Post pics of your CR's

[Raybo]

Upon further review, it seems that my motor will only turn from the bottom of the stroke (intake) to the top of the stroke (combustion) and then will not move any further. Is my motor locked up??? Could there be something stuck in my crankshaft? Maybe the crankshaft bearing is bad??? Help!!!

Are you saying that when you turn it over by hand, you can only turn it so far and then it locks up? When was the last time the motor was running? Did it ever run after the kickstarter started giving you problems?

[RyanHelderCR250]

Are you saying that when you turn it over by hand, you can only turn it so far and then it locks up? When was the last time the motor was running? Did it ever run after the kickstarter started giving you problems?

Yes. After it locks up you can turn it the other direction until a certain point where it locks up again. Last time the motor ran was about 3 weeks ago. The kick starter problem started yesterday when I was working on the bike.

[Raybo]

Yes. After it locks up you can turn it the other direction until a certain point where it locks up again. Last time the motor ran was about 3 weeks ago. The kick starter problem started yesterday when I was working on the bike.

Sounds like there is something inside the engine, to me. If you didn't hear any noises and the engine ran fine the last time you had it running, maybe you did something while you were working on it, dropped something inside or didn't tighten something enough, etc.. If the bike was running and then it wouldn't turn over the next time you tried to start it, then something happened after it was running, and that usually doesn't just happen on it's own unless the bike is running at the time.

What were you working on after the last time it was running, and up until the kickstarter problem began?

[RyanHelderCR250]

Yes. After it locks up you can turn it the other direction until a certain point where it locks up again. Last time the motor ran was about 3 weeks ago. The kick starter problem started yesterday when I was working on the bike.

Also, about 3 weeks ago I was riding and my engine started acting up. The first time I noticed it I was sitting there taking a short break letting the bike idle when there was a strange noise that sounded like something was bouncing around inside the motor. When it made the noise the bike cut off. I started it again and listened for the noise. When the noise happened again the bike tried to cut off again so I gave it a short blip of throttle. She kept running normally. So I took the bike back to my house. I asked a buddy of mine what he thought. He has been riding and fixing bike for 35 years. He said I should do a top end rebuild. Well while waiting for my parts I took off the right side crankcase cover just to be sure it wasn't something inside there (there wasn't). When I put the cover back on and torqued everything and tried to kick it slowly to make sure everything lined up. I kicked it slowly and then that's when the situation I described started happening.

[Raybo]

Also, about 3 weeks ago I was riding and my engine started acting up. The first time I noticed it I was sitting there taking a short break letting the bike idle when there was a strange noise that sounded like something was bouncing around inside the motor. When it made the noise the bike cut off. I started it again and listened for the noise. When the noise happened again the bike tried to cut off again so I gave it a short blip of throttle. She kept running normally. So I took the bike back to my house. I asked a buddy of mine what he thought. He has been riding and fixing bike for 35 years. He said I should do a top end rebuild. Well while waiting for my parts I took off the right side crankcase cover just to be sure it wasn't something inside there (there wasn't). When I put the cover back on and torqued everything and tried to kick it slowly to make sure everything lined up. I kicked it slowly and then that's when the situation I described started happening.

Ok, that sounds like something broke, cracked, or came loose inside the engine while it was running. Could be the top end, or bottom. Since you already have top end parts coming, do that first and look for loose metal pieces inside. Make sure the top end has nothing loose inside it before doing that and buttoning it up. It could be a broken ring, or something in the connection of the rod and piston, causing it to lock up, etc.. If you find nothing abnormal inside the top end, and after doing that maintenance, and the engine still won't turn over completely by hand, then the bottom end is about the only thing left that could cause it.

When you open it up for the top end work, you probably will see something obvious causing the piston to not move up and down correctly. Hopefully that's all it is, and the top end job fixes it

[RyanHelderCR250]

Ok, that sounds like something broke, cracked, or came loose inside the engine while it was running. Could be the top end, or bottom. Since you already have top end parts coming, do that first and look for loose metal pieces inside. Make sure the top end has nothing loose inside it before doing that and buttoning it up. It could be a broken ring, or something in the connection of the rod and piston, causing it to lock up, etc.. If you find nothing abnormal inside the top end, and after doing that maintenance, and the engine still won't turn over completely by hand, then the bottom end is about the only thing left that could cause it.

When you open it up for the top end work, you probably will see something obvious causing the piston to not move up and down correctly. Hopefully that's all it is, and the top end job fixes it

That's what I'm hoping for now. I haven't torn the top end off yet. If there is a loose piece of metal or something bouncing around inside, that would also most likely mean some cylinder work, correct?

