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Need tuning advice
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Author:  ZumaYellow50 [ Sun Oct 29, 2017 8:58 pm ]
Post subject:  Need tuning advice

Currently, my zuma stats are
05 Zuma 2 stroke
70cc kit
leo tt exhaust
Polini variator
Carbon Reeds
5.5 slider weights
Final gearing 14/sumthing
airbox hole mod
90 jet

Currently it ride strongly to 8800 rpm then it slowly climbs to infinity and beyond depending on how much road there is
I Know that aerodynamics play a huge part in acceleration and top speed
https://www.youtube.com/watch?v=qbAHLWj7WSY
Im thinking of changing the back tire to 130-70-10
probably changing the handle bars to ( picture below )
with the front end higher than the back end it should be enough to tuck down for maximum speed.
and with leo vince tt peak power around 9300-9550 rpm, supposedly smaller back tire should increase rpm

Changing back tire probably easiest
but handlebar be probably more aesthetic. fookin speedo and gas gauge XD

any advice or helpful tips or wisdom?

Attachments:
File comment: handlebars + height i want
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Author:  Poser [ Mon Oct 30, 2017 3:18 pm ]
Post subject:  Re: Need tuning advice

I can't be much help because I just installed my
Athena 70cc kit
with a 95 jet ,
the stock carb,
a new expansion chamber NCY pipe
and a higher flow air filter in the stock air box.

I just guessed on the jet size. Once I get the mixture right, I'll worry about the variator and clutch.

I have two questions:

1. What jets have others used successfully with a 70cc kit and muffler installed? I didn't change the low speed jet and at least on my Stella, that was the one that turned out to be most important. I figure I'm close. Let me know if I'm making a mistake and give any recommendations for low speed jets.

2. If I'm going to get 5 or 6 miles per hour more speed (45-49mph), am I overreving the motor? It seems that with the increase in power that I sould have a bit longer final drive ratio. Changing springs and weights isn't going to give me more top speed without higher sustained RPMs.

Thanks for looking. I've been messing with the Stella setup for many years, but left the Zuma stock. I moved to a place where the Zuma is my primary mode of transportation and one of the main routes is a 45mph road. So... Add a few CC to get up to speed and maintain.


UPDATE:

The 95 jet was extreme overkill. It bogged the whole thing. I put the stock 80 jet back in and suddenly I had a rocket above 35 MPH. I have no clue how fast it will go, but I think it may explode if I leave the throttle pegged. Red clutch springs. 5-5.5 variator rollers, stock compression spring.

I give the Calamari Racing guys a thumbs up for correctly setting up a kit that works without much fiddling.

Author:  ZumaYellow50 [ Mon Oct 30, 2017 4:13 pm ]
Post subject:  Re: Need tuning advice

http://www.pedparts.co.uk/blog/introduc ... ed-jetting

They have some decent guide lines there for jetting
Really depends on your airbox, 70cc kits needs very
Minor increase in jetting, exhaust has a Lil bit increase too.

You don't want a sustained 10k rpm all the time
You wanna aim for rpm that compliments your exhaust
That's where rollers and slider weights come in
Variator only effect accleration, it has a huge noticeable
Difference on 70cc.

If you zuma rpm too high you could either upgrade your crankshaft or change gearing.

Author:  jmkjr72 [ Mon Oct 30, 2017 7:36 pm ]
Post subject:  Re: Need tuning advice

What carb are you running can't be stock if your running a 90 mj a tk main jet of a 90 in a stock carb is pig fornicate rich
Next what bore kit and did you port it at all
Why did you put holes in the air box these engines like the air box and need the pressure the air box is the same as the 90cc engine

Going with a smaller rear tire you will gain. Acelleration but loose top end and you mess with your suspension as the tire is a big part of your suspension

Author:  ZumaYellow50 [ Mon Oct 30, 2017 10:28 pm ]
Post subject:  Re: Need tuning advice

I ported it slightly, spark plug looks nut brown

Yeah i heard that taller tires = better top speed, but i have feeling it will go faster and look better with
both the handlebar swap and lower backend, so it's easier tucking in.

but if it messes with suspension then i may have to rethink.

Author:  Poser [ Tue Oct 31, 2017 3:56 pm ]
Post subject:  Re: Need tuning advice

I had a Zuma with matiching tires (front tire size). It was a bad idea. The taller rear tire adds about 3MPH and doesn't seem to bother the low speed acceleration. I'm partial to the Michelin Boppers. If you find yourself riding on the shoulder much of the time, go with the stock tires to avoid punctures.

Author:  ZumaYellow50 [ Mon Nov 06, 2017 11:38 pm ]
Post subject:  Re: Need tuning advice

Poser wrote:
I had a Zuma with matiching tires (front tire size). It was a bad idea. The taller rear tire adds about 3MPH and doesn't seem to bother the low speed acceleration. I'm partial to the Michelin Boppers. If you find yourself riding on the shoulder much of the time, go with the stock tires to avoid punctures.


So mis matchin by height? the front was bigger than the back? like 120-90-10 and 130-70-10?
What did you mean by bad?

My planning is going on theory atm.
thinking a slightly less tall back tire would make it more lowered look while increasing rpms and easier tucking in ability.
and its cheap to try.

Handle bars seem like a female dog to install, gotta get the conversion kit, a speedometer, a gas gauge, hooking up wires
getting the height right. and expensive

Author:  jmkjr72 [ Tue Nov 07, 2017 3:55 pm ]
Post subject:  Re: Need tuning advice

To do say 50 mph with a 130/90 10 will be say 9000 rpm it will be just over 10000 to do the same speed with the 130/70/10

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