Puch Maxi Luxe Dies at Heavy Throttle

Puch Maxi Luxe circa 1985 badged as 1.5 hp. All stock. No air box. Previous owner apparently set up choke to stay mostly closed by bending up tang to throttle slide as this is the only way for the engine to run at more than 1/3 throttle. Current owner put 1k miles on it this way. Spark plug just changed and it was black (I didnt see). Carb was looked at as part of throttle cable swap and apparently choke set back to factory ops. Now it dies above 1/3 throttle. Fuel flow looks ok. Spray test at carb output passes. Heavy choking at air cleaner restores performance. We are going to put in a carb kit that includes new float and jets. My thoughts are possibly going to a larger jet size if necessary. Am I overlooking anything? Cheers Dave

Re: Puch Maxi Luxe Dies at Heavy Throttle

Put the airbox on it.

Re: Puch Maxi Luxe Dies at Heavy Throttle

Factory jetting was for the airbox. You will need to reject and probably adjust needle to compensate for more air with deleted airbox

Re: Puch Maxi Luxe Dies at Heavy Throttle

Re: Puch Maxi Luxe Dies at Heavy Throttle

roots to wings /

Very hard to follow your train of thought, but get it back to stock carb specifications as to what would've been on the bike when it was new and go from there. Bending shit to accomodate lack of tuning ability as the former owner did is probably not the way to go. See Myrons Mopeds to find stock specs and how you can turn your moped into a 2hp and go 30+ with no expense.

Re: Puch Maxi Luxe Dies at Heavy Throttle

Ok thanks all. Have added airbox to the list. Will also replace fuel lines as they are hard as a rock. So we will totally be back to stock and will see where we are. Will write back with results when we get the parts and do the install, probably a couple weeks.

I have rebuilt many carbs previously plus gone over the info available here and on Myrons site so I am not very concerned. I have little 2 stroke experience but lots and lots on pre war cars.

Re: Puch Maxi Luxe Dies at Heavy Throttle

roots to wings /

if you read everything on myron's and here on MA you would not have asked the question you did. what carb, needle, jet, atomizer, slide, and clip position are you running? you should know exactly what is supposed to be on the bike for your model year and hp and there is a chart on myrons that tells you exactly this. replacing floats and jets is fine, but likely won't do shit to fix what you are describing. getting the right internals in your carb can be the difference between your bike running or not well at all., assuming everything else is good. your plug should not be black running so lean i wouldn't think unless your mix is super rich. is your exhaust smoking heavy?

Re: Puch Maxi Luxe Dies at Heavy Throttle

Is your exhaust and/or exhaust port plugged?

Re: Puch Maxi Luxe Dies at Heavy Throttle

Hey folks go easy. This is *not my bike*. I just got brought into this about 2 weeks ago so I am trying to come up to speed. I just took the carb off again and can get the answers you want in a couple days. I have absolutely no idea what has been done previously other than what I have reported. How far off stock is it? I dont know yet. At least the rebuild kit plus putting the airbox back on should get me there in theory.

Re: Puch Maxi Luxe Dies at Heavy Throttle

OK I got the info. Bike is a Maxi Luxe built 1/78. Carb is 1/12/304. Jet is a perfect fit to a 73 drill so must be a Bing 66 size. No markings on the jet. Needle has 4 slots at top, was set at 2nd one down. Needle measures 1.9 mm diam just below adj slots and 1.25 mm diam near the needle point. Needle jet is close to 2 mm inside diam, can't get exact measurement. Slide is a 24 but someone took a small chunk out of it at the bottom. These measurements seem consistent with a 1.5 hp Maxi Luxe built in 1978.

When the rebuild kit comes in I will compare to what I found above. If the jet is wrong I can use the old one or chuck up the new one on my 10mm lathe and drill to a 73 size. Will also compare needle and needle jet.

Do you all keep the small filter screen on the banjo bolt or just go with an inline filter? The bike currently has both.

Cheers, Dave (edited)

Re: Puch Maxi Luxe Dies at Heavy Throttle

roots to wings /

those specs are all correct for the year make and model https://myronsmopeds.com/2020/12/puch-speed-versions/

id leave the banjo screen and put an inline filter on

sounds like you just have to put your airbox back on to get it running stock

Re: Puch Maxi Luxe Dies at Heavy Throttle

Pics of the 24 slide? Wondering if someone in the past did the CW Slide Mod for better idle...

Re: Puch Maxi Luxe Dies at Heavy Throttle

Here is a pic. Missing chunk on right side.

20211110_160005.jpg

Re: Puch Maxi Luxe Dies at Heavy Throttle

Oh weird. Yeah that’s not a mod, looks like what happens when the idle screw gets screwed down too far

Re: Puch Maxi Luxe Dies at Heavy Throttle

That makes sense as you can see thread marks. Supposedly getting a new one as part of the kit.

Cheers, Dave

Re: Puch Maxi Luxe Dies at Heavy Throttle

roots to wings /

thats not why you are bogging.

Re: Puch Maxi Luxe Dies at Heavy Throttle

SUCCESS!!! Clean out, partial rebuild, add air box, new fuel hoses. Last item probably did not do much.

Rebuild only partial due to shortcomings of the rebuild kit. Here are the items I could not use or were marginal:

Jet way too large, bigger than 70 drill. Old one was cleaned checked and reused

New fuel nipple had wrong turns per mm, reused banjo assy

New slide over 0.003" too small, cleaned old one and smoothed out the gouge

New float needle elastomer end was deformed and unusable, stayed with old one

New slide spring spring way too weak compared to old so stuck with old

Heat shrink packaging stuck to slide cover gasket and removed some material but was usable

Overall I give the rebuild kit a D minus. I have rebuilt many carbs but never found this many issues. And the new Gas cap fits poorly as well. But the new air box is nice so that is good.

Started right up and idle adj was easy. Went to full throttle with no issues. Road test max was a bit over 26 mph which is perfect. Current owner said it would no do over 20 mph before and acceleration is much better.

I have a very happy 14 year old lad now with his bike running again! Thanks all!

Cheers Dave

Re: Puch Maxi Luxe Dies at Heavy Throttle

roots to wings /

nice work. very simple to get that bike close to 30 for the cost of a 16t front sprocket and no cost mods.

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