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Suzuki_Don
Guest
Billy do you want to explain the shop towel in the exhaust principle please.
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Billy do you want to explain the shop towel in the exhaust principle please.
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TheCafeKid
Guest
It'll stuff up the exhaust noise so you can actually hear the motor spinning rather than all the clatter and noise coming through the pipes. It works quite well actually. Billy is right in that these noises bounce all around inside the cases. It makes it hard sometimes to pinpoint where it's coming from exactly. Using his suggestion, or a cheap mechs stethoscope or even a screwdriver (stick your ear to the handle, use the tip like a stethoscope) can aid in pinpointing where in the motor the racket is originating.
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TheCafeKid
Guest
Just another thought... And I dunno so it's why I'm asking... Was there any difference in deck height on the Kat head than the G head? I didn't see... The only thing From a G in this motor are the cams?
Not too long ago someone was talking about using bits from a 700 motor (short stroke) in a 750 motor... Or vice versa. Seems to me that there would/could have been issues with that...depending on which way it went.. Conrods longer or shorter,etc. Smacking the head/valves... Dunno if that's how it worked or not... Just wondering if there are any sorts of possibilities of something like that?
Not too long ago someone was talking about using bits from a 700 motor (short stroke) in a 750 motor... Or vice versa. Seems to me that there would/could have been issues with that...depending on which way it went.. Conrods longer or shorter,etc. Smacking the head/valves... Dunno if that's how it worked or not... Just wondering if there are any sorts of possibilities of something like that?
It's a 650G top end on a 550E bottom, just like mine, only his is done and mine is still a pile of parts in the parts washer.
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Suzuki_Don
Guest
JOSH all the 650 cams are the same with the same Part#. Good thinking though. Keep them coming. I am wondering if this noise only appeared after I lost the tension on my cam chain tensioner when the knurled nut came loose and went for a walk down the road. Another reason why I want to have a look under the valve cover to check things out. make sure it hasn't jumped a tooth. Although it is pulling really strongly on the road and I think the performance would be OFF if it was a tooth out. Does it sound like a bent valve?
bent valve=dead/weak hole=lack of power.
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Suzuki_Don
Guest
Thanks BB. I should have thought about it a bit more before asking the question. An impromptu thing, you know, mouth in gear, brain having a rest; or fingers typing in my case. I've just added 2 more points to the list of things to check when the valve cover comes off; so now it is up to 7 things to check. Refer to page 2 of this thread.
Hey Don, I had been only browsing lately and missed your post.
I have listened to your video clip, but can't quite put my finger on the cause of that sound. It certainly sounds different to the typical cam walk knock. Yours is very constant, suggesting that it's a part making contact with the cam cover, very loose shims, or even valves touching.
I had a look at that possibility on my spare 850 head. Both valves need to be around 3+ mm off their seats to make contact, so probably not the cause. I was thinking that you may have jumped a tooth on the exhaust cam when the tensioner failed. This would retard the exhaust opening but increase the overlap period. The valves would likely contact the piston crown before making contact with each other though.
Do as DD has suggested. Use a stethoscope to track down the exact area that the sound is coming from. I do the same, by using a large screw driver handle against my ear while contacting the tip against the engine. Either way will work well.
Good luck.
I have listened to your video clip, but can't quite put my finger on the cause of that sound. It certainly sounds different to the typical cam walk knock. Yours is very constant, suggesting that it's a part making contact with the cam cover, very loose shims, or even valves touching.
I had a look at that possibility on my spare 850 head. Both valves need to be around 3+ mm off their seats to make contact, so probably not the cause. I was thinking that you may have jumped a tooth on the exhaust cam when the tensioner failed. This would retard the exhaust opening but increase the overlap period. The valves would likely contact the piston crown before making contact with each other though.
Do as DD has suggested. Use a stethoscope to track down the exact area that the sound is coming from. I do the same, by using a large screw driver handle against my ear while contacting the tip against the engine. Either way will work well.
Good luck.
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Suzuki_Don
Guest
I Think I Have Found the Problem
I Think I Have Found the Problem
I think you are right Ian, the noise is constant and I think it is the cam chain rubbing against the cam cover. I used the screwdriver technique to isolate the noise before I took the video and in one of the early posts I said the noise was worse on the exhaust cam side of the top end than the inlet side. And the noise was right on the top end near the cams and sprockets and not lower down near the combustion chamber.
Anyway I removed the cam cover and found the cam chain appears to be running in contact with the inner section of the cam cover, more so on the exhaust side than the inlet side.
See pictures below.
This picture of the cam chain shows it not actually running on the lower rubber tensioner on the top of the head. Is this normal and does the corresponding rubber tensioner in the cam cover push the chain down onto the lower one in practice. JOSH did mention in an earlier post that the cam sprockets may be a bit higher than the original 550 sprockets. This looks like it could be the case.
