WR400/yz426 engine cobbling


3 replies to this topic
  • sch1sm

Posted June 15, 2013 - 04:18 PM

#1

alright new guy here, dont tar and feather me if this is on here already i tried searching it out to no avail.
i currently have a 2000 y426 and have just aquired a WR400 bottom end, crank and tranny complete.
now my perfect world dream is to take the yz top end and the e-line stator off the bike and transfer it to the new WR lower. but is it really that easy? or do i have a multitude of things to change/update to make the change?
would i be better off ganking the gears out of the lower and stickign them in the existing one?

  • MaxPower

Posted June 17, 2013 - 08:23 AM

#2

Either spin your exhaust cam on the WR one tooth or install a cam from a 05 yz450 to get the same benefit plus auto compression release and you will be 90% of what you are looking for



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  • sch1sm

Posted June 17, 2013 - 06:52 PM

#3

Either spin your exhaust cam on the WR one tooth or install a cam from a 05 yz450 to get the same benefit plus auto compression release and you will be 90% of what you are looking for

so i should be able to reuse the flywheel, cylinder and piston in the new lower?
i dont do heaps of engine work (hvac/boiler mechanic) but i do know a good amount about engines, that being said i dont want to get to a $500 hangup wit hit exploded all over the garage.
i thought i saw something about the con-rods being mismatched? if so do i have ot get a WR piston and see if the cylinder can be honed?

  • R_Little

Posted August 19, 2013 - 12:12 PM

#4

so i should be able to reuse the flywheel, cylinder and piston in the new lower?
i dont do heaps of engine work (hvac/boiler mechanic) but i do know a good amount about engines, that being said i dont want to get to a $500 hangup wit hit exploded all over the garage.
i thought i saw something about the con-rods being mismatched? if so do i have ot get a WR piston and see if the cylinder can be honed?

 

Correct...you need a 426 rod for a 426 piston in a 400 bottom end....the 426 small end and wrist pin is bigger.

 

You might be able to use a 450 piston with a 426 barrel on a stock 400 bottom end.






 
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