Can Anyone Help with This???

[Monkeyman]

You know, $30 and a phone call will get you some coasters (reed valve eliminator plates) from Chuckster. I just got mine and will install them some time this winter. If nothing else, that would eliminate the reed valves as a problem.

[chuckster131]

Interesting Tom,
I do notice that the throttle body is louder with the open intake verses the stock and maybe that is what you are hearing on acceleration. Can't think of anything else that would give off the noise, as long as you have the plug in the reed valve hose it is like having the coasters installed.
Keep us posted

[tomm]

Next clue in the puzzle . . .

I just did a compression test. Spec is 50 - 85 PSI. Rear cylinder checks in at 80. Started at about 50 and climbed up to 80 from there. Front cylinder reads 160 PSI. First stroke read 90 and it climbed up to 160 over the next 3 or 4 strokes. Did the check twice just to make sure I wasn't seeing things.

Also, the right plug on the front cylinder is pretty carboned up. The left plug looks reasonable. Both rear plugs look reasonable.

The manual says high compression is caused by:
1) Carbon buildup possibly due to damaged valve stem, valve guide, stem oil seal and/or damaged piston oil rings. May be white exhaust smoke.
2) Incorrect cylinder head gasket thickness.
3) Damaged or missing compression release cam spring.
4) Compression release weights do not move smoothly.

2 is out. So that leaves 1, 3 or 4, unless someone knows of other causes. Wondering now if this problem has absolutely nothing to do with the intake and cam chain extenders. Just really bad timing.

Time for some research on high compression.

Unless someone can suggest something else to check, it looks like I'll be starting to take apart the front cylinder head in the near future. Has anyone else done that? Would appreciate any insights into the process, like do I really have to remove the engine, or is there enough room to get the top end off with the engine in the frame.

[trosco]

I'd say that you broke the front cylinder tensioner when trying to force the install. So the front cylinder tensioner puts no tension on the cam chain. Now when you start the motor and while it is runing the noise is that cam chain whacking the spark plug housing and the reason you have no power is the cam timing is off on that front cylinder. The puffs of outbound air at the throttle body is your intake valve still being open when the compression stroke starts. If you haven't already bent a valve keep running the motor and things will get far enough out of time that you'll snap a valve or punch a hole in that front piston. Don't know where you got your compression specs but 50-85 psi is not right for a healthy cylinder either,

[tomm]

Originally Posted by trosco

I'd say that you broke the front cylinder tensioner when trying to force the install. So the front cylinder tensioner puts no tension on the cam chain. Now when you start the motor and while it is runing the noise is that cam chain whacking the spark plug housing and the reason you have no power is the cam timing is off on that front cylinder. The puffs of outbound air at the throttle body is your intake valve still being open when the compression stroke starts. If you haven't already bent a valve keep running the motor and things will get far enough out of time that you'll snap a valve or punch a hole in that front piston. Don't know where you got your compression specs but 50-85 psi is not right for a healthy cylinder either,

What you say makes a lot of sense, except for one thing. I just pulled the front tensioner and it looks fine. Both springs are intact, and the rod is extended just above the body of the tensioner. Before I added the extenders, it was about 3/16 recessed (5 clicks left). So with the extenders, that would be about right. But everything else adds up.

What is odd though is I stuck a finger in the tensioner opening and can feel the cam chain guide. It is recessed the same distance as the extender, and doesn't seem to have any give to it when I push gently on it. But it seems to be bent right where the tensioner hits it, and it seems to end right above that with a sharp edge. The picture in the manual shows it being a smooth curve and extending quite a bit above the tensioner with a rounded end. I think I have a snapped cam chain guide although I can't figure out how that would have happened. And I know the tensioner was fully recessed when I installed it.

I'll pull the spark plug tube to see if there are any marks on it, as soon as I can locate a 27 mm hex wrench. There shouldn't be any given that I added the extenders before I ran out travel, but I bet I'll find some.

Also, the compression spec is on page 5-32 of the service manual, although I agree that it is a low spec. I would normally think 120 or so.

[ponch]

Originally Posted by tomm

What you say makes a lot of sense, except for one thing. I just pulled the front tensioner and it looks fine. Both springs are intact, and the rod is extended just above the body of the tensioner. Before I added the extenders, it was about 3/16 recessed (5 clicks left). So with the extenders, that would be about right. But everything else adds up.

What is odd though is I stuck a finger in the tensioner opening and can feel the cam chain guide. It is recessed the same distance as the extender, and doesn't seem to have any give to it when I push gently on it. But it seems to be bent right where the tensioner hits it, and it seems to end right above that with a sharp edge. The picture in the manual shows it being a smooth curve and extending quite a bit above the tensioner with a rounded end. I think I have a snapped cam chain guide although I can't figure out how that would have happened. And I know the tensioner was fully recessed when I installed it.

I'll pull the spark plug tube to see if there are any marks on it, as soon as I can locate a 27 mm hex wrench. There shouldn't be any given that I added the extenders before I ran out travel, but I bet I'll find some.

Also, the compression spec is on page 5-32 of the service manual, although I agree that it is a low spec. I would normally think 120 or so.

Why don't you have Mac look at it? You two live in the same state and I am sure he wouldn't mind.

