Slow SA50P

[jimaddison]

Drilled out the exhaust already so that's taken care of. Just got a new filter that came today, and airbox is very well sealed. I am definitely interested in parts.

[jimaddison]

Also, this worries me:

So I was on vacation for a few days, came back and it was hard to get the moped started. I eventually got it with the kickstart. When I drove it, Everytime I hit 25 it would feel as though it pushes me back. I assume that it's the variator that is doing that as it's simply restricting my speed. It ran great, but at times it would smell a bit burnt, like a belt burning. Not good. Any ideas what that is? Am I ruining the piston? I bored out the exhaust and have messed with the idle screw, but I havn't done anything else besides that. I am almost ready to sell this thing...

[Rip_City_Spree]

Don't sell. Patience is key with these little bikes. My suggestion would be to get a temp gauge if you don't yet. You Will need if you have any plans of going fast. Get a good variator+some new rollers. Something isn't right. Harbor freight sells a cheap oil filter wrench or impact gun for the variator nut. Take it off and check the rollers. I'd check the belt and get a new one. If you don't like to tinker these bikes it might not be for you. But if your patient and put in your work you'll have one of the funnest scoots out there.

[Trafficjamz]

Also, this worries me:

So I was on vacation for a few days, came back and it was hard to get the moped started. I eventually got it with the kickstart. When I drove it, Everytime I hit 25 it would feel as though it pushes me back. I assume that it's the variator that is doing that as it's simply restricting my speed. It ran great, but at times it would smell a bit burnt, like a belt burning. Not good. Any ideas what that is? Am I ruining the piston? I bored out the exhaust and have messed with the idle screw, but I havn't done anything else besides that. I am almost ready to sell this thing...

By opening up the exhaust end of your engine, you have allowed more air flow though the engine.

The air box also needs to be modified some to allow more air in. The second inlet tab needs to be knocked out.

To keep the air fuel mixture where it needs to be, you need to add a bigger main jet to your carburetor.

When the engine is cold the engine needs more fuel in it's air fuel mix. Thats why you are having a hard time starting the scooter when it is cold.

[ped]

Also, this worries me:

So I was on vacation for a few days, came back and it was hard to get the moped started. I eventually got it with the kickstart. When I drove it, Everytime I hit 25 it would feel as though it pushes me back. I assume that it's the variator that is doing that as it's simply restricting my speed. It ran great, but at times it would smell a bit burnt, like a belt burning. Not good. Any ideas what that is? Am I ruining the piston? I bored out the exhaust and have messed with the idle screw, but I havn't done anything else besides that. I am almost ready to sell this thing...

hi lots of great advice here.
it was probably hard to start because you may need a carburetor clean and a new plug. your variator stops you when you hit 25 mph. you can order a new one from graphite9. also order a new belt, and rollers. you will see a big improvement.
have fun with it.

[Rancher1]

As I mentioned originally, you really should do the 3 power mods all together, as they work together. Personally, I'd refrain from riding it hard without a bigger jet in there now.

Removing the restriction plate behind the front pulley will allow some higher top speed, but again, I wouldn't be pushing it like that without the bigger jet and airbox tab knockout.

The brand of the pulley in the eBay link isn't specified, so I don't know anything about it. Back in the day Keli variators with a SEF ramp plate used to be the cheap go-to combo. I don't see many of them around for sale much these days. I'm sure the Polini set is top notch and will give the desired result.

Also previously mentioned, I'd inspect your belt for wear. 4k miles sounds like it could be worn a bit depending on how it was ridden. A worn/loose belt will cost you some performance. If you don't want to measure the belt, picking up a new one is probably not a bad idea.

4k miles for a piston/cylinder isn't concerning much for an OEM, assuming it was run stock and not abused.

Here's what I suggest:

- #78 main jet ($10).
- knock out that airbox tab.
- new belt ($27, OEM or http://scooterswapshop.com/store/scoote ... s/dio-belt).
- a bottle of premix 2-stroke oil, since you've made some power mods it would be a good idea to add extra oil to your fuel as your OEM injector isn't providing enough.

Then report back and tell us how it feels to you. If you want more mods after that:

- variator ($90, http://scooterswapshop.com/store/scoote ... ?limit=100)
- gears, maybe a 9:1 or 10:1 depending on how your power is looking and your need for top end speed ($50, http://scooterswapshop.com/store/scoote ... ?limit=100)

Then after that you have the bug and will do a Big Bore Kit (BBK), carb, pipe, oil plug, temp gauge, and maybe clutch. You'll be playing with jetting, clutch springs, center springs, and roller weights to get your transmission dialed in. After that, you might be completely infected and trying out all kinds of power variations and making the bike look pretty. Then porting, stroker, water-cooled, 5:1 gears, NOS, jet engine swap, divorce.

Just my opinion anyway.

[Wheelman-111]

Greetings:

Quoth the Rancher:

Then after that you have the bug and will do a Big Bore Kit (BBK), carb, pipe, oil plug, temp gauge, and maybe clutch. You'll be playing with jetting, clutch springs, center springs, and roller weights to get your transmission dialed in. After that, you might be completely infected and trying out all kinds of power variations and making the bike look pretty. Then porting, stroker, water-cooled, 5:1 gears, NOS, jet engine swap, divorce.

