Gear ratios?

[Troll]

What would be a good setup for a 60cc when it come to the transmission, 18*46 or 16*42

[carasdad]

What would be a good setup for a 60cc when it come to the transmission, 18*46 or 16*42
First folks need to know..what is it now? You say 60cc..so I assume this is a 4 stroke with a 44mm bore vice the stock 39mm bore?

[Troll]

Ya it's a 4stroke, it has 6gr sliders in a racing variater, racing clutch with high RPM springs and contra spring. (Not sure which springs cause they were installed before I got the scoot) besides that everything else is stock for now.

[carasdad]

Ya it's a 4stroke, it has 6gr sliders in a racing variater, racing clutch with high RPM springs and contra spring. (Not sure which springs cause they were installed before I got the scoot) besides that everything else is stock for now.
Is it a long case or short case engine? i.e. does it have 10" or 12" tires? Note that even some of the short case like the TaoTao T3 had 12" tires..just low profile ones. It is best to count what gear set you as not all engines have the same stock gear. Then you go from there..:tup:

[qwertydude]

Generally when you enlarge one gear you have to shrink the other one. I think you may have your gear combinations wrong.

So it might be 18/42 and 16/46. The 18/42 will give you higher gearing which if you have enough power will give you more top speed. The 16/46 will give you more low end torque but you might find you run out of revs. Generally when going with a bbk the taller gears benefit you more.

[Troll]

I posted the ratios the way they were posted on the site. If I can find them again I'll post a link to them. It's a short case with 10" wheels, I'm wanting to find the 12's for a short case or switch out all around to a long case. I was told the gears only make a difference on a stock motor and was gonna run them till I got anouther case to do a full mod rebuild.

[qwertydude]

Taller gearing makes no sense on the stock motor. You'll actually more than likely lose top speed as it may take your engine out of its power range or reduces your acceleration because the initial gearing ratio on a start is too tall.

[Troll]

Ok, I was just wondering. Thanks

[skuttadawg]

Blue = 1k yellow 1.5k and red 2k . You may want to try a gram heavier in sliders . To truly have it a screamer you would want a 50mm BBK with a big valve head which would have better flow than the stock head like on the top of this page http://www.scrappydogscooters.com/139QMB_50cc_Performance.html

Regardless what you do it will only go so fast and if you push it beyond its limitations expect part failure and shorter engine life . I had a "secret 63 " and put on an Air Sal 50mm BBK which had way more takeoff and uphill but had the same top end just did not have to redline it to do so .

It is much easier to build a small 2T scooter to fast than building a 4T .

[Troll]

My last one I ran a 72cc kit in it and always burnt out my crank bearings. This time I'm going to find a block and do it right from the crank up and go with an 80cc kit.