Genuine Black Cat Polini sport

[jackmisanthrope]

Did a top speed run today, GPSed at 51mph. Pretty happy with that considering there still some meat left on the bone.

[jackmisanthrope]

I still need to swap gears but I'm considering waiting till winter. I'm pretty happy where I'm currently at. Here's where I ended up:

47mm Malossi sport with head
17.5 dellorto phva w/ 102 main 33 idle and A20 needle one notch from bottom
Stock air box with snorkel removed
Stylepro reed cage and reeds
Oil pump removed and plugged running premix
Malossi multivar with stylepro racing front pulley w/ 7g glixal sliders
Malossi fly clutch with yellow springs and white contra and 6116424 malossi belt

Did I forget anything? I think that's it


Last top speed run

[Zino]

47mm Malossi sport with head
17.5 dellorto phva w/ 102 main 33 idle and A20 needle one notch from bottom
Stock air box with snorkel removed
Stylepro reed cage and reeds
Oil pump removed and plugged running premix
Malossi multivar with stylepro racing front pulley w/ 7g glixal sliders
Malossi fly clutch with yellow springs and white contra and 6116424 malossi belt
yasuni r with yasuni z bracket

you should add this to your signature line so the next guy knows what to build to
54 mph is quite solid adding gears could push you to 58-62 mph range 

[jackmisanthrope]

Thanks Zino, I added it on there.

I'm really digging these sliders. Love the way they shift. Great take off, good acceleration through the mid range but at about 40 or 45mph it feels like a turbo kicks in and it halls ass to top speed. Quieter than the rollers too, so that's a bonus.

[Zino]

I do like sliders better for the way they shift they also don't wear out so fast.
You have got great results with your build it will help guide,the next guy so he can rip around like the rest of us .

[jackmisanthrope]

Planning on putting the malossi gears in tomorrow. Anyone have any tips? Anything I should expect to fall out when I take the gearbox cover off? Any leftover washers when the jobs done? I haven't been able to find anything Genuine specific on youtube. 

[Zino]

you have to take the rear tire off to change gears .
I tapped from the back side gently with a rubber mallet from tire side to get gear shaft out.

use a press
you may need to heat up the malossi gear to get it to fit on the stock gear shaft

take pictures before taking old gears out .
you have 2 washers on the gear shaft one is concave put them on the same way you took them off.

use a new gear case gasket put a light coat of grease on both sides of the gasket for install ,this way you can easily remove the gasket if you ever have to crack the case again ,

make sure the gears spin freely and mesh with each other then put the gear cover on  torque to spec and re test that gears spin freely 
then refill with oil .

do not over fill the gear oil otherwise it will weep out and end up on your back tire .as you ride if you do
There will still be oil left over in case so you need no more than 90 cc

you will probably have to drop about a half gram in weights to get the same shift points prior to gear swap

[jackmisanthrope]

New gears are in. Got everything cleaned up and put back together

Dropped the sliders from 7g to 6g. 





It felt like it had more left but I backed off. It was only at 9200rpm. I could maybe go down a half gram and get 60 but I'll leave that to some younger guy. Lol My goal was to bring my revs down for normal cruising and that was accomplished. Thanks for the tips Zino. Only thing I ran into of note would be the 42 tooth malossi gear was thicker than the stock gear it was replacing. It had to be pressed on a little farther to allow for proper clearance. Also the gear box cover screws are 3 different sizes. It's easy to determine which goes where but paying attention when you remove them would probably be easier 😉




One other note, the washers Zino mentioned came out stuck to the inside of the cover. Keep an eye out for that.

[Zino]

57 mph on a scoot that used to do 40 mph is great work .
If your rpms are peaking at 9200 rpms .
you might have a few rpms on the available to push you over 60mph if you drop the weights

You just provided another solid blue print for a 55-60 mph build .

[jackmisanthrope]

Thank you, I'm extremely happy with how it's turned out. I've run it a few good times and I'm in the process of doing a gear oil change. Mostly just to make sure it's at the proper level but also to look for glitter. Everything looked clean.

Now I need to get rid of the 20 year old dual sport tires and get some street tires.

[jackmisanthrope]

Anybody use an app called Dragger? Pretty cool little bit of info.

[jackmisanthrope]

This thing has been doing something strange I can't figure out. After riding when coming to a stop my rpms get down to around 3k and hang there for a moment then drop slowly to idle. My original thought was air leak, mixture screw, something creating a lean condition. I have eliminated this possibility through extensive checking and testing. Is it possible for part of the transmission to cause a hanging rpm? A few things that lead me to believe this are it doesn't happen all the time and not on the stand only when riding, the faster I'm going before stopping and the faster I come to stop affect the rate at which the rpm decreases to idle and I'm about 98% positive it didn't start happening until I did the gear swap. Any input would be appreciated

On a positive note other than the above stated issue it's running fantastic. No other issues to report. It survived its first moped rally in Detroit this past weekend no problem.

[broyager]

I had the same thing on 2x scoots, both Buddy's, both with the same dell 17.5mm carb.

My theory is either a design thing, the reasonably long intake path, from snorkel entry through carb, down the large intake manifold etc, or that maybe fuel is collecting somewhere, and the hanging idle is excess fuel burning off.

Just theories, but I also am confident I don't have an air leak, and that my idle is not too lean. I've def had it on the rich side, but end up fouling plugs pretty quickly.

Using the 21mm dell, I've managed to tune that out pretty much, but idle can be a bit high still, when things are hot. Currently have idle set quite low which helps, but it's a fine line in terms of being able to start it comfortably. 1st kick this morning, once the choke is off I need to give it a few revs, so behaving well, in this weather.

You could try the snorkel back in, but cut a decent length off the tip, would probably need rejetting though

Great accel times btw

[jackmisanthrope]

Apparently I had my idle set to high. Brought the idle down from 1850 to about 1250 and it cured the hanging rpm. I did some tuning on my air screw when I swapped out my gears and apparently forgot to back the idle back down. This is slightly puzzling how 600 rpms can cause the symptoms I was having but I also had to back the screw out over a full turn, which seems like a lot for a decrease of 600 rpm. Anyways I'm glad I got it figured it's was driving me crazy.