BannedCR500Riders.com

I have a street CR500, I have been using it for my work bike and it has been a blast. It has been idling perfectly at lights and starts perfect when choked cold and without choke once it has been warmed up. It has roughly 3 hours since it had a top end done on it. Yesterday after fueling it up with a 32:1 mix as usual, the bike barely wanted to idle and stalled once. It seems to rev a little and then almost die, rev back up then almost die again, but only a few hundred rpm differance, when it revs up it is going to its normal idle, from there it just drops down. I managed to make it the 1/2 mile to my house. This morning it was extremely hard to start, when it did start it ran for a minute and died, would not start again. I pulled the plug and it is wet and very oily. I swapped plugs and got it to fire up just like normal and everything seems normal except the bike smokes badly. Very very bad. It ran for about two minutes with a steady smoke screen behind it. I am used to the bike having a little smoke when cold and first started but after that not much smoke at all, if any. Any ideas what may be the problem? I havent ran it since I since I shut it off after the smoke screen. Any help or ideas would be appreciated, thanks.

FWIW, I once had an RM250 that wore out the primary drive side crank seal. The transmission oil entered the crankcase and got burnt to produce lots of white smoke. The engine immediately ran like shit like it was rich, but of course the jetting was un-changed.

I suspect the same, I chased the seal twice, and found out the center gasket was gone, check the trans oil level and IF YOU HAVE TO RUN IT for a day or 2, an irridium NGK plug will burn anything

X2 check your oil level.

look on the bright side though, if the seal was bad on the other side you would have leaned it out and squeeked that new piston.

Thanks, the seal was the problem. Hopefully I will have it all back together tomorrow afternoon. Just depends if I can find the new seal tomorrow.

Thanks again

tat

If the one behind the rotor goes it will create an air leak and the bike will race at idle. If the seals are the same age, it might be next.

Good point , Posh Spice....

i'm a few weeks late on this, but there is one other thing you might want to consider...

when you fuel up, do you turn the gas off, fill it up, then pour in the premix oil and shake the bike? if so, you could be doing the same thing i did a couple times when i was running a 250 2 stroke on the street. the premix oil doesn't immediatly and a little will get in the fuel petcock. it showed the exact same symptoms yours did, but when i pulled the fuel line and drained alittle out, it was really thick with premix oil. i drained the float bowl, cranked it up, and it ran like a top.

my new technique is to carry a small bottle (or buy a water bottle or something from whatever gas station you are at) with me so that i fill the tank up and leave a hint of room to account for oil, pull the fuel line and drain some into the bottle, pour whatever amount of oil i need to make the 32:1 ratio i run, shake the bottle, reconnect the fuel line (leave it turned off) and pour the fuel back in. shake the bike a bit like you normally would at a gas station, turn the fuel on, and ride a wheelie out of the parking lot, lol.

so far, the new technique hasn't failed me once. the way i used to do it messed me up a couple times trying to figure out what the shit was going on. anyways, try it and see if it works for you.