Jump to content

Recommended Posts

I got a 2017 yz450f that just falls on it's face after running awhile. It will run great then land a jump and the bike just dies. After it sits a bit it fires up after about 20 kicks. Losing my mind can't figure it out. HELP!!!

  • Like 1

Share this post


Link to post
Share on other sites

Problems like that are going to be hard to diagnose.  But if it was me I'd be looking at a stator or possibly fuel pump.  Both those items can sometimes work when they are cool and then give you trouble when they get hot. After it dies you could probably full a fuel hose and make sure you're still getting flow from the pump.  The stator is trickier.  When it dies you could quickly check for a strong spark.  But strong is subjective.  If you see spark at all but it's questionable if it's strong and firing every time you'd probably have to test it with a multimeter.  Hopefully the Yamaha service manual describes how to test the stator.  But you'd have to perform that test very quickly after the bike dying.

Those are shots in the dark but hopefully that gives you a couple things you can check.  I'm sure some other folks here might have some other ideas.

Doc

Share this post


Link to post
Share on other sites

If you got a power tuner then hook it up next time the bike dies and see if there is an errorcode showing.

Share this post


Link to post
Share on other sites

Sounds a possible fuel pump issue. I would reccomend what Robt85 said. I would highly reccomend the power tuner Yamaha makes. It's an awesome tool to diagnose issues the bike may have, document hours on the engine for maintenance purposes and also to adjust fuel and timing. 

I know when I had a 14 250f I adjusted the mapping for the fuel the bike not only ran better but ran a lot cooler as well. Could be slightly lean but that's my two cents.

Share this post


Link to post
Share on other sites

My mate had similar issues , turns out the yz,s have a little sensor under the fuel tank somewhere , think it's like a $30 part 

Share this post


Link to post
Share on other sites

Check the wire harness, I had the same problem on my 16 250f. The wire harness got rub down and was shorting it out causing it to die in faces of jumps, on landing etc.
my problem was on the section of harness located between the tank and frame.

IMG_4097.jpgIMG_0149.jpg

Hope this helps

  • Like 1

Share this post


Link to post
Share on other sites

Lots of good advice in this thread but it looks like the poster is a "one post wonder".  He hasn't been back since he posted this about a week ago.

That's almost as bad as the guys who need help, keep a thread going for 2 weeks with people here helping them with every little step and they suddenly just disappear never telling anyone what the problem was or how they fixed it.  After they use 20+ hours of people free help here, once their bike is fixed they're gone.  They simply can't be bothered to spend the 2 minutes to reply and potentially help the next guy who searches for the same problem or just say "thanks" to the people that helped them.  :rant:

Edited by Doc_d
  • Like 2

Share this post


Link to post
Share on other sites
6 hours ago, Doc_d said:

Lots of good advice in this thread but it looks like the poster is a "one post wonder".  He hasn't been back since he posted this about a week ago.

That's almost as bad as the guys who need help, keep a thread going for 2 weeks with people here helping them with every little step and they suddenly just disappear never telling anyone what the problem was or how they fixed it.  After they use 20+ hours of people free help here, once their bike is fixed they're gone.  They simply can't be bothered to spend the 2 minutes to reply and potentially help the next guy who searches for the same problem or just say "thanks" to the people that helped them.  :rant:

I agree, that drives me nuts. I have had several problems in the past where I was able to find related threads but the OP never came back to say if the issue was solved or not. 

  • Like 1

Share this post


Link to post
Share on other sites

I appreciate this topic, since my issue sounds similar. I'm running an 18 though but it runs fine for hours and then sputters and dies, starts fine and run it a short ways and dies again, repeat. I tried gas from a different source and same issue. My tank breather hose seemed to be plugged some, would that cause the issue on an EFI?

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:


×