Jonway got more acceleration By jalat (Read 2,437 times)

[jalat]

I was just trying for fun and I moved that needle washer from middle to bottom and got remarkable upgrade for accelerating.

When looking speedometer the acceleration from 0 to 80km/h was 2.5-3 sec faster ;D


Don't loose this washer. It is small and you can easily loose it. Use good lock pliers when changing it's position.

Don't forget to put that another washer also around needle. I first messed that up and tried to figure out why it didn't get any better acceleration




Pictures are from my blog. Sadly it is written in Finnish language. I can put here a link for it but the translation is funny when used google translation

translate.google.com/translate?hl=fi&sl=fi&tl=en&u=http%3A%2F%2Fjonway250.blogspot.com%2F

[cruiser]

Hey Jalat. Thanks for that info on an easy and worthwhile tuning procedure. That is a big gain in low to midrange acceleration.

[yoster]

Woah.. has anyone else tried this to confirm? That's quite an increase in speed.. curious if there are any ill effects from removing that needle thing.

Anyone want to be test subject #2? LOL.

[cruiser]

I did this on my 50cc scoot with favorable results. Haven't tried the 250cc yet. Doing this might result in slightly decreased fuel mileage. If you raise the needle too much, the scoot may stumble (too rich) on acceleration.

[jalat]

I also have 50cc scoot and did this same to it few years ago. Major upgrade also. In that scooter there was 5 different levels for washer in that needle. Moved washer from middle to lowest. That made scooter stumble. But in the second lowest position was perfect. It accelerates also much better.

And what about the mpg. I don't know yet. But now I can accelerate faster to my wanted speed and then just cruise. It might not decrease mpg if you are not always running full open throttle.

I propably will cruise today all day Then I can tell you about the consumption.

[jalat]

It would be nice to hear if any of you guys try this also. It took about 2 minutes to change that washer. You need only screwdriver and thin pliers. Nothing else.

[jalat]

OH MY GOD!
Just cruised 115km on country road. Speed all the time between 60-100km/h and also about 10-15km in city.
And trust me. I'm accelerating now full open throttle in every intersection with this more power.
Consumption 3.09l/100km which is 76.12 mpg

Double win \o/ \o/
I got way more acceleration and decreased the fuel consumption. Never have that low consumption before!

[JR]

Thanks Jalat if I ever get some time going to do this myself!

JR

[yoster]

Jalat - can you write up an English version of the how-to?

[jalat]

I can try after when I get out work.

[cruiser]

I decided to try this on my scoot. When I opened the carb and removed the plastic needle valve retainer, I noticed no washer in the bottom and the clip on the needle valve was already in the lowest slot. I tried a washer, but was not able to lock the plastic needle valve retainer back down. The top of the needle valve was hitting against the inside of the plastic retainer, so I shaved a little off the inside of the retainer and was able to reassemble everything.

The scoot was a little rich on the bottom end and was not as crisp in acceleration. It appears the factory setting was better for my scoot.

[jalat]

Thank you cruiser. I am not sure if that washer was in my carb originally since I am the second owner of this scooter. But I believe that last owner did not put it in there. There might be different variants of these carburators. Just like there is diode next to regulator rectifier in usa version and not in europe version.

But it is good to give it a try because it is pretty easy to test.

Maybe my scooter was lazy originally and now accelerites like yours cruiser
(I believe yours accelerates still faster because I have 23g dr pulley sliders and rpm never goes higher than 5500)

[cruiser]

Hi Jalat. These engines develop max power at around 6500 rpm, so you are not getting in the max power range.

With 19 gram sliders, I believe I must have better acceleration than your scoot. I hit about 6000 rpm on initial acceleration and can pull over 7000 rpm on top end. I believe your top is 68 mph which is at 5500 rpm? That is a low engine speed for the road speed. You probably can go pretty fast downhill because you have a lot of rpms left.

[jalat]

you are right. My top speed is 68 mph. If I change 19 or 20 gram slider or rollers. Should I go faster? Maybe I should order a cheap set of rollers and test. Which would be the best weight?

Cruiser what is your slider/roller weight?
And what is your average mpg? Mine is about 70 mpg with these settings.

[cruiser]

Aug 4, 2011 0:49:17 GMT -6 jalat said:

you are right. My top speed is 68 mph. If I change 19 or 20 gram slider or rollers. Should I go faster? Maybe I should order a cheap set of rollers and test. Which would be the best weight?

Cruiser what is your slider/roller weight?
And what is your average mpg? Mine is about 70 mpg with these settings.

I have 19 gram sliders. My scoot came with 23 gram rollers. Top speed in both cases was essentially the same. I have not monitored my fuel mileage, but I think I'm in the low to mid 60's

I think you might gain 2 to 3 mph with lighter weights. The heavy weights have the engine developing max torque (5500 rpm) at 68 mph in your scoot. Dropping the weights to 19 or 20 grams will allow the engine to hit over 6500 rpm which is the max horsepower band. However, the torque drops off so there is a trade off. Around 70 - 75 mph is about max for this engine depending on tune and environmental factors. So, lighter weights will improve acceleration while sacrificing a little fuel mileage. If you are happy with your performance, you might just leave well enough alone. If your original rollers were 23 grams, then you could go to 21 gram sliders with improved acceleration and a minimal hit on fuel mileage and maybe a little more top speed.