How to check for cam chain wear?
06-10-2013, 11:14 AM
#31
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Compression test
Did the compression test today. I got only 105psi on the front cyl and thought "Aha" but then the rear was just as bad (110psi). That does not compute with what I feel is a healthy running engine. Got back here on the forum to check and saw that I needed WOT to open for air, and then they both hit 160psi
Cant be to bad for an engine with slightly tight valves and 60k km.
But the vibration mystery remain. I start to look hard on a used engine.
This has had a hard life with racing in it's first year, then the cct failure 4-5 years later. Maybe better pension it and use it for spares? Seems like it has two healty heads.
Cant be to bad for an engine with slightly tight valves and 60k km.
But the vibration mystery remain. I start to look hard on a used engine.
This has had a hard life with racing in it's first year, then the cct failure 4-5 years later. Maybe better pension it and use it for spares? Seems like it has two healty heads.
06-10-2013, 02:33 PM
#34
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Yes, clutch in or out.
06-11-2013, 12:20 AM
#36
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06-11-2013, 02:37 AM
#37
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The engine has not been damaged on the flywheel side so I doubt it. Anything there I should look for?
Clutch might be worth investigating. I imagine there would be something off balance. I doubt it is any form of vibration by the plates rather an unbalance causing a vibration. Clutch operates fine although I noticed it does grab very far out. Might be air in the slave.
06-11-2013, 11:00 PM
#39
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The vibrations get intense over 6k. Closer to a drill hammer than a VTR.
Last edited by Babelfish; 06-12-2013 at 02:25 PM.
06-18-2013, 12:39 PM
#40
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Checking the timing on the front cylinder now.
Not as bad as I remember it. On the pictures there is no tension on the chain and putting pressure on it on top of the chain the exhaust cam will move the timing mark ever so slightly away in addition to what is seen.
Is this enough to cause any problem?
Timing mark at crank:
Timing at front cyl:
I can lift the chain up from the wheel slightly but not much more than 1 mm.
Not as bad as I remember it. On the pictures there is no tension on the chain and putting pressure on it on top of the chain the exhaust cam will move the timing mark ever so slightly away in addition to what is seen.
Is this enough to cause any problem?
Timing mark at crank:
Timing at front cyl:
I can lift the chain up from the wheel slightly but not much more than 1 mm.
Last edited by Babelfish; 06-18-2013 at 12:41 PM. Reason: spelling
06-18-2013, 01:12 PM
#41
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To get to that FT mark for the Front did you turn the engine over from the rear starting point 450 degrees.
(7) Using a socket and tee bar in the center hole of the alternator cover turn the engine over (anti-clockwise) until the timing mark 'RT' lines up with the mark on the alternator cover which can be seen in the 2nd hole of the alternator cover.
(8)Remove the rear cam cover (it's much easier than the front one) also note models with the pair system will have a metal locating dowel between cylinder head and cam cover, not applicable on UK models.
(9) Now looking at the camshafts, the lobes should be facing to-wards each other, if not turn the engine over one full turn (360 degrees) until the 'RT' mark is re-aligned, they should now be facing to-wards each other and the marks RI and RE on the camshaft sprockets should be level with the top part of the cylinder head and will be facing away from each other, you are now ready to remove the rear CCT.
...
(12) Now turn the engine over anti-clockwise 450 degrees (one and a quarter turns) until the 'FT' mark lines up with the mark on the alternator cover, you are now ready to remove the front CCT using the same procedure as the rear....
(8)Remove the rear cam cover (it's much easier than the front one) also note models with the pair system will have a metal locating dowel between cylinder head and cam cover, not applicable on UK models.
(9) Now looking at the camshafts, the lobes should be facing to-wards each other, if not turn the engine over one full turn (360 degrees) until the 'RT' mark is re-aligned, they should now be facing to-wards each other and the marks RI and RE on the camshaft sprockets should be level with the top part of the cylinder head and will be facing away from each other, you are now ready to remove the rear CCT.
...
(12) Now turn the engine over anti-clockwise 450 degrees (one and a quarter turns) until the 'FT' mark lines up with the mark on the alternator cover, you are now ready to remove the front CCT using the same procedure as the rear....
