426 Backfiring/not starting


7 replies to this topic
  • Lunchbox8922

Posted December 26, 2004 - 06:52 PM

#1

My brother has been having some problems with his 2001 Yz426F, sometimes it just doesnt want to start, well kick it for long time and it wont start, and backfire alot while kicking. What could be the problem, we put a new spark plug in it and it started. but whats with the backfiring

  • bluerider450

Posted December 26, 2004 - 07:51 PM

#2

after you change the plug how long did it run ? there could be a little crbon build up . alittle popping is normal at least thats what i was told and have noticed
did the weather change alot recently because temperatures will throw the jetting off

  • BC3

Posted December 27, 2004 - 10:48 AM

#3

My 450 did that once when I had the IDLE turned up too high......piston position
is very important on most four strokes....I don't know how long you guys have had this bike....if your new to four strokes starting can be hard to get used to.
If you have had this bike for awhile and this is something that just started happening....you need to remove the tank and just start checking everything
Wire connecters, coil ground, intake manifold connection.Also try draining the
float bowl (water)


Hope this helps, BC :cry:

  • John_Lorenz

Posted December 27, 2004 - 11:30 AM

#4

My 450 did that once when I had the IDLE turned up too high......piston position
is very important on most four strokes....I don't know how long you guys have had this bike....if your new to four strokes starting can be hard to get used to.
If you have had this bike for awhile and this is something that just started happening....you need to remove the tank and just start checking everything
Wire connecters, coil ground, intake manifold connection.Also try draining the
float bowl (water)


Hope this helps, BC :cry:


Ditto What BC says, only tingk I will add is Clean the Carb, the air filter and check the Valve clearance.

A dirty carb will do this, but if your not used to starting a thumper, then you could be flooding it.

Follow this link, lern the drill, live the drill. love the drill -->The Starting Drill

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • bluerider450

Posted December 27, 2004 - 11:49 AM

#5

i like that starting drill iv had that enemy thing happen to me a few time i think because sometimes on a new plug ill be kicking it like crazy just after it was running flawless :cry:

  • Lunchbox8922

Posted December 27, 2004 - 05:15 PM

#6

Alright, thanks guys,ill tell him to look into checking it all over valve clearences etc.

  • SC 426

Posted December 31, 2004 - 06:33 AM

#7

I had the same problem with my 01 426. Initially, I had the valve clearance checked and 3 of 5 were out. This adjustment allowed me to start the bike. I continued having diffuculty. I was changing spark plugs every hour of riding time. I took the bottom of the carb apart and replaced needle, seat and float. The result was a perfect running 426. Once you get the carb set up correctly the bike rides 100% better. It will never stall now.

Good luck. This seems like a lot, but it is well worth it once the bike runs well. :cry:

Mark
01 426

  • Matt96xr6

Posted December 31, 2004 - 08:15 AM

#8

pull the hot start out. Especially if you have a DRD one. The plunger will get stuck and give you the symptoms you describe - no starting with the kick starter, back fire, but you can bump start it.





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