Modern Vespa

The blue light special on the speedo sensor is totally extraneous, but i like it. The speedo says that my top speed is about 140mph. I think it reads about 100mph too high...then again, a stock italian speedo isn't that accurate either. I did program the speedo to "1P", but i didn't program the wheel diameter yet. In the SIP speedo manual it says that the speedo's preliminary speed setting is pretty darn close to where i want it to be. If that's the case, then maybe i was going 140mph?

Lighting is a little bit too bright for the main headlight. There was one lone oncoming car that was coming up the hill as i was going down (after dark @ 9pm). When we passed each other, i could clearly see their face being lit up and their eyes squint. Right after that i lowered my headlight just a pinch. I don't think it helped that much.

Though i only rode about one mile down the road and back, the scooter handles quite nicely at the slow speed i was riding at. It feels much more planted than it did when i first bought it years ago. I still remember not enjoying the comfort of the handling when i used to ride it. It probably has to do with having a new front shock and swapping out to a different seat.

During my very short test ride my speedo was wrapped up in a towel and
dangling from the headset (i don't have my headset top installed just yet), so it was a bit awkward to hold the speedo with my left hand while riding with my right. Once i get the speedo mounted, i'll dual in the speedo functions.

I swapped on a Vape static cdi to see how that would work. I set the preliminary timing to 23 degrees. When revving up the engine to who knows what, the timing then drops (or maybe it just evens out) to about 21 degrees. I currently have the Koso rev signal sensor attached to the HT spark plug wire. That might not be the correct wire to attach to since my RPM isn't accurate...whatsoever.

I'm hoping to install the headset and speedo later today.

I think the blue light is cool. You need to get those ghost rider ground effects lights.

When you use a sensor you need to program a different circumference…

It will be the result of multiplying your actual circumference to the ratio of the speedo drive (0.75 for a Grimeca setup)…

I got the speedo plugged in and mounted. The upper headset clamped down, headlight installed, and popped on the headlight trim ring. Now it's finally looking like an assembled scooter! It's definitely a VERY tight fit to get everything to come together. I used a heat gun to get the wire harness looms and wires to soften up and get more pliable when installed the headset. It made it LOTS more easy to manipulate them by doing that.

WOW!! That's a real kick ass custom scoot!

I ordered up a 55/100 last night. It should arrive in a week...hopefully by this friday. So does the air flow change when that idle jets is cut down? And if my T5 airfilter is drilled out do i still need to cut down the 55/100?

And i'm not opposed to using either a static or a variable CDI on this engine. I just want to use the one that gives me the more reliability...not necessarily the most efficient power. I did a little bit of math with the VAPE variable timing/rpm graph for a P200 with a short 36 tooth 4th-

RPM / DEGREES / MPH
4500 / 24 / 47
5000 / 23 / 52
5500 / 21.5 / 57.5
6000 / 20.5 / 63
6500 / 19.5 / 68.5
7000 / 18.5 / 74
7500 / 17.5 / 79

I'd probably be spending most my time hovering around 5.5-6k rpm on the highway, but i wouldn't hesitate to open it up to WOT for a few miles at a time.

Do you happen to remember what the tire diameter numbers are that you programmed with the "1P"? In the instructions SIP says to choose "6P" for with the koso speed sensor. I seem to recall you mentioning something about that..

The restriction on the pilot is near the thread. The top half is optional. Try it without cutting. I doubt it matters to performance.

When you get it out in public, see if you can determine where the max power is. The Dyno phone app might help.
If you've gone >1.4mm squish and low compression, I see no reason it couldn't be 19 degrees at max power. Maybe more.

The unreliability with variable timing is more the fault of the jetting. Not withstanding, the rider, with a manic grimus, holding the throttle wide open, for another mile, just to get 1 more mph, while the engine is pinging and shuddering, with the power surging and oblivious this all means the piston is going to blow any second.

Phone apps...ugh. I have the tech skills of a luddite.

