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Discussion Starter #1
Hi,
I recently bought a 2006 VN900B6F as a spares or repair deal as no idea of its history but it was cheap. Bike doesn’t start but turns over fine so I did a compression test and got 130psi from both cylinders. My problem is I can’t find anywhere what the reading should be from a cold engine.
Anyone know this bit of info?

thanks
 

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130 psi is pretty decent for a gas engine. These are 9.5:1 compression engines, if you have 130 on each, I would say you're fine.

You will get better info from performing a leak down. That will give you an idea of how the valves and rings are sealing. If you are just looking for why it's not starting, I would start more with fuel and spark. A low compression engine will run, it will just run like crap - especially at lower RPM's.
 

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Discussion Starter #3
Thanks for the reply. Reassuring to hear that 130psi sounds ok. The non starting was down to the fact that the fuel tank was full of rusty gunk and what looks like 10 year old fuel. Spent today flushing out tank, replaced fuel pump, fuel filter, spark plugs, fresh fuel and with crossed fingers pressed the start button.
Happy to report it fired up and ran ok from cold but cuts out at tick over once warmed up so need to investigate further. Will try turning the idle speed up to see if that helps but other than that I don’t know what problem might be. A leak down test is a good idea but don’t have a tester although might invest in one.
I’m not familiar with these bikes so any hints appreciated.
 

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I would check spark plug color and see if it's running rich or lean. Some of the gunk from the tank might have worked it's way down into the injectors.
 

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hi, the service manual states:
Cylinder Compression, usable range: 142∼ 228 psi at 470 r/min (rpm)
*Using the startermotor, turn the engine over with the throttle fully open until the compression gauge stops rising; the compression is the highest reading obtainable.

I doubt that a 130 psi compression would be the culprit of your engine not starting...
 
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