strange 82 250R thing happened today!

[wpginterceptor]

Riding my fairly new after break in 250R today, and while wide open in 5th.. held it wide open for a few seconds and backed off.. hit about 65 mph and as I was slowing down she locked up! rear wheels locked up and motor shut off instantly!
Yeah I know what your thinkin, and so was I.. as soon as I came to a stop I put it back in neutral and kicked it over and she fired and rode again all eve like nothing happened.. and lots of power as usual.. runnin 32-1 mix

Any ideas??

puzzled..

[C.J]

Son,,, pull that top end apart right now and make sure she didn't hear seize.

Could also be that a bearing stuck for a second.

[shortline10]

Brand new fresh motor on an air fooler needs a couple tanks a fuel run threw it before you run it HARD !!!!!
Back in the day we would break the new race motors in quick by running them till you could feel them get TIGHT ,,, after a couple cycles of that old school method it was race ready but mind you that isn't the correct way to beak a motor in just the fast way LOL .....




Riding my fairly new after break in 250R today, and while wide open in 5th.. held it wide open for a few seconds and backed off.. hit about 65 mph and as I was slowing down she locked up! rear wheels locked up and motor shut off instantly!
Yeah I know what your thinkin, and so was I.. as soon as I came to a stop I put it back in neutral and kicked it over and she fired and rode again all eve like nothing happened.. and lots of power as usual.. runnin 32-1 mix

Any ideas??

puzzled..

[wpginterceptor]

rode it for another hour and no issues.. after an hour CAR drive home from the riding area, I started it no problem and parked it in backyard.. IDK

AND YES I broke it in.. ran about 4-5 tanks thru it before I rode it hard! as I said..shes running fine now, like nothing happened

[jakep53]

how is your jetting?? I know a 2 stroke after running wot and you let off if you don't feather the throttle once you let off sometimes it can cause a it to lock up!

[El Camexican]

Sounds like you either have a smeared piston or a transmission that went together wrong. At the very least I'd remove the pipe and manifold to look and see what the piston skirts looks like. Being in Winterpeg you could have cold seized it as well.

[rdonald1979]

X2 on checking the piston skirts!

[nicker71]

Same thing happened to me on my 84r, wide open 5th gear and she locked up but was already free after it came to a stop. I checked compression afterwards and she was low, I re ringed and honed it and she was good

[wpginterceptor]

rode it today for couple hours and no issues...

[yaegerb]

Same thing happened to me on my 82 many years ago. Found out that my main jet was way to lean. I would do some WOT plug chops if I were you.

[wpginterceptor]

I ordered up a 34mm carb, ill wait for that before I mess with the jetting

[El Camexican]

rode it today for couple hours and no issues...

And you may never have another, but the odds that your rings are sealing as well as they should are slim.

[wpginterceptor]

either way, if rings are gone.. ill wait for lack of performance, either way cant do much now other than a rebuild, and then ill do it.. otherwise she runs and no issues!

[wpginterceptor]

Finally got around to compression test and its 105-110 tops....

[El Camexican]

Finally got around to compression test and its 105-110 tops....

If you trust the gauge and are using it properly it's time to tear the engine down.

[onformula1]

It seized but was not a permanent lock up, tear it down before you have more damage on your hands, check the plug for a lean condition, you probably need to up the main jet at least 2 sizes, El Camexican is correct on the cold seizer those trikes did not run hot in the summer in Phoenix, AZ, but they can run very cold in Canada, think about blocking of some of the cooling fins, this is a common practice in snow/ice racing. (Old number plate or other zip tied or mounted to the down tube)

If you ever run wide open for a long period on time, hold the throttle wide open an hit the kill switch once in awhile.

[wpginterceptor]

hmm, yeah.. she starts 1-2 kicks and still pulls the front wheel in third... but whatever ;(

[onformula1]

Barrow or rent a different compression gauge.

Only use a screw in type, Throttle wide open.

[sledcrazyinCT]

Have you pulled the pipe to look for scoring on piston or cylinder wall as suggested? 105 is rebuild time so maybe the gauge you used reads low, or you did not have it screwed in plug hole tight enough, or there is a bad o ring seal on the pressure gauge to give that low a reading.

Report back with findings of what piston looks like from exhaust side, and see if you can borrow another compression tester to double check your reading as already mentioned.

[wpginterceptor]

OKAY: update.. got another guage and hooked it up and got a hair over 140 on 250r.. hooked old guage and same old reading 105! which guage do I trust?

like I said she starts 2nd kick usually and I can pull the front tire off the ground in third! and ive got maybe 10 hours ride time on rebuild, 14 hours run time total including warm up break ins

[El Camexican]

Let me guess, one came from Princess Auto and the other from Canadian tire? In that case I'd trust the Canadian Tire gauge:lol:

Is 140 low for a fresh engine like yours? Yes! Is 105 bad? Hell yes! Will it run anyway? You already know the answer to that.

Look, no offense but you seem hell bent on not wanting to accept that you've got a damaged piston, so why not just stop asking questions that can't be answered without picking up some hand tools and go enjoy your trike? I've ridden things that cold seized for years afterwards and nothing went wrong. Still did wheelies too.

All your missing out on is first kick starts and 4th gear wheelies.:lol:

[wpginterceptor]

no im just curious as to if the thing is running good or what it should be!

I weigh almost 300 pounds and 4th gear wheelies are not ez with my weight! im sure a guy at 150 pounds could pull wheelies in 4th with it...
just trying to get to the bottom of what should be etc..

