Puch Maxi KPL/MPQ

Probably Fred /
roffman
Oct 08, 2020 06:33PM

So the my son and I built a mild build kitted maxi that currently has a 15 mm bing carburetor 78 jet, prior It had a 14 mm carburetor 72 jet,

It currently gets around 14 mph per Liter with the 15mm bing 78 jet @ 35-40 mph/3/4 throttle but full throttle use on uphill or hi headwinds Which is more than half of the use,

The pipe is the top speed limiting factor but with the larger carburetor I get more power mid to high rpm which is good with the high headwind for uphill,

I don’t mind losing a little bit of that but will I get 8-9% more mpg going back to the 14 mm carb.

Why am asking because after a hour or so of all around Mostly open road use I‘m close to reserve and I need a bit more because I don’t like to gas up premix at whatever gas station pump and I don’t want to carry additional fuel Because I got shopping bags on the rack and such so anybody who has actual use mpg would be favorable to post what they get in actual use not guessing,

The maxi manual on these mileages is absolutely nuts! 3/4 speed and a rider that’s about the weight of an 12 -year-old

F94A6094-FE23-4EF8-8B0A-8050E64DA2B6.jpeg
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Re: Puch Maxi KPL/MPQ

Graham Motzing /
grahammotzing
Oct 09, 2020 08:20PM

This is the kind of question I would normally ask you!

I never pay much attention to mpg but my last two bing puch's have been in that 80 mpg zone. My polini with the phbg still is better than 60 but not sure how much. I only really notice when it's something like a hobbit or french bike that's below 50 and I can't go anywhere on a tank of gas.

My Sachs left me stranded today, I've been riding it off and on for weeks and not put gas in it. Speedo broke but it might be in the 100+ range? I dunno, it's slow, haha.

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Re: Puch Maxi KPL/MPQ

Matt Mahloch -- MBM Customs /
azzkikinvette
Oct 10, 2020 12:53PM

My gut feeling is that fuel economy won’t really change. The engine is still moving the same amount of air, but the velocity through the carb will be higher with a smaller carb. Ideal air fuel ratio is the same regardless of size. If you can down speed the engine you can increase fuel economy until you hit the point where your down speed enough you’ve increased load. (edited)

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