compession test results

[audijunky]

Hey Mro,
thanks for the advice, but I am not following. The washer is supposed to be in the pipe correct? How do I weld the washer to a bolt and the get it into the pipe? Do I put the bolt through the washer or weld it to it on its side? Any whoddles I have some new compression results . #1 175, #2 160, #3 165, #4 155!These seem awfully high to me. I warmed the bike up good. pulled all the plugs, and then tested w/ wide open throttle. If you look at my early test at the top of the post you will see a tremendous difference. Test done with the same compression gauge also. Any body know if this is good or bad. I remember seeing some specs earlier in this post saying max 156. How do you get to much compression?

[audijunky]

One more question, would going up a size on pilot jets affect compression? I would think not but with differences like that I dont know.
Thanks

[mro]

Compression is a matter of bore/stroke and condition of rings/valves. Have seen numbers similar to yours.

Weld washer edge on to bolt head (look like a lolly pop). Secure with lock washer/nut through hole in bottom of pipe.

Washer will be able to "stand up" in pipe. By rotating bolt you can close off the pipe by varying degrees.


mro
I know what I said, but do you know what I mean.
(don't know who quote is from)

[audijunky]

Thank you for your explanation kind sir.
So nothing to worry about on the compession ?

[DiverRay]

The higher compression may be from carbon build-up in the combustion chamber. You can use a spray can of Berryman's B12 Chemtool or SeaFoam to help loosen the carbon. With the engine at running temp (after a nice ride ) pull the air filters and squirt a LOT into each carb. bring it from an idle almost to dead, and then move on to the next carb. On the last carb, let it die, and turn the ignition off for about 5 minutes. Restart and take it for a quick run, higher RPMs in first or second gear.
That should clean out a lot of the build up.
Ray

[audijunky]

Hey Diver, I know it isn't carbon build up as I have just put the head back on after cleaning all the carbon out of the combustion chamber with a wire brush.
Do I need to do anything about the higher compression? Could I have torqued down the head bolts to tight?

[DiverRay]

No, you probably have a large bore kit in the bike, and just didn't know it! I would NOT worry about the test results, and just run mid grade or premium fuel to keep the knocking down.
Ray

[audijunky]

That my friend would be the coolest thing ever! (especially since I picked the bike up for 50.00!!) Yes, that..... is a decimal. Any way to find out, like measuring the bore? I really dont want to take the heads back off just for that though.

[80mdnt11]

50.00$$$$$$$$$$!!!!!!!!!! Man, do I feel violated That's a great deal! You should get 50.00 +++++++++++ enjoyment out of that!
As for comp. #'s--------Run It. Bought mine this spring, won't say how much $ especially after all I found wrong! One of the first things I did check was comp. My #'s were #1-162#,#2-160#,#3-156#, #4-160#, eng. warm throttle open. Did'nt touch top end, other than valve adj. + cam chain ( one of few I didn't have to!) Just run Premium + go!!!!!!!!

[80mdnt11]

Oh, btw--------- there would be away to check bore with volume/ i.e.-cc measurement I would think?

[79XS11F]

When you had the head off you must have used a new gasket .. right? if so you would know right then if the bike was big bored because the stock gasket would not fit properly anymore. It would overhang into the cylinder bore spaces.
The compression number will not be affected by the size of any of the carb jets. It is a measure of the pressure in the cylinder after the valves are closed but must be doe with carbs WIDE open to allow for the largest charge of air to enter the cylinder before the valves close.
Rob

[audijunky]

Thanks Rob,
For popping my balloon! Yeah I did use a new gascket and it fit perfectly so no unexpected big bore kit for me Well at least the compression is good thats a plus.

[79XS11F]

Sorry but at least you know what you got for jetting etc. Remember to re torque that head after 500 KM on the new gasket and then at every 5000 KM I think is the spec.
Rob

[audijunky]

Will do