426 not starting after full rebuild help please!

6 replies to this topic
  • philsyzf426

Posted June 20, 2015 - 01:56 AM


hi guys ive had my full motor ripped down and replaced new everything part from transmission rebuild was done by local reputable company armstrongs engineering {www.ardracing.com} in uk. now everything back together tried to start it last night and just wont fire up. checked most common things fuel is fresh and flowing ok my spark is strong compression is spot on but still not firing. noticed this morning my fuel tap is leaking very small amount would this cause problems? obvoiusily I will renew the fuel tap on Monday. any input greatly apprieciated. everything is stock apart from hot rods piton arm and hinson clutch. super unleaded fuel, motul 5000 oil also motul coolant. and yes I know the start drill for these.

  • grayracer513

Posted June 20, 2015 - 07:13 AM


Did the carb sit on the bench for a time while the rebuild was going down?  Could easily have a blocked pilot jet.

  • philsyzf426

Posted June 20, 2015 - 01:15 PM


hi yes it was but I stripped it down and cleaned it all. have also done same today stripped it down cleaned it all and I noticed seals aren't long away from needing renewed so will order on Monday then when received will fit and update. if not that any other ideas? not sure what jets are what but ive seen 175, 72, and 42 im around 708 feet above sea level temps around 10-23 mostly daily commute but as much off roading as I fit in with family life thanks for allthe help will upload my rebuild when fully finished

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  • Yamirider378

Posted July 18, 2015 - 07:22 PM


Recheck your valve timing its vary easy to set them a tooth off making them vary hard to start. I know from having that happen to me. Kick the shit out of it with the choke on and see if the plugs getting fuel. Also not sure if the 426 has a hot start but if it dose check to be sure it's not open.

  • Super426

Posted July 25, 2015 - 01:04 AM


Mid body gasket is gone... Time for a new mid body gasket (they just became available!) or get a new carb for $900 ish

  • philsyzf426

Posted July 31, 2015 - 05:23 AM


thanks for all advice guys tore carb down and cleaned with hydraulic cleaner in rattle can and compressed air couldnt find midbody gaskets so had them made up by local company and boom its on the back wheel amazing power i love these machines. few minor tweeks still needed as and when work and family life allow. leaking slightly from cam cover and the inner clutch casing around 1cm in gasket. hopefully just gaskets moved as all is new. then startor mod wr for my lighting system as im going to use it on streets aswell as trails/tracks.

  • Super426

Posted July 31, 2015 - 08:43 AM


Glad to hear u got it running! Wheelie on buddy

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