Topic: What’s This Sound??

[t_lilj]

Hey everyone,

I started hearing this metallic sound yesterday. Before the bike had been pretty quiet other than my cam chain. It’s a CB750K3, roughly 1100 miles on a rebuilt engine. I went on a ride on Saturday and it possibly overheated(?), I was on the freeway doing ~75 and it would start slowing down. If I stopped for a minute I could start going again just fine for a couple more minutes and then it’d start slowing again. I haven’t had time to check compression, but on Friday it was ~85 for all 4 cylinders. My thought is maybe my camshaft warped and my valves aren’t opening smoothly, but I’m new at this.
Thanks in advance.

[flybox1]

sounds like an exhaust leak around #4

[flybox1]

open a tappet cover and make sure oil is splashing around.  everything should be wet in there.
Pull all 4 of your plugs and post a picture showing all of their tips. Line them up L to R, 1234

When was the last time it had a complete 3000mi tuenup?
...also, your fuel is off 

[t_lilj]

I’ll check that tonight. The engine only has 1100 miles on it, but I’ve done a everything on a tune up except for valve clearance because I don’t have a 6 point wrench to get the covers off. On my petcock that’s the reserve position, not the off position

[flybox1]

Did you pick out the old exhaust crush washers and put new ones in when your exhaust went back on?

[Jerry Rxman Griffin aka MuthaF'er]

Or compression leak?

[t_lilj]

I didn’t have the tools/know how to rebuild the engine, so I aid someone else to do it last fall (regrets there), so I can’t say about the exhaust washers. Also it has been burning some oil, is there a special tool to do a leak test?

[flybox1]

eliminate the exhaust gasket possibility, first.

[disco]

Sounds like your valves are in need of adjustment. You can hear the metallic hammering.