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foureasy

New Member
Jul 9, 2009
478
0
0
tucson
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
 

Dcrac3r

New Member
Jul 4, 2009
5
0
0
washington
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.
 

foureasy

New Member
Jul 9, 2009
478
0
0
tucson
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.
 

TLDove

New Member
Jul 21, 2009
18
0
0
Lebanon,Pa
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
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,837
252
63
up north now
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!!!
I just did 7 carbs in 15 minutes!
 

foureasy

New Member
Jul 9, 2009
478
0
0
tucson
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).




 

foureasy

New Member
Jul 9, 2009
478
0
0
tucson
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).




 

gberry50

New Member
Jun 16, 2009
20
0
0
snowflake,az
check this out good working reed valve set up only worked on it for 36 hrs!!! from bar stock with hand tools ,man I need a small mill and lathe. It smoothed out the motor so much my speedo works again and my lights don't fall off after 2 or 3 miles .duh. but I do need help with nt carb jets, what size is the origional? .I had an expansion chamber but it was one of those with the rubber joints and copper pipe fittings for connectors what a pos that was for $75.00
spooky has one for $50.00 and bolts up direct buying that next.
 

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foureasy

New Member
Jul 9, 2009
478
0
0
tucson
throw that carb at your neighbors dog and get a dellorto 16/16 sha with a manual choke. about 75 bucks to your door. i have two pipes one is for stock motors ($80) and the other is for highly modified motors ($120) both prices include shipping.
 

sharkcruiser

New Member
Jul 14, 2008
71
0
0
charleston sc
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).




Good looking pipe! I bet that plucked your tuning fork when you first got on it
 

blahbada

New Member
Aug 7, 2009
2
0
0
Oakland, CA
anyone ever tried to make a supercharger from a smog pump? I hear it is possible, maybe only on a 4 stroker...? Let me know if anyone has info on it. seems like a legit way to make power on a small motor. force the air through!?