is my replacement engine a wr or a yz 426?


8 replies to this topic
  • 6fiddy

Posted June 07, 2006 - 11:59 AM

#1

I blew up my wr 426 engine. connecting rod separated from the piston and split thru the block like a freakin lazer beam. Anyway, I bought a used engine off e-bay. The guy I bought it from says he never started it. He was going to drop it in a quad and lost interest. The guy HE bought it from races supermoto and recently retired and sold him the engine for 1900.00 It has definately been modified. 444 big bore Wiseco Piston, Web cams, ported and polished head and the carb has some huge jets in it. Anyway, I pulled the side-cover off to look things over and found it has a yz stator and not a wr stator. Does anyone know how to check the serial #'s to determine what ive got here? If it is a yz, how easy would it be to put the wr gears from the blown engine into the fresh one? Thanks people...

  • byggd

Posted June 07, 2006 - 12:19 PM

#2

I blew up my wr 426 engine. connecting rod separated from the piston and split thru the block like a freakin lazer beam. Anyway, I bought a used engine off e-bay. The guy I bought it from says he never started it. He was going to drop it in a quad and lost interest. The guy HE bought it from races supermoto and recently retired and sold him the engine for 1900.00 It has definately been modified. 444 big bore Wiseco Piston, Web cams, ported and polished head and the carb has some huge jets in it. Anyway, I pulled the side-cover off to look things over and found it has a yz stator and not a wr stator. Does anyone know how to check the serial #'s to determine what ive got here? If it is a yz, how easy would it be to put the wr gears from the blown engine into the fresh one? Thanks people...

The manual might say but isn't the YZ a 4 speed and the WR a 5 speed?
:applause:

  • Numskull

Posted June 07, 2006 - 04:38 PM

#3

my clymer says there all 5 speed constant mess.

Alot of work to stick another tranny in her :applause: I think I would first put the motor in to see how she runs and play with your sproket ratio to obtain your gearing desires. Good luck and let us know how she runs :D

  • 6fiddy

Posted June 08, 2006 - 05:08 AM

#4

You wont believe this... the swingarm bolt that holds the engine/swingarm/frame together is to large to fit thru the case of the engine. Im thinking that the gear case/block is off a 250 or 400. Even tho the cylinder is clearly a 426. :prof: :D :applause: Im almost ready for a freakin UZI and shoot up the place! :prof: I can get my $$ back I think.

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  • GCannon

Posted June 08, 2006 - 08:38 AM

#5

Easy there 6fiddy. you have some work ahead of you but this still has the potential to become a great bike in the end but you will need some patience. :D sounds like you got some good expensive parts in the deal. However it may also indicate that whoever owned the engine may have been a serious racer to make that financial commitment. With this in mind you must consider a complete tear down and inspection ( Read Freshen Up) of the new motor. If you just slap it in and go (half ass) then you will have nothing but trouble. Do the in frame mock up and find any other interference issues like chain line, motor mounting ,pipe clearance make a list of issues. then remove the motor for tear down while the motor is apart fix the case swing arm bolt issue (line ream at local machine shop) this is now an excellent time to change stater, change transmission gears , check piston and ring, check cylinder head and replace valve seals, replace timing chain, replace main bearings, replace/inspect clutch plates. You now have a huge pile of parts to pick from at the other end of the garage. :applause:

Don't get in a rush. When it is all done you will be the proudest papa in town (of your new baby) :prof:

I would also like to say that i am sorry you engine exploded in the first place :prof:

  • 6fiddy

Posted June 08, 2006 - 09:07 AM

#6

Good advice...I dropped off the case collars this morning at a machine shop to have them wallowed out 1/16th in. to fit correctly. The clutch looks fine, the stator, well I dont know if its as easy as pulling it off and putting on the new engine, I wasnt even using it antway cause I took off my lights last year. The seller assured me the engine was fresh from the crank up. I took all the jets out of the carb that came w/ engine and put them in my carb cause it is Much cleaner and looks much newer. Im gonna have the YAM shop look it over B4 I drop in in like you said. Thanks for the optimism :applause: I Needed That :prof:

Easy there 6fiddy. you have some work ahead of you but this still has the potential to become a great bike in the end but you will need some patience. :prof: sounds like you got some good expensive parts in the deal. However it may also indicate that whoever owned the engine may have been a serious racer to make that financial commitment. With this in mind you must consider a complete tear down and inspection ( Read Freshen Up) of the new motor. If you just slap it in and go (half ass) then you will have nothing but trouble. Do the in frame mock up and find any other interference issues like chain line, motor mounting ,pipe clearance make a list of issues. then remove the motor for tear down while the motor is apart fix the case swing arm bolt issue (line ream at local machine shop) this is now an excellent time to change stater, change transmission gears , check piston and ring, check cylinder head and replace valve seals, replace timing chain, replace main bearings, replace/inspect clutch plates. You now have a huge pile of parts to pick from at the other end of the garage. :D

Don't get in a rush. When it is all done you will be the proudest papa in town (of your new baby) :bonk:

I would also like to say that i am sorry you engine exploded in the first place :lol:



  • R_Little

Posted June 08, 2006 - 10:31 AM

#7

You wont believe this... the swingarm bolt that holds the engine/swingarm/frame together is to large to fit thru the case of the engine. Im thinking that the gear case/block is off a 250 or 400. Even tho the cylinder is clearly a 426. :prof: :D :applause: Im almost ready for a freakin UZI and shoot up the place! :prof: I can get my $$ back I think.


That is because the bike you have is a '02 and the motor came out of an earlier model bike. They increased the swingarm pivot diameter in '02 1mm.

Just pull the spacers out of your old motor and press them into the "new" motor.

BTW the 444 motor rips but is harder to kick start...I have one in my bike

  • 6fiddy

Posted June 08, 2006 - 11:25 AM

#8

The spacers outside diameter are larger on the 02 so what I did was I had a machine shop cut the inside diameter on the collars to match the 02. worked like a charm. so far.... What jetting are you using and what type fuel do you use. I bought some cam2 100 octane. Any tips for me? Im all ears if you can assist me. Thanks Bud!!

That is because the bike you have is a '02 and the motor came out of an earlier model bike. They increased the swingarm pivot diameter in '02 1mm.

Just pull the spacers out of your old motor and press them into the "new" motor.

BTW the 444 motor rips but is harder to kick start...I have one in my bike



  • GCannon

Posted June 08, 2006 - 01:00 PM

#9

Good Luck let us know how it ends up.




 
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