derestricting Agility 50 question

[usedbike]

Hi,
I modified the CDI and installed the new variator boss in my Agility 50.  Now the scooter goes almost 45 mph but with a significant loss of power.  I did not change the jet in the carb.  What should I do to regain the lost power while keeping the top speed?

[zombie]

Nothing you did should have changed the power of the bike.
Take your new boss back out, and check the length of it compared to the original that came out. They should be EXACTLY the same . One millimeter is a big difference.
You may also find something went back together incorrectly, ie: missing "V" bushing, sideways roller, ramp plate not completely seated.

Something has to be wrong there for the output to change. Especially if that is ALL you did.

Also make sure the new boss has NO side to side play on the crankshaft or inside the variator bushing. Any side play will translate to a wobble, and in turn a loss of power.

[njagility]

If the scooter will do 45, it's not really low on power. It's unlikely the variator was assembled wrong either since you'd have to pretty much be in "top gear" (cones togther) to get to that speed. Now that you can get to a higher gear, maybe that's slowing down your acceleration? If so you may need to change the variator roller weights.

See http://www.kymcoforum.com/index.php?topic=12205.0

[BettinANDlosing]

Did you cut your cdi? I've heard some people say this actually changes the ignition curve for the worse. Sure it gets rid of any redline but robs power by retarding the curve. I usually sell customers the people 150 cdi to get rid of the limiter, works great.

[zombie]

It does nothing to change the curve. They start at 15* BTDC , and run in a straight line to 4* BTDC @ 8500 rpm. Same curve as is on every carbureted kymco made.

The limiter simply stops firing every other stroke at 8500. No voodoo involved.

[usedbike]

Thanks for the replies.  I did the aforementioned modifications in two steps.  The first step was to cut the wire in the CDI.  This raised the speed of the scooter from 30mph to 36mph with no loss of power at all.  The next step was to replace the boss in the variator.  I used a part ordered directly from Kymco.  Although the scooter will now go 45mph, it really struggles to get up to even 40 mph.  The power seems to be about the same up to 30 mph, but above this speed, the scooter really struggles to gain speed.  On a perfectly flat road it will slowly (very slowly) get to 45.  If there is even a very small rise in the road, the scooter will barely get above 30 mph.  I then disassembled everything to make sure I had assembled it correctly.  No problems were found.  I then replaced the rollers with 7.5g Ninja sliders.  This made things marginally worse (even less power).  Should I put the round rollers back in and install the 82 jet in the carb?  Will this larger jet restore the lost power?
Thanks!

[njagility]

Are you 100% sure you put the sliders in the right way around? I made the mistake of installing sliders (6gm) incorrectly once and performance was terrible. Also, 7.5 gm might be a little heavy for sliders - could be putting you into a higher gear more quickly than is best for acceleration.

[usedbike]

I went on-line to see a video of the correct way to install the sliders as the diagram that came with the Ninja sliders was basically useless.  With the original round rollers, the power is just as bad so I can't conclude that I installed the sliders the wrong way.
I am trying to determine if spending the time and effort to installed the bigger jet in the carb is worth the time and effort (to hopefully return some of the lost power).
Any input is welcome.
Thanks.

[njagility]

The only way you are ever really going to figure out if an 82 jet is better is to put one in and see. It's not all that hard to do.

I haven't rejetted an Agility 50 but I have rejetted and tuned a number of motorcycles. To do it right you have to do plug chops at wide open throttle to see if you're rich or lean (or have enough experience to tell from the way the bike responds) Also, in order to take full advantage of larger jets (probably larger than 82) - or even a larger carb - you may have to change the air filter system and exhaust system.

Really, the quickest way to find out if an 82 jet is better or not is to put one in and see. All the theory in the world can't replace one simple experiment. And it is a 50cc scooter. It's never going to be a rocket.

I'd again comment that I think 7.5 gm sliders are heavier than is normally recommended. Typically the optimum weight for a slider is less than that for rollers. Too heavy means it gets in to top gear faster, so you get slower acceleration and worse performance on hills.

[zombie]

What Niagility said.
 7.5 is good for Dr. pulley but 5.5 is what you need for Ninja sliders.
Do the jet swap, and you will gain some power. everything seems in order according to what you have done.
You can use a gram scale to lighten your sliders/swap the jet, and you will be good to go.
Also adding a 1500 - 2000 contra spring with give you a better power curve. You are on the right track. Just had the numbers wrong on the sliders.

[usedbike]

Thanks for the input guys.  The only reason I installed the 7.5 Ninja sliders is because that is what my local shop (they are now out of business) sold me and I did not know any better.  I will put the rollers back in (I think that they are 6.5), rejet the carb and see what happens.  What is this "contra spring" thing that people talk about?  I am not familiar with it?

[zombie]

It's the big spring inside the clutch. It "controls" how quickly the rear pulleys open. A stiffer spring will keep your gear ratio lower, longer, and give you better take off, as well as better hill climb ability.

I always suggest the Malossi RED spring for people over 150 lbs. The reason I use Malossi is because I know what it does, and I have little experience with other brands.
I have used Polini springs but they are NOT as strong as the Malossi.
You can pick one up for about 10 bucks.

If I were in your spot I would lighten up the Ninjas. You can even take them to the post office, and ask them to weigh them for you. A rat tail file in the parking lot, and you are good to go. That's what I did the first 6-7 times till I bought a gram scale.