So how do I fix the problem. Can I machine the chain tunnel out by 0.020" or so to give the clearance needed? I cannot go for a thicker gasket as that will alter the depth of mesh the tacho drive requires into the camshaft skew gear. Do I need to look around for a 650 cam cover. The one on the bike at present is off a 550 model. I was hoping to not advertise that it has a 650 top end on it. The 650 has different end caps on it.
Any suggestions guys.
I also checked the camshaft end float tonight and found that the exhaust cam has a clearance of 0.013" and the intake cam has a clearance of 0.016". Though I do not think this is the problem.
Another thing that I do not understand is how the motor was quite at idle when cold and yet develops this noise once it is thoroughly warmed up. Is the aluminium cam cover expanding towards the sprocket as it heats up and is the sprocket expanding towards the cam cover in the same way. Any other explanations.
Any suggestions greatfully taken on board. Maybe I have got it wrong, if so don't be shy. Does this condition I have found tally with the noise in the video.
I Think I Have Found the Problem
I think you are right Ian, the noise is constant and I think it is the cam chain rubbing against the cam cover. I used the screwdriver technique to isolate the noise before I took the video and in one of the early posts I said the noise was worse on the exhaust cam side of the top end than the inlet side. And the noise was right on the top end near the cams and sprockets and not lower down near the combustion chamber.
Anyway I removed the cam cover and found the cam chain appears to be running in contact with the inner section of the cam cover, more so on the exhaust side than the inlet side.
See pictures below.
This picture of the cam chain shows it not actually running on the lower rubber tensioner on the top of the head. Is this normal and does the corresponding rubber tensioner in the cam cover push the chain down onto the lower one in practice. JOSH did mention in an earlier post that the cam sprockets may be a bit higher than the original 550 sprockets. This looks like it could be the case.
So how do I fix the problem. Can I machine the chain tunnel out by 0.020" or so to give the clearance needed? I cannot go for a thicker gasket as that will alter the depth of mesh the tacho drive requires into the camshaft skew gear. Do I need to look around for a 650 cam cover. The one on the bike at present is off a 550 model. I was hoping to not advertise that it has a 650 top end on it. The 650 has different end caps on it.
Any suggestions guys.
I also checked the camshaft end float tonight and found that the exhaust cam has a clearance of 0.013" and the intake cam has a clearance of 0.016". Though I do not think this is the problem.
Another thing that I do not understand is how the motor was quite at idle when cold and yet develops this noise once it is thoroughly warmed up. Is the aluminium cam cover expanding towards the sprocket as it heats up and is the sprocket expanding towards the cam cover in the same way. Any other explanations.
Any suggestions greatfully taken on board. Maybe I have got it wrong, if so don't be shy. Does this condition I have found tally with the noise in the video.
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Don,
Those marks on the cam cover could have occurred when the chain was loose, you might have to use some marking color on them and put the engine back together to find out if that contact is still occurring.
Might be a good ideal to check the valve clearances next, and check compression too so make sure there isn't a bent valve from the tensioner escapade.
Those marks on the cam cover could have occurred when the chain was loose, you might have to use some marking color on them and put the engine back together to find out if that contact is still occurring.
Might be a good ideal to check the valve clearances next, and check compression too so make sure there isn't a bent valve from the tensioner escapade.
A few random thoughts...
So this is a 550 cover, does the 650 cover have more space under it?
The sound is a Clank, Clank, Clank, rythmic sound, so the chain would have to have one spot going around hitting something? Bad link? Bent side plate? Master link peened too tight? If all the links were the same, they would all make noise, more like a constant chain rubbing swoosh noise as each link hits the same, instead of a clank? Your noise sounds like a bigger piece of metal than a chain link.
Is the sound once per rev or is it slower, like once every time the chain does a full lap around the sprockets? We have had a few bikes lately that made a click, click every time a spot on the chain went past the cam sprockets, we have not found why this happens. Did you use a new chain on this engine?
Does it make the sound if you run it without the valve cover installed?
If you slow the idle way down, what happens to the noise?
Could you, for test purposes only, run the engine with two or three valve cover gaskets to raise the cover up? You would have to leave the tach drive out, but it might tell you something.
Definitely check the valve clearances, cam timing and compression.
So this is a 550 cover, does the 650 cover have more space under it?
The sound is a Clank, Clank, Clank, rythmic sound, so the chain would have to have one spot going around hitting something? Bad link? Bent side plate? Master link peened too tight? If all the links were the same, they would all make noise, more like a constant chain rubbing swoosh noise as each link hits the same, instead of a clank? Your noise sounds like a bigger piece of metal than a chain link.
