Proma circuit pipe question

OK so I know the Proma pipe from treats has a header ID of 23mm. I just got one from Europe that has a header ID of 26mm. It is in fact for an e50 Puch (flat port). I have read on some threads here that the Proma Circuit hits a wall around 8k-8.5k depending on setup and that some people weld on a bigger header to gain some extra mph up top. So my question is: does this mean that mine from Europe with the 3mm bigger header will in fact rev out more and give more top speed than the treats Proma? If so about how many rpms more?

Re: Proma circuit pipe question

Link to the eu pipe?

Re: Proma circuit pipe question

Thomas Peffer /

I will send you a screenshot of the pipe and website when I get off work later today

Re: Proma circuit pipe question

Thomas Peffer /

Btw I measured it with a micrometer just inside the header opening and it showed just over 26mm. (The one from treats measured only 23mm) (edited)

Re: Proma circuit pipe question

That's probably the puch shop aka PSR version?

Does it have the integrated silencer too?

I don't know but they look cool, if you have both run them back to back and let us know. For science!

Re: Proma circuit pipe question

Thomas Peffer /

Yeah as soon as I get my Puch out of winter storage 2 months from now I will do a back to back exact same run and post the results. And the silencer is intergrated BUT...the header on this one is definately 3mm larger (edited)

Re: Proma circuit pipe question

Thomas Peffer /

This is it (and whatcha know...I ended up getting the last one)

8744944A-3175-473B-87A0-8754FEA2143E.png

Re: Proma circuit pipe question

Here's a 25mm circuit

And a 28mm.

Seems like more options on the market

Re: Proma circuit pipe question

Thomas Peffer /

Okay guys so now there is clearly bigger header ID pipes for proma circuit and techno circuit on the market. No more needing to havk and weld a bigger header to our famed pipes perhaps? Maybe now we can blast over 10-11k+ on both pipes and still keep killer lows and mids on our Puch setups 😎 (edited)

Re: Proma circuit pipe question

> Thomas Peffer wrote:

> -------------------------------------------------------

> Okay guys so now there is clearly bigger header ID pipes for proma

> circuit and techno circuit on the market. No more needing to havk and

> weld a bigger header to our famed pipes perhaps? Maybe now we can blast

> over 10-11k+ on both pipes and still keep killer lows and mids on our

> Puch setups 😎

Yeah, I don’t think you’re going to be seeing 10k+ out of a circuit pipe with 3mm difference.

Re: Proma circuit pipe question

Thomas Peffer /

Well that tecno circuit pipe listed above is 28mm versus the 21.5mm one from treats so that one is almost 7mm difference

Re: Proma circuit pipe question

some of those proma pipes like to shoot their baffles off. just be ready to have an alternate solution to reattach it.

Re: Proma circuit pipe question

Thomas Peffer /

There certainly has to be some kind of top speed gain running either of these European pipes versus the treats ones. Bigger headers on otherwise the same proma and tecno circuit pipe(s) should let them rev out way more especially on kitted setups. There is only one true way to know for sure....send 'em both

Re: Proma circuit pipe question

Thomas Peffer /

@Graham Motzing: this proma circuit exhaust does NOT have an integrated silencer. It is a seperate piece just like the treats one that is held on to the stinger with a clamp

Re: Proma circuit pipe question

> Garrett The Kid wrote:

> -------------------------------------------------------

> > Thomas Peffer wrote:

>

> > -------------------------------------------------------

>

> > Okay guys so now there is clearly bigger header ID pipes for proma

>

> > circuit and techno circuit on the market. No more needing to havk and

>

> > weld a bigger header to our famed pipes perhaps? Maybe now we can

> blast

>

> > over 10-11k+ on both pipes and still keep killer lows and mids on our

>

> > Puch setups 😎

>

> Yeah, I don’t think you’re going to be seeing 10k+ out of a circuit

> pipe with 3mm difference.

not on header OD. header OD only meters power at higher rpms & you would only “find more speed” if you were geared too high & not hitting all your rpms already.

you might also see more rpms if you are geared appropriately & this larger header produces more power in “over rev” & you can now pull the bike in the “over rev” portion of the hp curve.

if you want a circuit to rev to past 10k, you gotta have exhaust port timing up somewhere around 180-190 degrees.

Re: Proma circuit pipe question

I think LA/sacto guys back in the day were doing this, probably shaw or Nate k came up with it?

Someone at a rally around 2006 had a mk65 with the modded header proma that was absolutely screaming. Might have been when all the latebirds showed up to bbq14? I don't remember but highest rpm proma I've ever heard. Sounded like a dirty bike just nutso.

