Bike Won't start when hot


8 replies to this topic
  • the.brains

Posted March 12, 2016 - 11:28 PM

#1

Hey guys

So I'm really at my wits end with my 2013 yz450f .

I changed my spark plug to the cr8eix, replaced my idle/hot start plunger and cleaned the throttle body.

I fired her up 2-3 kicks and warmer her up before killing. I geared up and tried to start, nothing. I felt a kick back 1 or 2 times after kicking through the stroke.

I then push started her to get going, but she would not start any other way throughout the entire day.

What old be wrong? What am I missing out?

  • Slow and Jerky

Posted March 13, 2016 - 05:25 AM

#2

I would check the valve clearances. You said you cleaned the throttle body, did you pull the the injector and clean it (using a battery so the plunger was moving)?



  • the.brains

Posted March 13, 2016 - 07:33 AM

#3

Hi slow.

Valve clearances were done 8 hours ago.

No I didn't do this. I didn't remove the injector, although I did run injector cleaner through it in my previous tank of fuel.

Could you advise me on how to connect to a battery and what to clean with ?

  • Slow and Jerky

Posted March 13, 2016 - 07:42 AM

#4

I would still check the clearances, the thing about the valves on these is that as they wear they get tighter and eventually you lose enough compression that it makes it so it won't start with the  kick starter but bump starts fine.

 

Here is a video for cleaning an injector

 

 

It's not a bike injector but the same principle. You will need a torx bit with the little hole in the end, the head on the screw is one of those security heads, I don't recall the size, but it's they are nothing special.



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  • the.brains

Posted March 13, 2016 - 08:54 AM

#5

Thanks so much Slow.

I will check my valve clearances and clean my injector. Will report back once completed.

  • Krannie McKranface

Posted March 13, 2016 - 05:18 PM

#6

I would add that you need more pressure to get a good cleaning

 

Add a rubber tube to the input to the injector

Fill it up with solvent

Insert an tapered airhose tip

Clamp all in place

Now cycle the injector with 90psi of solvent behind it

Spray the injector into a white rag, and stop when no more color comes out



  • the.brains

Posted March 15, 2016 - 11:12 AM

#7

So I finally got time to strip her down. Set her to TDC and immediately I noticed she was 1 tooth off on the exhaust cam. I set her correctly and checked valve clearances- all perfectly within range. I didn't go any further down to clean the injector.

I bolted everything, 2 kick she fired up, let her run for 10 minutes of so to warm up. Killed and she fired back up first kick so everything seems to be resolved... Yay :) thanks very much everubody

  • Slow and Jerky

Posted March 15, 2016 - 11:17 AM

#8

So I finally got time to strip her down. Set her to TDC and immediately I noticed she was 1 tooth off on the exhaust cam. I set her correctly and checked valve clearances- all perfectly within range. I didn't go any further down to clean the injector.

I bolted everything, 2 kick she fired up, let her run for 10 minutes of so to warm up. Killed and she fired back up first kick so everything seems to be resolved... Yay :) thanks very much everubody

 

That's good to hear, but you should seriously consider replacing your timing chain, if it jumped once it will do it again and could be much more catastrophic.



  • the.brains

Posted March 15, 2016 - 11:28 AM

#9

Hey slow.

I replaced the chain < 10 hours ago.

I think the timing was wrong when it received the bike back from the shop.





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