2 stroke troubles.

Hello all I have a 2001 cr125 that i purchased a few years ago. I got it from a kid that said it had a new top end. It didnt by far. You could start and ride the bike for about 15 mins and it would die. I found the compression to be very low. I pulled the top end apart and found the cyl to be chipped in a spot on a port and the top of the piston to be beat with the ring stuck. I purchased a new wiseco top end piston kit. I had the piston coated by swain industries. I got the piston back from coating and sent the piston and cylinder to eric gorr to have replated to the piston diamater. I got it back checked the ring gap to be at .011 i called wiseco and they said that would be perfect and to leave it. I installed the cylinder on it coating it with some 2stroke non synthetic oil. I got it all assembled and put fresh 90 octane fuel mixed with valvoline non synthetic oil mixed to 32to1. I got the bike to fire up and ran at idle for about 4 mins. I was told by wiseco to do this 3 time to let it get warm and shut off to let cool. I tried to start it the second time i got it to kick over 2 time and it locked up. I cannot get it to turn over. I tried to do everything right i figured if it was an oiling issue i wouldnt have got it to run for 4 mins. I need help please could it possibly be in the bottom end? :thumbsup:

This was by far thee most information post I have ever read on here. It sounds like you know what you're doing. You pretty much did everything correct as putting the new piston in and checking the gaps and tolerances in the piston, ring, and cylinder. Sounds to me like your main bearings are gone. Pull the cylinder off again and find out whats causing it to lock up. If it kicked a few times I'm almosst positive that is either a lower rod bearing or main bearings. Did you install wrist pin, circlips, etc? Did it buy new ones? What did you torque the nuts at on the cyl and head.

I tried to do what i thought was best. I spent the money and wanted to have it correct. I checked the rod for up and down movement. It didnt have any. It did have some side to side movement and thought that would be ok. I did have a new wrist pin and new circlips they came in the piston kit. I live in new mexico if i do have to have the engine torn down will i be able to to that? Do i have to take it to a dealer? The only honda dealer near me usually treat me bad due to the bikes age. They dont have parts for it and always give me crap for it. I really dont have alot in the bike other than they piston, coating and cylinder plating. I really wanted to have a good bike and well it is being a pain. I did have it running for 4 mins with no problem. I downloaded the manual and appreciate the help thank you Robert Turnbull

take it apart and see what happened. eric gorr may have hosed the clearance. thats just one possibility, obviously theres other things that could have went wrong.

come to think of it does gorr even do plating or is he just a middle man ?

if you can show it was bad machine work he should be liable for the repair cost. or who ever did the replate.

did you try to take the plug out and see if it will kick over,

Did you drill the holes in the piston, or does a 125 not require that?

Eric gorr is in fact a middle man. He has melinium plate them is my understanding. I did pull the plug and it wouldnt kick over. I didnt drill holes because the new piston has holes drilled in it. I guess my next step is pull it apart and see what happened. If it is a lower end issue how hard is it to change the main bearings and install a wiseco crank and rod assembly?

Sounds like either a lower rod bearing or the crank bearings....but it could be a a circlip if it did not properly seat.. When you had the top end off......did you clean out the lower end really well? Also did you spin the rod and crank and try to feel any rough spots in the bearings?...spinning the rod by hand you can feel rough spots easily.

Eric gorr is in fact a middle man. He has melinium plate them is my understanding. I did pull the plug and it wouldnt kick over. I didnt drill holes because the new piston has holes drilled in it. I guess my next step is pull it apart and see what happened. If it is a lower end issue how hard is it to change the main bearings and install a wiseco crank and rod assembly?

Here are some videos that might help you make that decision. You can do a bottom end if you are careful and follow your manual really closely. I would assume from your first post that you are having bottom end problems. Just thank your good luck that it didn't run long enough for your bottom end to grenade the top end you just spent a bunch of money on.

Did the coating tighten the piston to cylinder wall clearance? you will know as soon as you pull the cylinder off.

Update. I pulled the top end apart and found it all to be ok. The piston was not stuck to the cylinder and the cylinder and piston look good. The issue is in fact in the bottom end. I rolled it over quite a few times before i put the piston and cylinder on it. I didnt feel any bad spots. I had it running 4 minuites and then shut her down. I let it get cool went 45 miles to eat pizza came back kicked it over 2 times then locked down. I dont know who to send the bottom end to to have it repaired? What do you think it would cost to have it done? I really dont want to just quit now i have too much time in it lol. Plus money

Have you ever worked on a clutch? I was wondering if it would help troubleshooting if you removed the clutch plates and tried rotating the crank...

And for what it's worth, we've got some decent repair people over here in Tucson.

I havent ever worked on a motorcycle clutch. I work as a diesel mechanic so i dont know that a motorcycle clutch would be to hard to work on. I havent pulled the clutch cover off. Its odd i kicked it over twice and then it just locked up. I dont know if it could be something in the kick starter or what? Thanks Robert

Update. I pulled the top end apart and found it all to be ok. The piston was not stuck to the cylinder and the cylinder and piston look good. The issue is in fact in the bottom end. I rolled it over quite a few times before i put the piston and cylinder on it. I didnt feel any bad spots. I had it running 4 minuites and then shut her down. I let it get cool went 45 miles to eat pizza came back kicked it over 2 times then locked down. I dont know who to send the bottom end to to have it repaired? What do you think it would cost to have it done? I really dont want to just quit now i have too much time in it lol. Plus money

Send it out to Pro Circuit. I think they will stand behind there work. My buddy did with good results.

I havent ever worked on a motorcycle clutch. I work as a diesel mechanic so i dont know that a motorcycle clutch would be to hard to work on. I havent pulled the clutch cover off. Its odd i kicked it over twice and then it just locked up. I dont know if it could be something in the kick starter or what? Thanks Robert

It's pretty easy to work on the clutch. Drain the oil, pull the cover, undo six bolts, pull out the plates. I'm curious if the crankshaft will rotate at all, either direction, after you pull the clutch. Pulling the clutch out will let you check the kickstart assembly as well...

The guy opens up the clutch at about 2 1/2 minutes into that first Rocky Mountain ATV video:

Frankly, if you are a diesel mechanic, you should be able to do the bottom end yourself. Just get a factory honda service manual, watch those video's I posted, and do it. If you really don't want to do it yourself, then I would recommend calling Eric Gorr again. I don't know what pro circuit's prices would be but IMO, Eric will be cheaper and you will get the same quality work. Everything I have seen with pro circuit is that they charge a premium for their service.

Sounds like the kid he bought it from beat the crap out of it. I'm wondering if there is just something stuck in the bottom end?

FYI for anyone reading this and looking at buying a used bike:

They all come with a "new top end". It's just that the seller always neglects to add "needed" to the end of that statement.

Sounds like the kid he bought it from beat the crap out of it. I'm wondering if there is just something stuck in the bottom end?

FYI for anyone reading this and looking at buying a used bike:

They all come with a "new top end". It's just that the seller always neglects to add "needed" to the end of that statement.

LOL! so true. Unless they have reciepts showing the work, it wasn't done. You have to factor the price of your engine rebuild into the price of the used bike. That is why the 4 stroke used bike market really sucks. Nothing like buying a ticking time bomb for $4k.

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