This is a serious problem

Tyler6357

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Mar 15, 2012
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Santa Barbara, CA
Still think it’s a problem with the reduction gears.
Still, it might be a good idea to take the clutch plate off, check that the clutch pads are in good and don't have grease on them, and then set the flower nut correctly. Just make positive that when you pull in the clutch the wheel spins freely and when you release it the wheel is tight without slipping.
 

Hzryder

New Member
May 16, 2021
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Update so weird thing the new piston kept freezing by the intake port I got curious and threw the old piston in and it worked so I took it out again and out new rings on it and now it seems to be running normal I took a 5 mile ride yesterday and it did great
 
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Tyler6357

Well-Known Member
Mar 15, 2012
1,286
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Santa Barbara, CA
Update so weird thing the new piston kept freezing by the intake port I got curious and threw the old piston in and it worked so I took it out again and out new rings on it and now it seems to be running normal I took a 5 mile ride yesterday and it did great
Sweet!! It always feels nicer riding after you've fixed it. Oh, don't forget, with new rings you might go a little heavy on your oil/gas mix for a tank or two because you have to break in the rings again.
 
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Denis Zen

Active Member
Mar 30, 2021
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Riding up highway 101 at sunset
One thing you might want to try is a "listening scope or rod" . Place a long piece of solid metal against the motor and place your thumb over the end and place your ear against your thumb. The sound should get louder the closer you get to the problem.

I know its not precise but it will get you closer. Good luck homie!
 

Larry Trotter

Active Member
Nov 26, 2017
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I can’t imagine rings catching on an intake port to the extent of locking up the engine without causing extreme massive damage to the piston, rings and cylinder. I really doubt that was the problem.
 

Tyler6357

Well-Known Member
Mar 15, 2012
1,286
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Santa Barbara, CA
I can’t imagine rings catching on an intake port to the extent of locking up the engine without causing extreme massive damage to the piston, rings and cylinder. I really doubt that was the problem.
I agree with you, it's impossible for a ring to lock up the back wheel without breaking, but it stopped happening after he put new rings on, so....I'm at a loss to explain it. Usually when the back wheel locks up it's a clutch issue.
 

mapbike

Well-Known Member
Mar 14, 2010
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chain, wheel, clutch has been my guess since I first seen this thread.. wheel said to be good to go.

Maybe I read it wrong, but it seems I remember it being said multiple time that engine would die when the clutch levwr was pulled in.... scratching my head in that each time I seen it or at least thats what I think I seen...lol

Definitely have never seen or experienced an engine lock up with out destroying pr at least causing significant famage to something and these little HT engines are definitely not durable enough in the upper assembly to take multiple lock up with shelling out the Jug, rings or piston or all the above at the same time.

Im also very curious about what issue was actually causing the problem amd hope OP lets is know at some point.
 

Larry Trotter

Active Member
Nov 26, 2017
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I am sure you are right. Earlier in the post he said without the cylinder on there was a click every revolution of the crank. I am thinking something got into the reduction gears and is causing grief. If it is a chunk of something it may have finally fallen out and cleared things up. Probably a mystery to never be solved.

Definitely an engine lockup due to rings catching in any port would cause mostly total distraction of lots of top end parts.
 
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wrench

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Aug 20, 2019
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Update so weird thing the new piston kept freezing by the intake port I got curious and threw the old piston in and it worked so I took it out again and out new rings on it and now it seems to be running normal I took a 5 mile ride yesterday and it did great
Kinda sounds like a Soft Seize
If the new piston to cylinder side wall clearance (PTCSWC) is too tight You will get a soft seize from thermal expansion. PTCSW clearance min is .003"

A soft seize usually causes no damage to the cyl boar just some minor scuffing.
You will see scuffing in the cyl boar and on the piston if this was happening.

When the engine heats up it will soft seize when the engine cools down it will start back up and run normal until it heats up again.
 

Thomasp

New Member
Dec 15, 2021
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I'm dealing with the same thing and my piston is definitely getting stuck. I have had to lube the jug several times to get the two apart. It is a month and a half old and it is shot. I have a new kit that should be here on Wednesday next week. Also the store I bought it from on eBay refunded my money yesterday. . I can get short bursts out of it the past couple days. Coasting downhill and bursting up hill. Better than pedaling but it still sucks because if it wasn't seizing like it is. It's a pretty kick ass motor.
 
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Thomasp

New Member
Dec 15, 2021
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I just got through the ring comment. I'm ordering a new piston set to try it out for mine. Mine is also locking up on the intake side. It makes me wonder if one or even both of the rings are getting past the pin or something. One of the pins looked like it was barely blocking the ring groove.
 
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Hzryder

New Member
May 16, 2021
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I just got through the ring comment. I'm ordering a new piston set to try it out for mine. Mine is also locking up on the intake side. It makes me wonder if one or even both of the rings are getting past the pin or something. One of the pins looked like it was barely blocking the ring groove.
I did find out that the piston wasn’t the right one if you run your finger down the cylinder you’ll feel a slight incline my piston must’ve misformed somehow and didn’t work yd100 piston and jug won’t fit I tried that the wrist pins are two different sizes yd100 10mm bt100 12mm my fix was putting new rings on my old piston and it worked great I’d go to trdmoto for a rebuild kit because bbr and everywhere else are out of stock however you can find the pistons on eBay or use an ms chainsaw piston
 
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Hzryder

New Member
May 16, 2021
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Please do let us know what you find.
Hey Larry i die find the problem I ran my finger down the cylinder and felt a slight incline type deal the bbr piston would catch that incline and the stock piston didn’t I tried multiple bbr pistons and they all got stuck so that was the initial problem
 
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