Modern Vespa

Hi Roody,
Really enjoyed that ride video! Watched it twice.
You guys over there are lucky bastards. Period.

Some FWIW rookie-blab things:

Get rubber trim for the glove-box. New tuning just buzzes everything.

Don't ride without motorcycle gloves on a kitted bike, from experience.

Your idle settings are rich.
There isn't a "2xx turns out" rule. At some point you'll want to take it out with a screwdriver/socket and play around with that mixture screw. It's makes a big difference.
The bench settings are just the starting point.

CHT in 4th will go up for sure, compared to 3rd under the same load. What I want to see is CHT get to a known safe temperature* and stop climbing. Then you can relax and enjoy the rest of the rides.

*Depends on your kit/setup/sensor.

Hahaha. At the moment, with the correct ish main jet, I am really liking it. Pulls well and is nice and crisp. I won't be selling it unless it goes tits up again. Even then I will probably just rebuilt it again. Keeps me busy and justifies the tools I purchased.

I enjoyed the ride as the bike was behaving. The ride was around Stainton and Acklam where I live. Just a few miles out and its all countryside. Really nice when the weather is good but that doesn't happen often.

Yes, the glove box rattle drives me mad. I usually wear gloves but can't find the fuckers. New ones are on order. Glad to hear that the CHT will be higher in 4th as I noticed that straight away. A quick down gear into 3rd and higher revs soon lowers the temp so thats good.

So here lieth the issue. Even with the standard 155/60 pilot, the engine still runs with the mixture screw fully home. The engine sounds shite and the revs take a bit to settle with loads of popping, but I cannot get it do bog down when blipping it, to indcate it is running lean. Shall I try a smaller pilot jet? Just to confirm, I should be messing around with the pilot and mixture screw when the engine is warmed up properly?

In the video your main sounds on the rich side. That will not be helping but don't change it yet.

55/160 is not a small pilot jet. This is the jet for a stock P200. Put in something like a 48/160. Then you'll see. Don't ride it though.

Winding the mixture screw in to cut out at tickover only works if all the jetting is correct first. Not a big deal at this stage.

Reduce the pilot until you have to use the mixture screw to get it to respond. Like Ray said, doesn't have to be 2.5 turns but over 2 and less than 3 is where they run best.

Thanks. I will try that sometime today. At least it's rich and not lean.

Smallest that I have is a 52/120 or 50/140 and it still does not bog when revving from idle. When fitting the 55/160 and mixture screw all the way in, it now stalls. With mixture screw out 3.5 turns, sounds good again. Just been out for a quick ride. Much crisper when pulling away with the 55/160. Feels much better. Less 4 stroking at low revs too. WOT in 3rd for 1 minute gave a temp of 150 which fell and levelled out to 138. No popping or weirdness on the overrun.

Need to try and get it under 3 turns. That jet kit have a 58/160?

52/120 and 50/140 are both richer than 55/160 where it matters.

If no surging or popping on the rundown, that's all that matters. Really sounds like it's getting there. Once the vortex is on it will just need a tweak.

Yes, the 58/160 is the first size up. I will fit that tomorrow and give it a try. Got dyno tomorrow afternoon. I might not fit the vortex. Seems to throw everything out and the gains don't seem worth it according to some reviews.

Fit the vortex. The jetting will change but not so much.
Will the guy doing the Dyno check the jetting performance or adjust it too?

He told me he has jets but to bring my own. He said he uses a lambda sensor and jets accordingly to get the best performance but on the safe side. The biggest jet that I have is a 145. I will fit the vortex when I get there as I don't want to run the risk of being too lean on the way over there. It's only a few miles but still. He may have some bigger jets but I am unsure.

Dyno not done today. He had some lad there with a Lambretta GP? that had an RD350 enigne. Kicking out 63 bhp. Still working on it. Fuming.

A genuine Rossa 350?

Not sure. He mentioned he had fabricated some parts himself. It sounded mint. Reminded me of my old RGV 250. Lovely sound. Some lad from Rotherham.

Would anyone like to guess what BHP mine will be kicking out? I literally have no idea what I should be expecting. Bear in mind, the squish is on the high side at 1.4mm.

Not a fan of bike engined scooters. Might as well just buy a twisty. Or the actual whole bike.

If you're lucky it will be over 20bhp as it is.

I will be more than happy with 20 bhp. The guy said he had £15000 in to that scooter. I also don't see the point but each to their own I guess.

Dyno not until tomorrow as he is busy. Oh well. Just been for a 30 mins ride. At one point I was doing about 50-60 in 4th and the temp went to 168. Not WOT. I was probably 1/3 to 1/2 throttle. Road had slight inclines and declines. I am a bit weiry of WOT in 4th as the temp rises a lot. Once the bike has been on the dyno, and all is ok, I will WOT in 4th to see where the temp settles. It's just a bit discouraging with the temps. Plus I am a bit scared. Lol.

