9 to 1 slower than stock.... help.

[HI808SYM]

So i was running stock gearing in my SYM dd50 (11 to 1) and I was topping out at around 52mph (reving out a little at the top end but getting there fairly quick).

i have heard people getting to 60mph with the 9 to 1.

I have 43mm bore (60cc i believe)
stock block
stock airbox and carb.
carb jetted to 40 pilot and 100 main.
kelly pulley with SEF ramp
1000 RPM center spring
1500 rpm clutch spring.that i have)



any help would be greatly appreciated.

i want to keep my stock airbox and oil pump (dont want to premix)

what do you think.....

[Wheelman-111]

Greetings:

I suspect the issue is that you didn't tune the variator load to the new taller gears. If you keep the stock load - whatever that is on the SYM DD - the RPM-controlled CVT attempts to "Shift" the belt at the same RPM as it did when you had 11:1s.
In 5-speed manual auto terms, the tranny goes into " "5th gear" too soon, dropping the engine RPMs down below peak power as you go "uphill" against the taller gears.

Try dropping mass from the stock 8.5 or 9 gram rollers, but not too much. A total decrease of 3 grams, like from 51 to 48, will tell you if you're going in the right direction.

Remember that if you didn't increase engine power, your top speed may remain exactly the same as it was, presuming the SYM engineers tuned the stock drivetrain correctly in the first place. In that event, the only time where you'll see higher speeds from a gearing change is when going downwind or downhill.

[Trafficjamz]

Get a tach for your scooter if you want to do transmission tuning, It helps a lot.

53mph on stock gears sounds very fast. I have not heard of any one under 72cc going 60mph with 9.1:1 gears

[HI808SYM]

thanks for the input guys. I will try lighter weights, but i think its the small size of my engine thats limiting my top speed.

time to upgrade.....

thanks again.

[Wheelman-111]

Greetings:

Gears alone may not make your scooter any faster (except downhill...), but they shouldn't have to slow it down any either.
Until the BBK arrives, consider installing a half-gram lighter rollers. Your speed of 52 is pretty impressive as it was.

[konaking]

Your lucky if you go 50 with that set up

[konaking]

What kind of weights are you running. I like to keep my weights as close to stock as possible with a small set up like that

[HI808SYM]

dropped weights from 8.5grams to 8 grams all around. got my 52mph back ant at least its not reving out at the top anymore.

I was reading the ZX trans mod earlier and it was saying something about getting a bigger belt so that it rides/sits HIGHER on the rear pulley (from a stop) restoring some low end power lost due to the taller gearing.

I understand that the SYM dd50 already has the "bigger" ZX rear trans.

question is can i just get a bigger/longer belt to ride higher on the rear pulley to restore some of my low end??

currently running stock belt and kelli variator w/sef ramp.

[evilone]

question is can i just get a bigger/longer belt to ride higher on the rear pulley to restore some of my low end??

Longer belt will make you lose the top end you just got back.

[HI808SYM]

thanks,

I should have read through the entire thread (zx trans) before asking.

did anyone have "success" with using the bigger rukus front variator to get the top end back after putting on the bigger belt. I have read that people tried it but results were a little unclear.

[eliteguy50]

thanks,

I should have read through the entire thread (zx trans) before asking.

did anyone have "success" with using the bigger rukus front variator to get the top end back after putting on the bigger belt. I have read that people tried it but results were a little unclear.

If your engine has the power, you will gain the top end. If your engine does not have the power, then the ruckus variator will not change anything.

[Bear45-70]

Engine basics 101.

Torque controls acceleration, gears multiply torque.

Horsepower determines top speed, gears have no effect on horsepower.

The exception to the top speed thing is if the engine runs out of the ability to rev higher because of too low of a gear ratio.

[Wheelman-111]

Greetings:

The Bear is egg-zackly right. One other exception: Drag and rolling resistance fight Horsepower to limit top speed.
When drafting a truck, car or even another scooter, drag decreases. If tou have taller gears, you'll go faster. Ditto for downwind or a stout tailwind.
A larger Vario face can increase overdrive, but the limiting factor can be the diameter of the fixed outer pulley facing it. Koso and others made a (pricey) Alu outer face.
JiangWayne carried one not long ago.
Ultimately Torque x RPM dictate top speed.