82 kawasaki ar80 won't rev

[g3ssexy]

I've got an 82 kawasaki ar80 that won't rev easily past 7000 rpm. it will rev to about 8000, but doesn't make much power after around 6500-7000. max hp is supposed to be at 8500 rpm and the "redline" is at 10,000 rpm. It's not a carb issue either. i completely cleaned the carb and the filter is in good shape. could it be that the ignition is retarded? the bike only has 3000 miles on it, and i doubt the flywheel has ever been off as it needs a special tool to get it off, but that's my only guess. should mention that i cleaned the carbon out of the exhaust and stinger, so it's not that either. any suggestions would be appreciated!

Thanks

 

[BigAl8295]

Your spark plugs torqued correctly?

 

[HerrDeacon]

Have you tested the compression? It sounds similar to my MB5 before I rebuilt the engine. You may also have an air leak (at carbs or engine oil seals). As a simple check first, try a new plug.

 

[g3ssexy]

forgot to mention that is has a new plug with the proper gap. haven't done a compression test on her, but she has a lot of power around 6,000 rpm and always starts easy.

 

[HerrDeacon]

You have a timing light? Worth taking a look at to see if the timing advances when its supposed to. I don't know the AR80 but I'm betting it should be advancing around the 6000-7000 mark.

 

[g3ssexy]

we've got one at my work. how do i go about checking it? sorry, i've never used a timing light

 

[HerrDeacon]

Here's a screen print from the manual for the MB5 that explains it pretty good, it should be pretty similar on the AR but the advance maybe at a different RPM.