Buddy 50 budget tuning

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Joined: Wed Mar 07, 2012 1:00 am
Location: Santa Fe, NM

Buddy 50 budget tuning

Post by mattytee »

Last summer, I found a 2018 Buddy 50 for $1200 with just over 1500 miles on the odometer.

Why a 50cc? In New Mexico, 50cc scooters need neither registration nor insurance. This saves at least $100 a year in ownership costs. Also, a motorcycle endorsement is unnecessary. I do have one, though, as I've been riding scooters and small motorcycles for many years.

Altitude here is 7500 feet. The Buddy was a bit anemic. Maximum speed, derestricted, was ~38 bMPH (34 MPH) and it took a while to get there. Speed decrease on hills was dramatic. Drove for a few hundred miles this way, mostly WOT. Wasn't looking for a higher top speed, but definitely wanted more acceleration and better hill speeds. My goal was to accomplish this as cheaply as possible.

This scoot now launches hard off the line and has good acceleration. Speed holding on hills is MUCH better. Gets to ~45 bMPH (performance loss is around 30% due to elevation).

Final build:

Cast iron 2-ring 72cc Taiwanese kit $108 (eBay)
MLM People's sidebleed pipe for Buddy $150 (Treatland.tv)
5 gram no-name sliders $10 (eBay)
Gates PL30508 $16 (eBay)
Colder NGK BR9ES plug $4 (Amazon)
Modified airbox (free)
85* main jet $8 (jet kit from Amazon)

Total cost $296

* This jet would be too small at lower elevation. I'd guess 95 or larger at sea level

I think I got the last discounted pipe. It had been mounted but not run. A few scratches that were hardly noticeable. Handmade in USA. This pipe is amazing quality!
Hopping up a Buddy 50 could be done for under $350 using the Scooterworks stage 2 kit, or under $400 for name-brand (Malossi, Yasuni, Dr Pulley, etc).

Things to consider:

- Factory rollers had flat spots at ~1700 miles and the belt width was already reduced ~1mm -- this was with stock bore and pipe. I would have expected them to last longer, maybe all the WOT riding?

- Sliders do seem to work better than rollers; variator closes further, belt travel was still good with lighter sliders (use Sharpie on the variator to show belt travel)

- Factory clutch shoes and bell were both pretty glazed at ~1700 miles and were given a thorough sand/scuff

- Factory airbox is too restrictive for an expansion chamber, suspect that this is why people lose bottom end with the Prima pipe

- Cheap BBK needed a lot of port chamfering before use, rings would have been destroyed without taking care of this. Definitely not bolt-and-go. Higher end kits may be better in this regard

- Jetting the carb takes a lot of trial and error -- lazy way is to disconnect from intake and airbox, then flip the carb upside down without disconnecting throttle cable, choke, etc

- Plug may be on the cold side?

- Bought 1500RPM clutch and contra springs also ($17) but I need a 38mm socket before I can make the swap

Main jet dimensions for the stock Buddy 50 carb, per jetsrus:

THREAD SPEC = m4 x 0.7

Links for posterity:

https://www.ebay.com/usr/dragonparts020 ... 2749.l2754
https://www.treatland.tv/MLM-genuine-bu ... pe-495.htm
https://www.amazon.com/Round-Main-Scoot ... B07ZH44KBQ
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