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how easy is it to hot seize a 2 stroke? should you let it idle before shutting it off

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I was riding with a friend, he was on a 01 cr250. we rode the gravel road for about 10 km to a friends house and as far as I know he wasnt redlining it, or keeping it WFO for too long. when we got there he shut the engine down. it went from being ridden kinda hard for 15 minutes, then shut right down... and we believe that caused it to heat sieze. ended up being a 350$ fix and we dont want another one of those.

we were told that after riding hard, we should let it idle to cool down for 2 minutes before we shut the engine off on 2 strokes only otherwise it can heat seize. is that true?

any other tips to help prevent seizing a 2 stroke?

we already know to let it idle for 5 minutes before we ride it for the first time of the day :)

thanks

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the damage occured BEFORE it was turned off... not BECAUSE it was turned off.. you have/had a tuning issue that caused the damage

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the damage occured BEFORE it was turned off... not BECAUSE it was turned off.. you have/had a tuning issue that caused the damage

hmm interesting.

this was supposed to be a new engine with 10 hours on it and a wiseco piston... when we took it apart it didnt look like a wiseco piston, hell it didnt even look like a new piston. it was the exhaust rings that were fried and the cylinder walls also got scratched or something.

a friend of ours who is a good mechanic said if we put it together it would still run, not the best though, is that true? we ordered a new piston and head anyways.

sorry im not very smart on this subject, im a 4 stroke guy. do you figure it was running wayyy too lean or what? should I check the sparkplug?

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what clearance was done with the wiseco ?

pictures always help .

i personally let all my bikes warm up and normalize before i shut them off , 2 minutes is a lot . i might do 1 minute if i am screwing around , for a cool down . i usually will only do this if the engine uses dissimilar metals like an aluminum head and steel cylinder or if it has forged pistons , especially wiseco's .

i think it happened while you were riding it not when you shut it off . its not a bad idea to look at your plug and see how its running . thats usually the first thing i look at .

i have never had a bike hot seize , two cold seizes but no hot seizes .

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Well one thing that is off is letting it idle will only let it get hotter or stay the same depending. You need air flow through the radiators and you get that from speed to cool it.

IM sure it has to do with to lean of main jet possible to lean of a gas/oil mixture. Its not all that easy to "hot sieze" one. Just tune it right and it will be rock solid usually. Just dont ride it 5th gear pegged for to long. Lol. i would actually see the rod and crank going before a properly warmed up and sized forged piston...

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any time you suspect a heat related issue, you must check all the basics... jetting, air leaks, crank seal, spark plug heat range, oil .... e.t.c.

I would love to see the parts.. but of course, the first step is a thorough look at the carb. Cleanliness and jetting... paying a good amount of attention to intake manifold damage or possible reed cage leaks.

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what clearance was done with the wiseco ?

pictures always help .

i personally let all my bikes warm up and normalize before i shut them off , 2 minutes is a lot . i might do 1 minute if i am screwing around , for a cool down . i usually will only do this if the engine uses dissimilar metals like an aluminum head and steel cylinder or if it has forged pistons , especially wiseco's .

i think it happened while you were riding it not when you shut it off . its not a bad idea to look at your plug and see how its running . thats usually the first thing i look at .

i have never had a bike hot seize , two cold seizes but no hot seizes .

im not too sure about the clearance. do wisecos have a special look to them that you could tell from far away, or is there some sort of marking on them? my friend says just by looking at it that its not wiseco..but im not 100% sure what kind it is. I will try to get some pictures tomorrow.

the bike started fine the first thing, ran fine on the way there. then it wouldnt kickstart. we needed to pullstart behind the truck every time (4 times) but once it started it ran fine. we even rode it home. then took it apart to see the exhaust side of the piston/rings all seized and stuff.

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im not too sure about the clearance. do wisecos have a special look to them that you could tell from far away, or is there some sort of marking on them? my friend says just by looking at it that its not wiseco..but im not 100% sure what kind it is. I will try to get some pictures tomorrow.

the bike started fine the first thing, ran fine on the way there. then it wouldnt kickstart. we needed to pullstart behind the truck every time (4 times) but once it started it ran fine. we even rode it home. then took it apart to see the exhaust side of the piston/rings all seized and stuff.

that means it got hot....really hot....

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that means it got hot....really hot....

so you figure it was ridden wwaayyyyyyy too hard?

or could it have been a tuning problem?

I am leaning towards it being ridden too hard...

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Probably jetting.

Whats your mix ratio?

uhhhh, thats another tough one.

it was a friend riding another friends bike.

the bike had a half tank, so we topped if off with the normal gas weve been using the whole time.

im not 100% sure about the ratio, its a friends bike and a friends gas. we used the bike/gas a few days before with absolutely no problems though.

I think it might have been ridden too hard on the gravel road. he was trying to keep up with my crf 450 most of the time, and he was also chewing in the snow in the ditch so who knows what really went wrong.

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uhhhh, thats another tough one.

it was a friend riding another friends bike.

the bike had a half tank, so we topped if off with the normal gas weve been using the whole time.

im not 100% sure about the ratio, its a friends bike and a friends gas. we used the bike/gas a few days before with absolutely no problems though.

I think it might have been ridden too hard on the gravel road. he was trying to keep up with my crf 450 most of the time, and he was also chewing in the snow in the ditch so who knows what really went wrong.

you mean topped it off with straight gas no premix??

That would be the problem!

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you mean topped it off with straight gas no premix??

That would be the problem!

lol no no, thats not what I meant.

I meant it was the normal premix that weve been using on the 2 strokes for a month now. they used the same gas 2 days before with no problems.

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ok good lol

try and find out his ratio and his jetting, i cant help you with the jetting though, i dont know what would be wrong/right

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yep... she seized all right.. and the consistent vertical scratches on the "non-seized" portions of the piston suggest it had some dirt for lunch at one time too.. this machine doesn't have a K&N filter by chance?... we see a lot of these in the shop when they get a gulp of sand

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yep... she seized all right.. and the consistent vertical scratches on the "non-seized" portions of the piston suggest it had some dirt for lunch at one time too.. this machine doesn't have a K&N filter by chance?... we see a lot of these in the shop when they get a gulp of sand

um, not 100% sure which air filter. I will check on that tomorrow (its a friends bike not mine) I think its twin air.

BUT the bike was ridden in the sand before we bought it. im pretty sure we put a new filter in, but who knows what happened.

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high temp... probable sand ingestion... it's for sure time to find a mechanic you trust and have a top to bottom look over... it would be a damn shame to put a bunch of new parts in it without determining the extent of the machines issues, and just having it eat the new parts. The advice on this site is generally good, but the internet is no substitute for a good set of experienced eyes and hands on-site... digging in and getting to the bottom of the problem.. good luck to you

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had a RM125 with a new wiseco piston and rings do that exact same thing. I ran 6th gear wide open a little too long on a back road when I started to loose power with an eventual rear tire lock up.

I had no dirt ingestion then, but I remember those pics looked just like what happened to mine. mind you this was 15 years ago...

Your buddy may have shut it down about the time it was loosing power. All i did was re-hone and toss a new piston and ring back in. I never did use Wiseco again even though it was my own fault.

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Ok, let me get this straight.

You don't know the jetting.

You don't know what oil or fuel is being used.

You don't know the pre-mix ratio

You don't know what piston you have.

You don't know when the the air-filter was serviced (if ever)

You don't know what type of filter you have or the oil used.

You see where I am going with this. :):banghead:

I think the problem isn't just with the bike. :banghead::foul:

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