'01 Elite AF16 build questions for y'all

Does your Spree/Elite already run great, and you're trying to make it quicker/faster? Need a monster motor swap? Discuss your ideas here.

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imightbekarl
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'01 Elite AF16 build questions for y'all

Post by imightbekarl »

Hey 2 stroke wizards! I recently picked up an '01 Elite SR in really nice shape that has been built by the previous owner. I'm looking to continue building this beast of a scooter, but I'm looking for clarity/direction on the build going forward.

Here are the current parts on this build:
  • Polini Corsa 72cc kit
    Polini Variator w/6g rollers
    Polini 24mm PWK D Slide Carb w/ 118/42 jets
    Stage 6 pod filter
    TWH intake manifold
    Stage 6 clutch
    TWH clutch bell
    Arrow exhaust
    16x42 Gearing (9.1:1)
    RRGS Lowdown Forks (310mm)
    NCY Disc Caliper
    TWPO 220mm rotor
    NCY bearing throttle
    JDM Dio Taillight
    JDM Dio ZX Wheels
    Lithium battery

Running 32:1 premix with Castor 927 oil on a NGK B8HS plug & 92 octane fuel

Right now the bike runs really well. I bought it with a 110 main jet in the 24mm carb and it liked to get into some pretty high temps when cruising above 35mph or going WOT for about a minute or so I'd be seeing temps over 350, and if I tried to go over 40-45 mph for a minute or two I'd see temps between 370-385 and I'd pull over to let it cool down. Since then I've put a 118 main jet in there and it's brought down the temps enough that I can run over 40mph for a couple minutes without getting into danger-range. Keep in mind this is my first time tuning a 2-stroke.

Question #1: What are normal operating temps for a 72cc AF16? Will a bigger carb keep temps down? I see most of the builds coming out of Hawaii are running a 28mm carb where I'm running a 24mm. For now I've just toyed around with the main jets from 110-118 and the 118 is still pretty hot after WOT or cruising above 35-40mph but the bike seems to still be happy.

Question #2: Is the TWH intake manifold too big for the 24mm carb? Could that have an affect on the high temps I'm seeing?

Question #3: What's next? I'm looking at a Dio ZX transmission swap to run the larger pulley on the rear and get a little bit more punch in the low-end. Other than that I see mini stroker builds around the polini corsa that look cool. What type of crank is recommended to run with the corsa?

Question #4: Liquid cooling...what's the deal? I see big-boy stroker builds running liquid cooled setups with the radiator on the front of the bike. Does anyone run liquid cooling on a corsa or mini stroker setup? Is that stupid? I'm more interested in being able to run the bike really hard for longer periods of time without overheating that I am in winning races or setting speed records, should I even be looking at this stuff?
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motormike
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Re: '01 Elite AF16 build questions for y'all

Post by motormike »

I'm not your tuning wizard, #ifyouarekarl...lol
There's a few guys here that will reply hopefully.
Sounds like the bike is well appointed to make real speed.
Good luck with those temps...motor... :urban:
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Wheelman-111
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Re: '01 Elite AF16 build questions for y'all

Post by Wheelman-111 »

Greetings:

(1.) The Corsa can handle 380, but I'd be looking carefully for (2.) an air leak if the temps rise quickly. 24 is plenty big for a 72cc carb. At one time the Hawaiians had an abundance of cheap 28mm Taiwanese OKO PWK clones so that's what they used. They provide very little (if any) more in the top end, and they're very hard to tune. I ran a 26 on my Corsa and it also was too big unless the weather was freezing.
(3.)The ZX pulley indeed does help the low end with taller gears, but 9.1:1 is too short for the mighty Corsa with all the trimmin's you describe anyway. 8:1 or 7.8:1 with a ZX will give the same or better low-end as your 9s, but a lot more top speed. You might want to consider a Polini-for-Ruckus front variator, which requires just a little machining around the starter housing to fit. Otherwise the ZX might sacrifice a little top speed.
(4.) Stroker builds require machining the crankcases and leave precious little "meat" around the cylinder studs. And that's only WHEN the machinist knows what he's doing. Liquid cooling will certainly increase performance potential for racing, but this stretches the limit of the AF16 power unit. If you're riding to ride, I'd give a hard pass to strokers, mini-strokers and LC cylinders as more trouble than they're worth.
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Most of my money is spent on scooterparts. The rest is just wasted.
"ISO": '03 Vespa ET4 Malossi187 74MPH
Flash 9: 2001 Elite SR Contesta 72 ZX Tran, 9:1 Gears, Stock Airbox/Carb/Pipe 58.8 MPH
Punkin: 2010 Vespa/Malossi S78, 61MPH
imightbekarl
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Re: '01 Elite AF16 build questions for y'all

Post by imightbekarl »

Wheelman-111 wrote: Sat Jun 25, 2022 9:23 pm Greetings:

(1.) The Corsa can handle 380, but I'd be looking carefully for (2.) an air leak if the temps rise quickly. 24 is plenty big for a 72cc carb. At one time the Hawaiians had an abundance of cheap 28mm Taiwanese OKO PWK clones so that's what they used. They provide very little (if any) more in the top end, and they're very hard to tune. I ran a 26 on my Corsa and it also was too big unless the weather was freezing.
(3.)The ZX pulley indeed does help the low end with taller gears, but 9.1:1 is too short for the mighty Corsa with all the trimmin's you describe anyway. 8:1 or 7.8:1 with a ZX will give the same or better low-end as your 9s, but a lot more top speed. You might want to consider a Polini-for-Ruckus front variator, which requires just a little machining around the starter housing to fit. Otherwise the ZX might sacrifice a little top speed.
(4.) Stroker builds require machining the crankcases and leave precious little "meat" around the cylinder studs. And that's only WHEN the machinist knows what he's doing. Liquid cooling will certainly increase performance potential for racing, but this stretches the limit of the AF16 power unit. If you're riding to ride, I'd give a hard pass to strokers, mini-strokers and LC cylinders as more trouble than they're worth.

Thank you for the thoughtful reply! I'm still playing around with the jets, and I'm currently running a 118 main with slightly better results, I'll be trying a 120/122 this weekend to see if I like the temps any better and also doing a pressure check to make sure I'm not leaking anywhere.

I have the ZX transmission kit ready to go, but I'm going to hold off until I get the carb dialed in. I got lucky and have a spare polini variator for my ruckus, so I can look into using that as well.

I think I'll be skipping the liquid cooling at least for the foreseeable future.
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