Air Cooled 250R problem

[CuRt]

I was out riding with my friends went down the road like a mile or so i lost all power and i shut it off let it cool down went back to his house checked the piston it looked fine it seems like its getting too hot. Anyone ever had a problem like this with their air cooled Rs? HELP :? .

Thanks
Curtis

[Trikeaholic]

needs a new top end, once it gets hot, and the cylinder expands, the worn rings cannot compensate for the expansion of the metal, thus you loose compression. It doesnt take much slop to lose compression. I think Im basically correct, but see what some others say.

[250rmanfmf]

Trikeaholic is right, time for a new topend

[atc86r]

been there done that. measure ring gap. stator needs to be checked also.

[CuRt]

Umm, how often do you have to rebuild em i just put a new piston in it less than a month ago when i start it when its hot or cold it still feels like the same compression, not easier to kick at all we were ridin for about a hour putting along in first through some new trails and mud too dont know if that would help at all.

Thanks
Curtis

[atc86r]

do you rejet and check plugs? very possible to ruin piston in 1 day. or have them last years. some places give bad bore jobs. whenever i get a new bore job i do compression test to get a baseline.

[TimSr]

Ill be that annoying guy that always disagrees! Normally the piston swells faster than your cylinder, and when your bore is shot, youll have more compression when its hot, which is what makes them so hard to start when theyre cold after the bore is shot. Also when a TriZ decides to stop flowing coolant, it will often swells the piston and siezes in the cylinder like a cork, but then will kick back over 10 minutes later when it cools down. I know this firsthand! If it is losing compression past the rings, it will be really obvious by the black streaks on the piston. The other possible place for a compression loss is the head gasket, and youll usually be able to spot that visually as well.

When it lost all power, did it lock up, or was it any harder to kick over? What did the plug look like at that time? Did you change the plug when it died? Did it recover and go back to normal after it cooled down? Are you certain that is actually a loss in power, and engine is actually bogging, and not a clutch slippage problem?

[BIGKAHUNA]

Sounds like you gotta bad chrome reverse throzzle rod...just my opinion but worth checking :-D .

[wanta250r]

What about an intake leak.

[CuRt]

Well when it died it just stopped, let it cool didn't even try to kick it over. I kicked it over after it cooled it was same amount of compression. The plug was fouled when i pulled it out after i got it home, it was running fine other than the plug sucked. Its jetted for 75-80 or so so i dont worry about that the plugs i run are BR9ES, its puzzling but rode it for 3 hours tonight and it ran great, beat my friends 84 R with Vforce reeds.030 over and a unknown pipe but he has little tires but didnt beat me to bad out of the hole either.

Thanks
Curtis

[Albino]

My 84 250r did the same thing 3 or 4 times after a fresh rebuild at the dealer,only it wouldn't start after I shut it off,until it cooled down that is.That was a year ago,no problems since. I just restored it,painted,polished and rebuilt every single part on it including the tranny,top-end and rear shock.Everthings done but the plastic(which is in good shape)have some sweet pics but can't post them here cuz I'm stupid.Maybe I could send them to somebody here to put them on for me?No?Yes? :oops:

[TimSr]

You might have had nothing more than a fouled plug. I wouldnt do anything unless the problem continues to duplicate itself. One problem could be the plug. I run 7's , I think stock is 8's, and the nine is one colder than stock. Another possibility is the main jet too big, and the needle set lean to compensate for it. Mine was like that when I got it. You could trail ride all day, but when you opend it up for a little bit, it would foul a plug. As I said, though, I wouldnt touch anything until youve established that its consistant, and I would pull and check your plug frequently to see what it looks like under different riding circumstances.

[Cokera]

My 84 250r did the same thing 3 or 4 times after a fresh rebuild at the dealer,only it wouldn't start after I shut it off,until it cooled down that is.That was a year ago,no problems since. I just restored it,painted,polished and rebuilt every single part on it including the tranny,top-end and rear shock.Everthings done but the plastic(which is in good shape)have some sweet pics but can't post them here cuz I'm stupid.Maybe I could send them to somebody here to put them on for me?No?Yes? :oops:

I'll host and post your pics anytime...

[Albino]

I attached the pictures to an email to you.Will that suffice or do I have to put them on your site.I am taking more tonite of the finished product.Thanx, Albino

[Cokera]

No Problem here are the pictures.