426 Cold Weather Problems!

7 replies to this topic
  • Eric_F

Posted December 25, 2004 - 06:16 AM


You guys have never failed me when I've had problems before, so here goes :cry:

My WR starts perfectly in warmer weather, but recently it has become a pain, taking anywhere from 10-30 kicks to start. ~60-80 degree weather it's the first kick and I'm in business. Once running, it seems a bit lean. Also, I have NEVER been able to start it with the choke on. I have always had to have it off, hold my hand near it, then when I kick and the engine fires I'll slowly pull on the choke to engage it, otherwise it just won't start. This has been the same ever since I got the bike. My first question is: Would the fuel screw play a part in this, or is it just due to cold weather, and what are the increments of adjustment for it? Secondly, what's up with the choke, and are there any adjustments for it? I'm debating on replacing the pilot jet, but I am unsure at this point.

Lastly, Have a merry Christmas everyone!

  • wildo

Posted December 25, 2004 - 11:03 AM


In very could wether near or belowe freising your bike will need more fuel to run as good. You may end up needing a rejet. You should have to pull the choke all they way out before kicking it to get it going. Try working the throtel to this will spray fuel dirctly into your intake without the engin spining over. This will normaly flood my 426 in warmer weather but any thing belowe 50 deg. F I have to do this. If the first two triks dont help try adj. your pilot out by 1/4 ture increaments. be sure your carb is clean before you go adj. on it.

  • Indy_WR450

Posted December 25, 2004 - 11:30 AM


72 starter jet for winter! 68 for fall / spring and 65 for summer! :cry:

  • Eric_F

Posted December 25, 2004 - 01:58 PM


Thanks, any recommendations on carb cleaning? Just use PJ1 cleaner?


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  • PumpkinHumper

Posted December 25, 2004 - 07:39 PM


72 starter jet for winter! 68 for fall / spring and 65 for summer! :cry:

Listen to Indy. He knows his jetting. The starter jet makes a HUGE differance in starting.

  • Eric_F

Posted December 26, 2004 - 03:59 AM


72 starter jet for winter! 68 for fall / spring and 65 for summer! :cry:

Thanks Indy.

Would the starter jet be causing the choke problem as well, or is that an entirely different issue?

  • PumpkinHumper

Posted December 26, 2004 - 07:27 AM


A friend of mine was telling me that he dosn't use the choke on his YZ426 in the summer when temps are 75-85deg. He says that he read in the manual that at these temps the manual says not to use it. Only use the choke in really cold temps. Not that this ever worked for me. I always have to use my choke.

The starter jet only afects the jetting when the choke is pulled on. When the choke is closed it has no affect after that. In the winter jetting gets lean cause cold air is ense air. More air = more gas. Going bigger on the starter jet richens the choke circuit.

I downloaded Garret Berg's jeting chart (somewere on TT's site) a while ago and inserted my stock jetting spec's. It then gives you a starting point for temp and altitude for the main, pilot, and needle. It worked very well for me. Along with a few tips from Indy.

In the winter when the temps are say 20 deg. I fo 1 size bigger on the main, and pilot. I go from a 65 starter to a 72. I also raise the needle 1 clip position. And adust the fuel screw.

  • Eric_F

Posted December 30, 2004 - 03:13 AM




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