ring index pin

FileStyle · Feb 22, 2012

anyone ever have one fall out of the ring groove and into the cylinder, killing it? working on a customers motor, they didnt know why it had stopped running. after I went through the usual things that cause a motor not to run, I removed the cylinder and found scars in the cylinder and noticed top index pin was gone! cleaned bottom end as best I could. when I get time tonight I 'am going to replace the cylinder and piston head and replace in bike to to see if it will start. I swept a magnet through the bottom and found a bunch of small particles, hopefully I got it all out! scratg

Al.Fisherman · Feb 22, 2012

Never had it happened to me, but have read a few posts where it happened.

2door · Feb 22, 2012

Yes. I got a customer returned engine from Dax that had the pin out and jambed in between the piston and the cylinder and seized the engine. Luckily the customer had not forced anything and there was no damage. I'm still running that engine today; it has about 1400 miles on it. The pins are steel and pressed into the aluminum pistons. They can come out.
Tom

FileStyle · Feb 23, 2012

I repaired the top end, replaced cylinder, piston and rings. had removed any foreign material, that I could see, prior to rebuild. re-installed motor into bike and it was a no-go!!! now I 'am thinking something is also wrong in the lower end. it will turn over and then stop , like the clutch is slipping, it could be, but I doubt it as it was working fine before. is it possible for the lower end to go bad? it feels like the crank spins freely. I did see a hot spot on the crank ( bluish tint) ???? Iam not sure. any advice out there? may have to buy just a lower end or just go ahead and buy new motor.

Al.Fisherman · Feb 23, 2012

FileStyle said:
I repaired the top end, replaced cylinder, piston and rings. had removed any foreign material, that I could see, prior to rebuild. re-installed motor into bike and it was a no-go!!! now I 'am thinking something is also wrong in the lower end. it will turn over and then stop , like the clutch is slipping, it could be, but I doubt it as it was working fine before. is it possible for the lower end to go bad? it feels like the crank spins freely. I did see a hot spot on the crank ( bluish tint) ???? Iam not sure. any advice out there? may have to buy just a lower end or just go ahead and buy new motor.

There may be other replies,but if I was testing to find your problem, I would start by making sure that the clutch and hub turn independently...(clutch disengaged). Now with a 14mm socket turn the nut on the magnet (I say clockwise so you don't loosen the nut), and see how it feels. You might need to remove the flywheel for a better feel. Spark plug and chain removed.
I had a member have basically the same problem, after numerous phone calls, and him doing as instructed, he found a head nut in the engine. He dropped it some how as he had only 3 that he could account for, the 4th in the case. Think, can you account for ALL of your parts?

Al.Fisherman · Feb 23, 2012

2door said:
Yes. I got a customer returned engine from Dax that had the pin out and jambed in between the piston and the cylinder and seized the engine. Luckily the customer had not forced anything and there was no damage. I'm still running that engine today; it has about 1400 miles on it. The pins are steel and pressed into the aluminum pistons. They can come out.
Tom

Did you repair the piston (reinserting the pin) or run without the pin?

2door · Feb 23, 2012

Al.Fisherman said:
Did you repair the piston (reinserting the pin) or run without the pin?

Ron,
It has over 1000 miles running without the alignment pin. My guess is that with only one ring able to turn that the times when both ring gaps are aligned is not enough to effect compression. I didn't trust trying to get the pin to stay in. If it came out once it could come out again. The other one was tight, no wiggles. Might have been the hole was drilled a wee bit oversize. I didn't even plug the hole.
Tom

FileStyle · Feb 23, 2012

yes, all my parts are accounted for, except all of the pin. I found some metal inside case (just very small shavings) I'am thinking from the cylinder and or piston. I replaced the piston head and cylinder, wrist pin and bearings.

Al.Fisherman · Feb 23, 2012

FileStyle said:
yes, all my parts are accounted for, except all of the pin. I found some metal inside case (just very small shavings) I'am thinking from the cylinder and or piston. I replaced the piston head and cylinder, wrist pin and bearings.

Did you match and measure parts, the placement of the wrist pin hole placement in the piston, the skirt could be hitting the crankshaft. .

Al.Fisherman · Feb 23, 2012

2door said:
Ron,
It has over 1000 miles running without the alignment pin. My guess is that with only one ring able to turn that the times when both ring gaps are aligned is not enough to effect compression. I didn't trust trying to get the pin to stay in. If it came out once it could come out again. The other one was tight, no wiggles. Might have been the hole was drilled a wee bit oversize. I didn't even plug the hole.
Tom

Tom
1,000+ miles that's good. The only thing that would concern me is the crappy ports, and that a ring could get hung up. I think that the pin placement has more to do with that.

2door · Feb 23, 2012

Al.Fisherman said:
Tom
1,000+ miles that's good. The only thing that would concern me is the crappy ports, and that a ring could get hung up. I think that the pin placement has more to do with that.

So far, so good, Ron. Keep your fingers crossed. Maybe it's that Opti-2 that's keeping things moving.

Tom

Rocksolidperson · Apr 19, 2012

i had mag end bearings fail on me, that was catastrophic D:

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