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Vpfalcon wrote:
I have a 1980 100 Sport, I put an ET3 motor into it. It runs fine, pulls very well in gears 1-3 but flattens out and won't pull in 4th. The motor was rebuilt then sat in a garage for 5 years. I paid $400 for it. I checked the compression after I put it in the Scooter and it's 90 psi. 4 gears is nice but I want more out of it. New rings might help.
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If it all works I will have an ordinary looking old smallie with a lot of speed.
Any comments or suggestions?
Are you a big guy? I'm about 200 lb and my '74 Primavera pulls 4th just fine with only a copycat LML 3 port top end like yours, a PHBL 24 carb and a nice Simonini pipe like yours, nothing fancy(but I do like that new box type). My gearing and even the porting are stock, the motor's never been split.
What is it you want again? Just pull 4th nicely even up a modest grade? Or be able to go really fast, like 60-65 on a smallie? Or be able to get up to any legal off freeway speed as fast as possible? How much money have you got? If it's the first, pulling 4th w/ no sweat, w/ your pipe maybe just a little bigger carb & manifold and you're there. Piaggio didn't build a dog when they put out the ET3. Put the rest of the cash into those nice, and safer too, rims you know you want
First things first. Assuming the motor was broke in and there're not brand new rings in there now, get new rings and a professional hone on a professional machine. They will be able to tell you if there's serious out of round or taper. Rings are cheap so it's cheap insurance. Check your timing and be sure the carb is happy(red tipped float needle?).
Now how do you like it? Unhappy, order that carb setup.
Different targets and somewhat different solutions. Or hit all 3 targets and get out your wallet, nothing wrong with that if you know where you're going.