On the other hand, may be someone put a potato in one of the tail pipes.

[tomm]

Originally Posted by ponch

Why don't you have Mac look at it? You two live in the same state and I am sure he wouldn't mind.

On the other hand, may be someone put a potato in one of the tail pipes.

Good idea. I just sent him a PM, although I understand he hasn't been around much lately. Hopefully, he'll check in and be open to helping me.

And negative on the potato. That would be Maine, not New Hampster. And I already checked the exhaust for one of those little critters.

[ponch]

Originally Posted by tomm

Good idea. I just sent him a PM, although I understand he hasn't been around much lately. Hopefully, he'll check in and be open to helping me.

And negative on the potato. That would be Maine, not New Hampster. And I already checked the exhaust for one of those little critters.

I am sure you read the manual, but there is a caution when working on the camchain extenders:

This is a non-return type cam chain tensioner. The push rod does not return to its original position once it moves out to take up camshaft chain slack. Observe all the rules listed below:
When removing the tensioner, do not take out the mounting bolts only halfway. Retightening the mounting bolts from this position could damage the tensioner and the camshaft chain. Once the bolts are loosened, the tensioner must be removed and reset as described in “Camshaft Chain Ten- sioner Installation”.
Do not turn over the crankshaft while the tensioner is removed. This could upset the cam chain timing, and damage the valves.

I'll PM you.

[tomm]

Originally Posted by ponch

I am sure you read the manual, but there is a caution when working on the camchain extenders:

Yup, read that caution multiple times. Followed the directions to the letter.

Going to go out and buy one of those lighted telescoping mirrors today to see if I can look around inside, but I'm pretty sure I know what I'll find based on feeling around in there.

Only thing I can think of is the guide is supposed to be hinged on the bottom and free on the top, and somehow, the top got pulled away from the chain and then got stuck on something. When I pushed in on the tensioner to install it, the guide didn't pivot against the chain like it should have but instead creased in the middle, either immediately or as soon as I started the engine. The rest is history.

I have no explanation for how or why this would have happened because like I said, I read the instructions multiple times and followed them exactly.

But figures. Hundreds of folks have probably done this mod before me without problems. Doesn't sound like anyone has ever experienced this.

[ringadingh]

Id take a look at your #3 & #4 causes for high compression, before you start tearing into the motor too deep.

[tomm]

Originally Posted by ringadingh

Id take a look at your #3 & #4 causes for high compression, before you start tearing into the motor too deep.

I agree. Got all winter to sort this out. At least I have something definitive to work with now, meaning the high compression. And that I have to start looking into that top end on the front jug.

Everything else is just a guess.

[tomm]

Originally Posted by trosco

I'd say that you broke the front cylinder tensioner when trying to force the install. So the front cylinder tensioner puts no tension on the cam chain. Now when you start the motor and while it is runing the noise is that cam chain whacking the spark plug housing and the reason you have no power is the cam timing is off on that front cylinder. The puffs of outbound air at the throttle body is your intake valve still being open when the compression stroke starts. If you haven't already bent a valve keep running the motor and things will get far enough out of time that you'll snap a valve or punch a hole in that front piston. Don't know where you got your compression specs but 50-85 psi is not right for a healthy cylinder either,

Think I understand why the compression spec is so low. It's that KACR compression release. Manual says it reduces compression when the bike is starting and raises it back to normal when the bike is running. Since the bike isn't running during the test, the compression on a normal cylinder would be low.

[tomm]

Update - Spoke with Mac about the problem. He thinks the cam chain slipped. Engine probably stopped with one lobe on the cam right at the top, and when I removed the tensioner, the cam rotated off the lobe under pressure from the valve spring and slipped the chain. It all seems to add up.

I also pulled the spark plug tube, and with a mirror and a bright light, I can see the bottom of the camshaft gear, enough to see the timing marks. Also pulled the alternator outer cover so I could rotate the crankshaft by hand. By counting teeth on the camshaft gear (there are 45), I could roughly approximate where the timing should be (I think within a tooth). Looks to be about 8 teeth off. That also seems consistent with the camshaft rotating off a lobe. Probably wouldn't have slipped just one tooth.

Anyway, Mac said he would be willing to do the repair for me. I've done a lot of bike work, but think this might be just a little over my head.

Although this sequence of events must be really unusual as I can't find any other reference to it anywhere on the web, It obviously can happen. I think if I were to do cam chain extenders again, I would pull the spark plug tubes and the alternator outer cover before I removed the tensioners, and rotate the crankshaft by hand until the crankshaft timing marks were lined up, the pistons were at TDC on compression, the valves were fully closed, and I could check the tension on the cam chain with my finger through the spark plug tube opening. That way, there would be absolutely no chance of this happening. Oh well. Like Thomas Edison once said. I've never failed. I've just found 10,000 ways that don't work.

[Netnorske]

This sounds like a nightmare scenario for sure. With Mac on the case, I'm sure you will be on the road to recovery in short order. Sounds like you know your way around a bike motor though. Good luck with the repairs.

[Cajunrider]

Tom if there is such a thing as luck, yours sure wasn't very good with this project. This is the first case I've heard of this happening. Hope all works out for you.