Hard Starting. Time for Reshimming?

[Chris Kitchens]

It's been quite a while since I've reshimmed my valves but it seems like the last time I did it, I was having trouble starting my bike. Does hard starting mean its time for some valve work?

[JeffInNC]

Could be. Have you checked the valve clearances? If they are tight, especially the right intake, that'd most likely be the issue.

[honda424]

if you have already reshimmed before.. and they are moving again.. then ya its time for a valve job.. and pry new piston and rings at the same time

[MotorMan1515]

Like honda424 said, if you're having clearances move, it's time to replace the valves and have the valve seats cut. CRF's titanium intake valves are almost "fragile" and once they start to go, there's no chasing them. That's why I went with Kibblewhite SS intake valves to solve it. Also like he stated, if you're in there, why not spend the little cash to replace the piston and rings, I would recommend having your cylinder flex-honed (usually like $15-20) if you do so.

[sdobbs20]

when checking clearances, check all the valves. then rotate the motor over 3 or 4 times. if clearances change then most likely a valve job is needed. make sure to roll motor over 3 or 4 times every time you check or change shims.

[Chris Kitchens]

Like honda424 said, if you're having clearances move, it's time to replace the valves and have the valve seats cut. CRF's titanium intake valves are almost "fragile" and once they start to go, there's no chasing them. That's why I went with Kibblewhite SS intake valves to solve it. Also like he stated, if you're in there, why not spend the little cash to replace the piston and rings, I would recommend having your cylinder flex-honed (usually like $15-20) if you do so.

From what yall have told me, I definitely need new valves. I only have about 9 hours on the piston thats in there though so I'm gonna leave that. Also, what is flex-honing the cylinder?

[MotorMan1515]

Ball-hone, flex hone, same thing. Basically just restores the cross hatch pattern to better break in the piston rings and great a better seal.

[daeven]

I'm in the same boat as the OP. Where do you guys get the valve work done? I got a cheap 2004 CRF250R that had essentially negative clearance on one valve, so I assume valve seat work is in order. I can check and adjust valves all day long, and I'm sure I can figure out replacing valves. Valve seats are another thing.

I've found crfheads.com, but I don't know anything about them. Any recommendations?

Thanks!

[Charlie C]

Nothing but good reviews on CRFheads.

If you call around, you might find a small local machine shop that can do them. If there's a motorcycle repair shop near you, ask them if they can reccommend somewhere or if they can have it done at a reasonable price. Normally for a machine shop to cut the seats is between $20 and $30 each.

[fransn]

I own a CRF250R 2004 and have had the same problem also when I run into starting problems I noticed that I'm loosing compression, when I checked the valve clearance it was 0mm on the intake valves. Out-valves are ok. I've had my valves replaced 2 times over the last 2 years with standard titanium valves but the problem kept comming back after 10 to 20 hours. Now I've had prox steel intake valves installed hopefully it will solve my problem.

This winter I rebuild my topend with a new piston kit and I just couldn't get the bike to start. I have the brand new steel valves (1 hour engine time) with proper clearance. It's pretty cold at the moment (alost freezing) and the bike won't start at all with the choke pulled out completely..it doesn't do anything not even firing one time . I tried starting it without the choke and that seemed to work at least it fires up and when it fires give it a little bit of gas to keep it running..

Any idea what this problem could be? NOTE: once the engine is running I can pull out the choke and it will run at higher rpm's so it's doing something.

[Charlie C]

I own a CRF250R 2004 and have had the same problem also when I run into starting problems I noticed that I'm loosing compression, when I checked the valve clearance it was 0mm on the intake valves. Out-valves are ok. I've had my valves replaced 2 times over the last 2 years with standard titanium valves but the problem kept comming back after 10 to 20 hours. Now I've had prox steel intake valves installed hopefully it will solve my problem.

This winter I rebuild my topend with a new piston kit and I just couldn't get the bike to start. I have the brand new steel valves (1 hour engine time) with proper clearance. It's pretty cold at the moment (alost freezing) and the bike won't start at all with the choke pulled out completely..it doesn't do anything not even firing one time . I tried starting it without the choke and that seemed to work at least it fires up and when it fires give it a little bit of gas to keep it running..

Any idea what this problem could be? NOTE: once the engine is running I can pull out the choke and it will run at higher rpm's so it's doing something.

When it's really cold, a larger pilot jet would help out on starting. Also, you can crack that throttle more than once. On my kids old 08, 5 cracks of the throttle and it would run for about 15 seconds than stall. Had to do it sometimes 3 or 4 times with the choke out before it would finally stay running and warm up.

[JeffInNC]

I just got my son's 07 head back from CRFHeads. Brent does a fantastic job! Head looked like brand new, beryllium copper intake seats, cleaned, ported, new valves, springs, etc...

Received ready to bolt on. Bike now has compression like new and starts on the 1st kick!