Modern Buddy

so i got my new tuned pipe for my rattler 110 yesterday from scooterworks in chicago




it sounds great and makes it fly

it made this bike into a wheelie machine

the pipe is tuned to make max power in the stock rpm range 5500 to7000

so just bolting it on was an instant improvement

NICE

That looks very cool!
Not sure how the original expansion chamber looked, but that one looks huge.

Looks like it on a dyno.

What kinda b4 and after numbers are you getting?

Can you post up some hp/tq curves?

That think looks like it should breathe fire. Watch your ankles!

hows it going man that pipe looks great is it faster than the buddy.so when we going to go ride probably sping huh

What jetting changes did you make?

Mine is definitely lean above half throttle with the same pipe, stock jetting and a .5 mm shim on the needle jet.

Stock jetting:
85 Main
35 Pilot

That's the dyno at Scooterworks. I was sent the same picture about two months ago by the guy developing it. They designed it to work well with the stock airbox and jetting, and to boost power in the stock RPM range. For those who want more than that they are currently working on a high (er) rpm big bore kit, larger carb, different pipe etc if you want to go all out on it. To get the best results you need to change the contra spring in the transmission too. I haven't been able to try them out yet but it's also supposed to respond well to heavier 13g weights instead of the stock 12g. I can verify that it does not perform better with lighter 11g weights and the pipe + air filter + contra spring. All this info is also at yahoo group genuinerattler too.

Yesterdays test ride with the Prima pipe, stock air box, needle jet shimmed .5mm, and 2,000 rpm compression spring revealed less indicated top speed than stock. 52 indicated was about it, though I was hesitant to hold the trottle open an excessive length of time with a new setup............I've seen 62 indicated stock.

At 45-50 mph the last 40% of throttle input has no effect, which tells me it can probably use more fuel through the main jet. I haven't done a high speed throttle chop and plug check yet, but I did check the plug after riding around the neighborhood and it was a milk chocolate tint on the electrode and insulator.

I have a 38 pilot jet (1 step richer) and 90 main jet (2 steps richer) on order, we'll see what they reveal.

I also tested a 2.75" x 3" Uni Filter pod, and the scoot would start and idle ok, low speed throttle off the line decent, then it would just bog like the plug was fouling. If I pinned the throttle right off idle it would pull through it, but it was basically not ridable. This filter indicates how restrictive the stock airbox is and how lean the carb might be is as delivered, similar to all of KTM's bikes out of the crate in order to meet US emission regs.

It will be interesting to see how much richer it needs to be in order to use the Uni Filter.

I'm running a Polini air filter on my 110 with the Contra spring, pipe and I'm waiting on my 13g roller weights. There's a second fuel adjustment screw on the stock carb that you have to adjust when you take the stock airbox off. Took forever to find it, directly behind the main idle adjustment screw. Using that to adjust the low idle made it possible to tune it much better, mine would bog down too at first until I adjusted that.

nissanman wrote:I'm running a Polini air filter on my 110 with the Contra spring, pipe and I'm waiting on my 13g roller weights. There's a second fuel adjustment screw on the stock carb that you have to adjust when you take the stock airbox off. Took forever to find it, directly behind the main idle adjustment screw. Using that to adjust the low idle made it possible to tune it much better, mine would bog down too at first until I adjusted that.

That's the air screw for the idle and pilot circuits. Typically they should be in 1.25 - 2.25 turns out range if your jetting is in the ballpark.

Not knowing squat about scooters - Would the 2,000 rpm compression spring I installed be limiting the top speed? It won't pull over 50 now on the same section it pulled 61 in stock trim.

the stiffer the comp spring the lower your top end will be

you should try stiffer clutch springs instead

aruntoo wrote:the stiffer the comp spring the lower your top end will be

you should try stiffer clutch springs instead

Thanks! Maybe heavier rollers?

as i said befor the pipe is designed to run in the stock RPM range

so if you put in lighter rollers antand a 2000 rpm spring now you are not using the pipe in the RPM range it was designed for

if you add the stiffer spring you also need hevier roller weights

if you are reving it to 9000 RPM you are losing power

Yup... heavier

bikebuda wrote:as i said befor the pipe is designed to run in the stock RPM range

so if you put in lighter rollers antand a 2000 rpm spring now you are not using the pipe in the RPM range it was designed for

if you add the stiffer spring you also need hevier roller weights

if you are reving it to 9000 RPM you are losing power

I understand torque and horsepower curves, I don't understand what mod's have what effect on final drive ratios.

You're implying heavier rollers will alter the final drive ratio thus increase top speed?

Is the primary function of the heavier compression spring to improve belt engagement?

Also, does anyone know a source for a shop service manual for the engine/transmission?

Only one of those mods affect final drive ratio. Weights only change the rate at which the ratios change to work with the power curve of the engine. Since you haven't changed the gearing, or the final pulley size top speed is theoretically unchanged. You may see an increase on top end due to a higher final RPM of the engine with the new pipe... nothing to do with weights.
If anyone knows where to get a shop manual for the 110 I've been looking too (in english of course). I'm not talking about a generic "automatic scooter" manual either.

ok here it is get a tack first

the rollers ultimately will determine at what rpm the engine stays at


if you hold it wide open and the rpm stays at 9000 you are doing yourself no good


keep the engine pulling in this RPM for best acceleration and top speed

if you over or under rev the engine it doesent have the power to obtain top speed

Yup

Understanding (visualizing) how the transmission achieves final drive ratio to capitalize on the engines peak torque and horsepower is what I'm trying to obtain.

My previous experience is with sprockets, ring and pinion, and transmission ratio's which don't apply to a CV scooter tranny.

Ideally I would like to achieve the maximum streetable 0-40 mph acceleration and a minimum 60 mph top speed. The stock compression spring with heavier rollers may be the correct approach.

I do have other 2-wheeled alternatives for speed