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cam noise
- bls5050
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The bike is a 1980 KZ1000ST (the same bike in the KZ1000ST Resuscitation thread in the Projects Forum). The bike is stock as a rock, with the exception of a K&N filter in the stock airbox.
The bike fires up and runs fine. Pulls like a team of mules. Spark plugs come out dry with a light grey/tan coating. The problem is that at idle, you can hear a "whirring" sound coming from the valve covers. Using a "screwdriver stethascope(SP?)", the sound in even between the front and rear cams, and louder on the right side. The cam chain appears normal. Most of the info I found using the search function referred to chain slap at idle from the cam chain. This is not a "rattle". This is a very distinct "whirring".
I switched to Shell Rotella oil, and this got rid of all other oddness from the motor, but the cam noise is still there, maybe it's more pronounced because all the other noises are gone? This morning I pulled the valve cover to check top-end lubrication and valve clearances. Valves are well within specs. One thing that I noticed when I pulled the valve covers was that oil was pooled up on exhaust valves #1 and #4 to the gasket surface. But the cams appear to be getting plenty of oil otherwise.
My question is, is this normal, or is this a problem? Remember this: Your only paranoid if you're wrong!
1980 KZ1000st
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- Patton
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Am thinking cam chain sound has generally been more audible on the bicycle style cam chain as opposed to the later Hy-Vo design, even off the show room floor....1980 KZ1000ST..stock...K&N filter in the stock airbox...runs fine... at idle, you can hear a "whirring" sound coming from the valve covers...cam chain appears normal...not a "rattle"...very distinct "whirring".
...is this normal, or is this a problem?...
Often, a good close carb sync will noticeably reduce cam chain noise at idle rpm.
But the sync is perhaps more curative to rattle than whirring.
Good Fortune!
1973 Z1
KZ900 LTD
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- bls5050
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In a related matter, I just finished ripping the oil filter that just came out apart to read the filtering media. There was a slight amount of magnetic material, I assume from the rings reseating after sitting for more than fifteen years, but nothing out of the ordinary, so the motor isn't "making metal".
1980 KZ1000st
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- larrycavan
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- bls5050
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1980 KZ1000st
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- Patton
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Perhaps sprocket needle bearing is shot, which might also explain the magnetic material found in oil filter.I took the valve cover off again and looked at the top idler sprocket. It seems like it has alot of play. It can move side-to-side maybe 1/8 inch, but it can move slightly up and down and back and forth on it's shaft, also. The FSM and the Clymers manual dont list wear specs on this part, so is this normal, or is this a possible culprit?
Good Fortune!
1973 Z1
KZ900 LTD
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- Kapahulu
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1978 KZ1000, 1976 KZ900, 1975 H2, 1973 H1, 1973 H2, 1978 RD400, 1977 RD400, 1974 RD350
2strokeworld.com
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- Patton
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As the idler sprockets aren't part of scheduled maintenance, they would be changed when worn or damaged (same as cam chain). Permissible cam chain stretch is addressed in the FSM.At what mileage should the idler sprocket be changed?
As with most engine components, conscientious periodic maintenance should enhance longevity.
Good Fortune!
1973 Z1
KZ900 LTD
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- TerryK
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1977 KZ1000
GSXR swingarm and rear brake
WM6 rear Akront rim
Wiseco 1075c pistons
33 smoothbores
stage 3 Web Cams
Head porting
Dyna S ignition
Lockhart oil cooler
Wiseco header
1980 Z1R drag bike
1200cc
38 Flatslides, .
500' cams
7" slick
Dyan 4000 SP ignition
etc
Ontario, Canada
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- larrycavan
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- Patton
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www.z1enterprises.com/detail.aspx?ID=2178
www.z1enterprises.com/detail.aspx?ID=332
www.z1enterprises.com/detail.aspx?ID=2177
www.z1enterprises.com/detail.aspx?ID=349
Good Fortune!
1973 Z1
KZ900 LTD
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- bls5050
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I looked at the idler assembly, and it was not immediately apparent as to how to get the idler sprocket off of it's shaft. Maybe a press-in part?
1980 KZ1000st
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