drilled carb- same top end

Gunther McCilicutty /

So I drilled my Bing on my Puch Maxi Luxe 1.5hp from 12mm to 14.5 mm. No real top end improvement to speak of(maybe 2-3 mph faster), but the low end is killer now. I am doing 25 mph up pretty steep hills.

With the 72 jet it would not get over 25 mph flat ground while four stroking the whole way. Put the 70 in and it is like 100% better with a 33-34 mph top end (plug chop said I was running lean, so I taped up the air filter and not it is just right and I have the same top spead. With the pipe and the air filter it was a huge difference in the 72 to the 70 jet...then I had to still tape up the filter to get it richer.

anyone got any opinions?

Re: drilled carb- same top end

so are you running stock pipe?

Re: drilled carb- same top end

If you are taping up your intake in an effort to correct mixture you are undoing some or all of thr possible benefit of your drill job

Re: drilled carb- same top end

what size is your intake & intake port?

Re: drilled carb- same top end

Gunther McCilicutty /

yes I know...but with the 72 jet and the air filter not taped it was four stroking and not getting over 25 mph. With the 70 jet and the partially taped air filter I was going 33-34 mph.

I have a Biturbo pipe...I know I know..cheapy.

Re: drilled carb- same top end

Gunther McCilicutty /

intake port looks to be about 14-15mm and the intake is drilled to 14.5 like the carb.

Re: drilled carb- same top end

Gunther McCilicutty /

I am running a Biturbo

Re: drilled carb- same top end

shit talkin' hippy /

that sounds about right for that setup, with some moddesst porting, new rings, high flow filter of some sort, HC squish head, proper timing, and a regear, ya should be able to hit 40-45 pretty easy

-bad lowend can be fixed with gearing and more compression, proper timing too

-then to combat your lost topend with your gear change you can get a little more agressive with your exhaust porting as to make use of the much larger than stock headder you have on that biturbo

-alot of the power that's available in the biturbo and most cheap pipes is lost because the waves and flow are messed up due to the exhaust flange not matching the pipe, so in order t use the pipe for all it is, ya need to do your best to match the two,

-1, by opening the flange to match the 28mm of the pipe

-2, by trying to widen the exhaust and raise it a bit to keep that flow pattern as Parallel as possible so as to not change that wave or flow until it hits the first cone of the functional portion of the pipe,

-3, read up on exactly how far you can go with the port, like keeping an eye on how close the pins on the piston are to the port and to not short circuit the flow by invading the Transfer's space, and chamfering

Re: drilled carb- same top end

Gunther McCilicutty /

I have not tried porting yet. I want to get the max out of my semi-stock setup. I plan on buying another maxi or magnum to tweek out.

I will try to get a bigger front gear to gain speed. like I said the lowend is waaayyy better with the drilled carb (going 25 up hills as apposed to the 15-20 like before).

My top end os ony 2-3 mph faster but I want to do 40 with the semi-stick set up. Not air leaks to speak so I have no clue what the issue is with the jetting. If I have the 72 in it only gets to 25 mph with out the air filter taped up.. with the 70 jet and half taped up air filter it goes 33-34.

Re: drilled carb- same top end

Hmm.. how does your spark plug look?

Re: drilled carb- same top end

What gears are you running. Sounds like you have plenty of power and may jsut need taller gears.

Re: drilled carb- same top end

sounds like your jets are wrong. some times they get mixed up when being made. especially the knock off ones. compare them side to side. if they dont look exactly the same there is something wrong. human eye wouldnt be able to detect a 70 compared to a 72. at least mine cant.

Re: drilled carb- same top end

Gunther McCilicutty /

I'm running 16 x 45 gears.

the 72 jet I bought from Treats and the numbers are stamped different...like kinda square as apposed to the round nimbers.

with the filter taped and the 70 jet the plug looks like coffee with 2 creamers.

Re: drilled carb- same top end

why not just buy some more jets? dont tune your air to your jets, tune your jets to your air. get me?

Re: drilled carb- same top end

Gunther McCilicutty /

word. I may just go buy more jets, but I want to believe in Treats to send me the right jets.

Re: drilled carb- same top end

Not necessarily so. In addition to a correct air/fuel mixture, proper airflow also controls fuel intake _velocity._

Re: drilled carb- same top end

they may have sent the right jets according to what is stamped on the side, but the stamp could be wrong.

Re: drilled carb- same top end

Gunther McCilicutty /

yeah.. I trust Treats with my life. they always send me the right stuff.

anyone have any 72 and 74 jets they want to trade for a brand new 15 tooth front sprocket? I bought the 15 tooth but what I should have bought was a 17 to increase my speed.

Re: drilled carb- same top end

shit talkin' hippy /

yeah,with everything perfect and some taller gears low 40s is as much as your gonna get with that set up.

Re: drilled carb- same top end

Gunther McCilicutty /

I would be ok with 40 with the setup. Like I said,

I want to buy another Puch this fall for my winter project and want to trick it out. So I will have one tuned semi stock reliable Puch and then my hot-rod Puch project to play with. I just want to make my Maxi Luxe do about 35-40 and be reliable enough to take it to the store, work, and long back country road rides.

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