Jump to content
Sign in to follow this  

Trying to diagnose a problem on 01 yz250f heres the symptoms

Recommended Posts

I was riding my bike and the idle got funny on me, couldnt seem to get it right again, the header is getting really red hot, looks like its going to melt on the ground and it pours out antifreeze out of the overflow. I thought tight or bent exhaust valve, but I just took it to the shop and paid to get it done, they are all in spec and now I'm not sure where to turn. Any input is appriciated

Share this post


Link to post
Share on other sites

that sounds lean, but the bike is not really desgned to sit still and idle, does it still spew coolent when riding?

Share this post


Link to post
Share on other sites

Clogged pilot jet (buy a new one) and or misadjusted fuel screw.

Bad/old fuel can do this too.

If the fuel screw suddenly enables the bike to now run when gently closed, it can be a bad needle jet emusion tube (worn 'oval') or a leaking float needle valve.

Share this post


Link to post
Share on other sites

Thanks guys. The only thing is the bike runs too good for it to be the carburator, I mean, can a bike start 1st kick and idle and need a carb clean?

Share this post


Link to post
Share on other sites
I was riding my bike and the idle got funny on me, couldnt seem to get it right again, the header is getting really red hot, looks like its going to melt on the ground and it pours out antifreeze out of the overflow. I thought tight or bent exhaust valve, but I just took it to the shop and paid to get it done, they are all in spec and now I'm not sure where to turn. Any input is appriciated
Thanks guys. The only thing is the bike runs too good for it to be the carburator, I mean, can a bike start 1st kick and idle and need a carb clean?

I am a bit confused. Does it idle properly or not?

Share this post


Link to post
Share on other sites
I was riding my bike and the idle got funny on me, couldnt seem to get it right again, the header is getting really red hot, looks like its going to melt on the ground and it pours out antifreeze out of the overflow. I thought tight or bent exhaust valve, but I just took it to the shop and paid to get it done, they are all in spec and now I'm not sure where to turn. Any input is appriciated

Start the bike from completely cold. Let it run for 1 minute tops. Gently unscrew the rad cap. If there is a lot of pressure there, the head gasket may not have been installed properly.

Share this post


Link to post
Share on other sites

sounds like its super lean if the header is turning bright red, have you tried adjusting the fuel screw

Share this post


Link to post
Share on other sites
Start the bike from completely cold. Let it run for 1 minute tops. Gently unscrew the rad cap. If there is a lot of pressure there, the head gasket may not have been installed properly.

1 more vote for head gasket.. how soon after its running does antifreeze pour out? if water is not circulating it will get hot too, you could get a temp guage on the radiator and see if its getting as hot as the motor. good luck!

Share this post


Link to post
Share on other sites
sounds like its super lean if the header is turning bright red, have you tried adjusting the fuel screw

Incorrect.

Red header is because it is thin wall tubing and the bike has insufficient airflow.

Fuel screw is for idle only, it is set for a perfect hot idle and you are done with it.

Share this post


Link to post
Share on other sites
Thanks guys. The only thing is the bike runs too good for it to be the carburator, I mean, can a bike start 1st kick and idle and need a carb clean?
He said that he was having idle troubles...so that is why I said fuel screw.

The OP does not make a lot of sense. However, a lean fuel screw will not make a header glow. The amount of fuel between the fuel screw closed and at 2 turns is like a drop of fuel every few seconds. It is really miniscule.

A bike that will not idle cannot have a glowing header as the bike is not running.

Share this post


Link to post
Share on other sites
The OP does not make a lot of sense. However, a lean fuel screw will not make a header glow. The amount of fuel between the fuel screw closed and at 2 turns is like a drop of fuel every few seconds. It is really miniscule.

A bike that will not idle cannot have a glowing header as the bike is not running.

Going off the OP I thought idle problems, I have seen bikes that have a lean idle condition that idle high causing a red header. That is what came to mind after I read the OP. I do understand that a bike that will not idle at all, therefore not run at all cannot have a glowing header. 👍 The OP was a bit confusing. But anyway hope he can figure it out. Sorry I am of no help.

Share this post


Link to post
Share on other sites

Ok, I figured it out, I have a db dawg in my exhaust to quiet it down, turns out that was clogging my exhaust causing a ton of back pressure and my fuel screw was set to rich so all the gas was just sitting in the header causing it to be red hot. Wouldn't even think 2x about the db dawg because its been on the bike for over a year. Now without that in my exhaust and with the carb properly adjusted, bike runs great!

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...