Confused about jetting


3 replies to this topic
  • hyperlite33

Posted December 29, 2007 - 04:18 PM

#1

Hey guys,
I tore the carb apart on my '01 426 and found it had a 42 pilot, 158 main, 72 starter jet and 3 turns out on the fuel screw. It has been a bear starting it and the plug always looks a little wet.
I went to the local shop to get a 38 pilot (like people at the same elevation say runs good) and the shop said they have never carried a 38pj and to go with a 42 pilot, 160 main on a stock bike...bigger with aftermarket pipes.
Does anyone have any starting points or opinions...I am at 5200' and have an FMF powerbomb/FMF powercore setup.

  • n8sz1

Posted January 01, 2008 - 01:34 PM

#2

I have the same bike, same year. I run a 40 pilot, 158 main at denver elevations, 155 in the mtns. and the stock starter jet. My bike starts and runs well. I play with the fuel screw almost everytime I ride, 2, 2 1/4, 2 1/2 turns out, depends on conditions that day. Hope this helps.

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  • 642MX

Posted January 01, 2008 - 01:50 PM

#3

Hey guys,
I tore the carb apart on my '01 426 and found it had a 42 pilot, 158 main, 72 starter jet and 3 turns out on the fuel screw. It has been a bear starting it and the plug always looks a little wet.
I went to the local shop to get a 38 pilot (like people at the same elevation say runs good) and the shop said they have never carried a 38pj and to go with a 42 pilot, 160 main on a stock bike...bigger with aftermarket pipes.
Does anyone have any starting points or opinions...I am at 5200' and have an FMF powerbomb/FMF powercore setup.


How did the bike run? Is the starting issue the only complaint?

  • hyperlite33

Posted January 04, 2008 - 10:38 AM

#4

I have the same bike, same year. I run a 40 pilot, 158 main at denver elevations, 155 in the mtns. and the stock starter jet. My bike starts and runs well. I play with the fuel screw almost everytime I ride, 2, 2 1/4, 2 1/2 turns out, depends on conditions that day. Hope this helps.

Thanks for the info...I am going to put mine back together today and try again with the same specs as you have there. Where do you live?

How did the bike run? Is the starting issue the only complaint?


The one time I did get to ride it, it was 30deg out...I let it warm up while I was getting ready and once riding it, it popped and backfired when letting off the gas bad. It seemed that a couple laps later it started running better, so I wrote it off as being bad gas...that's when my chain broke!:busted:
For the next couple weeks, I started it to get some stabil in it untill I could get a new chain to ride it with no problems. The next weekend after putting stabil in it, it would try and turn over but wouldn't fire!:banghead:





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