Modern Buddy

Hello..

So i thought i was a mechanic for some reason and that i would be able to put my new prima pipe on my 50cc buddy. Though i did partly do it because someone one here said it was easy but oh well..

well getting it on there was easy.. But then it just wouldn't start at all..

So i figured i needed to change the jet, so i put on the #90 that came with my exhaust (the stock one is 75 i believe)..

After putting the #90 in the carb, i can start the engine but only if i open the throttle a little, and even then it seems to struggle. A lot of smoke comes out of the exhaust (looks like way more than it should be).
Also it won't idle at all.. OH and the back wheel doesn't spin at all no matter how much i open the throttle!

Then i figured maybe i should try a smaller main jet.. So i put the #80 on there and it's exactly the same.. All the same symptoms..

I know it's my own fault for thinking that i knew what i was doing, but could you guys please help me out? it would be much appreciated!

Wierd. Wish I had an answer for you as to why it won't start up. Seems like an exhaust swap would not cause any problems like that.
Did you keep the scooter upright during the install?

I plan to add the Prima on my 50 at some point. Keep us posted as to what it takes to get her up and running again.

Did you touch the variator, belts, clutch, or anything of these during the install? I'd think it would atleast idle even with a belt that was lose or off, but I doubt that is the case. Have you tried using the main jet that come with your bike?

Have you adjusted the idle also? Or is it the same as stock? If your idle is too low, I'd turn it a bit higher. It'd odd for the pipe to cause all these issues if you left everything alone besides the jet. Swap out the pipes and jet to make the bike back to 100% stock, see if it will run normally, if not, your dealer needs to look at it.

What's your elevation and did you touch anything else?

The variator, clutch, or anything?

Just bolting on the exhaust should not cause it to not start, nor should it require a jet that is 15pts higher than stock. That's a huge jump.

I did not keep the scooter upright during the installation..

is that bad? what now? man i guess i was not prepared for this project after all..

oh i'm about 30 feet above sea level btw

Oh another thing is.. when i was removing the stock pipe, there was this extra little plastic canister attached to a little pipe coming off the side of the main pipe.. if that makes any sense.. its kinda late.. anyway i figured maybe that is the catalytic converter.. but could that have something to do with it? the prima exhaust doesn't have the extra little pipe off the side to acomodate it.

kuskus wrote:I did not keep the scooter upright during the installation..

is that bad? what now? man i guess i was not prepared for this project after all..

oh i'm about 30 feet above sea level btw

Oh another thing is.. when i was removing the stock pipe, there was this extra little plastic canister attached to a little pipe coming off the side of the main pipe.. if that makes any sense.. its kinda late.. anyway i figured maybe that is the catalytic converter.. but could that have something to do with it? the prima exhaust doesn't have the extra little pipe off the side to acomodate it.

What do you mean you didn't do it upright?

Did you lay it on its side or something?

That little plastic canister shouldn't be giving you any fits.

The little plastic canister is for the emmissions stuff so don't worry about it. Laying it on it's side would only make a mess (possible oil spillage etc.) but shouldn't affect it's running condition. It will change the air/fuel flow of the scooter. Did you try any carb adjustments (idle or air) when it wouldn't start? Don't worry about the wheel for now, I'm sure it will turn once the engine is running. My Rattler wouldn't start up right after I put my new pipe on either. Had to cut down on the air mixture at the carb.

Hey thanks for the help guys

So it should be working fine?

As far as the idle/air adjustments.. I kinda messed with the little black knob on the side of the carb, but i didn't know what i was doing and didn't want to make it worse so i put it back the way it was. Any suggestions as far as that goes?

Well usually laying it on the side shouldnt do anything major, but maybe the engine got flooded and thats why it makes so much smoke then dies? Not sure. I'm thinking that little black piece you tampered with may be the issue and isnt the way it was stock.

So how do i fix it if the engine is flooded?

I don't think the little black knob is tto blame because i only messed with that at the very end.. and i'm pretty sure i put it back more or less the way it was..

hmm this sucks..