I was going through my notes and i'm second guessing what my actual squish is for this build. I originally planned to go with a 57mm crank, but then i changed my mind and went with a 60mm AND a stock head. I do have a 1.5mm packer at the base. So if i had kept my stock head, then i'm guessing my squish would have been somewhere around 3.5mm. But since somewhere during the build i installed a SIP zero degree head instead. Which means my squish should have been tightened up quite a bit. I'm really surprised i don't that number written down. I'm also surprised that i don't have a compression test # written down either. The engine is definitely much more difficult to kick over! I'll just have to do a compression test and then whip the head off and do a few squish tests before i go any further with the jetting.

You can poke long bits of solder through the plug hole to measure squish.

If it's difficult to start (granted the cylinder/piston setup is healthy) is usually to do with ignition setup wrong (timing or flywheel) or something is fouling.

not difficult to start, just more difficult to depress the kickstart lever since the compression is now higher.

I'd be surprised if your compression is higher (130-175psi), that you can feel it when you kick it.

If it's higher than 175 you've got some crazy science going on.

Are you saying i have weak legs? Looks like i need to go back to the gym and do more squats and leg presses! Those SIP zero squish heads really bump up the compression. The SIP head that i installed in my pink 200 boosted my compression to 177psi. I did do a comp test last night. I came up with right at 150psi. I think stock compression for a 200 is around 110~125psi? So adding another extra 25~40 psi to that number is quite noticeable in the quadricep.

Not weak legs… sensitive legs…

You're probably doing enough squats working on the Vespa.

If I remember correctly, stock compression reading should be around 130-150psi.

But actually compression tests aren't very useful on a 2 stroke.

I always think of it as taking a blood pressure reading for blocked arteries.

Piston ring and piston + bore measurements seem more useful for an engine health check.

Pièce de résistance arrived today in the mail...

The badge is so nice…!

Looking sharp!

I was wondering when that would go on. Scoot is all decked out. Looks like the end is near. You need to find another project for us to watch.🤔

I currently have a three more scooter projects that have been patiently waiting for the past couple years. A second VB1, NSU Prima 3k, and a PX200. My plans for the VB1 is to keep it on 8" and build a 6 Days tribute. The NSU Prima will get an engine swap. I'd like to use a vespa GT200 engine, but it's too wide to fit under the side cowls. I'm thinking an 150cc ET4 engine could fit? If i had unlimited funds, i'd swap in a stock lambretta 200 engine. But before i start on those three projects, i should really finish my two other lammy projects. And before i finish those two projects, i should finish my old ford highboy Cummins swap project...and get the ol datsun 240z up and running again...and my jeep Cj7 stretch project. But before all of that, i REALLY need to finish building my ktm 640 adventure project! I'm really looking forward to bringing that bike down to the mojave desert (or possibly even further down to Sonora?) and put it through it's paces.

First off, i swapped back over to the VARIABLE cdi. I set the preliminary timing to 24 degrees. Should i be setting the timing to 24 degrees at 4000 rpm?

I just installed the 55/100 jet. I left it full length and did not cut it down.

Current 24/24G jetting is at-
AC120/BE4/135 main
55/100 idle
60 choke
BR8ES plug
2mm hole drilled in the carb's float bowl.


I just checked the squish and compression-
1.50mm squish
150 psi compression
SIP 60mm crankshaft (125/-5 valve timing)

This is all with a stainless steel JL Right pipe.

I haven't done a test ride just yet. It's about 40 degrees out, raining and windy. Lots of pine cones and tree branches are out on the roads

Don't even know how to respond to your post! I thought I had tons of projects. I definitely won't be going through withdrawals from lack of your craftiness. I need to finish a Messerschmitt KR200 engine repair-overhaul for a friend. 😜

I would start at 25@4000 and see what happens.

Jetting is hopefully rich enough and can reduce from there. If it is rich enough there will be a spluttery lump at just over 4000rpm. Reduce the main jet until this goes away.

Did you measure the port timing for how the cylinder is set up?

That solder is nice and thick. Just out of interest, if it's 1.50mm at the edge, what is it at the inner edge of the squish area? And how wide is the squish area? Wondering what the squish angle of that head is relative to that piston.

I didn't measure my port timing when i just had the head off (it's all reassembled now). In my notes from a year ago (or maybe two...or three?), i'm reading that there's a 170 for exhaust and 127 for the transfers. I'm not sure how well those numbers will play with the JL pipe that i'm using. I'd really like to keep it installed on this scooter, but if they don't play well together, then i guess i'll go after a box exhaust.