Re: Proma circuit pipe question

Dirty30 Dillon /

I'll second what's been said, header diameter is not the RPM limiting factor on these pipes. Honestly, a lot of overrev is probably lost with that smaller ID, long length stinger, but most of the high rpm is due to pipe design as natural to a circuit. Just like anything, sound also takes a longer time to travel around corners and this delays the pulse just as if it was a much longer pipe.

Re: Proma circuit pipe question

> Dirty30 Dillon wrote:

> -------------------------------------------------------

> I'll second what's been said, header diameter is not the RPM limiting

> factor on these pipes. Honestly, a lot of overrev is probably lost with

> that smaller ID, long length stinger, but most of the high rpm is due to

> pipe design as natural to a circuit. Just like anything, sound also

> takes a longer time to travel around corners and this delays the pulse

> just as if it was a much longer pipe.

i’m pretty sure a proms circuit has a tuned length of like 34” or something nuts. someone in boston YEARS ago measured it all out & made a “straight” proma circuit & you guesses it…it was long & low revving.

Re: Proma circuit pipe question

Dirty30 Dillon /

> LSLB RXb wrote:

> -------------------------------------------------------

> > Dirty30 Dillon wrote:

>

> > -------------------------------------------------------

>

> > I'll second what's been said, header diameter is not the RPM limiting

>

> > factor on these pipes. Honestly, a lot of overrev is probably lost

> with

>

> > that smaller ID, long length stinger, but most of the high rpm is due

> to

>

> > pipe design as natural to a circuit. Just like anything, sound also

>

> > takes a longer time to travel around corners and this delays the pulse

>

> > just as if it was a much longer pipe.

>

> i’m pretty sure a proms circuit has a tuned length of like 34” or

> something nuts. someone in boston YEARS ago measured it all out & made a

> “straight” proma circuit & you guesses it…it was long & low revving.

I can concur on that from my experience, somewhere betwen 33.5/35, but I can't recall if my numbers (years ago now, haven't had an E50/ZA50 in quite some time) included the distance between the piston and exterior exhaust port.

Re: Proma circuit pipe question

I've revved a proma up to 11.5 on a V1, but the power band is used up around 9.5, so basically, I just made more noise. Bike was good for 54mph on short-ish straights (750-900') on a kart track, with rpms peaking at 10.5k, with not much gain from over rev after 9.5.

(Measured using trail tech guage)

I lengthened and enlarged the header on a V1 polini, and it gave me a longer, higher power band. There's a thread about it here somewhere.

Same pipe fitted to a BRN 90 V1, and it stopped dead at 8k.

Re: Proma circuit pipe question

> baird co wrote:

> -------------------------------------------------------

> I've revved a proma up to 11.5 on a V1, but the power band is used up

> around 9.5, so basically, I just made more noise. Bike was good for

> 54mph on short-ish straights (750-900') on a kart track, with rpms

> peaking at 10.5k, with not much gain from over rev after 9.5.

>

> (Measured using trail tech guage)

>

> I lengthened and enlarged the header on a V1 polini, and it gave me a

> longer, higher power band. There's a thread about it here somewhere.

>

> Same pipe fitted to a BRN 90 V1, and it stopped dead at 8k.

did you port the polini cylinder at all?

& did you modify the stinger at all?

that’s neat that it would just stop dead on a BRN 90. did you ever get that cylinder to rev past 8k with any other pipe?

Re: Proma circuit pipe question

Modded the proma to center bleed with no muffler.

Also ran a stock proma with no muffler on the polini (bike's only used on the track, so I don't care about the noise.)

Stock proma revved out about 9k, and was 4mph slower than the modded one.

Polini was slightly ported, and case matched.

I also have a stock polini V1 with stock proma and muffler on my cimatti grand prix xl, and it's a 54mph street bike, with 17" wheels and 11-38 gearing. Still climbs hills and takes off super quick.

Never put the rpm guage on, so no idea what it's limit is.

The BRN 90, I ported, malossi reed valve, 21mm polini CP, and I made a straight chamber. It revs up to 12.8k. dyno'd at 7.5 hp.

I figured i'd get a lot more than that out of it, and don't know why the 74cc polini is still faster. Not by much, like 3mph, but that's enough to lose a race.

> LSLB RXb wrote:

> -------------------------------------------------------

> > baird co wrote:

>

> > -------------------------------------------------------

>

> > I've revved a proma up to 11.5 on a V1, but the power band is used up

>

> > around 9.5, so basically, I just made more noise. Bike was good for

>

> > 54mph on short-ish straights (750-900') on a kart track, with rpms

>

> > peaking at 10.5k, with not much gain from over rev after 9.5.

>

> >

>

> > (Measured using trail tech guage)

>

> >

>

> > I lengthened and enlarged the header on a V1 polini, and it gave me a

>

> > longer, higher power band. There's a thread about it here somewhere.

