high compression tuning and gas mileage

[mason79]

okay this question popped up, i tested my compression twice with a year in between, it shows 175 lbs across the board

is it true that all else being equal ths higher comppression alone will make more horespower?.

someone suggests i take seafoam and blow this stuff ( carbon) out, is that a myth?

if i like the high compression, can i work with it? it was pinging until i raised my needles 1 notch from stock and it runs very well, except the mpg went from 32 to 28, which is not good

the plugs look good, the jetting is all stock the only mod is a slightly holy stock exhaust on the right side and a uni drop-in air filter

and i did turn the idle screws 1.5 turns out they were 2.5 turns before the needle change and i left them, at 2.5 for the mileage check, do they affect gas mileage? now they are at 1.5 no mileage check available yet.

could it be the floats like i said the bike runs very well, except the idles moves higher when the engine is fully hot.

[DiverRay]

If you KNOW the motor is stock, it's time to CLEAN THE CARBON!! You can have all kinds of problems with a carbon buildup. If the engine is knocking, and you can't really hear it, you can cause piston failure.
I would take a spray can of Berryman's or Seafoam, pull the bottom of the air cleaner, and spry into all 4 carbs once the engine is warm. After about 1/3 to 1/2 of the can, try to kill the engine with the spray. Turn off the ignition, and let it set for about 10 minutes. Restart the bike, take it out and run it up to redline in second gear, to clean the last of the carbon off. I use the freeway for this part, as it's a little fast for around town.

[81xsproject]

There is also the water method and the MMO method. With a spray bottle mist some H2O into the intake(s) while it is running (have never done this, but it is supposed to be one of the best ways). Or, do the Hobbieman and pull your plugs, move a corresponding pair of pistions CLOSE to TDC (1&4 or 2&3), fill cylinders w/ MMO, turn crank to TDC or until MMO comes out the sparkplug hole, soak overnight, then w/ a turkey baster or a long piece of vinyl tubing extract most of the MMO. Repeat for other pair of pistons.

On a personal note, I have done the MMO method only because I hadn't yet learned the H2O trick.

[mason79]

yeah i just got done trying the berryman spray, but more of the stuff drain out than got sucked in the carbs, so i sprayed the whole can in the gas tank which is near empty, i'll try that, i'll ride it tommarrow
and how can you real tell if it is carbon build-up? yes the engine is stock....175lbs compression?

[GtrMn]

Haven't checked in a while but mine may be high...165+ So what the heck is MMO

[mason79]

marvel mystery girl

[GtrMn]

Haha that stuff actually works? Always thought it was snake oil.

[fredintoon]

RedeX tune-up

I guess the snake-oil wells will never run dry, eh?
back 'ome they'd give you a shot of RedeX upper cylinder lubricant with your gas. One shot per gallon at a penny a shot.
Or you could do a "RedeX tune-up" Run the engine at 3/4 throttle and pour RedeX into the carbs until the motor nearly stalled and you couldn't see for white smoke, let the revs build up again and repeat until the quart can was empty. It was supposed to loosen the carbon deposits in the firing chambers and on the valves and blow it out of the exhaust.
My bro-in-law knew an old guy who ran a funeral business. The guy's Jaguar sedan did most of it's miles at 20mph in funeral processions. He'd bring it round "for a tune-up" All Terry did was take the Jag on the motorway and drive it flat out (no speed limit then) for a hundred miles.
Perhaps that's Mason's answer, 100 miles at full throttle to blow the carbon out?