Placing a bet on "the lower side" of 18hp

Here are the Dyno results for the bike when I first purchased it. When I got the bike it had a Pinasco Centre Plug 177 kit in it. But was running a 60mm crank and 1.5mm spacer. So I assume that would be 190cc. This was with a 20/20 carb with a 106 main jet. Here are the Dyno sheets from that bike. I

I hope the new setup is better.

Dyno done. Disappointing. On the up side, it's safe to ride regards the jetting. This was without the vortex fitted as I did not have any bigger jets in case it needed them.

What is your current setup on the engine ?

Remember that two dynos can be calibrated way different. Results are not usually 1:1 between dynos.

How did the jetting change?

Or it didn't?

It made 15.3 bhp when the rear tyre was inflated properly. Jetting is good throughout the range if a little rich low down. Lambda was reading 12.5 ish all the way. I thought 14 was the figure to aim for. I could be wrong, I have been in the past. Lol.

Jetting didn't change. He said it was safe and good. Pretty lucky there with the jetting but Jack basically set this bike up by proxy.

I just don't understand how the previous kit (Pinasco 177) with a 20/20 carb has more power than this one. Only 1.7hp more but still. Could this have something to do with the high squish at 1.4mm?

Great. So now you can post more UK countryside ride videos

If you could trim down that squish clearance closer to 1 you'll feel more power and likely a reduction in CHT, if your experience is like mine (1.35 to 1.1).
You sure don't seem to be lacking on that ride video, though.

To be honest, it's a massive improvement over a standard 150. Of course I will be posting more videos now I know the bike is good to go. I think I will leave it as it is. The only way to reduce the squish would be to take it all to bits again and either skim the head and/or reduce the thickness of the base gasket which is currently 0.25mm. Actually the base gasket is 0.4mm thick. I had to make my own paper gasket as the normal gaskets were not big enough to cover the huge transfer ports on the cylinder. I now have 0.15mm gasket material. I may change to this when I can be arsed.

I am glad that you like the videos. Lol.

Here is a partial video of a ride from Whitby to Saltburn. Took the coast road. I have gloves now. They arrived yesterday. Apologies for frequently glancing the the temp gauge. It's become a bit of an obsession.

Well, it appears this is the end of this thread and challenging journey. The bike runs well and is jetted correctly. I would like to thank you all for your help and advice. A special thanks to Jack and 108 for putting up with my never ending questions. Hopefully the bike will run good for a long time. 😅. I have learned an awful lot, all of which is important and essential. Just been for another ride to Whitby and back. Around 80 miles. Didn't miss a beat.

Congrats!

Thanks. It has been a big old pain in the hoop but finally got there. Let's be honest, I would be fucked without the help I received from this forum.

Hey roody - I'm glad you got it sorted and it's running without seizing! JetEye Jack is pretty amazing at this proxy tuning stuff.

Could you summarize the exact setup you landed on? I read back a page or two but still couldn't find what you ended up with.

And congratulations on dialing it in, and sticking with it. Big win!

So full setup is:

Vespa PX 150 (2016)
ReedSpeed Ignition
Timing set at 17 degrees btdc
Pinasco Vespone RX 190
Sip 2 Fast Flow Tap
BGM 24/24 carb. 62/160 (@ 2.5 turns) 120/BE4/138
Pinasco Chamber Cover
Polini Road Exhaust
Pinasco Race 60mm Crank
No Air filter.

I was expecting a bit more power but squish is currently 1.4mm. I am happy.

Thanks. Long time coming but got there in the end.

It's not the end. Just the end of the beginning. The polini box is the main issue with the lower power. The 20/20 carb and stock inlet in 2nd and 3rd.

Polini box is a high torque exhaust with peak power coming early. The RX is sold as a racing kit and would really need an expansion.

Ride it as it is for a while but knowing there's another 10bhp in it, might play on your mind.

It has the 24/24 carb fitted. I like the high torque. 18nm is a lot more than standard and helps pull my 195 lbs up hills. Like you say, there are things that still can be done to increase the power. I will leave it as it is for now and enjoy it.

So slight issue with the bike. Sometimes, but not always after a wot run, when lifting off to zero throttle, the bike surges for a few seconds. I can feel the bike lurching. The idle jet passes all other tests for it not being lean. The temp of the engine is not a factor as this happens at all temps between say 120 and 150 celcious. Whilst at WOT there are no noticeable issues. No pulsing, surging etc. At WOT the engine temps rise but then fall and plateau. Any ideas? Thanks.

I'd look into the main jet being too big…

Does the bike start smoking if you just leave it idling for 5-10mins, not revving it at all?

Or not?

Not tried that but I will on Fri when back from work. Thanks for the quick reply.

Carb slide could be binding a bit.

Only really happens in 4th. Rarely 3rd gear. I will take a look at the weekend. Thanks.