[AVL Power!]

I checked my bike's compression yesterday and got a reading of 148 which was pretty scary. Compression at sea level would be 14.7 and after doing the math I found that 139 should be the compression even with high compression pistons 148 sounds too high. Electra X stock comes with 8.5:1 compression which would be around 124.95 or 125.

So what bumped my compression? carbon deposit on the piston head? I am totally clueless 

[ace.cafe]

If the quench band is not in spec, which most AVLs are not, then you are about at the maximum allowable compression for pump fuel right now. It might even ping with the 148psi that you have.

To know the compression ratio, you first must know the volume of your combustion chamber, and then you can divide that into the 500cc volume that gets compressed into it, and you'll get your ratio number.
The ratio number is not necessarily related to your actual cylinder pressure psi number, because your psi number is including the valve timing in the equation, and the basic compression ratio number doesn't include valve timing.

From my experience with the Iron Bullet, you don't want to raise the compression any more than what you have now, if you are using pump fuel.

[AVL Power!]

I get it. So I am assuming that I am pretty close to 9.5:1 compression or a little more than 9.5:1? is it because of carbon layers on my piston crown area?

A friend had similar issues, he clocked 155 psi and later figured that his piston's crown had a thick layer of carbon

[barenekd]

You have great compression. If it's not pinging, just keep on truckin'. If it is pinging, try higher octane gas.
Bare

[ace.cafe]

I get it. So I am assuming that I am pretty close to 9.5:1 compression or a little more than 9.5:1? is it because of carbon layers on my piston crown area?

A friend had similar issues, he clocked 155 psi and later figured that his piston's crown had a thick layer of carbon

I'm guessing that you have around 9:1 compression ratio with a 148 psi reading and std cams.
Roughly figured.

[Bullet Whisperer]

I had the testbed machine for Hitchcocks running  at 9.2:1, the C.R. is the swept volume, added to the combustion chamber volume [measured at tdc], the sum of these two figures is then divided by this combustion chamber volume to give the C.R.
 As already stated above, the cams and their timing will influence the actual cylinder pressure obtained in your engine. The AVL engines have a decent squish band and, provided the clearence of this over the piston is 1 mm or thereabouts, it will combat pinking to some degree over an 'Iron' engine with a simillar C.R.
 B.W.

[ace.cafe]

I had the testbed machine for Hitchcocks running  at 9.2:1, the C.R. is the swept volume, added to the combustion chamber volume [measured at tdc], the sum of these two figures is then divided by this combustion chamber volume to give the C.R.
 As already stated above, the cams and their timing will influence the actual cylinder pressure obtained in your engine. The AVL engines have a decent squish band and, provided the clearence of this over the piston is 1 mm or thereabouts, it will combat pinking to some degree over an 'Iron' engine with a simillar C.R.
 B.W.

Thanks for catching that, BW.
I left out the adding of the chamber volume in the example I gave, and I shouldn't have made that mistake. I'm glad you caught it.

[Arizoni]

dampking
I agree with bare.  If it isn't pinging, enjoy!
If it does ping under a heavy load, switch to a higher octane fuel.

More than one has paid a lot of money to have parts that will give the higher compression your engine apparently has.

[AVL Power!]

It doesn't ping at all if the bike is in correct gear at the right rpm. I am using a VM34 and needle is at 2nd last notch, it was in the 2nd notch and I was leaning out so moved it to 2 slots down and raised it. She pulls hard even with a heavy pillion without pinging but if at wrong gear at very low rpm then she pings. I guess I am safe with this compression

Thank you for all the information, surely learning loads about my bike everyday!

[AVL Power!]

I checked few petrol pumps and figured that we don't have many pumps with 95 or 97 octane. Since I will have to use 91... is there any way to refine the fuel that I am using? maybe additives? do they help in any way?

My friend was also saying that engine oil additives are used to clean the internals? how good are they?

[barenekd]

Since your bike isn't pinging, why do you want more octane?
If you could actually get real gas in all octanes, like the good old days, you would know that lower octane gas actually gives more power. The higher the octane the more additives, the less gas you're getting in there. If some of the additives, not required for octane increases, but is used to increase performance, is also in there, then it's a different story. the bottom line, is that adding octane additives themselves does not improve power.
Bare

[AVL Power!]

I got it now. I will stick to what I am using, maybe change to shell.

[AVL Power!]

My bike did 30,000 KM on meter and few guys were saying that I should get the piston crown checked... also few suggested me to use "Engine Flushing Agents". I have never used these things so kind of confused. Are there good engine flush for draining carbon? won't hurt my engine right? My left and right brain lobes are really having a tough time!

[ace.cafe]

Leave it alone.

Stop listening to people who have no idea what they are talking about.

[barenekd]

Just to keep the confusion going, there are gasoline additives that are supposed to clean carbon and such out of the engine. TCP is one of them that is included in somebody's gas, or it's available over the counter. It's also supposed to clean the injectors, too.
Marvel Mystery Oil is another one. If you add it to your gas and oil it will cure anything. It will release sticky lifters and valves. It will remove carbon from pistons and valves. supposed to work great. I've used it a bit and found the results non-conclusive. I've had a lot of people tell it's the best thing since...whatever was the last best thing. It's been around since the '20s and is still going strong. Must be something to it.
It's been used in aircraft engines since it came out and people do swear by it. The FAA won't approve it, but kinda looks the other way when it's used.
I'm sure that some of the stuff works to a degree. the problem is that it's your problem to find out what that degree. Why bother?
Bare