Pieces of piston ring?

6385 Views 81 Replies 19 Participants Last post by David C., Apr 2, 2015

David C.

Discussion Starter · Feb 11, 2015

We removed the crankcase cover where the clutch is to see if we could figure out where the knocking was coming from, this is what we found in there; (not the penny of course, that is there for size reference.)

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magentaman

· #21 · Feb 12, 2015

I think I would start by pulling the clutch apart. And you are right, the pieces and the knock can be separate issues.

The pieces in question could be left over from a previous parts failure that some lazy mechanic didn't fish out.

David C.

Discussion Starter · #22 · Feb 12, 2015

magentaman said:
I think I would start by pulling the clutch apart.

Really? Did you see the picture in post #13? The clutch LOOKS ok, but I'm a machinist, not a mechanic...

magentaman said:
The pieces in question could be left over from a previous parts failure that some lazy mechanic didn't fish out.

Interesting theory, I believe that you are probably correct. Someone probably replaced the clutch at some point, and left some of the swarf in there.

I'mKOHD

· #23 · Feb 13, 2015

David C. said:
Really? Did you see the picture in post #13? The clutch LOOKS ok, but I'm a machinist, not a mechanic...

Interesting theory, I believe that you are probably correct. Someone probably replaced the clutch at some point, and left some of the swarf in there.

Agreed, but I would question if something was missed or incorrectly put together in the clutch assy. Looking at the parts fiche for your bike it shows a judder spring seat and a judder spring ( as mentioned in an earlier post). Looking at the manual for my VT1100C2 does not show these parts used for my application.
I would remove the clutch and take it apart and inspect parts and compare to an online fiche for your bike, or your manual when you get it.
Inquiring minds want to know what you find/or not.

magentaman

· #24 · Feb 13, 2015

David C. said:
Really? Did you see the picture in post #13? The clutch LOOKS ok, but I'm a machinist, not a mechanic...

I did, but you can't see the whole picture with the clutch pack assembled

Furball Zen

· #25 · Feb 13, 2015

Scaredofmyownshadow said:
Doesnt look like piston rings to me. If those pieces were whole, the diameter looks way too small to be rings. I was thinking snap ring also. Does a magnet stick to them?

Having built a few motors, they do look like part of the compression ring. What Is a Compression Ring? (with picture)

OP, have you checked the compression?

David C.

Discussion Starter · #26 · Feb 13, 2015

Furball Zen said:
Having built a few motors, they do look like part of the compression ring. What Is a Compression Ring? (with picture)

OP, have you checked the compression?

No, I have not checked the compression yet.
I have the good fortune to be surrounded by mechanics here. My next door neighbor employs four of them, all have become friends of mine, but not one of them does motorcycles, just cars, diesels, forklifts, and heavy equipment. The head honcho thinks that it can't be compression ring because of the damage that the pieces would cause going from cylinder to crankcase. (His opinion, of course.)

One guy that works for me is a machinist and a mechanic, and he has some motorcycle experience. I have some experience myself, although I consider myself a machinist, I do have some experience as a mechanic, both cars and motorcycles.

We have all heard the stories of the difficulty of replacing the timing chains during re-assembly, but I think that with the shop manual, we could probably get it done.
I will check the compression next.

Furball Zen

· #27 · Feb 13, 2015

Being a 'mechanic' and not having 'motorcycle' experience means nothing. Just because youre not an expert on a v-twin doesnt mean you cant work on them. True, i they were pieces of the top rings its hard for them to get into the crankcase past the rest of the piston, but it doesnt mean they arent and werent left there after a rebuild or something.

I also could be wrong at my guess. But in most non start cases were fuel and spark are verified, compression should be the first thing to check. Just dont forget to leave one of the plugs in the cyl when you check it

David C.

Discussion Starter · #28 · Feb 14, 2015

Furball Zen said:
Being a 'mechanic' and not having 'motorcycle' experience means nothing. Just because youre not an expert on a v-twin doesnt mean you cant work on them. True, i they were pieces of the top rings its hard for them to get into the crankcase past the rest of the piston, but it doesnt mean they arent and werent left there after a rebuild or something.

I also could be wrong at my guess. But in most non start cases were fuel and spark are verified, compression should be the first thing to check. Just dont forget to leave one of the plugs in the cyl when you check it

Two of the guys that are helping me are Daniel and Randy. Daniel said that I don't need to test the compression if it's running. It will be at least 100 psi or it wouldn't run. Randy says, not a bad idea to check it anyway, it's free. So I borrowed Daniel's compression tester. Problem is that it's 14mm and the plugs are 12mm so it won't screw in there. So I call around, surely someone has an adaptor, Oreilley's doesn't have it, Advance doesn't have it, Auto zone has one, but I would have to buy the whole compression tester for $40. I only have $500 in the bike so far and I want to get it going without forking out a whole lot of cash. I could make an adaptor, after all, I have a full blown machine shop right here.

