I have a 98 bayou 400 that has a knocking sound when running, that is consistent with rpms. It seems to have good power still and doesnt seem to burn oil. what could be making this obnoxious noise? Im thinking it must be valve related. was told when i bought it that the valves were adjusted recently but didnt solve the problem.

SOURCE: timing problem

hi idont believe that you have piston to valve problems as the valves would simply bend, this would then reduce your compression and your m/c would not run correctly .
wot you may be suffering from is just large valve clearance or worn camshaft and or valve gear,however this must be investigated further
hope this is of help ian

SOURCE: Valves, plugs, etc.

They are not likely to need adjustment yet but they should be checked as part of your service. My bike suggests every 6000 miles (not a Suzuki). Your dealer can tell you the correct service interval for them over the telephone. A service manual is very handy for this information, even if you don't do the work yourself.

Earl Norager

• 355 Answers
• Posted on Aug 13, 2009

SOURCE: knocking sound during acceleration

I WOULD CHECK TIMNG AND MAKE SHERE YOUR GETING OIL TO UPPER END WHEN THEY DID UPGRADE DID THEY UPGRADE CAM BEARING TO IF NOT YOU COULD HAVE DONE MOTOR DAMAGE SEEN LOT OF THIS CANT USE STOCK BEARING NO NO OR YOUR LIFT IS TO HIGH FOR THE MOTOR ORAPLACATION HOPE THIS HELPS

SOURCE: power valve not opening up properly, oiling up plugs.

you should have little punch marks.they need to line up.

SOURCE: Bike is making a knocking noise that sounds like

The tappets in your engine are hydraulic and there is no adjustment to them. As the engine warms up and expands, the tappets expand to maintain zero backlash. I've seen the rollers on the end of the tappets go bad and when they do, it sounds like someone with a sledgehammer in the motor. But, I've never seen one go bad at 3000 miles. The earliest I've seen one go bad is 13K miles.

If I had to guess, with only 3000 miles on a 2001 model bike, I'd guess bad gas. Put some fresh gasoline in the tank and make sure that it contains no more than 10% ethanol.

Good Luck
steve