>

> >

>

> > Same pipe fitted to a BRN 90 V1, and it stopped dead at 8k.

>

> did you port the polini cylinder at all?

>

> & did you modify the stinger at all?

>

> that’s neat that it would just stop dead on a BRN 90. did you ever get

> that cylinder to rev past 8k with any other pipe?

Re: Proma circuit pipe question

Thomas Peffer /

UPDATE: since it got mild here in Ohio yesterday (50 degrees) I went and pulled the bike out from storage for about an hour and tested out the Proma with the bigger header. The verdict? No difference anywhere on the butt dyno compared to the Treats proma circuit that has the 23.5mm header. So there ya go.

Re: Proma circuit pipe question

> Thomas Peffer wrote:

> -------------------------------------------------------

> UPDATE: since it got mild here in Ohio yesterday (50 degrees) I went and

> pulled the bike out from storage for about an hour and tested out the

> Proma with the bigger header. The verdict? No difference anywhere on the

> butt dyno compared to the Treats proma circuit that has the 23.5mm

> header. So there ya go.

i’ve always believed header OD really only meters power at high rpm.

thanks for the follow up!

Re: Proma circuit pipe question

Ok so I have a side question I’m new so don’t beat on me to bad built many 2 stroke motors this is my first moped just trying to get it to run decently I have a 78 puch maxi Za50 2 speed trans haven’t flipped the 2nd gear yet but will in time mine came with a 14mm Bing I have installed the treats 50cc for the people kit it’s just basically a little better than stock porting I have the super street high compression head on it and a promo pipe I bought a assortment of jets from about 60 to 76 and when I took the atomizer out the jet was a different style and was bigger in diameter on the threads than the original puch jets I received to jet it now is there anyone who can tell me a good starting point for the atomizer and jet to work off with the items I have bought It did fire right up with the carb the way it was but I did not ride it due to me not wanting to break it in lean it ran for 2 minutes tops and I didn’t see any kind of smoke out the pipe so I figured it must be to lean and shut it down before risking hurting anything checked temps the engine wasn’t hot it was warm but I don’t want to trash a fresh top end

C0A73409-C8F2-4C73-BD33-1DBB3D30DEF6.jpeg

Re: Proma circuit pipe question

> Cory Loew wrote:

> -------------------------------------------------------

> Ok so I have a side question I’m new so don’t beat on me to bad built

> many 2 stroke motors this is my first moped just trying to get it to run

> decently I have a 78 puch maxi Za50 2 speed trans haven’t flipped the

> 2nd gear yet but will in time mine came with a 14mm Bing I have

> installed the treats 50cc for the people kit it’s just basically a

> little better than stock porting I have the super street high

> compression head on it and a promo pipe I bought a assortment of jets

> from about 60 to 76 and when I took the atomizer out the jet was a

> different style and was bigger in diameter on the threads than the

> original puch jets I received to jet it now is there anyone who can tell

> me a good starting point for the atomizer and jet to work off with the

> items I have bought It did fire right up with the carb the way it was

> but I did not ride it due to me not wanting to break it in lean it ran

> for 2 minutes tops and I didn’t see any kind of smoke out the pipe so I

> figured it must be to lean and shut it down before risking hurting

> anything checked temps the engine wasn’t hot it was warm but I don’t

> want to trash a fresh top end

start a new thread

or use the search function

The easy way is to put the largest jet you can get in there and make it 4 stroke

then lower the jet until it doesn't 4 stroke

search search search

Re: Proma circuit pipe question

> Cory Loew wrote:

> -------------------------------------------------------

> Ok so I have a side question I’m new so don’t beat on me to bad built

> many 2 stroke motors this is my first moped just trying to get it to run

> decently I have a 78 puch maxi Za50 2 speed trans haven’t flipped the

> 2nd gear yet but will in time mine came with a 14mm Bing I have

> installed the treats 50cc for the people kit it’s just basically a

> little better than stock porting I have the super street high

> compression head on it and a promo pipe I bought a assortment of jets

> from about 60 to 76 and when I took the atomizer out the jet was a

> different style and was bigger in diameter on the threads than the

> original puch jets I received to jet it now is there anyone who can tell

> me a good starting point for the atomizer and jet to work off with the

> items I have bought It did fire right up with the carb the way it was

> but I did not ride it due to me not wanting to break it in lean it ran

> for 2 minutes tops and I didn’t see any kind of smoke out the pipe so I

> figured it must be to lean and shut it down before risking hurting

> anything checked temps the engine wasn’t hot it was warm but I don’t

> want to trash a fresh top end

Nice bike , but , PLEASE , use punctuation . ;)

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