HELP! My CR500 Failed...Seized Then No Comp???

[thestuz]

hey ride red, i had the same thing happen to my engine. after rebuild and just run in, i took it for some high speed runs.
it handled it well but dtarted to lose power and compression(felt like it was running out of fuel).
i pulled in the clutch and coasted to a stop. the bike had no compression. after 20 mins of tryin to kick start, i started pushing it home. as i was rolling down a hill, i put it in 3rd and tried a jump start in a vein hope and it fired straight to life like nothing happeded.
totally dumbfounded, i headed home to do some investigations. on the way home it happened again,but as soon as i felt it happening, i pulled in the clutch and pulled over. it ran shitty then fired up good.
i proceeded home ,took off the exhaust and looked in to see what looked similar to yours yet with less ring stick.

i pulled off the jug,honed the marks off the bore, smoothed off the marks on the piston and slapped it together. it still runs like a raped ape but down to 150psi.

my engine was run in
32-1 full synthetic castrol oil
ran fine before the seize
65/175 PJ / new reeds.
THE SEIZE HAPPENED AT "CONTINUOUS HIGH RPM WHEN THROTTLE WAS BACKED OFF" both times.

these days when i take it to top speed, i bring in the clutch and use the brakes rather than a long continuous decel.

my theory is these bikes dont handle high rpms well on decel without fat jetting.others will disagree.
good luuck with the rebuild. ive got a cheap 89.25mm wiseco goin cheap if your game

[gregrobo]

THE SEIZE HAPPENED AT "CONTINUOUS HIGH RPM WHEN THROTTLE WAS BACKED OFF" both times.
where does the top end lubrication come from
fuel and oil when you go full tits you get piston hot when you back off at full tits you have no oil and a hot piston and you have a siezed bike and you did it twice genius

[lewisclan]

use the kill switch hold it down and open the trottal open to cool the motor thats the only way I get motors to last in the dunes and I go through at leaset i every time we hit the sand dunes

[AlisoBob]

full synthetic castrol oil

WTF is that?



I suppose you buy 100% organic Diet Coke too?

[BigSteve]

full synthetic castrol oil

WTF is that?



I suppose you buy 100% organic Diet Coke too?

Well, since Castrol DOES offer mineral (2T), synthetic-blend (Actevo 2T, A747), and full synthetic (TTS) 2-stroke oils in the US, I'd guess he means FULL SYNTHETIC.

[AlisoBob]

I'm all hung over, I read that as CASTOR oil.....

.... my bad.... carry on.

I bet if he DID run castor, it wouldnt have stuck....

[thestuz]

THE SEIZE HAPPENED AT "CONTINUOUS HIGH RPM WHEN THROTTLE WAS BACKED OFF" both times.
where does the top end lubrication come from
fuel and oil when you go full tits you get piston hot when you back off at full tits you have no oil and a hot piston and you have a siezed bike and you did it twice genius

was stuck on a highway, had no choice. but whats wrong with travelling high rpms?
done it all my life on all my other 2stroke road bikes. gr, rd, rgvs and never had ant problems till i did it on the cr.

and yeah, "castrol fully synthetic 2 stroke oil" some oils here are only synthetic based. this oil is the best on the market in the way of dynthetics over here.

[BigSteve]

I'm all hung over, I read that as CASTOR oil.....

.... my bad.... carry on.

I bet if he DID run castor, it wouldnt have stuck....

Last ride I had three bottles, all with a couple oz. left in the bottom: gold cap Yamalube 2R, Mobil 1 2T, and Motul 800 2T...so I ran it on some "custom" premix.

[britincali]

927 is the only way to roll.

[AlisoBob]

927 is the only way to roll.

Your bike is living proof Brit..... They should put your fukin' face on the lable.

[britincali]

Cooked to the point of stalling and not restarting untill it cooled, (and running fine after) pinged on (hard) and hammered to shit in the dunes and both bikes take it

[gregrobo]

[quote="thestuz"][quote="gregrobo"]THE SEIZE HAPPENED AT "CONTINUOUS HIGH RPM WHEN THROTTLE WAS BACKED OFF" both times.

was stuck on a highway, had no choice. but whats wrong with travelling high rpms?
done it all my life on all my other 2stroke road bikes. gr, rd, rgvs and never had ant problems till i did it on the cr.

proberly nothing wrong with travelling at high revs but you have to remember that it is a large piston and that at high revs its going to get hot and when you back off it has no lube as mentioned pull in the clutch and give it some unburned fuel and oil for a few seconds is this on your steely if so there radiators arnt as efficient as the crfs or cr 250s so its probly running hotter as well

[thestuz]

yeah. that i have learnt now the hard way. but now i just try stay away from continuous high rpms, or bring in the clutch and coast to a stop/slower speed without starving the engine of fuel.

[AlisoBob]

We've held our 500's WFO clear across El Mirage ans Soggy dry lake....

Pinned WFO for at least a mile and a half.

Never had it stick.... or even thing about it.

I'm telling ya.... 927

[BigSteve]

We've held our 500's WFO clear across El Mirage ans Soggy dry lake....

Pinned WFO for at least a mile and a half.

Never had it stick.... or even thing about it.

I'm telling ya.... 927

No problem...even using up old Mobil 1

[gregrobo]

niether have i im running yamalube at the moment

[Roostius_Maximus]

I've dragged my lard thru mucky soft fields WFO for a mile in 5th that'd be way harder on things with that kinda load than on the dry, no squeakage here, nick tried to stick with me and was down on mainjet size, melted a dimple in the top of the piston and 2 hours later locked it up from debris that melted off the bottom of the piston and stuck, but kicked it loose and rode it home 6 miles, CAST!