I spent a lot of time tracking down this particular spool of solder. I roughly has a 2.63mm diameter. And since it's a rosen core, it compresses down quite nicely. I'll have to do some more measuring on my piece of squished solder in order to get those other measurements for you.

Sounds fun. Does the NSU have a similar swingarm setup at the front of the engine?

The NSU's frame and engine is pretty similar to a lambretta. So it would be fairly easy-ish to fab and weld brackets to a tube frame with whatever kind of engine is fitted.

I can't stop staring at the legshield. I don't know if I'll be able to sleep tonight with the image dancing around in my head. I feel like Tom Green in "How Freddy Got Fingered" when he drove by the field with the horses breeding.

I bought that NSU for $30 a couple years ago. Most of the damage was done by an excavator. I feel as though the seller came out ahead on the deal.

Maybe but after you get it all straightened out it will be that much more special. It's terrifying to look at but very intriguing. You're getting a special award when that one's done. That would be worth the trip up just to see in person.

I checked the timing with a strobe gun this afternoon. I wasn't sure how accurate the RPM gauge is on my SIP digital speedo, so i temporarily hooked up a spare Trailtech TTO tach to my spark plug wire was well. My preliminary timing is still at about 23~24 degrees (i didn't adjust it to 25 degrees @ 4k rpm just yet). Both tachometers read the same, which is right about a max at 10,400 rpm. I'm pretty sure my cylinder porting and JL Right pipe wouldn't even be able to support that kind of rpm. Right now i'm concerned that my tachs aren't accurate, so i'm hesitant to go any further.

Good news on the sip rev counter accuracy. 10,400rpm is still fine. Just. Conrod snapping risk on your set up starts at 11,000rpm.
However, the ability to achieve 10,400 does mean your jetting is not so rich. So work to do there before riding around too far. With port timing at 170/127, if the jetting is richened to max out at under 8k on the stand, it should be rich enough on the road, to work the jetting down from.
Call me Mr safety but I always fit a fan cover when revving the nuts off a scooter.
JL pipe is fine with your numbers. Next time the cylinder is off another 10 degrees on the exhaust will help. And when taking the flywheel off again, another two degrees advance won't hurt either. Such a nice scooter deserves to be set up well.

Would i just up my main jet to richen it up? I currently have a 135 main installed. I'll have to check to see if i have a 138 or 140 in my stash of jets. I would like to limit the rev to 8k while on the centerstand. So advance the timing another two degrees...so bring it to about 26 degrees at 4k rpm?

Call me sceptical, but I don't think you'll be reaching 10000rpm.

Your trousers and seat will know if you reach those revs…

Reed valve, malossi 210 Scooter & service newline pipe hardly reaches those numbers…

I'm thinking the exact same thing. I'll see if i can find a third tachometer to compare with.

Probably nothing wrong with the tacos, just need setting right.

I can't remember which setting it is, but it's definitely not default.

If I remember right, Malossi vespower was 2 sparks per revolution. I think the vape is 1.5, but don't hold me on that one.

I have the trailtech set at 1 pulse. I don't know if i set the pulse yet or not on the sip speedo. I'm pretty sure i did? But no doubt if it's reading 10.4k then something isn't programmed correctly.

Vape needs 6 per revolution if speedo BOX is connected to regulated AC. Don't know how much it needs with the KOSO filter…

Sorry, I can't stop looking at your NSU. It's so macabre especially with the black tire mark as it drug itself into that corner. I imagine you finishing an engine install and the next morning all the body work is mysteriously perfect of its own doing like the movie Christine! Carry on I'll put it to bed now. 😳

Whodat,
Do you have an under-plug CHT you can temp up to (short term) go along with your new sensor?
Something reasonable to reference/compare to.
You're going to get some wild numbers.

That's a great idea Ray! I still have the Koso "under the plug" CHT sensor that i can use to get some baseline readings.

I don't think anyone has been able to make AC connection to the vape work properly…

The koso sensor seems to be the normal route for the vape. I'd love to know how to avoid adding another sensor for the vape…