Puch maxi bogging after driving full throttle for 2-3 min

Hey, my 70cc maxi is running a bit strange. it runs like a dream when all the from the takeoff to top speed but there is an issue where if I drive full throttle for 3-4 min the engine starts to bog down and if i let the throttle go a bit back it picks right up again. it drives 65kmh (40mph) with a 14-36 gearing. to a reading a about 240 F when driving I could be a bit higher. Some more information

70cc airsal

timing at 13 degrees before the top. gap of pointers at 0.35mm

16-36 gearing

blue springs clutch upgrade

15mm bing jet 74 needle at 2. from the bottom

spark plug ngk b4hs but I upgrade to an ngk b6hs

the motor was rebuild under 200km ago

28mm stock pipe ( i know I could get more speed of a different one but I like to keep the esthetic )

i live in scandinavia so the weather im driving in is 50℉ - 65.℉

Re: Puch maxi bogging after driving full throttle for 2-3 min

Sounds like it's running out of gas after those few minutes .

Maybe float level too low ?(edited)

Re: Puch maxi bogging after driving full throttle for 2-3 min

Yea float is either too low, or the flow is restricted somewhere.

Re: Puch maxi bogging after driving full throttle for 2-3 min

Bill Mazzacane /

Any engine will starve for fuel if the fuel tank isn't properly vented.

Bill M.

Re: Puch maxi bogging after driving full throttle for 2-3 min

the flow in from the peacock is pretty good. its a steady full stream. how would I adjust the bowl to allow more fuel in it?.

a note to ad to the hole thing. before i had a 72 jet ind it . with the needle at 2. from the top. and it didn't do that at max speed. should i try to move the needle up to 2. from top or?

Re: Puch maxi bogging after driving full throttle for 2-3 min

Blaine- The artist formerly known as Plumber Crack "(OFMC)" /

If it runs fine before it dies, the float level is ok. If fuel flow is good from the petcock, it’s probably restricted at the banjo fitting of the carb. There’s originally a small screen in it that gets clogged. That, or it’s crudded shut at the seat.

The other thing that fits your symptom is a plugged vent in the cap as someone has already mentioned. Simple enough to check by opening the cap when the moped begins to die.

Re: Puch maxi bogging after driving full throttle for 2-3 min

if I should guess I'm leaning towards the small mesh in the carb. thanks for the tip I will try that.

Re: Puch maxi bogging after driving full throttle for 2-3 min

Sounds like your jeting is to fat. Is it a real bing 15mm carb or Chinese?

Re: Puch maxi bogging after driving full throttle for 2-3 min

Blaine- The artist formerly known as Plumber Crack "(OFMC)" /

> Rocco Taco Wrote:

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

> Sounds like your jeting is to fat. Is it a real bing 15mm carb or

> Chinese?

No it doesn’t.

Re: Puch maxi bogging after driving full throttle for 2-3 min

> Blaine- The artist formerly known as Plumber Crack "(OFMC)" Wrote:

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

> > Rocco Taco Wrote:

>

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

>

> > Sounds like your jeting is to fat. Is it a real bing 15mm carb or

>

> > Chinese?

>

> No it doesn’t.

It could be a rich bog , He could be four stroking. He said “ if i let the throttle go a bit back it picks right up again”.

Re: Puch maxi bogging after driving full throttle for 2-3 min

Blaine- The artist formerly known as Plumber Crack "(OFMC)" /

He also said it runs like a dream for three to four minutes. Does that sound like a fat jet to you?

Re: Puch maxi bogging after driving full throttle for 2-3 min

> Blaine- The artist formerly known as Plumber Crack "(OFMC)" Wrote:

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

> He also said it runs like a dream for three to four minutes. Does that

> sound like a fat jet to you?

Probably runs fine for a few minutes when the engine is cold. are you able to start it after it bogs out and the engine is hot? And does it run fine for a few minutes then start acting up again?

Re: Puch maxi bogging after driving full throttle for 2-3 min

Blaine- The artist formerly known as Plumber Crack "(OFMC)" /

Yes it runs fine hot or cold, but cuts out after a sustained wot because fuel flow can’t keep up at wot because there’s a restriction in flow. The carb bowl fills up after slowing down for a bit, which allows another blast at wot until the bowl is sucked dry again.

Re: Puch maxi bogging after driving full throttle for 2-3 min

> Blaine- The artist formerly known as Plumber Crack "(OFMC)" Wrote:

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

> Yes it runs fine hot or cold, but cuts out after a sustained wot because

> fuel flow can’t keep up at wot because there’s a restriction in flow.

> The carb bowl fills up after slowing down for a bit, which allows

> another blast at wot until the bowl is sucked dry again.

Okay but wouldn’t it show signs of bogging in the first 30 sec if it was restricted and could not maintain the correct float height.

All my kitted bikes, if I turn the petcock off for a few secs they start starving for fuel.

Maybe you should actually try that to see if experience the same issues.

Anyways if it’s a chines Clone bing, everything I’m writing was pointless.(edited)

Re: Puch maxi bogging after driving full throttle for 2-3 min

Blaine- The artist formerly known as Plumber Crack "(OFMC)" /

> Rocco Taco Wrote:

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

>

> Okay but wouldn’t it show signs of bogging in the first 30 sec if it was

> restricted and could not maintain the correct float height.