Definitely check your air screw... don't know the exact location on a 50 but it's most likely hidden by the black idle adjustment screw (look for a little brass screw with a slotted head on it). It'll be easier with the pet carrier removed too. Screw it all the way in, then back out about 2 turns and tune it from there. If the carb is flooded just crank the engine a bit without adding any throttle and hopefully it'll work itself out. If not there is usually a drain screw on the bottom of the carb bowl for such disasters. I'm willing to bet you're 75% of the way there so don't dispair

So i guess i was worrying for nothing, i think the engine was just flooded.. I ran it for a little while and it started working normally.. heh i feel dumb now

So now it works.. but when i accelerate, i don't really go anywhere at first and then i just take off suddenly... Though i'm guess that's just a tuning issue and that once i put the new weights and spring in there it will be a lot smoother..

i do wonder about the rubber tube that the little emissions canister thing was hooked up to.. now it's just kinda hanging there.. what am i supposed to do with it? The other end is hooked up to the transmission enclosure..

Thanks again for the help everyone

Do weights first.

Then see if you need a spring.

You probably shouldn't

Yeah that's what i was going to do next.. Actually i tried yesterday but the cheap impact driver thing i got to take the nuts off isn't even powerful enough to do so...

Guess i shouldn't have gotten the $20 one heh

Anyway how about that rubber tube? what should i do with that?

Anyway how about that rubber tube? what should i do with that?

I had the dealer install a prima pipe on my kitted 50cc and they told me there are pretty much no emissions with the new pipe. I don't think you need the rubber tube anymore.

Don't feel bad, my dealer had a hell of a time with my pipe and tuning process. They installed light roller weights (~5g) and a jet that was only a few steps up from the original.

That strange sudden acceleration happens to me also... I don't know the cause. Perhaps it has something to do with the air fuel mixture in the pipe or something. Keep tying different combinations of rollers/ jets and good luck!

Scootbeast wrote:

Anyway how about that rubber tube? what should i do with that?

I had the dealer install a prima pipe on my kitted 50cc and they told me there are pretty much no emissions with the new pipe. I don't think you need the rubber tube anymore.

Don't feel bad, my dealer had a hell of a time with my pipe and tuning process. They installed light roller weights (~5g) and a jet that was only a few steps up from the original.

That strange sudden acceleration happens to me also... I don't know the cause. Perhaps it has something to do with the air fuel mixture in the pipe or something. Keep tying different combinations of rollers/ jets and good luck!

No emissions? I think you need to talk to your dealer again. That's funny.

Scootbeast wrote: I had the dealer install a prima pipe on my kitted 50cc and they told me there are pretty much no emissions with the new pipe. I don't think you need the rubber tube anymore.

Don't feel bad, my dealer had a hell of a time with my pipe and tuning process. They installed light roller weights (~5g) and a jet that was only a few steps up from the original.

That strange sudden acceleration happens to me also... I don't know the cause. Perhaps it has something to do with the air fuel mixture in the pipe or something. Keep tying different combinations of rollers/ jets and good luck!

The acceleration is what it's supposed to do, it's the expansion chamber filling.

We refer to that as "hitting the pipe"

Eazy wrote: The acceleration is what it's supposed to do, it's the expansion chamber filling.

We refer to that as "hitting the pipe"

If you weren't looking for improved acceleration (the improvement you're noticing from a standing start), what were you looking to improve on (other than aesthetics) by installing the pipe?

I'm not complaining about the acceleration so much as the fact that the scooter doesn't go anywhere for a good second when i first open the throttle, the suddenly takes off..

kuskus wrote:I'm not complaining about the acceleration so much as the fact that the scooter doesn't go anywhere for a good second when i first open the throttle, the suddenly takes off..

It needs to build up compression in the chamber... maybe give it a little more throttle on standing starts, but put your weight up front first. If you put in different weights and higher rpm spring in it might even further 'delay' your takeoff, fwiw.

I read that adjusting the air screw in the carb can help with bottom end response.. has anyone tried that?

kuskus wrote:I read that adjusting the air screw in the carb can help with bottom end response.. has anyone tried that?

I did a rattler recently with the prima pipe and 5g rollers.

I adjusted it to where it idled to the point it was turning the tire a little.

0 to 3 was kind of sluggish, but 4 to 45 was OMG FAST!!! for a 50.

I backed it out because it was almost scary to ride in the rain.

you adjusted the air screw or the idle screw?

kuskus wrote:you adjusted the air screw or the idle screw?

Idle.

The black one on the side of the carb.

kuskus wrote:I'm not complaining about the acceleration so much as the fact that the scooter doesn't go anywhere for a good second when i first open the throttle, the suddenly takes off..

This is a sign of a poorly tuned transmission. The effect you are feeling is analogous to starting off in second gear in a manual transmission vehicle. You probably need lighter roller weights then probably slightly tigher clutch springs.