fuel octane, my understanding,

it was to my understanding that higher octane gas is used for higher compression engines, because gasolines explosive properties change under compression, so 81 octane on an 6:1 engine is good but not on a 10: engine, and vise versa,

so with this understanding using high octane fuel in my 49cc moby would degrade performance and not improve it? unless i had a high compression engine kit?

just want to clarify im correct or am i mistaken?

noco said:

your right that higher octain will resist preignition from compression...but the higher octain will not hurt your performance....in these little motors youd just be paying more for gas...octain is a reference to the length of chains of molecules that the petro is made of....longer molecules will resist burning more and will have a longer burn time...

as for your explosive power thing...gas does not explode in the combustion chamber it is a controlled burn that heats up the nitrogen in the air wich expands and pushes on your piston...so basically if air wasn't 80 percent nitrogen(an inert gas) a internal combustion engine would not work...i may have side tracked myself but i hope i was helpfull

hey if we all didn't have ADHD then would any of us have built a bike???

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lol! yeah thanks for clearing that up, so our bikes would not run on mercury!


i just hear so many people talk about how it makes there bike so much faster with higher octane,

strange though, my old honda atc ran like crap on high octane,

noco said:

really on the honda??? wow it shouldnt have effected the performance if you advanced you base timing it should have given you better performance because of the longer burn time...did the honda maybe need a tune up???

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TUNE UP?? LOL!!! it was my 1982 honda atc 200 big red, its gas tank was a milk jug duct taped to the frame, the muffler was from a car but it was strapped on with hose clamps, i bottomed it out and cracked the block, it leaked oil, but it burned more oil then it leaked, it idled at half throttle, it shot 3 foot flames out the manifold rust holes every time you shifted, the axles were bent and the rims were smashed,
the cdi was from my pocked bike, the frame was more jb weld than it was steel,

SO YES! IT NEEDED A TUNE UP!! lol, but that damn thing never let me down, i would be 50kms away from home at 3 am in a -20 80kmh 3 foot deep snow storm and it never left me stranded, you can beat the crap out of a honda, you can abuse it like i did, but you can never NEVER kill a genuine vintage honda,

sigh i loved that bike,

noco said:

yeah!!! if you werent in ontario id say lets hang drink a few beers and play with a engines and a mig welder.... you sound like you'd fit in with my friends

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lol i think we would get along fine!, im for keeping stuff going the cheapest way possible, and having a blast doing it!, i do have my one thing i wont skimp on though, and right now thats my moby!,

well if your every around dundas or im ever heading your way lets make sure to meet up!