[Raybo]

That's what I'm hoping for now. I haven't torn the top end off yet. If there is a loose piece of metal or something bouncing around inside, that would also most likely mean some cylinder work, correct?

Maybe, maybe not, depends on what it is, if it's just a cracked ring maybe not, you'll just have to look at the cylinder to see if it's damaged. Might be able to just hone it a bit. Or the piece may have fallen down in the bottom and may not have affected the cylinder at all, just make sure you get it out, and check for damage.

[RyanHelderCR250]

Maybe, maybe not, depends on what it is, if it's just a cracked ring maybe not, you'll just have to look at the cylinder to see if it's damaged. Might be able to just hone it a bit. Or the piece may have fallen down in the bottom and may not have affected the cylinder at all, just make sure you get it out, and check for damage.

Will do. Thanks! And I'll let you know what happens!

[LincolnTWilliams]

Just picked this up. First two stroke in awhile. Guy did an awesome job building it. Unfortunately he had an injury and had to free up some cash... Well fortunately for me I guess. I haven't had a chance to ride it much but coming of a CRF250, it feels awesome!!!

[RyanHelderCR250]

Just picked this up. First two stroke in awhile. Guy did an awesome job building it. Unfortunately he had an injury and had to free up some cash... Well fortunately for me I guess. I haven't had a chance to ride it much but coming of a CRF250, it feels awesome!!!

📎ImageUploadedByThumper Talk1405700138.634537.jpg📎ImageUploadedByThumper Talk1405700149.899819.jpg

I like those graphics... What kit is that??

[RyanHelderCR250]

Will do. Thanks! And I'll let you know what happens!

So we tore down the motor yesterday... And found the culprit

Luckily, the crank and rod are fine. I'm replacing the top end (obviously) as well as the main bearings and seals on the crank. Grand total through cheapcycleparts.com and motosport.com: $350 ($50 for overnight shipping...

Edited July 19, 2014 by RyanHelderCR250

[Raybo]

That looks ugly! Are you replacing the crank main bearings and seals because you think that was the reason for the piston problem? I just don't understand why you're going to the trouble and expense to get into the crank bearings and seals. Aren't you going to have to split the cases to get to that stuff? I've never replaced main bearings or seals so I'm out of my element there.

What does the cylinder look like? By the looks of the piston I would expect some fairly deep scarring of the cylinder wall. Also, did you find and get that missing piece of piston skirt out of the engine?

[LincolnTWilliams]

I like those graphics... What kit is that??

Thanks. It's a throttle jockey kit.

[RyanHelderCR250]

That looks ugly! Are you replacing the crank main bearings and seals because you think that was the reason for the piston problem? I just don't understand why you're going to the trouble and expense to get into the crank bearings and seals. Aren't you going to have to split the cases to get to that stuff? I've never replaced main bearings or seals so I'm out of my element there.

What does the cylinder look like? By the looks of the piston I would expect some fairly deep scarring of the cylinder wall. Also, did you find and get that missing piece of piston skirt out of the engine?

A buddy of mine is helping me with this whole project a it is my first time. We tore down the whole engine because we looked down into the bottom and there were tiny pieces of the piston everywhere! Had to clean it all out somehow... Anyways he checked out the bearings and he said we should replace them. New seals, bearings, complete gasket kit, OEM top end kit are all being shipped as I type. The cylinder (surprisingly) had ZERO scars in it! I have no idea how, but the cylinder is in almost perfect condition. We are having it honed out just to be safe. Everything is supposed to be going back together on Tuesday.

[Raybo]

A buddy of mine is helping me with this whole project a it is my first time. We tore down the whole engine because we looked down into the bottom and there were tiny pieces of the piston everywhere! Had to clean it all out somehow... Anyways he checked out the bearings and he said we should replace them. New seals, bearings, complete gasket kit, OEM top end kit are all being shipped as I type. The cylinder (surprisingly) had ZERO scars in it! I have no idea how, but the cylinder is in almost perfect condition. We are having it honed out just to be safe. Everything is supposed to be going back together on Tuesday.

Ok, that makes more sense. I'm glad to hear that you have some experienced help for this "expanded" project. When I saw the bite out of that piston I figured there might be multiple pieces of metal down inside the engine. Those broken metal pieces are likely what was locking your engine up.

Keep us informed!

[RyanHelderCR250]

Yeah that's what we found. Literally countless metal fragments in the bottom

[BillDirt1]

Street legal 1987 CR500. Don't know why I sold it !

[Raybo]

Street legal 1987 CR500. Don't know why I sold it !

Cool! How did you manage to get it licensed? Don't think that is possible where I live, but would be nice to be able to jump on my '97 CR125 and run to the store!

[cr125pro]

[n16ht5]

My 88 CR250 in summer mode

 

winter mode