get fast

appearently i cant post pics yet so you are going to have to use your imagination.

the motor i am building right now is a 66cc or an "80" if you are bad at math, the first thing in order was a pipe. so i built one out of stainless. i was amazed at the difference, i'm mostly a 4 stroke (harley) kinda guy, so i was expecting the first version to barely run. anyways the primary pipe is 1"d and the chamber is 3"d for 3" and the ends of the chamber taper from 3" to 1" in 2".(a picture would be worth at least this many words) now is when i ordered the dellorto 16/16, more on that soon.
next on the agenda was a little more compression and reshaping the combustion chamber. i took 1.5mm (about .060) off the top of the cylinder, and squared it up at the same time (it was almost a half degree off square). now the head needed a nice bevel around the combustion chamber so the piston won't hit. with this done the midrange picked up considerably, it made a bigger difference than the pipe.
last but not least was the carb. it finally came in yesterday, (after more than a week) 73 dollars to your door. anyways, bolted it on to establish a baseline and get a plug reading. total crap! way too rich. pulled the air cleaner off, now it's rich but it runs. took out the main jet (82) and matched it up to some holley air bleeds. everyone on here keeps talking about buying all kinds of jets, well i'll let you in on one of my secrets. SOLDER!! go buy some resin core solder and a lighter, and some super tiny drill bits. anyways, i ended up with a .025" hole in the main and gained about 5 mph. wow what a difference, it just keeps pulling.

keep a look out for my updates, on the menu is a full port job specifically for high rpms and top speed and a new pipe design once the motor is done. clay

Cool!! Your jet size of 0.64mm seems about right. I have similar mods and run 0.65mm with the stock carb (I tried a Cheapie Delorto knock off and never could get that carb to work right, so I went back to stock.) and expansion chamber and increased CR with squish zone.

Actually no secret on the solder and drill method. Norman does it, Ghost0 and others do it.

WELCOME!!!

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This is the kind of thread I will break lurker status for. I plan on doing about the same build, i just want to eventually run e85. (i come from turbo cars)

pics would for sure be cool though.

there is a problem with e85 on a two stroke though. the alcohol cleans all of the lubrication from your crankcase, the only way to keep the crank and rods from rusting is to drain your fuel every night and run a couple bowls of regular fuel through the motor to lube it back up. this comes from two stroke drag quad experience, it's a huge hassle on something you ride almost every day. then again the motors only cost a bill.

Very nice! How did you figure up the pipe?

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Everywhere I go I smell like a lawnmower

that pipe was pretty much a stab in the dark

It looks outstanding. I look forward to seeing what you craft in the future

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Everywhere I go I smell like a lawnmower

need tips on good after market parts just get ready to order motor not sure what to get gonna build a board racer frame for vitage bike hope to ride soon wish i thought of all this sooner

I just did 7 carbs in 15 minutes!

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If it ain't broke, and you mess with it long enough, it will be.

it's been awhile. a little more port work, a new and (much) improved expansion chamber, and a speedo. with the original pipe and carb we were clocking 32mph with a 36t sprocket and a calibrated bicycle speedo. adding the new and improved pipe gets you 36mph with the 36t sprocket, and the race port with a 31t sprocket gets you 41mph (46mph on a 2deg grade).