Jump to content
Sign in to follow this  

01WR250F Wierd Starting issue

Recommended Posts

So this all started when I re-jetted using the JD Jet Kit. After trading emails with JD (very helpful), and having many issues, I set the carb back to the way it was prior to re-jetting. And now, I can't get it to start correctly.

So, when the bike is cold, it starts right up. Runs good, idles good. If I shut it off, it starts on first kick without hot start, if I restart it right away. If I let it set for 30 - 60 sec. or more, forget it. Won't start.

Anyone have these issues before, or ideas of what could cause it? Below are my stats:

Main: 175

Pilot: 42

Stock Needle: 3rd clip position from top down

Stock fuel screw: working between 1.5 to 2 turns out

SF Bay area - practically sea level

50 deg outside and 70 deg inside shop - doesn't make a difference

Any help would be appreciated!!

Share this post


Link to post
Share on other sites

I bought one of these bikes 4 months ago for my son. Previous owner stated the same problem of hard starting stock bike. The local yamie dealer suggested he install a yz cam in it. After he did that it solved all the starting problems. My sons bike will start on first or second kick every time. This is a very nice bike and I couldn't find a better bike for my son. I dont have any other specific info on that but that is the known solution for that model.

Share this post


Link to post
Share on other sites

Ya, I have heard the same. I have owned the bike since new, and it can be a bear to start at times. When I have had the carb set just right, I could count on it. Used to race it even doing hairscrambles. But this is just kicking my but.

How much did it cost? Did you have a shop do it, or did you DIY?

Share this post


Link to post
Share on other sites
Check your float needle valve and the oring there to see if it is seeping fuel.

I thought maybe that, but then figured that it would be leaking out the overflow if the float needle valve was leaking. Right?

Share this post


Link to post
Share on other sites

Well, it may be just leaking enough, that when combined with a hot bike it is making the mix overly rich. Hot start does not make a difference? Could also be just a too high a float level.

Share this post


Link to post
Share on other sites
Well, it may be just leaking enough, that when combined with a hot bike it is making the mix overly rich. Hot start does not make a difference? Could also be just a too high a float level.

No, hot start doesn't help. Nor does cold start, or both. I checked the float level, and it was dead on spec.

Share this post


Link to post
Share on other sites

Well , assuming it is a carb problem, then a slight leak at the float needle valve would be my first guess.

In some instances, the crank position sensor can go bad, often exhibiting a issue like hard to start hot or high speed missing.

Share this post


Link to post
Share on other sites

William1,

How would you test the crank position sensor? Or know if that is it?

I will pull the carb AGAIN, and leak test the float needle.

Thank you very much for your help so far.

Share this post


Link to post
Share on other sites

Unfortunately, there is no definitive test for a sensor in the process of failing. If one has completely failed, you can test for that. Otherwise, it becomes a process of elimination, ie, everything else is absolutely correct so it must be....

Check the float height again too. Check the oring at the needle seat.

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

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×