No. It’s a restriction in flow. Not a “no fuel”

> All my kitted bikes, if I turn the petcock off for a few secs they start

> starving for fuel.

Why are you turning your petcock off at WOT? Is this some kind of seize test?

> Maybe you should actually try that to see if experience the same issues.

To see if running out of fuel acts just like running out of fuel? The point?

> Anyways if it’s a chines Clone bing, everything I’m writing was

> pointless.

So Chinese clones are fundamentally different how?

Re: Puch maxi bogging after driving full throttle for 2-3 min

it's a copy of a 15mm bing. here in denmark puch's and other mopeds come only with 12mm bing and are restricted to 18 mph. moped in Denmark can be was ridden by 15-year-olds and therefore they are restricted. so the bike didn't come with a original 15mmm bing.

but what is the difference from the real one and the copy?

Re: Puch maxi bogging after driving full throttle for 2-3 min

no fourstroking

Re: Puch maxi bogging after driving full throttle for 2-3 min

The clones can be very finicky...I've had good luck with them after changing all the internal parts over to og puch tho...jet, atomizer bowl, lapping the needle seat. Blah blah.

They're really no good outta the box...

Re: Puch maxi bogging after driving full throttle for 2-3 min

I can just about guarantee you that its float height, the needle is opening enough to 'keep up' with WOT fuel flow demand for a minute or two but its not quite open enough to keep up with sustained high rpm.

The telltale sign is that after it starts to bog, you let off the throttle and idle it for a few minutes, then your WOT is back... for a minute, then it bogs.

Like every single bing-kitted moped i've ever built has done this, you have to adjust the float level to be just on the very slight edge of leaking. Even when you know exactly what you are doing, it still takes a couple tries.

look up in the puch manual how it says to adjust the float, basically you just bend the tab on the float so its almost bottoming out.

you can also grind material off the float to 'sink it' so its sits lower in the bowl. Eventually it will bottom out on the top and not press on the needle, so sometimes you have to cut it down to sink the float enough

Re: Puch maxi bogging after driving full throttle for 2-3 min

> Blaine- The artist formerly known as Plumber Crack "(OFMC)" Wrote:

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

> > Rocco Taco Wrote:

>

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

>

> >

>

> > Okay but wouldn’t it show signs of bogging in the first 30 sec if it

> was

>

> > restricted and could not maintain the correct float height.

>

> No. It’s a restriction in flow. Not a “no fuel”

>

> > All my kitted bikes, if I turn the petcock off for a few secs they

> start

>

> > starving for fuel.

>

> Why are you turning your petcock off at WOT? Is this some kind of seize

> test?

>

> > Maybe you should actually try that to see if experience the same

> issues.

>

> To see if running out of fuel acts just like running out of fuel? The

> point?

>

> > Anyways if it’s a chines Clone bing, everything I’m writing was

>

> > pointless.

>

> So Chinese clones are fundamentally different how?

We don’t know that he’s actually running out of fuel but you seems more then confident that is the issue without any evidence the back it up. And no I’m not try to go for a sieze test lol, sometime I forget to turn my petcock on, it’s common for humans to make mistakes.

And trust me you don’t need to reply to make me look like an idiot, I already do that fine in my own. Your just putting your self in a bad situation.

Re: Puch maxi bogging after driving full throttle for 2-3 min

The answer was found. in the carb at the fuelhose connection there were a tobacco thin leaf that when the vacuum from the engine went high enough closed itself off. removed it. works all good now.

Thanks for all the help!

Re: Puch maxi bogging after driving full throttle for 2-3 min

Yes! I was riding a ciao around that had a little leaf in the jet well and every time I hit a bump it would suck it up then die. I would have to let it turn off completely before it would start back up. It was very exciting.

Re: Puch maxi bogging after driving full throttle for 2-3 min

> Rasmus Langberg Wrote:

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

> The answer was found. in the carb at the fuelhose connection there were

> a tobacco thin leaf that when the vacuum from the engine went high

> enough closed itself off. removed it. works all good now.

>

> Thanks for all the help!

A leaf of what ?

Re: Puch maxi bogging after driving full throttle for 2-3 min

Blaine- The artist formerly known as Plumber Crack "(OFMC)" /

You’re welcome.

Re: Puch maxi bogging after driving full throttle for 2-3 min

looked like a cut tobacco leaf from a standard cigarette

Re: Puch maxi bogging after driving full throttle for 2-3 min

smoking is prohibited near gas

Re: Puch maxi bogging after driving full throttle for 2-3 min

How did a cut leaf get past any filter ?

Guess you'll be inspecting all new parts a bit closer, going forward .

Re: Puch maxi bogging after driving full throttle for 2-3 min

> Rasmus Langberg Wrote:

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

> The answer was found. in the carb at the fuelhose connection there were

> a tobacco thin leaf that when the vacuum from the engine went high

> enough closed itself off. removed it. works all good now.

>

> Thanks for all the help!

ha HA wow that one i have never seen, crazy!

Re: Puch maxi bogging after driving full throttle for 2-3 min

i should run a filter but i don't. i have one ready and never used but havent got around to cut the fuel line and put it in between

Re: Puch maxi bogging after driving full throttle for 2-3 min

ahh! man you gotta get that going, fuel filters are key to life! i usually have the petcock one, a big inline one, and whatever is built into the carb (sha/bing)

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