Bottom line is today is Saturday, and the Clymer shop manual is supposed to arrive on Tuesday. I have to try to be patient. The weather down here in Georgia is good enough to ride right now, and I have an itchy throttle hand!

Also, I found out yesterday that Randy has motorcycle experience. He said that a friend of his had an 1100 Gold Wing and the guy tried to rebuild it. He put the timing chain on wrong and bent some of the valves. He became frustrated and GAVE the bike to Randy. Randy bought new valves and re-worked the rebuild, had it running within 2 days.

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David C.

Discussion Starter · #29 · Feb 14, 2015

Compression tester adaptor side 1

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David C.

Discussion Starter · #30 · Feb 14, 2015

Compression Tester Adaptor side 2

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David C.

Discussion Starter · #31 · Feb 14, 2015

Of course, I didn't have the tap (m14 x 1.25) so I had to single point the thread, but no big deal. I now am the owner of a compression tester adaptor m12 to m14.

Checked the compression, 70 PSI in both cylinders. Is that good or bad?

"Captain D"

· #32 · Feb 14, 2015

You GO BOY!!!

I hafta make my own tools too, from time to time...

skullcap

· #33 · Feb 14, 2015

Maybe squirt a little oil in the cylinder and open the throttle and test again. Or open the throttle and test dry, and then try some oil. Just a little bit.

skullcap

· #34 · Feb 14, 2015

Oh, and did you make an o-ring seal on the engine side?

David C.

Discussion Starter · #35 · Feb 14, 2015

skullcap said:
Oh, and did you make an o-ring seal on the engine side?

Yes, I basically copied the existing sample only with the smaller thread, and I happened to have the right o-ring. Does 70PSI sound low to you?

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Scared

· #36 · Feb 14, 2015

Do as suggested and put a little squirt of oil in the cylinder and do the test again. Did you have the trottle wide open during your first test? If not, start again, wide open trottle. Dry, then again wet. Compare results.

"Captain D"

· #37 · Feb 14, 2015 (Edited)

"I dunno but I been told" >

Yes, you aughtta follow instructions in the tester box...

70 sounds a little low, BUT they should both be nearly the same...
It`ll run on low compression
I dunno?

Good Luck,
Dennis

EDIT
I read a lot!
tractor, motorcycle, Ranchero forums and Flywheelers too

All suggest WOT and a teaspoon of oil

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XApacheDoc

· #38 · Feb 14, 2015 (Edited)

The difference in readings between a dry cylinder compression test and a wet cylinder test will let you know where the problem lies. If your compression goes up with the teaspoon of oil in it then you have a problem with the rings if it stays the same it is most likely the valves. I don't know what your bike's compression should be but mine is supposed to be 192 +or- 14 PSI. So i am pretty sure 70 is low.

Scared

· #39 · Feb 14, 2015

XApacheDoc said:
The difference in readings between a dry cylinder compression test and a wet cylinder test will let you know where the problem lies. If your compression goes up with the teaspoon of oil in it then you have a problem with the rings if it stays the same it is most likely the valves. I don't know what your bike's compression should be but mine is supposed to be 192 +or- 14 PSI. So i am pretty sure 70 is low.

Yeah but if those are pieces of rings laying in the bottom of the pan, a wet test may have the same results as a dry test. 70 is pretty low.

With the plug removed can you put that cylinder at bottom dead center and with a bore scope or small flashlight, inspect the cylinder walls for scoring? Maybe take both plugs out and shine a flashlight through one and look into the other. If pieces of ring broke off and made it all the way past the piston, there will be some scoring. That would help verify the ring problem.

David C.

Discussion Starter · #40 · Feb 14, 2015

skullcap said:
Maybe squirt a little oil in the cylinder and open the throttle and test again. Or open the throttle and test dry, and then try some oil. Just a little bit.

70 PSI (both cylinders) dry with throttle open, 120 psi front, 125 PSI rear cylinder with oil and throttle open. Either way, I have to tear this thing apart and see what the slap (knock?) is. I suspect a bad piston arm, but we shall see.

How about parts? Is there an OEM source for pistons and piston arms? What about cylinders? (I know that Honda no longer carries anything for this model. (It's 1985 VT500C)

I have a friend just up the road that does coatings on pistons, and I have a cylinder hone here.

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