Bump start only


5 replies to this topic
  • dougcrf

Posted June 19, 2015 - 05:59 AM

#1

I couldn't seem to find anything on my particular issue here so I figured I would ask for some advice on what to check next.

A little history would probably help.

2000 YZ426. Bought it a few months ago and to my knowledge it still had the stock piston and rings in it. Ran great and started first kick pretty much every time I ever rode it.

 

About a month ago or so I installed a brand new 35 watt stator to run a 35 watt headlight the old owner gave to me when I bought it. Ran great with that setup for a good few weeks and then I shut it off one day and it wouldn't start again. I put a new spark plug in it and still nothing. It seemed to me that it wasn't getting gas into the cylinder (plug was always dry after kicking the it like crazy)

 

I thought after finding out I could push the kick starter through the comp stroke (with a fair amount of force) without using the decomp lever, it was maybe a low compression issue..So my next step was check valve clearances. Checked the valves clearances and every single one of them were within spec. I decided to try to bump start it down the driveway and it fired right up instantly and ran just as good as it did since the day I bought it, but still would not start by using the kick starter at all.

 

So, thinking at this point, the piston rings are shot, I tore it down and checked the ring end gap on the comp ring and it was WAY out of spec... I put a new Wiseco piston kit in it and replaced the timing chain while I was in there.

 

Got the bike back together last night and it still would not start by kicking it. Rolled it down the driveway, bumped the decomp lever as I was clicking it into 1st gear and it fired right up like it did before I tore it down, so no change at all....

 

I'm not sure if maybe my new stator went weak on me? or if that can even happen? I do have blue spark when I check it from the plug, but I have to have all the lights out and very dark in the garage to see the spark. Never had an issue being able to see spark before on previous bikes I have owned over the years. I may put my original stator back in tonight and see what happens.

Thanks in advance for any ideas you guys can give me.

 


 



  • grayracer513

Posted June 19, 2015 - 06:12 AM

#2

Put your old, unmodified stator back in.  See if that fixes it. 

 

Rewound stock stators for YZF's with carbs are notoriously unreliable.  The problem is simple; there isn't enough to the stator in the first place to work with on a conversion to add lighting coils.  They were built to just cover the needs of the ignition system, and when you take half their capacity away to wind lighting coils on the stator frame, it leaves the remaining ignition side at a very marginal level.



  • dougcrf

Posted June 19, 2015 - 06:17 AM

#3

Put your old, unmodified stator back in.  See if that fixes it. 

 

Rewound stock stators for YZF's with carbs are notoriously unreliable.  The problem is simple; there isn't enough to the stator in the first place to work with on a conversion to add lighting coils.  They were built to just cover the needs of the ignition system, and when you take half their capacity away to wind lighting coils on the stator frame, it leaves the remaining ignition side at a very marginal level.

So would a newly purchased 35 watt stator such as what I installed from somewhere like trial tech or wherever still be considered a rewound stock stator then?



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  • grayracer513

Posted June 19, 2015 - 06:28 AM

#4

If it fits under the original YZ flywheel, it's a converted stator, whether it was new or used to begin with, and subject to the same thing.



  • dougcrf

Posted June 19, 2015 - 06:31 AM

#5

If it fits under the original YZ flywheel, it's a converted stator, whether it was new or used to begin with, and subject to the same thing.

 

Ahhh gotcha. I will throw the original stator back in tonight and post up my results.

Thanks so much.



  • dougcrf

Posted June 19, 2015 - 02:30 PM

#6

Put my factory stator back in and what do you know, started right up first kick with no choke..oh well, least it has a new top end now lol!

Thanks grayracer for the replies.





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