Bike won't start when hot

Any ideas on what to check?

I tried with both the hot start button on and off.
there's gas
Battery got weak fast but I connected a jumper and it still didn't help.

some history:

Dealer had some work done after is started smoking a bit (bike still started ok, it was just smoking). They did the following:
-Piston Kit
-replaced gaskets, o-rings and seals for: Valve cover, head, tensioner, ignition cover, water pump, clutch, shift shaft, Left and Right main seals, rocker arm, timing and counter shaft.

If it makes any differance, earlier this year I had the crab seals replaced and carb cleaned.

My initial thought was valve clearance was off, but dealer re-checked it, cold and hot, and said it was fine. they did find the voltage regulator was off (??) and replaced that.

Stator might be going out, but like I said I couldn't start the bike even with a jumper connected to it, so I don't think it is power related.

any suggestions on what to check next?

Thanks

Check for spark?? Fuel to cylinder?? Compression?? Intake air flow?? Exhaust??

Those are the basics to check, then it gets more into depth. I would also check the kill switch button and make sure it is not grounding out, that would keep your machine from starting for sure.

Let us know what you find and everyone can help from then on. Its hard to guess so basics first please

FE350 said:

Check for spark?? Fuel to cylinder?? Compression?? Intake air flow?? Exhaust??

Those are the basics to check, then it gets more into depth. I would also check the kill switch button and make sure it is not grounding out, that would keep your machine from starting for sure.

Let us know what you find and everyone can help from then on. Its hard to guess so basics first please

Click to expand...

Thanks FE350, but the bike does start when cold, it's just a hot start issue. So spark, fuel, air flow and Exhaust should be fine, right?

Yup, sorry bout that my mistake.

I would check carb settings, idle and air fuel mixture settings. They can play havoc sometimes. How many hours on it from rebuild? I know my 06 KTM was a nighmare. If I touched the throttle at all or if my idle screw was high it would not start hot at all as in never. Just a thought, Try putting your fuel mixture to stock setting and drop idle screw and use throttle, bring it up slowly and see if you can find a point that it will start.

Does the carb leak fuel out from of the overflow hoses when upright or tilted to the side a bit?

Try hot starting with the gas cap off.

Thanks FE350 and Husabutt

I started to take apart the carburetor so make sure there no gunk in there. Once I have the bike back together I'll do as you guys suggested. Plug was fouled too, wonder if that has anything to do with the hard start condition (i.e why would the plug spark fine when cold but not when hot..)

matikrimerman said:

Thanks FE350 and Husabutt

I started to take apart the carburetor so make sure there no gunk in there. Once I have the bike back together I'll do as you guys suggested. Plug was fouled too, wonder if that has anything to do with the hard start condition (i.e why would the plug spark fine when cold but not when hot..)

Click to expand...

Possibly if there is a crack and when it gets hot it expands and shorts to ground as the electrode will take the path of least resistance. It takes allot more electricity to fire a cold plug than a hot one. If the plug is worn out such as excessive gap and loss of electrode it will be harder to fire than a new one.

Just thinking out loud, is when your bike gets hot is after riding it for a while? How is the fuel level when hard start happens? Will it do it after a two min idle in the driveway after shut off?

FE350 said:

Possibly if there is a crack and when it gets hot it expands and shorts to ground as the electrode will take the path of least resistance. It takes allot more electricity to fire a cold plug than a hot one. If the plug is worn out such as excessive gap and loss of electrode it will be harder to fire than a new one.

Just thinking out loud, is when your bike gets hot is after riding it for a while? How is the fuel level when hard start happens? Will it do it after a two min idle in the driveway after shut off?

Click to expand...

Yes, as long as it got hot enough (I.e fan started working). If bike is still cold it will turn back up without a problem

Sent from my GT-N5110 using Tapatalk

I have had the same problems with my 06 450E. I cleaned the carb and jets and messed with the fuel screw a bit. Sounds like there has been some really good advice on this page as well though.

Pulled out the jets and cleaned them, although they were pretty clean. was hoping to check the valve clearance before I put everything together but can't find the f$#king gauge....

I wonder what would made the spark plug look like that. can it just be wrong jetting?

I'm going to go put the bike back and see what happens now that it has a new spark plug in it. and will also play with the fuel screw, I do think the dealer might had left it a bit to closed.

thanks guys!

My money is on the jetting. get a jetting kit from me and it'll start when hot. that or your money back.

regards

Taffy

I think I found what was causing the problem - I played with the Idle Speed Adjusting Wheel like FE350 hathat39 suggested and that solved the problem. It took me a while cause I thought the mixture control screw is all I should have played with, but then re-reading the post and RTFM made me realize the Idle Speed Adjusting Wheel also exist.

I have no idea why would the dealer play with it when they took the engine out to replace the piston, but for whatever reason I guess they did.

The only thing I noticed now is that the engine idling speed is kind of high when I'm seating in traffic or at a red light. but this is based only on my hearing, so I'm not 100% sure this is not normal.

Anyway, thanks again to all of you that took the time to help, and hopefully this will help the next dumb ***..

matikrimerman said:

I think I found what was causing the problem - I played with the Idle Speed Adjusting Wheel like FE350 hathat39 suggested and that solved the problem. It took me a while cause I thought the mixture control screw is all I should have played with, but then re-reading the post and RTFM made me realize the Idle Speed Adjusting Wheel also exist.

I have no idea why would the dealer play with it when they took the engine out to replace the piston, but for whatever reason I guess they did.

The only thing I noticed now is that the engine idling speed is kind of high when I'm seating in traffic or at a red light. but this is based only on my hearing, so I'm not 100% sure this is not normal.

Anyway, thanks again to all of you that took the time to help, and hopefully this will help the next dumb ***..

Click to expand...

Turn air fuel mixture screw in and back out as per service manual instructions, Then back out screw until it starts to chug a bit then turn slightly in, this will ensure your mixture is correct. Set idle after to spec. This should allow for correct start and correct running.

Glad you figured it out.