Hi guys, firstly this is not an engine knock from pre-ignition let me explain. Did a full top-end overhaul with rebore to 1 oversize. Replaced valve stem seals and lapped all the valves. Did a leak test afterwards and everything ok. Assembled the engine and did a few heat cycles just to make sure everything beds and settles down. Last was carb adjustment and carb balancing, everything went great no issues. Had to replace the fuel tap as the unit i had was seized. Anyway a few days ago was trying to diagnose why the engine wasnt revving past 4000 rpm only to find i had a fuel delivery problem, engine would run fine when i changed over to prm on the tap so that i still need to address. Here is the issue now. Start up the engine runs real smooth with a little choke at start. Once the engine is warmed up and choke off I hear a strange knocking noise from around 1200 rpm to 2000 rpm then it goes. I cannot pinpoint where the noise is coming from sounds kinda metalic. I havent removed the tappet cover yet to check timing chain or anything else below that cover. Valve clearance was set to 0.03 to 0.05 mm on all valves during assembly. Tensioner is good and operated as it was suppose to after installation. If it was crank big-ends the noise should be there all the time correct. The frequency of this metalic knock doesnt change as rpm is increased stays the same then dissapears. Engine revs cleanly without this knock after 2000 rpm. Any other ideas what I should look for. Oil light goes out almost immediately once she fires up. Also oil in the sight glass quickly drains out on start up. Suppose I need to drain the oil as well and check for any metalic particles.
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Is the airbox installed and fully sealed.Ed
To measure is to know.
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Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846
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KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection -
Ed, I have it installed and seal up the best i can. Looks ok.Comment
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Oil in sight glass goes away when running because its all being pumped around the engine. Level drops down as normal. Engines not low or out of oil, its just that the volume filling up the oil gallies and top end consume a lot of oil.MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550
NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.
I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.Comment
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If it doesn't change with RPMs, then just something vibrating...? someone recently on here had a front fender that was rattling.Comment
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Gents just to reply.
Noise is while the engine is running bike stationary
Im very aware why the oil goes from the sight glass, just an observation regarding oil pump etc.Comment
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frequency.........
Start up the engine runs real smooth with a little choke at start. Once the engine is warmed up and choke off I hear a strange knocking noise from around 1200 rpm to 2000 rpm then it goes.
The frequency of this metalic knock doesnt change as rpm is increased stays the same then dissapears. Engine revs cleanly without this knock after 2000 rpm.Comment
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Start it and start touching everything. Side stand, center stand, mufflers, guage covers, fender.. anything you can think of that could vibrate against metal.MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550
NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.
I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.Comment
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First off WELCOME, It says "frequency" of metallic knock doesn't change from 1200 to 2000 rpm., that means the knock doesn't get faster as the rpm's go up. I'm with dgates 1, something vibrating. If it were something like rod bearing, main bearing, clutch basket, cam bearing, starter clutch, the frequency would get faster as the rpms went from 1200 to 2000.. Sounds interesting, please keep us updated what you finally find is the cause.1983 GS1100E, 1983 CB1100F, 1991 GSX1100G, 1996 Kaw. ZL600 Eliminator, 1999 Bandit 1200S, 2005 Bandit 1200S, 2000 Kaw. ZRX 1100Comment
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This is my thought as well. I have used a long screw driver to try and pinpoint this noise , with no success. I have had the bike off the main stand on the side stand still nothing . Only changes are when the rpm increase above 2000rpm. yea frequency doesnt change . Ill try and do a video tomorrow maybe you guys can hear what im hearing. . For me it seems to be coming from the top of the engine. I have even run it in gear on the main stand same result. Took the tank off and setup up fuel supply and same result.
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Harbor Freight sells a mechanics stethoscope. I use mine a lot at the shopMY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550
NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.
I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.Comment
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