Compression test numbers.

Ok I have been fixing up a 2003 VFR I wanted to be sure compression was good before final assembly. I found them all to be the same at 75 PSI on the first stroke. I thought it was a little low even for a cold test but the tester I bought is a new one that I have not used before. My old tester did not have the adapter needed. Thanks for any imput. I could not find a thread with this info for a 6th gen.

 

You already know that compression tests are most reliable when done on an engine at operating temperature with all plugs out and throttle held wide open ?

For first stroke 75 psi seems OK, but what's the max, and is it even across all cylinders ??

 

Were you turning the engine over by hand? Like mentioned above, all the plugs need to be out, the throttle at wide open, and the battery with a good charge in it to get a reading. Crank until the needle stops moving. With the compression ratios of these motors in the 11:1 neighborhood you should be seeing around 150psi when its all said and done. Unless something really bad happened to the motor though(serious overheating, run without an airfilter, overrevving to the point of bending valves, run with no oil, etc.) There shouldn't be anything wrong with the compression. What do you know about the bikes past?

 

I did have a good battery and like I said they are all the same. The throttle was not open and it was cold. The bike was wrecked. Im putting it back together and it only has 1800 miles on it. It did go up to 150 after pumping a while. I aways go with the first number on cars. Anyway I used the starter. I am sure its good. I just worried because I had new plugs and it was running rough, I found out the plugs were fouled by bad gas. Runs great now I just need to get tires and a chain and im good to ride. Ill post an old pic.
PS I gave 700 usd for this beast. It has cost about 2500 to get it done and I still need to assemble it.:biggrin:

 

Well reaper, I'd say you got a hell of a project for a good price. Hope to see pics of it when its done. Curious to see what that rear wheel looks like.

 

Correct even numbers across the board are the most important to see, not what the gauge reads. Gauges vary in calibration, so does a number of other various factors, elevation, humidity(air moisture content, etc, etc. Basically each cylinder is pulling it's weight.

 

thanks to all. most of the time on cars it works or it dont. It has never failed that on will be way off if its a burnt valve or busted ring. Anyway I am stoked about the finish of the bike im glad the engine is good to go. I put new exaust and gaskets on it and that fixed the pecking. thanks again to all