2000 Kinetic Magnum/Spaco 12.10 tuning questions

Hey All,

Not sure how many folks still ride Kinetics (I am prepared for the hate...I think) but I figured I'd post anyways. I've seen a lot of posts on the forums regarding Kinetics and Spaco carbs and there seem to be experienced and extremely knowledgeable folks who know about them, hopefully you all can help.

I'm still new to mopeds, but I'm consulting Fred's guide, the forums and the wiki in order to become as self sufficient as possible with my bike. Basically, I bought a 2000 Kinetic Magnum (it is variated, as I believe all Magnums are) with 200 miles on it a few months back. I ran it at a little richer oil to gas ratio until I was over 300 miles on the odometer as the manual suggested this to break in the engine. It had a stock pipe until a week ago, and everything else about it is stock as well (or so I thought). Once I started running at the proper oil to gas ratio (50:1), I saw a little gain in acceleration and top speed, but I couldn't get over 22mph or so before the bike would start four stroking. At that point, I assumed I needed to downjet as everything I read indicated my mixture was running rich. As a precaution, I took off both my carb and air filter and cleaned both, but neither was dirty that I could tell. I took the bike out for a ride and I didn't notice any difference in performance. After the ride, I moved my air filter (original Piaggio air filter) just slightly with my hand as it looked a little crooked. I rode it again immediately and the bike was totally different. Better acceleration and it topped out at 27mph with no four stroking at WOT. I tuned in my idle screw and thought I was hot shit. Fast forward to a few days ago, I ordered a Vespa Piaggio techno circuit exhaust, as well as new jet screws from 50 - 60 (I assumed I was running somewhere around 45 - 48). I popped on the new exhaust and took apart my float bowl to upjet to accommodate the new pipe. Turns out I was running a 54 (not 45) screw the whole time, which is way bigger than I expected. I popped in a 57 (a little big I thought, but a good starting point) and road around for a while. Acceleration was a little lackluster, but the top end was sooo much faster. When I got back I attempted to better seat the air filter. After I did this, my acceleration was terrible and the bike struggled to get up to 20mph. I popped the 54 screw back in, seemingly no difference from the 57. I also attempted running without my air filter (no real change in performance) as well as running with the choke open (again no real change, after riding with it open for a bit I closed it and noticed a small gain in power but again no real difference).

To cut to the chase:

How does the air filter affect the actual performance of this bike? I read in the performance section that some bikes require an air filter for better engine performance, but I am unsure if this applies to my carb setup or if I should be running with the highest possible flow (which I attempted by removing the air box entirely)

How does the mixture screw on my carb affect jetting et cetera? I have seen others mention adjusting this screw but I am unsure of the best way to go about this. I assume opening the screw increases the gas mixture and closing it restricts flow, but again I am uncertain by how much or if to adjust this.

Also, due to the 54 jet I was running, I am unsure that my current carb is a 12.10. It seems it could be a 12.12 but I am unsure of how to determine this.

I apologize if I missed any details.

Sorry to write a goddamn novel about this problem, and apologies if I missed something obvious. Thanks a ton


Re: 2000 Kinetic Magnum/Spaco 12.10 tuning questions

From one of your previous posts it looks like you have a genuine dellorto carb that is a 13.13. The size is where the arrow is pointing. The adjustment screw controls the idle speed.


Re: 2000 Kinetic Magnum/Spaco 12.10 tuning questions

Sorry for the confusion, thanks for the quick response though. I did buy a dellorto 13.13 but I didn’t put it in on yet. I wanted to get the hang of tuning with just an exhaust and a new jet before attaching that new carb.


Re: 2000 Kinetic Magnum/Spaco 12.10 tuning questions

Oh okay, your current carb should have the size listed in the same place. Either 12:10 or 12:12. Some of those spaco carbs have another adjustment screw, the one that came with my kinetic was a 12.10 with only the idle adjustment. I’ve never attempted to run any of my bikes without the airbox due to things I’ve read on the forum. But I swap out the stock air box for the malossi hi flow filter. On a kitted bike with a pipe the jetting is typically 65-72 on a stock cylinder with a pipe I’d imagine you would be between 55-65

Re: 2000 Kinetic Magnum/Spaco 12.10 tuning questions

Check out the tuning spreadsheet (in the Vespa/Kinetic section) for jet sizes


Re: 2000 Kinetic Magnum/Spaco 12.10 tuning questions

jet it to where the top speed is best and add higher stall clutch sprimgs n start messing with your variator weights.

Re: 2000 Kinetic Magnum/Spaco 12.10 tuning questions

Thanks for the tip on the jetting sheet. I looked over that in the past, but it was hard for me to tell what to make of it, as the only Kinetics on there seemed to be 70cc/kitted bikes and its also unclear whether all of the performance upgrades from the vespas on that sheet would translate to a Kinetic.

To cut to the chase, I popped a 52 jet in (smaller than the 54 I was running with a stock pipe) and while acceleration between 10-20mph is a little sluggish, I'm topping out at a little over 30mph now. Still a little confused as to how my performance has improved with my new pipe and down jetting, but I plan on messing with a few more jet sizes just to see what's what.

Still not sure what the best mixture screw setting is, or how is it actually affecting my acceleration (Does it effect performance between 1/4 - 3/4 open throttle? I read that somewhere but even with continued adjustment, I'm not sure what is really happening.

As for messing with variator weights and clutch springs, I'm assuming most Vespa-related info on these topics would translate to my bike, but if anybody knows otherwise, please let me know.

Thanks everybody for all of the help.

Re: 2000 Kinetic Magnum/Spaco 12.10 tuning questions

Kinetics use a slightly improved version of the Vespa engine, so your jetting should be similar to a Vespa with similar mods. Looking at the spreadsheet, your jet should be somewhere between 50 and 65 depending on elevation and if you have any air leaks. If it's running lean it will go real fast but overheat and seize up. So you want to go on the rich side if you're in doubt. Usually I go richer until I hear four-stroking and then go one or two jet sizes smaller until it stops:


The screw on an SHA is for the idle speed, there's no fuel adjustment other than changing the jets. Taking the filter off will make it run leaner (more air) and of course your engine can suck in dirt, so you should run some kind of filter.

More info on SHA tuning here:


Once you have the jetting mostly dialed in you can do a plug chop to see if you got it right.


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