wr450f

[mr_plow]

hey guys just got myself a 04 wr450f.

so far i have replaced all the plastics, done an oil change, done abit of wiring and put on a 2010 headlight.

i have noticed it blows abit of white smoke on startup, it goes away eventually but then sometimes on full throttle it will blow a puff of smoke.

im booking it in the bike shop to do the cam chain + tensioner, fork seals, front brake rebuild, valves + shims and jetting check.

is there any other things i should have done while its in the shop?

 

[my67xr]

white smoke on startup could mean water in the cylinder, it turns into steam then evaporates
possibly cracked cylinder, leaking head gasket.....
have you pulled the spark plug out to check for rust on the earth electrode?

 

[liljohn_92]

Ooh wr450's are nice, look into cutting the grey wire for more timing and a yzf450 throttle stop so it goes to wot.
Have a look online there's a few virtually free mods to get them responding better.
Have fun mate!

 

[Hillz]

be prepared to use fuel... those things chew more than a 250 2 stroke

 

[GooseMan]

hey man thats what I'm getting (eventually). If the shop is taking it apart that far then I'd be getting the bore honed and new rings which might even get rid of your smoking prob. Also make sure they re-seat the valves in too.

So does it only smoke when put under load or just when revving high? White smoke is oil right? Check your breather hose on the crankcase is not blocked or kinked etc, get the bike shop to check valve stem seals, they could cause smoking, Pistons rings also cause this if they are worn out. Check the colour of the spark plug too for a reading.

 

[my67xr]

grey/blue smoke is oil, white is water
the spark plug will be carboned up if the rings are shot

 

[DHZ_XR8cing]

Could be valve stem rubbers. White and blue smoke do look fairly similar in small amounts

 

[mr_plow]

cheers guys, its a bloody great bike to ride!

the smoke is def white, just a startup when giving it a couple of revs then at wot. i pulled the spark plug and replaced it, the old one wasnt too bad, i will check the new one because ive done about 2 hrs riding since it went in.
i noticed that there was abit of oil coming out of the breather hose, but i think it was from the oil level being too high, i changed the oil to the right level and oil doesnt seem to come out now.

what is involved in the valve stem seals?

im hoping its not the rings, i just had to do them on my boxer 320 mini skid and it was expensive

I think the grey wire mod is for US bikes? seems to hit the limiter so has been de restricted

 

[GooseMan]

cheers craig for the correction, now I know.probly won't need new rings then but it wouldn't hurt to do a comp test and if its low then replacments would be great.

 

[mr_plow]

Results are in

Crank stuffed
Rod stuffed
Piston stuffed
Rings stuffed
Cylinder stuffed
Cam journals stuffed
Cams stuffed
Valves stuffed
Cylinder head stuffed.

Expensive repair bill

 

[my67xr]

ouch, that's gotta hurt
so would that be around $1500 for split and rebuild ?

get yourself a 2 stroke next time, a lot cheaper to fix, lol

 

[liljohn_92]

grey wire mod supposedly accesses the yz ignition map instead of the wr map have a looksee here http://www.yamaha-forum.net/forum/showthread.php?t=6703

 

[GooseMan]

Sorry to hear champ, it might almost be cheaper to buy another engine for it.