YZ 426 starting problems

4 replies to this topic
  • quaddad

Posted January 22, 2006 - 05:27 PM


ok we installed a hot cams auto decompression cam. this thing is still a bear to kick over. you can feel it at tdc and it is hard to kick past this, i thought the can was supposed to take care of this. i think we also have some jetting issues. this motor was just rebuilt with a je 13.5 to 1 2mm over piston. it has the cam and a ported head. the carb has a 158 main , havent checked the piolet yet oh and we are at sea level, we had to pull it off the other day to start it, when you kick it will backfire every now and then.........HELP


  • 642MX

Posted January 22, 2006 - 05:44 PM


Sounds like your timing is off. They take some force to kick, but it shouldn't be that hard. 158 main is to lean, I run a 165.

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  • kgilpin

Posted February 02, 2006 - 03:05 PM


Mark I am thinking of doing the cam change on my 02 YZ426f also. Why did you go with Hot cams in Lu of Yamaha's cam? I'm trying to find the best way
thanks KEG

  • quaddad

Posted February 02, 2006 - 04:19 PM


we used the hot cam, just figured it was easier. we got our starting problems fixed. the pilot screw was out way to far. ended up with a 190 main, i know that sounds way rich but the motor runs great. my son dont use the choke, gives it one shot on the throttle and it starts second kick. this thing is really strong. a buddy of ours has a new honda 450r quad and our 446 is way stronger. getting ready to put a few practices on the motor and then race it for the first time.


  • havens151

Posted June 12, 2006 - 11:41 AM


I am in a similar situation....what did you end up with on the pilot? 1 turn?

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