06-18-2013, 01:51 PM
#42
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Cams are pointing up and away from each others as they should.
New cap was allready in the post before teh old one broke. It has been bad for years.
06-19-2013, 06:04 PM
#43
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Please don't take this wrong, but questions like this lead me to think you have a serious lack of mechanical knowledge, and are chasing a phantom problem with the chain(that the type in the Hawk, I have NEVER seen stretch a mesurable amount). Same with your post about checking compression. I would suggest you take it to your buddy who helped you before.
IMO, the pistons hitting the valve is what is probably causing your issue. If there was any kind of mark in the top of the piston, the material has been compromised. ANY TIME parts touch in an engine in a situation like you describe(a broken chain tensioner), the valve AND piston should be replaced. Leaving a dent in a piston has left it compromised, and the amount of pressure the combustion chamber see's, it's just a matter of time now until the piston fails, which is what you may be experincing. It's not the cam chain, it's not a bad valve, it's the whole rotating assembly being far out of balance now. If you are that worried about it, tear it down and see whats wrong. If the vibration is that bad, the problem will be evident in a complete teardown and inspection. Otherwise, you are just chasing your tail.
Start at the top, go through the carbs, then work your way all the way to the oil pan. I suspect you'll find a piston that has been compromised.
06-20-2013, 01:29 PM
#44
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Are you sure that is on FT it might be the pic but it looks like the F mark to me which is different from FT.
Ignore that I juts read that the cams are pointing up and away so the T must be there I juts cant see it in the image
(:-})
Ignore that I juts read that the cams are pointing up and away so the T must be there I juts cant see it in the image
(:-})
Last edited by cybercarl; 06-20-2013 at 01:33 PM.
06-20-2013, 02:50 PM
#45
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06-20-2013, 03:27 PM
#46
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Please don't take this wrong, but questions like this lead me to think you have a serious lack of mechanical knowledge, and are chasing a phantom problem with the chain(that the type in the Hawk, I have NEVER seen stretch a mesurable amount). Same with your post about checking compression. I would suggest you take it to your buddy who helped you before.
IMO, the pistons hitting the valve is what is probably causing your issue. If there was any kind of mark in the top of the piston, the material has been compromised. ANY TIME parts touch in an engine in a situation like you describe(a broken chain tensioner), the valve AND piston should be replaced. Leaving a dent in a piston has left it compromised, and the amount of pressure the combustion chamber see's, it's just a matter of time now until the piston fails, which is what you may be experincing. It's not the cam chain, it's not a bad valve, it's the whole rotating assembly being far out of balance now. If you are that worried about it, tear it down and see whats wrong. If the vibration is that bad, the problem will be evident in a complete teardown and inspection. Otherwise, you are just chasing your tail.
Start at the top, go through the carbs, then work your way all the way to the oil pan. I suspect you'll find a piston that has been compromised.
IMO, the pistons hitting the valve is what is probably causing your issue. If there was any kind of mark in the top of the piston, the material has been compromised. ANY TIME parts touch in an engine in a situation like you describe(a broken chain tensioner), the valve AND piston should be replaced. Leaving a dent in a piston has left it compromised, and the amount of pressure the combustion chamber see's, it's just a matter of time now until the piston fails, which is what you may be experincing. It's not the cam chain, it's not a bad valve, it's the whole rotating assembly being far out of balance now. If you are that worried about it, tear it down and see whats wrong. If the vibration is that bad, the problem will be evident in a complete teardown and inspection. Otherwise, you are just chasing your tail.
Start at the top, go through the carbs, then work your way all the way to the oil pan. I suspect you'll find a piston that has been compromised.
I am looking at the chain as one of several possibilities, but from your answer I deduct that this is not a likely candidate (an explanation here would also be nice. The serious unknowledable might learn something).
Same go for the piston theory. What exactly cause the vibration?
The " it's the whole rotating assembly being far out of balance now." tells me nothing. What is out of balance and how? Surly someone with your mechanical experience can come up with some plausible explanation other than the "rotating assembly being far out of balance".