Is the sound once per rev or is it slower, like once every time the chain does a full lap around the sprockets? We have had a few bikes lately that made a click, click every time a spot on the chain went past the cam sprockets, we have not found why this happens. Did you use a new chain on this engine?
Does it make the sound if you run it without the valve cover installed?
If you slow the idle way down, what happens to the noise?
Could you, for test purposes only, run the engine with two or three valve cover gaskets to raise the cover up? You would have to leave the tach drive out, but it might tell you something.
Definitely check the valve clearances, cam timing and compression.
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Suzuki_Don
Guest
Thanks guys for the replies. I have checked the cam timing and it seems to be spot on. The 650G motor has 34 tooth cam sprocket and the E model has 30 tooth cam sprocket. I am using 30 tooth cam sprockets. There must be more space under the 650 cam cover to fit the larger sprocket for the G application. I can't imagine they would have two different cam covers for the 650 engines.
A good idea to run the engine with two gaskets to see if the noise goes away, through supplying more clearance in there. Thanks Tom. I will also try some permanent marker on the section that is scored to see if it wears away as per Ed's suggestion. Thanks Ed.
I did fit a new camchain when I rebuilt the motor. There is no joining link, it is a one piece endless chain.
I ran out of time last night to check the shim clearances. Maybe tonight if I can sneak out of the house for 15 minutes.
Any suggestions about the fact that the cam chain does not run directly on the rubber thingo in the head between the two cam sprockets.
I was not game to run the motor with no cam cover in place, thought I would get covered in oil.
A good idea to run the engine with two gaskets to see if the noise goes away, through supplying more clearance in there. Thanks Tom. I will also try some permanent marker on the section that is scored to see if it wears away as per Ed's suggestion. Thanks Ed.
I did fit a new camchain when I rebuilt the motor. There is no joining link, it is a one piece endless chain.
I ran out of time last night to check the shim clearances. Maybe tonight if I can sneak out of the house for 15 minutes.
Any suggestions about the fact that the cam chain does not run directly on the rubber thingo in the head between the two cam sprockets.
I was not game to run the motor with no cam cover in place, thought I would get covered in oil.
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Don, in the photo of the lower tensioner the exhaust cam sprocket looks as if it's touching it. If not it's blo*dy close. Some of those tensioners are a good tight fit and some aren't so tight. Maybe the cam chain is pulling it over and it's getting knocked back by the exhaust sprocket. Worth checking you've got the arrow pointing the right way.
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Suzuki_Don
Guest
Thanks wally, I will check that. Where is the arrow that you speak of.
Here is a better picture Wally. And I agree it does look close, I will have to check that when I get home from work. Well spotted.
Thanks
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Oil will go everywhere, but if it makes the noise when the cover isn't there, you will know a few things the noise isn't caused by.
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Suzuki_Don
Guest
Thanks Ed. That is good to know.
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Suzuki_Don
Guest
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Suzuki_Don
Guest
Tonight I measured the depth of the 550 cam cover where the cam chain had been rubbing the aluminium away. I also have a later model 650 cam cover which I took measurements on as well. This later cam cover will not bolt onto my head as two of the bolt holes do not line up, but everything else on the cam cover is the same as the 550 cover.
I measured the depth with a vernier gauge from the surface of the cam cover where it meets the head to the portion inside the cover where the chain had been rubbing.
The 550 cam cover measured at about 45mm.
The 650 cam cover measured at about 49mm.
So it looks like there is about 4mm difference between the two cam covers. I know the 650G cams have 34 tooth sprockets compared to the 550 sprockets with 30 teeth, but I still think there is something to be gained by milling some material from the inside of the 550 cam cover to give extra clearance.
As a trial I intend to fit the 650 cam cover and gasket and see if the noise is still apparent with that setup. If the noise is still there then I have to look elsewhere. If it goes away I will be well on the way to fixing the problem.
The cam cover may leak a bit of oil out of the front left while I am riding the bike to warm it up, but I will have to live with that.
I measured the depth with a vernier gauge from the surface of the cam cover where it meets the head to the portion inside the cover where the chain had been rubbing.
The 550 cam cover measured at about 45mm.
The 650 cam cover measured at about 49mm.
So it looks like there is about 4mm difference between the two cam covers. I know the 650G cams have 34 tooth sprockets compared to the 550 sprockets with 30 teeth, but I still think there is something to be gained by milling some material from the inside of the 550 cam cover to give extra clearance.
As a trial I intend to fit the 650 cam cover and gasket and see if the noise is still apparent with that setup. If the noise is still there then I have to look elsewhere. If it goes away I will be well on the way to fixing the problem.
The cam cover may leak a bit of oil out of the front left while I am riding the bike to warm it up, but I will have to live with that.
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