Starting problems 426F

4 replies to this topic
  • inline6er

Posted February 07, 2010 - 02:42 PM


My 426F has ran awesome since I got it. I just rejetted the carb since it was bogging alot. Here are the specs:
444cc kit (13.5:1 compression) Stage 2 hot cams
Main Jet: 170
Pilot Jet: 45
Fuel screw/Setting: 1 turn out
Needle/Position: middle clip
Filter: UNI
Pipe/muffler: FMF power bomb and powercore
Altitude Range: 100
Temp Range: 60 degrees

Once the bike starts it runs great, however if I stall its almost impossible to get it started. When I first rejetted it ran great, thats why I think this may be an ignition problem. Any Ideas of what to check would be very helpful.

  • 642MX

Posted February 07, 2010 - 04:40 PM


Is your fuel screw set properly?... I run a 42 pj with the fuel screw somewhere around 1 1/4 turns out.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • inline6er

Posted February 08, 2010 - 04:54 AM


Hmmm, you have a point. Before I put the 45 in, it would start really easy. 2 or 3 kicks even when cold. Thanks for the tip. Looks like our bikes have about the same mods, so I'll take your advice.

  • inline6er

Posted February 08, 2010 - 03:57 PM


OK, change the pilot to 42, set the fuel screw at 1 1/8 and no luck. I will try to mess with the ignition system and check the compression. Hopefully can find something cause I wanna ride next week.

  • s14 2510s

Posted February 09, 2010 - 04:01 AM


I run a 48 PJ in my 444 but its an ice bike.

Related Content


BIGBORE FOR YZ450F 2006? by Taattie94

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 5 replies

Wilson the Blue Privateer by jetfuel

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  50 replies

Megabomb Fitment by 288yz450

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply

1998 yz400f will not idle. by trolley

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  32 replies
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info

  • 0 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.