Carb, bad gas, or a mix of both?


5 replies to this topic
  • tehehodi

Posted June 22, 2014 - 02:23 PM

#1

Bike:
2000 Yamaha yz426f
Stock exhaust, stock air filter.

I took it on its maiden voyage Saturday after plating and I know it kinda sputters at cruise/part throttle sometimes. Didn't think much of it but when I was on my way home from this short ride, it came to a sputtering/backfiring stop like it ran out of gas. I was riding up an incline and it had plenty of fuel in it. I tried numerous times to try and kick start it again after the incident and it would randomly start for like 5 seconds then backfire and then die and not start again. Towed it home and now it starts up just fine on the stand. Maybe I'm to short but I leaned it up against a crosswalk light and it still wouldn't start. (I don't normally have to do this but I thought that maybe I wasn't kicking hard enough)

Maybe a carb cleaning and new gas? This gas has been in it since winter. It idles fine, but I know when I try to go from a little bit of throttle to WOT or close to it would hesitate then kind of sputter then kick in like vtec or something.

What do you guys think?

  • walent215

Posted June 22, 2014 - 07:11 PM

#2

Bike:
2000 Yamaha yz426f
Stock exhaust, stock air filter.

I took it on its maiden voyage Saturday after plating and I know it kinda sputters at cruise/part throttle sometimes. Didn't think much of it but when I was on my way home from this short ride, it came to a sputtering/backfiring stop like it ran out of gas. I was riding up an incline and it had plenty of fuel in it. I tried numerous times to try and kick start it again after the incident and it would randomly start for like 5 seconds then backfire and then die and not start again. Towed it home and now it starts up just fine on the stand. Maybe I'm to short but I leaned it up against a crosswalk light and it still wouldn't start. (I don't normally have to do this but I thought that maybe I wasn't kicking hard enough)

Maybe a carb cleaning and new gas? This gas has been in it since winter. It idles fine, but I know when I try to go from a little bit of throttle to WOT or close to it would hesitate then kind of sputter then kick in like vtec or something.

What do you guys think?

could try cleaning the carb and installing new fuel but it sounds kind of like a bad coil if it only does it after it warms up then starts up fine after cooling down.



  • tehehodi

Posted June 22, 2014 - 07:35 PM

#3

Makes sense. Is there a way to test the coil via the manual?

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  • tehehodi

Posted June 22, 2014 - 08:38 PM

#4

Found the tests in the manual. I'll check that and report back.

  • tehehodi

Posted June 23, 2014 - 02:19 PM

#5

Thanks for the tip!

Just tested my coil. Resistance should be .20 - .30; it's reading .14

Tested the secondary coil, got no resistance at all.

I think I found the culprit.

Checking the CDI now.

  • walent215

Posted June 24, 2014 - 07:55 PM

#6

10-4, no problem.....I know the dealer tested mine and got some weird numbers that made it seem ok but was off a tad...glad you found the problem







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