Exhaust and Variator Tuning

pocphil · Post by **pocphil** » Fri Apr 27, 2007 1:48 pm

I've been watching the "should I buy a Prima Pipe thread" and after seeing a lot of mis-information I'm going to chime in and hopefully shed a little light on the situation.

VARIATORS:

The STOCK Buddy 125 ships with 18x14mm rollers, the stock weight is 13 Grams. That's what it says on the build sheet. We've removed and weighed a few Buddy Rollers and they appear to actually weigh between 11.9 Grams and 12.2 Grams. This seems to be consistent with what we've seen from a few other variator manufacturers.

If you don't know why that is important read this web page written by a guy I race YSR's with:

http://www.teamcalamari.com/zuma/variator.html

Even if you think you know everything about variators it's still cool to see the animated .gif of a variator in action.

If you take any scooter and go to a lighter roller weight you will feel improved accelleration because the RPMs are going higher before you start to increase your gear ratio.

Great! - Phil, sell me a set of ultra-light weights...I want to go hella fast!

Not so fast, Buddy-San:

If your roller weights are too light, then there isn't enough mass to push the variator all the way forward. This will result in good acceleration, but a crap top speed. As the engine speed finally gets moving enough to move the pulley forward and raise your gearing, you will be above the optimum RPM of the engine, and it will not have the power to get you moving any faster.

Do NOT attempt to service or alter your variator or clutch until you've read and understand the following:

http://beedspeed.com/html-pages/HowToFi ... eights.htm

The factory (and their highly educated engineers) opted for the parts they put in that motor for a reason. They put those rollers in because they work. Even with a performance exhaust you aren't changing your HP/RPM profile enough to REQUIRE changing rollers. If you're a fat guy (over 250) you may want to drop to a 11 Gram roller just to overcome your mass with a few more RPM's. This may drop your top speed a little, but you'll get moving faster.

EXHAUSTS:

Slipping on that Supertrapp muffler is nothing more than a wild-ass-guess. It is a UNIVERSAL muffler designed for ATV/QUAD/MiniBike applications. When was the last time something "Universal" worked best? It is designed to be adjusted (by removing discs) to suit your application. Basically claiming you can personally adjust the backpressure to find a balance between sound and HP. Guess what you need to do that? A DYNO. Until you have a DYNO to test your changes all you are doing is inserting discs until the neighbors call the police and then taking one disc back out and apologizing. Backpressure is NOT a bad thing. That's where useable torque comes from. These little motors do NOT put out their maximum usable HP at absolute redline. If that was the case I'd say cut the pipe off 4" from the motor and run it wide open.

The Prima Pipe was designed specifically for THIS application.
The Prima Pipe works well straight out of the box.
The Prima Pipe gives a good balance between sound and performance.
The Prima Pipe usually doesn't require any jetting changes.
The Prima Pipe is made of Stainless Steel.
The Prima Pipe has welds that are the most beautiful I've seen.
The Prima Pipe has an excellent chrome finish.
The Prima Pipe costs $200 less than any other comparable pipe.
The Prima Pipe looks and sounds incredible.

If you haven't ordered your Prima Exhaust yet, you're obviously just worried about the $$$.

For those new to the scooter thing:
I designed, patented and hand-built the POC and POC II exhaust system for the Bajaj 4 Stroke Scooter. A pipe PROVEN to increase performance dramatically. We sold over 350 of them. If I thought I could build a better exhaust than the Prima I would have already done it and I would be pimping the hell out of them on this forum. I don't think there's anything I could do to improve on the Prima Pipe.

I have a Prima Pipe on my Buddy 125. I haven't re-jetted. After installing the pipe I gave it about a week to settle down (voodoo) and with a minor air/fuel mixture adjustment (at the screw, no jet replacement) the bike is running fine and faster. I don't know about my mileage because I don't bother with math on any vehicle getting over 50 mpg.

I am not the least bit worried about my warranty. I honored the warranty on EVERY Bajaj equipped with a POC pipe. A well designed exhaust will NOT cause your engine any more stress.

Now everyone repeat after me:

The Scooter-Tuners Mantra:

I AM SMARTER THAN THE ASIAN MAN IN THE WHITE LAB COAT WHO DESIGNED MY SCOOTER.

I AM GOING TO BUILD MY OWN SYSTEM THAT IS MORE EFFICIENT, FASTER AND RELIABLE THAN A COMPANY WHO HAS BEEN DOING THIS FOR 30 YEARS.

I AM GOING TO RUIN THIS SCOOTER - EVEN IF IT KILLS ME.

Sounds pretty ridiculous, doesn't it? Well, so do about half of the phone calls I get. How fast does the Buddy really need to go to impress you folks?

Yes, there will be a cylinder kit / big carb / Variator modification available shortly for the Buddy 125. I talked with Genuine about this a few days ago.
It will be coming soon. If it gets here soon enough I'll mount it on my Buddy 125 and test it by running it WFO on the Lake Erie Loop for 685 miles.

Make some noise - Call your favorite dealer and order the Prima Pipe, if they won't stock it - Call me - we like our Buddies to be seen AND heard.

rablack · Post by **rablack** » Fri Apr 27, 2007 3:43 pm

Great post pocphil. Thanks for the information.

Does anyone know if there is an aftermarket pipe for the 50cc 2T Buddy? Or one planned? I understand 2 stroke pipes are a whole different thing.

Post by **ericalm** » Fri Apr 27, 2007 4:47 pm

Spoken like a man who wants to sell some pipes!

pocphil wrote:Yes, there will be a cylinder kit / big carb / Variator modification available shortly for the Buddy 125. I talked with Genuine about this a few days ago.
It will be coming soon. If it gets here soon enough I'll mount it on my Buddy 125 and test it by running it WFO on the Lake Erie Loop for 685 miles.