The engine has lived with these vibrations for a while now. It's more than 20 000km since I replaced that valve.
Today I was at the track and had another 30 laps with two long straights keeping the revs above 8000 for long periods. The badly damaged piston still work. I find that quite amazing and would love to find out how that's possible.
06-22-2013, 12:44 PM
#47
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What way is wrong msethhunter? With a post like that I can't with the best of my ability see that the right way ( the intended way) is anything else than the negative. So I guess that is the way I should take it, not?
I am looking at the chain as one of several possibilities, but from your answer I deduct that this is not a likely candidate (an explanation here would also be nice. The serious unknowledable might learn something).
Same go for the piston theory. What exactly cause the vibration?
The " it's the whole rotating assembly being far out of balance now." tells me nothing. What is out of balance and how? Surly someone with your mechanical experience can come up with some plausible explanation other than the "rotating assembly being far out of balance".
The engine has lived with these vibrations for a while now. It's more than 20 000km since I replaced that valve.
Today I was at the track and had another 30 laps with two long straights keeping the revs above 8000 for long periods. The badly damaged piston still work. I find that quite amazing and would love to find out how that's possible.
I am looking at the chain as one of several possibilities, but from your answer I deduct that this is not a likely candidate (an explanation here would also be nice. The serious unknowledable might learn something).
Same go for the piston theory. What exactly cause the vibration?
The " it's the whole rotating assembly being far out of balance now." tells me nothing. What is out of balance and how? Surly someone with your mechanical experience can come up with some plausible explanation other than the "rotating assembly being far out of balance".
The engine has lived with these vibrations for a while now. It's more than 20 000km since I replaced that valve.
Today I was at the track and had another 30 laps with two long straights keeping the revs above 8000 for long periods. The badly damaged piston still work. I find that quite amazing and would love to find out how that's possible.
Ask yourself these few questions.
"Was the issue present before the valves hit the piston?"
"Does it get worse as RPM's increase?"
Sounds like you already know those answers.
If the answer to either of those two questions is "Yes," then tear the engine down and have a good look at the rotating assembly (pistons, crank, rods, etc.). If it's bad enough to cause you enough concern to pull the valve covers off and check things like cam timing, chain wear, etc., then it should be bad enough to quit riding the bike, and see what is wrong. If you are still riding it, it tells me a couple things. Either it isn't all that bad and you a feeling something that either isn't there and chasing your tail, the engine is on it's last leg and about to buy the farm, or, you lack the experince to tear into the engine and find out what is going on.
Have you done a leak down test? Have you checked BOTH sets of cams for proper timing? Have you really torn into the engine to see if there is an underlying issue at work? Have you checked to see if the keyway on the flywheel looks buggered up? What do the cam lobes look like? There are so many things to look at, I could keep going and going and going. There are so many things it could be, and you have checked the basics it seems, but also seem a little afraid to really dig into it to see what is causing the vibration. I have seen even small dents in pistons cause huge problems, up to the piston coming apart after a few thousand miles, and vibrations that are beyond what is considered "normal," even when they don't come apart. IMO, if the top of the piston doesn't look like it did when it came out of the factory, it should be replaced, save for some carbon deposits. Pull the tank off, the air box off, and start at the top. Work your way to the bottom of the oil pan and inspect everything. Seems to me, that if your cam chains aren't showing signs of wear (which this type of chain will stretch so minutely, it's almost not mesaureable), your compressions are normal, you need to start digging deaper into the engine.
Start with a leak down test. Just because compressions are normal, doesn't mean that the engine is healthy. You are going to have to dig deeper.
Like I said, I'm not trying to be a dick, but I also don't feel like writing a book for someone on here who's experince is at your level (not trying to slam you). If you really want to learn the bike, get a manual, tear into it, and learn it. Learning it over a few internet posts is going to end up either costing you a lot of time, a lot of money, or both for an issue like this. You have checked the basics. It's time to go beyond that and just do it, and report back with what you find, or have questions about. But, you need to tear it down. And like I said, if it's bad enough to cause you concern and start this process, stop riding it until you either find the issue, or give it a thumbs up and everything looks okay.
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