WR400 -> 426 Conversion Jetting

2 replies to this topic
  • gearb0x

Posted May 27, 2007 - 05:36 PM



Ive just finished building a Wr400 with a 426 crankshaft/cyl/jug & hot cams.

I was wondering what other people who have done use for their jetting. I jsut quizzed a moto shop and they seem to think that (assuming my Wr400 is jetted stock) my setup will be fine

Any Thoughts?

I might just take it for a spin rev it out, pull the plug and have a look


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  • mall0y

Posted June 16, 2007 - 02:04 PM


I know for a fact that the stock setup wont be fine. I just finished up the same exact project (minus the hotcams). Went to start it for the first time and it took atleast 20 kicks... when i did get it started it would pop really bad on decelleration. I put 2 and 2 together and realized that this meant that the bike is running pretty lean. I'm researching stock jet sizes now (i'm new to the 4 stroke bike world) so i can play around with it tomorrow. I will let you know what i find.

  • gearb0x

Posted June 17, 2007 - 12:34 AM


strange, mines running PERFECT. Its using lots of juice though, i presume because its a fresh rebuild.

I'm doing a 800k ride this weekend, so if the fuel consumptions not better after that ill play with the jetting, otherwise its perfect


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