Just my opinion anyway

That's some jolly funny stuff rat thar! But in my case, when I'd taken the Flash 7 about as far as I'd cared to go, I noticed Ms. Wheelperson eyeing it with a wistful look. I already had purchased Golden Boy last fall,

ReFlashFrnt_resized_1.jpg (102.46 KiB) Viewed 7750 times

so... "Honey, would you like the little red scooter?" She agreed but with all the Sturm und Drang it wasn't all that much fun for her to ride around from Stop to Stop. We de-tuned, offered it as a Mother's Day present, and she flat loves it. Uh, except the 50cc iteration was a little slow, so... Installed the Polini Contesta for a little more off-the-line thrust. And maybe a pipe... Uh-oh, HERE WE GO AGAIN!!

[jimaddison]

Alright boys,

Ordering a main jet TONIGHT but need the correct number. I've seen a ton of people say #78, but others have been talking about low 80s like an 82. What is going to be the BEST for my moped?

I'll be honest guys, I'm going to take the restritor plate off the variator, upjet, and knock the tab out of the airbox and see what happens. I should get 5 extra mph from that and I will be fit as a fiddle.

This opening up the tab on the airbox idea.... I still have NO idea what that means. Does anyone have a picture or diagram they can use to show me?? It is just not clicking.

Thanks guys

[jimaddison]

This may be a dumb question, but how do I know when I've jetted correctly? Runs smooth not sounding like it's lean?

[Wheelman-111]

Greetings:

Graphie Axted:

Wheelman, your the gear guru. What's a stock dio going to spin (rpm) at 60mph on stock gears?

I blush from your compliment. Let's see; 12.112523:1 final drive ratio, with 0.832 multiplicand from the variator, 10" wheels with 90/90 tires, so round off the hypotenuse and carry the three: Ta-Daaah!!

Zero RPM. Of course you will have to drop it off the 10th floor balcony .

[jimaddison]

CodeMan those pictures help a ton!

Question. If I go out to my garage right now and remove my variator plate and knock out the tabs.........will I be ok? So what I'm asking is, what if I don't "re-jet"? Will a stock main jet be sufficient?

[Rancher1]

CodeMan those pictures help a ton!

Question. If I go out to my garage right now and remove my variator plate and knock out the tabs.........will I be ok? So what I'm asking is, what if I don't "re-jet"? Will a stock main jet be sufficient?

Will you be ok running with a lean main jet? Maybe, it depends on how you drive it. Down the block to cousin Vinny's house, sure. Anything more and you are running the engine hotter than it's designed to run at. Push the heat too high and the engine will 'seize', which sometimes isn't too bad but other times can destroy your cylinder/piston. My suggestion is to NOT run it without changing the jet. Your stock jet is a #68 and you should be running at #78 or higher. That may not sound like a big jump, but it actually is. The exact jet you need depends on how the bike feels and sounds. Every bike is unique. If you get a chance, check out the Spree Wiki with the topic Tuning a Carb or something like that. If you read that you'll understand better why running a too small jet is bad and how to find the correct jet.

http://scootrs.com/tech.cfm?tip=tunecarb

I suggested a #78 jet as a starting point because that's what the stock non-restricted version of your bike runs. Your specific bike may like it's jet slightly bigger or smaller. If you want to take it a step further, buy a few different sized jets to experiment with, but it's always safer to run it too big (rich) than lean.


On the off topic of pulleys, does anyone know how the Polini setup compares to a Keli variator w/ SEF ramp regarding max top end?

[jimaddison]

Codeman, so I took the tab out of the airbox, I dremmeled the washer out of the exhaust, and I am in process of taking the plate off of the variator. Which jet would be most appropriate? I'm not doing any more mods except for that.

[DeanP]

Codeman, so I took the tab out of the airbox, I dremmeled the washer out of the exhaust, and I am in process of taking the plate off of the variator. Which jet would be most appropriate? I'm not doing any more mods except for that.

Ha Ha! It's a disease. Just wait, you'll want more speed and power. Then comes the BBK!

[jimaddison]

UPDATE!!!

Hey guys, first off thanks for all the help and knowledge through this process. I, myself, successfully de-restricted 2 of the parts but when I couldn't get the nut off the variator, I knew it was time for professional help. I ordered a #78 main jet off of Ebay and dropped my torn apart bike off at my mechanic's. He took off the restrictor plate, put the new jet in, put it back together, and tuned it. Here's the restults:

Before my moped was maxing out on the top end 22 mph. When I bored out the hole in the exhaust, it just wasn't running as smooth as before.

After: My moped goes 35 on flat land, I have no idea how fast it goes down a hill because it's off of the spedometer. It starts right up and doesn't take any time to warm up. I can tell the fuel/air mixture is just right and it purrs like a dream. I am VERY happy with the results of this process. It ran me about $100 to do everything, but being able to keep up/go faster than my town's traffic is worth it! Cheers