139QMB Valve spring size? By cdoublejj (Read 3,271 times)

[jct842]

Just get a 150cc gy6 engine and a welder even with exotic upgrades you still have a 50cc basic motor. We used to hear from some of the guys that did the exotics and some of their scooters must have had $2000 $3000 in the motors. and then they would blow up!

[cdoublejj]

bud i've done that before i have s 1974 Honda Z50 that does 75mph and can get there quick. easy stuff. I'll be pushin it 239cc later in an attempt to break 90mph. whoe other story. Its also more power than i want for my scoot and far far more expensive.

Predetonation can be reduced by taking care to reduce or shave sharp edges in the combustion chamber ...all of piston included. google images nascar pistons. look how smooth they are. i'm not certain there wil be enough C:R to detonate 01 octane but, if it is we might be able to tell if the amount decked is a lot.

[Alleyoop]

Is this you...LOL

[cdoublejj]

only in first and second. it's geared very very tall. the front and rear sprockets are almost the same size. the rear hub has to be machine to get the next sized down sprocket which i will need but, again this is all another. story. when i pick that project up again, i'll try to cross post my on going build log from planet minis forums over here.

Any ways if i source some springs or find any thing cool about crank balancing out i guess i'll post back. i found some cool information over OMB forums about crank balancing.

juicemotoparts.com/crankbalancing

www.neme-s.org/Model_Engineer_Files/2924-Balancing%20Single%20Cylinder%20Engines.pdf

i'll try to get some specs on my springs and post back for what it's worth. If i don't forget and fall off the earth.

[cdoublejj]

OIL PUMPS!!! did that one guy ever post back with his oil pump mod? I just saw a super chinsey 100cc upgrade kit and i includes a pump and gear. It would be so nice if there higher volume pumps out now!