimming the ti valves. once they move they are gone.

[Keith72]

Right intake is zeroed out. Time for a valve job.

[funkinalive]

unfortunately the posts above are correct, once those valves start moving they dont stop and actually wear even faster between adjustments. the kibble white intake kit is a good idea and will last you a lot longer than the stock units, provided that you get the valves seats cut.

[redrooster65]

You can shim it and it will give you some time to plan the rebuild/order parts. Intakes with piston and ring would be a good plan. To do all four with KW you order the valves and the spring kit individually

[klx450junkie]

You can shim it and it will give you some time to plan the rebuild/order parts. Intakes with piston and ring would be a good plan. To do all four with KW you order the valves and the spring kit individually

I'm going to shim it for now and do the whole top end next Month. Thanks guy's for all the great input.?

[Keith72]

You need to make sure that whoever does the head measures the valve guides and makes sure they are ok. Especially on the exhaust valves.

[funkinalive]

You need to make sure that whoever does the head measures the valve guides and makes sure they are ok. Especially on the exhaust valves.

+1?

the unicam exhaust rocker design adds a side load to the exhaust valves that can wear the guides, so eventhough the valves may look good the guides may need inspection

[redrooster65]

So what are the long term effects of running with worn guides?

[funkinalive]

if the valve is allowed to deviate from its center-line enough, it can rapidly wear the valve seat and valve itself. if left unchecked, the valve can bend at the stem or crack the edges due to eccentric closing of the valve.

[Charlie C]

Not to mention burn oil too.

[klx450junkie]

Not to mention burn oil too.[/quote

The shop that will be doing the vavle train work said the same thing. He will check it all out re-grind and replace the guides if needed. You can snap a valve off if there is too much side load due to worn guides.?

[redrooster65]

Makes sense and I know a lot of the guides are out of spec, however I have never herd of an exhaust valve related failure.

[klx450junkie]

Well I took it apart today to see what shims I would have to order. Bad news the valve that was tight is .024 higher than the other valve WOW. I cant shim that so it's off to the machine shop for a valve job. Has anybody ran a cross the same problem?

[funkinalive]

Well I took it apart today to see what shims I would have to order. Bad news the valve that was tight is .024 higher than the other valve WOW. I cant shim that so it's off to the machine shop for a valve job. Has anybody ran a cross the same problem?

yes, exact same problem.

[klx450junkie]

yes, exact same problem.

I wonder if it is a cooling issue on that side.

[funkinalive]

I wonder if it is a cooling issue on that side.

as was posted in many threads, there are many theories as to why this happens. heat also being a contributing factor: as the valve seat rounds the contact area between the valve and seat decrease. therefore, less area for heat to dissipate from the valve to the head. as we all know: the more heat, the more wear. also just a "theory"

[APE Jay]

Quit working on it and just ride it. In stock for immediate shipment. Bolt it on and go. Brand new oem head, APE SS valves, springs, titanium retainers, $575.00

http://www.bigborethumpers.com/newheads.html

[klx450junkie]

Quit working on it and just ride it. In stock for immediate shipment. Bolt it on and go. Brand new oem head, APE SS valves, springs, titanium retainers, $575.00

http://www.bigborethumpers.com/newheads.html

Nice, but I got the head done with all new SS valves,springs,guides,piston set and gasket set for 640.00:thumbsup:

[klx450junkie]

Had the bike out in the desert for a week. It ran sweet... Thanks all.