Modern Vespa

Looks like you need some support under swing arm bolt.

already fixed, thanks

I've just fitted a Vmc 177 super g kit to my px 125 and so far I'm very pleased with it.

Spec.
vmc kit just bolted on no mods.
bgm fast flow carb
drilled heart on a standard filter
jetting Ac160, be3, 128 main.
Polini box exhaust
Its running a little rich at the moment but I'll leave it like that while I run it in.
Happy with the power I've got, compared to a px 200 I owned 25 years ago it feels like a 200 but a bit more of everything everywhere.
'On small wheels' supplied the kit and Dave the owner has been very helpful with the installation and setting up the jetting of the carb.

Orange scooter, orange cylinder head, orange hoodie. I fully approve.

Not noticed before you say it This is my friend and he like orange very much. His PK and PX is orange. But this engine is not for him

What is that exhaust? The tailpipe is huge!

Looks to me like that's a SIP Road 1.0 that got cut open and a 3-cm pipe inserted. Amirite?

Those Kyiv backyard sheds look a heck of a lot like the sheds in Belgrade btw.

That engine sounds great and should be a solid runner. No reason you shouldn't get 18 or 19 HP out of it without too much effort of the port timings are good and the exhaust is up to the job.

This is my old SIP Road 2. I used it with long chromed decorative pipe, but it was bad idea - tailpipe was cracked and I losed it on the road. I went to my welder and he have on hand only 27mm pipe and I had no time to wait or search for smaller pipe. So he weld this big pipe.

At the end there is Polini Box on this engine. I put my SIP only for test. I'm very excited too about how this engine will run on the scooter. But it owner now in the frontline defend our country from russian invasion. So only after our victory. It is not a backyard. It is so called "garage cooperative" - big guarded territory with a lot of garages(can vary from 20 to 500)

Polini will be good for power and fit, but will run out of RPM's before the cylinder, I think. Others on here can say better than I. The VMC+Polini Box is a proven combination around here. Slava Ukraini! I hope your friend is home soon in good health to take it for a victory lap!

OK, yeah, not a backyard per se, but kind of the same thing. The scale here isn't the same as what I'd seen in Ukraine many years ago, in Kherson -- there was this 20-acre patch of single-car garages, probably like 500+ units in there, where I had to go find this mechanic. It was big enough to get lost in there. Anyhoo the overall look is the same! I hope he'll be really happy with the results when he gets back. I can't speak for the VMC but I'm finding that my Polinibox + Malossi Sport runs out of steam around 7500. FMP notes that the Polini isn't as restrictive on revs as some people say -- he's got some videos of some setups pulling strong till over 8000.

Time to jetting.

So lip machined to fit 125/150 cases? Rotary intake?

MRP intake, RD350 reed block.

In that case, you should have gone with a bell crank and hogged out the intake for maximum flow.

Yes, But the only bellshaped crank that i found where i bouth the Crono was de Uncle Tom one. At the moment of the purchase my pockets were not deep enough hehehe. Maybe later i will try to move to those cranks.

Mazzucelli make one for the P200 that you can use with a base spacer. Fits the LML with no modifications other than needing the conversion little end bearing. I've run that setup for two cranks and several top ends on my LML's now.

Nice. I will look for it. It worths the change to a bell shaped one? Does it feel more power? Gains? Im running in this crono yet. Maybe for a hundred km's more and then i will do the test for GSF Dyno. With the stelvio i was on 20-21PS (GSF Dyno)

I can't say for sure it's worth the change, but it changes the overall geometry a little bit, plus is supposed to increase the low end power. I know that I get 27 HP on GSF Dyno with my build, which is a BGM177, but allegedly pretty similar performance.

Hi guys. How do You see this spark?

That JJN looks like it's at risk of a seize. The JJM doesn't look bad, though.

Ok, i will ride a couple of day with JJM. I dont understand why , with JJN 2nd clip, the negative is light chocolate and the spark edge just black. Im using RN2C Spark , relative to B9ES which is the one recommended by VMC. Ambient temp is 28*C. Maybe try B8 ?

Sorry for offtop but maybe someone can help with advice.
I have Super G kit and want use temp gauge. Is it good idea to drill hole for sensor in one of marked places?



Sensor is 14mm length


I'm also interested will this sensor works properly as it marked like water sensor?
But on the other side I saw very similar sensor whi similar sensor which Scooter Center recommends for their BGM cylinder head.

This is what I have

I'm pretty sure FridayMatinee and Charlieman22 have both installed a temp gauge into that spot. I'll let them speak up for sure. If your kit takes a long thread spark plug, then you should be fine.

When you install it, you want to keep it shallow enough that the tip of the sensor can bottom out onto the head. It needs that contact to get fast and accurate readings.

Cool thanks! Sorry for my misunderstanding and bad english but you mean that tip of sensor must touch the body of cylinder head?

And yes it its for long thread spark plug.

Yes, that sensor tip must touch the head. And I'm sure your English is better than my Ukrainian.

I'm cheating and use google translate

Sensor at the lower position is preferred

Google translate has come a long way since I was using it to read Russian Bluetooth forums chasing intellectual property leaks and trade secret theft.

Hi Roland!
Love your work.
Here is what I did: Vintage vespa with sidecar (**Now In Technicolor ! **) (Page 78)
page 78... of my Shevchenko novel.

I love the sensor in the head.
By far my preference.
Three things to watch out for.

1. Place the hole so that you can tighten the sensor with a socket wrench. careful not to place it where you can't tighten it.
2. Don't over tighten the sensor when you put it in. a drop of loc time is a good idea
3. Your measured temperatures will be 50 degrees F hotter than under the plug. 300°F under the spark plug is 350°F with the sensor screwed into the head.

Thanks for great advice!
But now I'm really confused about how to screw in and tight the sensor? With socket? But there is wire and connector on the way...
Only what I see is the nose pliers

I use a deep 3/8" drive socket with the wire fed out the top. You can get it hand tight enough with that to hold it in place.

I did indeed try to run my sensor that way. But I wasn't successful. I was using the SIP probe which is maybe 4.5mm I think. It broke off when finger tightening it. So I have parts of 2 sensors in my cylinder head. I do plan on using the much more robust 10-12mm type eventually, I really dislike the under the plug ring. I can't get it to not leak there.

And the sockets I've got you can get a spanner on them for just such an occasion.

The Koso uses an M10x1.0 sensor. much better option.

I've learned that lol. Now I just gotta order a new power box for the speedo. Then if that works I'll get that Koso one and redo it.

I'm in an abusive relationship with that damn speedo

Roland - the answers above covered it.
I think I let the wire poke out the top of the socket and put a vice grips on the socket itself.

I was more worried about having to remove or replace it down the road, and not being able to get a tool on it.

The tip of the sensor needs to poke the bottom of the hole and make good contact, but it doesn't need a great deal of tightness and you don't want to strip your nicely threaded hole!

I'm sure you will handle it no problem.
I do suggest: go ahead and put a second sensor under the spark plug temporarily. Get the scooter hood and hot, and then unplug the spark plug sensor and plug in the head sensor.

You will see a great deal of difference. Takes some getting used to the new range of "safe".

Perfect! I do it as I also have spark sensor too.

Thank you all guys for such clear help!

hi guys, i have a question, it is possible that the crono use similar Main Jet used on stelvio. With the stelvio a was on MJ132. I did some test with 3 MJs. 138, 148 and one drilled with a 1.5mm bit. The best i get was with 138. I will try a smaller MJ to see if that gets better.

Are you monitoring cylinder Temperature?

Did it actually run with a 148 main jet?