Intake valce problems on a 2008 crf 250R

shaffstall721

shaffstall721

PR Member
Intake valve problems on a 2008 crf 250R

Guys,

I have been having problems starting my bike but once it starts it is fine, I have had the valves re shimmed but i heard changing the intake valves and re cutting the seats will do the job (stainless valves instead of titanium)

Does anyone have any recommendations on what to do, or who can do it?

It starts good once i get it hot, but starting it takes 50 kicks, or bump start.

If you know anyone with experience please tell them to call or text me

4404206221

Thanks,
 
If you have only shimmed the valves once, I would inspect the head and see if there is any wear. There should be three angles on the seat. The new heads since 06 do not wear as easily and most of the wear should be in the valve itself.
 
Thank you, but not too long ago the motor was complete rebuilt, new crank, rod, piston and bearings, the whole thing and the guy who did it didn't say anything about the head, I'm going to try a larger pilot jet, and see it that helps. It seems a lot of people have this problem with that year bike, but if the pilot doesn't help i will pull the head and take a look.
 
Have any decent dealership or qualified person (Parma Dave?) do a leakdown test. This will tell you how much pressurized air is leaking past the valves and / or rings. Compression tests are pointless, as the 4Ts use an automatic decompressor for starting. This system holds 1 exhaust valve open during cranking.

Going off of what Hudak posted above, some mechaincs or automotive type machine shops will use valve grinding compund to "lap" the valves and seats during a rebuild. If you lap the OEM ti valves, you WILL destroy them. The ti valves have a type of anodized hard coating to reduce wear. Lapping the valves removes this coating
 
I had that happen to a bike I had. I had the valves shimmed and two weeks later it did the same thing. I had to get new valves.
 
Do the compression test first to find out if this is even the problem. Most likely from description it is.
If you are mechanically able, you could try Pulling the head Inspecting the seats and valves, and if they aren't completely wasted, getting some compound and lapping the valves to the seats. This May give you a little more time without a Total valve job expense. The flip side is you must clean the abrasive compound out VERY VERY thoroughly from everywhere, and you have just as much (actually a little more) work, But if it fails only thing wasted was time and a head gasket.

OK! OOOPS!
06 and later honda's had Titanium valves. SO ixnay on the LAPSAY of the VALVESAY!

find a reputable MOTO machine shop and replace valves and seats... if that turns out to be the problem.

GOOD LUCK!!!

Its not that often I am wrong! But when I am, I am usually DRUNK! Stay thirsty my friends.
 
Thanks guys, I took it to someone that was recommended after reading this post, I believe it needs new valves also, (at least the intake)

Ill give you an update once we figure it out.
 
You must log in or register to reply here.
Back
Top