Buddy 50 with after market exhaust bogging around 30 mph

[buddys_n_blasters]

Hey everyone,

I recently came into my second Buddy 50. Unfortunately, it bogs down between about 25-33 mph. If it makes it past that, it takes off all the way up to 55 and runs great. The only piece of it that is not stock is the exhaust. It is a tecnigas after market exhaust. Given this is the only non-stock piece I'm assuming it is the culprit. Problem is, I have no idea how to fix this. I did all the basics - new plug, new gas, new battery. Everything is in order and it works great except for this bogging issue.

Can anyone help me here? I'm not even sure where to start

[sc00ter]

Is it the expansion chamber style exhaust. There are 2 different ones, a R and a RS. One favors take-off and the other top end. I forget what one does what nor how to tell them apart. Both do require at minimum different roller weights from stock and stiffer torque spring most of the time, to get them in their proper power band.

[ohiomoto]

Generally speaking, fuel delivery, intake, or exhaust issues wouldn't be intermittent.

Any chance that the variator and belt are hanging up? Sc00ter pointed out that they can be used to tune performance. Worn weights or variator pullies could cause the issue you described.

[az_slynch]

I think sc00ter is on the mark on the pipe. I have a Techno circuit on a Piaggio Ciao that made great power up top with was pretty gutless down low. I had to tune the clutch on that to allow the engine to hit the pipe earlier in order to have acceptable takeoff.

I'm thinking you could put a 5 or 5.5 gram rollers in it and maybe a base level torque spring, the NCY black one works well.

[buddys_n_blasters]

Update:

I pulled the old rollers and weighed them: 7.5 grams as expected.

I replaced them with 6.5g rollers and the problem resolved entirely. Great acceleration now all the way from 0 - 50. I think the top end took a hit, probably maxes out around 50mph now. Not the end of the world for the way I use it.

No need to mess with any springs, or so it seems.

Thanks everyone!