I should add the copper head gasket is prob not so good either and that could be an issue..

im at crossroads of doin another topend... what am I missing out on 15 psi lol
will it make that much of a diff?? if so then yes ill do it!

I do have a bigger carb sittin here to throw on it, just deciding what to do first ;)

[El Camexican]

Then the short answer is: pull the top end and inspect it.

I am 99.99% sure something is not right. You should get the piston and cylinder measured as well and check the ring gap again. It will run better with more compression.

[onformula1]

OK, just ride the living He!! out of it!

What's the worst that can happen??? You will own two ATC125r engines??? It could be worst.

[Scootertrash]

So you hammered on a new build (possibly without a proper break in), the motor locked up, the compression sucks, and you may have used a substandard head gasket. You come here asking for advice on what to do and get great advice from several members who have their fecal matter in a group when it comes to motors and you ignore it?


https://www.youtube.com/watch?v=UXoNE14U_zM


211700

[wpginterceptor]

broke it in more than properly!! spent a good amount of time and fuel breaking it in correctly!

and the compression doesn't suck.. it is a lil weak 140.. but they say 140-160 is normal! BUT yes it is a fairly fresh rebuild

anyways, im pulling it apart AGAIN this afternoon


I appreciate all the input I get on here.. im NEW to 2 strokes! BUT ASK ME ANYTHING ABOUT A 4 STROKE! ;) and makin power

Gonna pull the head off this afternoon and pull exhaust to check rings and piston.. bro in law figures its head gasket as head bolts are always loose :(

[nik0708]

Did you pull the clutch in when you shut the throttle????

[wpginterceptor]

didn't do a plug chop

[oscarmayer]

90* of all my 2-strokes I do when new run 180-220 psi even before break in. just an FYI....

[wpginterceptor]

checkd the rings, they look fine.. no scoring.. head bolts were a lil loose, they were torqued down to 23 pounds! retested with his guage 150 psi.. it has a 71MM piston in there, Im leavn it thanx

[El Camexican]

Guessing you just pulled the head and not the jug, right?

[wpginterceptor]

no we didn't..
looked thru the exhaust port and rings looked good, inspected cyl wall and no scoring!

I have a spare jug, and im gonna get that bored and honed for a rebuild, thus im leaving my current setup as is

[onformula1]

Guessing you just pulled the head and not the jug, right?

Nailed it!, its very nice you are trying to help, but I have a feeling its not working :lol: Throttle on!

Remember there are many factors in a seizure like-

Piston, rings, bore, wrist pin bearing, wrist pin, rod bearing, and X2 crank bearings, not to mention the cylinder base & cylinder head surfaces and gaskets.

[wpginterceptor]

Sounds like you either have a smeared piston or a transmission that went together wrong. At the very least I'd remove the pipe and manifold to look and see what the piston skirts looks like. Being in Winterpeg you could have cold seized it as well.

YUP did exactly that and all looks normal..

[wpginterceptor]

Guessing you just pulled the head and not the jug, right?

no, did just like you said

[El Camexican]

You pulled the manifold and look at the intake side of the piston?

[wpginterceptor]

yeah that's what you said originally.. now your saying let me guess didn't pull the jug! no im not gonna bother.. I have a spare jug ill send that away to get bored.. not gonna spend another 200$ on boring and honing a good jug.
Just gonna run it as is and slowly work on other jug and order a piston etc.

[El Camexican]

To be clear I suggested you take a look at either side of the piston BEFORE you said your compression was low. Then when you said you were getting a low reading I suggested you tear the top end off.

At this point, no offence, but I don't even know if you know how to take a proper compression reading. I do know that in cold weather and at less than 800' above sea level it should be over 140psi in a fresh engine like yours, but I'm not going to plead with you to take it apart and look at it closely. No big deal if you vent your cases with a rod, they made lots of ATC's.


So lets just assume that all internal combustion engines occasionally lock up for no reason :rolleyes: It happens on my new truck the first Monday of every month. Happy trails:beer

[wpginterceptor]

My first reading was with a Chinese (crap) compression guage.. I got 105 psi! ouch... but someone said by the sounds of my bike it didn't sound accurate as I said It has lots of power and starts 1-2 kicks max!

so I grab a guage from work and got a 141 psi! (rechecked it immediately with Chinese guage and still got 105 psi... then THREW IT IN GARBAGE)
thirdly (just to be accurate) I then used my brother in laws guage and got a 148 psi.. so im in the 140's! and have ABOUT 10 hours or less riding time on it..

hope that clears it up

my bro in laws guage is a MAC tools guage ;)


no offence taken... just wanted to know what it should be reading, being a fairly fresh rebuild.. and appears im in that boat! 140-160

and yes, something is not right.. it locked up in fifth gear as I was winding down from a top speed run.. I got up to about 65 mph, and let off... as I got to about 30 mph she shut off and locked up! I immediately thought the worst.. as I came to a stop I expected it to be locked up.. I then kicked her in the guts and fired up like nothing happened!!!

im guessing its something in the gearbox....

Ive had a snowmobile lock up on me once, and I couldn't start it till a couple hours later as she was locked up good. but the sled didn't run right after the lock up "Top end", THIS is different! bike hasn't changed.. im afraid to hit 5th gear though!

Ive never had the case apart, and previous owner told me he locked up 5th gear once and thought it was top end! hmmm was it..................