A member heard just the opposite from his dealer. Weird. Check it out here:
topic1355.html

Unless what's coming is just the big carb and variator and not a cylinder kit.

Post by **jrsjr** » Fri Apr 27, 2007 5:20 pm

Hey Phil,

Thanks for that post! I hope that clears up a lot of questions about varaiators and the Prima pipe.

Now I have a related question for you. According to the PGO site, the BuBu (Buddy) 125 has a Bore and Stroke of 51.5mm * 60mm. To get 177cc from that motor requires a bore of 61.3mm. That's a big overbore on such a small cylinder. My question is, will the Buddy engine case accomodate a 61.3mm piston without machining? If not, that would be the end of the rumored 177cc bolt-on kit.

Thanks!

San Francisco · Post by **San Francisco** » Fri Apr 27, 2007 5:49 pm

How refreshing and informative. So nice to see someone back up their
statements with data and research.

I can rest easier now knowing my Italia with the Prima can is fine the
way it is.

Bonus Comment: Super funny, your Scooter-Tuners Mantra. I wish some
members would take the hint and not post unsupported statements on MB.

Sidenote: So true, how fast does a Buddy need to go. Mine hauls ass
around town. Any faster would be dangerous, careless, and dare I say,
immature. I guess one could soup it up for simulating trackdays or a night
on the drag strip, but I don't need the Buddy for that.

lobsterman · Post by **lobsterman** » Fri Apr 27, 2007 6:52 pm

pocphil,

Excellent information. I'll be going over the CVT stuff more later, thanks for linking that.

For me, the only thing stopping me from doing the Prima pipe is I can't justify the $200 to my wife. She still thinks I bought the scooter for my commute.

(honey, if you're reading this, that last bit was a joke)

glhboy · Post by **glhboy** » Fri Apr 27, 2007 7:04 pm

San Francisco wrote:How refreshing and informative. So nice to see someone back up their
statements with data and research.

I can rest easier now knowing my Italia with the Prima can is fine the
way it is.

Bonus Comment: Super funny, your Scooter-Tuners Mantra. I wish some
members would take the hint and not post unsupported statements on MB.

Sidenote: So true, how fast does a Buddy need to go. Mine hauls ass
around town. Any faster would be dangerous, careless, and dare I say,
immature. I guess one could soup it up for simulating trackdays or a night
on the drag strip, but I don't need the Buddy for that.

If you are referring to me, all I know is how my bike reacted after a pipe installation. Give me a break man. I posted my information based on what I know and how my scoot was. I would say 99% of the other people I know installing a pipe on a scooter that wasn't fuel injected needed a jet change.

San Francisco · Post by **San Francisco** » Fri Apr 27, 2007 10:49 pm

lobsterman wrote:For me, the only thing stopping me from doing the Prima pipe is I can't justify the $200 to my wife. She still thinks I bought the scooter for my commute.

(honey, if you're reading this, that last bit was a joke)

Well I heard that there was a safety concern on the stock Buddy can.
There is a danger that the current can may start a fire and the Buddy
may melt or..... God knows what.

The recommended fix is to install the Prima pipe, for one's safety.

So better get that Prima pipe installed ASAP, to be safe.

golfinguy · Post by **golfinguy** » Sat Apr 28, 2007 11:12 pm

Phil, thanks for the good information - those are quite educational.

ChaseG · Post by **ChaseG** » Mon Jul 14, 2008 8:55 pm

Anyone familiar with a louder engine noise after the Prima Pipe was installed? and. . . The knocking in the gear box? Any thoughts on these 'problems'? Thanks.
-Chase

MikieTaps · Post by **MikieTaps** » Mon Jul 14, 2008 9:40 pm

I have a louder, lower exhaust note... my engine isnt louder itself...

I havent had any knocking yet. I love my Prima Pipe!

sotied · Post by **sotied** » Tue Jul 15, 2008 12:46 am

MikieTaps wrote:I have a louder, lower exhaust note... my engine isnt louder itself...

I havent had any knocking yet. I love my Prima Pipe!

Did you have to rejet when you added the Prima or was that just another upgrade that you planned.

What's the difference between a Prima and an MRP?

Price/performance/looks?

Thanks,

Jeff

MikieTaps · Post by **MikieTaps** » Tue Jul 15, 2008 6:30 am

the rejet was the Ducati tech's call. I was planning on it going in, and he agreed.

MRP apparently, I have no first hand experience, but apparently they have horrible customer service, and a marginal at best product. Prima is the scooterworks house parts company, and scooterworks is the sister company to genuine... the exhaust is specifically designed by the company that imports these scoots... go with prima.

ScooterLou · Post by **ScooterLou** » Thu Apr 21, 2011 4:10 am

As for cost justification, especially city commuting, anything that helps other commuters know you are there is worth the expense.

Lou

Skootz Kabootz · Post by **Skootz Kabootz** » Thu Apr 21, 2011 5:33 am

All the years here and I've never seen this post. Very informative. Good one to bring back from the dead.

TCaruso · Post by **TCaruso** » Thu Apr 21, 2011 12:14 pm

What about decals? Can you comment on the effect of drag on a low powered vehicle?

Just kidding. I was under the impression the Prima pipe was more for looks and for sound. I'm glad to read it does improve performance.

dtcrouch · Post by **dtcrouch** » Thu Jul 04, 2013 6:09 am

the knocking heard is belt slap