What jet do i need? Puch/Biturbo

Its a 2hp single speed Maxi Sport, all stock with a 14/Bing. The only upgrade will be the Biturbo. I know about the plug chops but was hoping I might find some one who could help me skip that step. Any help would be appreciated. I’m preparing myself for all of the nasty emails calling me lazy, but I figured that’s what forums like this are for. Thanks for any help you might offer.

Re: What jet do i need? Puch/Biturbo

I'm fairly new to this but I've been learning a lot about the jetting. Its very crucial to make your ped run good. There's no real right answer. I would start with the 64 which I think is stock for the 14 and see how it runs. Basically just through the pipe on and see how it runs. You can adjust the needle for richer or leaner. lean down/rich up. You really might not have to do much with just a pipe.

First time I got a pipe, carb, high airflow, i was under the impression you really need to up jet high. I put in a 70-72 and it ended up being too rich. Then I put the needle all the way down and its pretty good, maybe a little rich. I would say somewhere between 64 and 72 max. Also check for airleaks. Sometimes your ped will run funny and you may think its the jet but bings are notorious for airleaks, Thanks harold for pointing that out!! I'm battling with one right now!! i can't get that fucker to seal. to check for airleak just run and spray carb cleaner at the intake. If it dies out, you have an airleak.

Re: What jet do i need? Puch/Biturbo

id say a 68.

Re: What jet do i need? Puch/Biturbo


Re: What jet do i need? Puch/Biturbo

I say no jet at all. Better safe than sorry, and no jet is definitely the biggest you can get.

Re: What jet do i need? Puch/Biturbo

This is exactly the kind of sarcastic advise I have come to loath from some members In the Army. I'm not completely stupid when it comes to the workings of a moped. I came here to see if anybody could just help me get close to start. luckily a few members have been extremely helpful with advise, and I thank you for that. Where I have problems is when someone clearly plays on another persons inexperience and offers advise that sets people back or may do damage to a bike just for a laugh. I come here because I know there are people with lots of knowledge of mopeds that would be kind enough to help a fellow member. Personally I think some people do a disservice to forums like this.

Re: What jet do i need? Puch/Biturbo


I'm not a member. Don't confuse people who post on the board with members. The members of the Moped Army are the ones with little pictures by their names.

Do you ever get people who come up to you and ask a question that everyone asks? A question that could be answered simply by opening their eyes and looking around? There are countless threads on this board about what size jets to run, and you are running _the_ most common performance combo for beginners! The information is here. You even know enough to say "I know about the plug chops but was hoping I might find some one who could help me skip that step." Aside from plug chop, there is nothing else that can tell you what size jet to run and be accurate

You want to skip the most important step, and you know it. That's just lazy all around. Too lazy to search, to lazy to plug chop. It's been my experience that if I told you to run a 68, you would just run the first jet you can find that is bigger and call it good.

You expect a bit of teasing if you are asking this kind of question.

Re: What jet do i need? Puch/Biturbo

apple juice. proven faster acceleration.

Re: What jet do i need? Puch/Biturbo

only straight AJ though. that mixing shit makes no sense.

Re: What jet do i need? Puch/Biturbo


Re: What jet do i need? Puch/Biturbo

Well i do have to say thank you for the professional manner in which you dispensed your reply. I am running "the most common performance combo for beginners" Thats because I am a Beginner. Amazing how that works huh. Obviously I am aware that the info is in some thread out there but against all assumptions I didn't try to skip the plug chops all together. Nor was it out of laziness, more so due to a lack of available time to devote to my moped. We do share one thing in common, we have problems with the threads. I don't spend enough time reading them and it sounds like you may spend to much. I have had people come to me and ask the same obvious questions over and over, and it is frustrating. But I have never tried to make someone feel dumb for asking. The inherent problem with your argument is that I'm not everyone. I'm just one guy. A guy who is going to take the information offered and do my plug chops. But maybe i wont have to do as many as i would have if i just blindly started on my own. Nice how that works huh.

Re: What jet do i need? Puch/Biturbo

Give the guy a break. Is this what the forums were made for? to ridicule people when they ask questions? NO. If you dont have advice that is actually HELPFUL, then dont bother posting stupid stuff. I hate it when people think they are being hilarious when they post that kind of stuff. Go over to MRA im sure they would appreciate your assanine comments over there.

Randy-I would say somehwere in between 62/66. Do plug chops till you hit a nice tan coffee color on your spark plug.

Re: What jet do i need? Puch/Biturbo

I have just started working on a 79 Maxi 2sp this year. 1st ped.

I have installed a 15mm bing with a 14.5mm intake and biturbo exhaust. I had to fab a riser to make the carb sit level.

The carb came with an 82 jet. I have gone down to a 78, and have yet to put any kind of air filter on it. It still seems to be 4-stroking slightly at top end.

68 to 74 might work well for you. Just be careful about going to low, it's fast but risky.

Re: What jet do i need? Puch/Biturbo

Yeah, Randy - guys like Responsible Jon are the CLASSIC moped snob I've run into more than once on these boards.

Typically lame responses like - "do you know how to use the search function?"

Gimme a break, man. Get over yourself, Jon......it's a freakin' M-O-P-E-D, dude. IF we were debating world economics or domestic policy.....then you might have a leg to stand on when you say 'learn something then come talk to me.'

Since this is mopeds....um.....yeah. You lose, chief.

Randy....I'm actually going to have to be in the same boat as you, man....with my new Polini (put the whole thing together tonight...was at the studio until 2:30!) and 15mm bing. OH and Jon....I actually HAVE used the search function...and know a shitload about mopeds....and I STILL have to ask a few people about the proper jet to use for my new kit since I can't run the damn thing at WOT for the first 200 miles or so.

I'll probably have a new thread tomorrow asking around. I have a feeling I can keep the stock jet.....I just want some assurance that it's big enough so I don't seize my shit while breaking it in.....

15mm Bing, stock jet (82? actually haven't looked yet)

64cc Polini

Techno Estoril

All on a sick 78 Magnum XK.

Re: What jet do i need? Puch/Biturbo

Internet theories aside,

Jake - I have posted many helpful comments, and try to help everyone to enjoy learning to fix their own mopeds. I've never had a problem with you, and I respect you running your own moped parts business, it's tough to run a business and be responsible. Your suggested jetting I would wager, is right on.

Ben - A guy can't joke around? Who would seriously think running no jet would be the best bet? Who wants a boring question and answer forum? Everyone should have to read a FAQ before they can post. I'm not commenting on Randy specifically, but I"m willing to bet that 75% of people here who modify their Tomos or Puch mopeds are running an incorrect jetting. I am a moped snob, but I'm the nicest most friendly moped snob you will ever meet in real life. Just refer to the internet theory when trying to understand my post.

Oh, and apple juice really does help cure knock and ping, so add some if you advance your timing.

Re: What jet do i need? Puch/Biturbo

How many Macs do you distill to get enough Apple juice to add to one tank of fuel?

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account