this could be bad.......

[perley03]

just rebulit my friends 03 pred
mods: new valves, springs, retainers, guides,
wiesco high compression piston and rings
wristpin
honed stock cylinder (spec's turned out ok)
all new gaskets
we started it, ran it for about 20 mins up and down the driveway just past 1/4 throttle never really revved it
changed oil
noticed making weird nocking noise on top end
reprimed oil system, knock went away
ran it for prob 2 hours trail riding never really beating on it
then took it up the road and got 77.8 mph on gps
came back to house road down the trail and it just stopped. tried to turn it over and nothing. went and got truck and loaded it on and took it home. i pulled the valve cover off and thought it was the cam chain but that came out ok. then pulled plug and found this......see pics ....the whole electrode is shoved up into the plug and the ground tip is completly gone....gonna tear off head later and find out where it went..

has anyone ever had this problem??? the dealer told me no further mods need to be done to install this piston. we ran 93 octane and the plug is a NGK DCPR8E
any advise????

[perley03]

ok...just took off head...here's the deal
evidently dropped an exhaust valve and it bounced around inside and had fun while doing it. the piston is junk now, but the cylinder seems to be fine. i dont know about the head though....it seems to be beat up pretty damm hard
gonna go back to the dealer and show him the destruction and ask him why he said the exhaust valves were fine.....cant wait to see the look on his face

[polaris bob]

My first guess would be that you did not install the valve keepers properly.

You might want to pull the whole motor down and check out the crank and rod, my bet is that they are the worse for wear after that little run in with the valve bouncing around in there for awhile.

[Bradracer18]

I agree with Bob.....better check everything over now. And....in my opinion, whoever put the valves in was at fault........and even more so....whoever rode it/stood near it when running should have heard the valve hitting I would have thought.


You also can have the wrong base gasket....which can be too thin and cause the piston to hit the valves.....I doubt it is this, but could be.

[perley03]

the thing was that it was the old exhaust valve that broke off....not the new intake valve. also when we were riding it there was no hard noise....there was probally 5-6 hrs on it and it started and rode fine. we already changed the oil and rechecked the valve clearance and everything was fine. like i said, i rode it up the road and got 77 on gps and then took it down the trail just barely going in second and then it just stopped. thats when it wouldnt turn over again. im taking out the piston today and bringing the whole top end up to the dealer and gonna get some answers. i priced a new head, without the jug and its $392 alone.

[perley03]

ok...
new head: $629.09
new cylinder: $369.02
new weisco piston kit: $138.56
that is over $1000 right there
now i found on ebay....a complete top end kit...including new head, cylinder, piston, for $150...its a 440cc kit
is it worth it???

[polaris bob]

LOL So which story are we to believe???



Quote…”we started it, ran it for about 20 min’s up and down the driveway just past 1/4 throttle never really revved it
changed oil
noticed making weird knocking noise on top end
re-primed oil system, knock went away
ran it for prob 2 hours trail riding never really beating on it
then took it up the road and got 77.8 mph on gps
came back to house road down the trail and it just stopped.”


Quote…”the thing was that it was the old exhaust valve that broke off....not the new intake valve. Also when we were riding it there was no hard noise....there was probably 5-6 hrs on it and it started and rode fine. We already changed the oil and rechecked the valve clearance and everything was fine. Like I said, I rode it up the road and got 77 on gps and then took it down the trail just barely going in second and then it just stopped. That’s when it wouldn’t turn over again.”

[MAaudioX10]

Originally posted by perley03
ok...
new head: $629.09
new cylinder: $369.02
new weisco piston kit: $138.56
that is over $1000 right there
now i found on ebay....a complete top end kit...including new head, cylinder, piston, for $150...its a 440cc kit
is it worth it???

The 440 kit hp output is equal to a stock 500. Nothing special. That is a cheap price. The heads are all the same, it is just the jug and piston that is different.

Do some research and see if you can get that jug machined and sleeved for a 558.