Who has done Just a Big Bore Kit

[itzmepete]

Anyone done a big bore 72cc kit on a Sr50 94 to 2001? Just the big bore kit and maybe muffler, with stock car rejetted. No gears or clutch work and what kind of top speed preformance gains did you get. Pete

[burnt_toast]

Dac, this post is calling for you..

[Dac]

no this one is not calling for me.
i did a gear change.

you need a gear change to keep your motor from over revving. With a stock carb/pipe your bike is not going to last as long or go as fast.
A scooter motor is like a car stuck in one gear. Say stock is 1st gear, no matter how much you mod your motor, with stock gears you are never going to go that fast.
now say that 8.44:1 gearing (good for a 72cc kit) is like 2-3rd gear. With the motor turned up (via bore kit) The take off will be the same, Some times a hair better. and being in a higher gear you can go faster.

My Bike is a 96, i got a CMR bore kit ( a weak 72cc kit) , stock carb, stock pipe, 8.44:1 gearing, and a pod air filter.

My bike is not 100% broke in, but i have taken it full speed a few times. Even with my fat * i got it to 50mph. Take off is d*** good. All around its not a bad bike.

[happyman]

no this one is not calling for me.
i did a gear change.

you need a gear change to keep your motor from over revving. With a stock carb/pipe your bike is not going to last as long or go as fast.
A scooter motor is like a car stuck in one gear. Say stock is 1st gear, no matter how much you mod your motor, with stock gears you are never going to go that fast.
now say that 8.44:1 gearing (good for a 72cc kit) is like 2-3rd gear. With the motor turned up (via bore kit) The take off will be the same, Some times a hair better. and being in a higher gear you can go faster.

My Bike is a 96, i got a CMR bore kit ( a weak 72cc kit) , stock carb, stock pipe, 8.44:1 gearing, and a pod air filter.

My bike is not 100% broke in, but i have taken it full speed a few times. Even with my fat * i got it to 50mph. Take off is d*** good. All around its not a bad bike.

Dac i did as you said and give the really nice folks at VT a holler and ordered a huge pile of parts for two scooters and the one thing Koeni was wanting me to do was change gears. i aked him which ones and he said to run the 9.1 gear as he kinda felst that was going to be all it would want.. i am going to run stock carb myself as he said its will work very nice. i wan tot continue to run my oiler is why .. anyway he shaid it should run bout 60mph or so + or - . oh yeah am going to run the cast iron molossi if i don''t likeit its easy enough to change/ this may help the others make decisions too

[itzmepete]

So I think my best bet right now is to upgrade my cylinder to a 72cc kit, I already cleaned out the carb and it runs great so re-jet it with a #100 jet and instead of buying the aftermarket R1 muffler, get the gear set instead.
Maybe replace the Variator rollers. I should get a hipo ramp and new rollers, can't be that much. But Cylinder kit, Carb Jet and Gears for starters. Then Muffler and Variator. All Agree???

The bike has 2200 miles. The muffler can wait as well as the speed variator. 50 to 55 mph is fine by me.

[stillspeeding]

with the stock gears and a bore kit - it will blow a stock derestricted engine needs 9 to1 ratio=53mph, with a dio rear pulley conversion maybe 59mph, so far know one has done it, i have it on my 107cc stroker

[itzmepete]

Where do you come up with this? A stock derestricted engine won't pull a 9 to 1 and if it did, it would bog down at the first incline or headwind. My stock factory derestriced does 35 and slows down 33 on a slight incline or really strong headwind. Like wise down that same incline does 38 and with a tailwind does 38. The stock bore doesn't have the torque to push 9 to 1.

[Dac]

a stock bore will push a 9:1 gears. but yeah, it will slow the take off a little. As for the "53mph" stuff. thats total s***.

[darat]

well i have done a few things to my se and areo so this is no different its not hard to put a bore kit in.