Modern Vespa

I want to know if tbe kiddos have realised yet that dad liberated it for an alternate purpose, other than. It's intended use of being ground into the flooring



Well that's my experience of the stuff

Actually my oldest daughter (7 years old) helped me pack it into the crankcase! Omg it will never come out of the carpet. Ever. It's oil based so it works amazing in our hobby to keep stuff out of sensitive areas. A little dab to keep in woodruff keys or pins and even if it gets into oil it will incorporate.

I have her running better now and I have done the jetting. Seems like the porting and timing work has made a difference because I had to get up to a 72 main and enlarge the 38 idle jet to 42. The power gains feel mostly up top with no gains or slight losses of torque. I really feel like the 16mm intake and the proma exhaust meant for the 50cc cylinder is now really restricting it.
SIP cancelled my order for some unknown reason, so I may make my own manifold from some tubing? Maybe also bake out and modify my factory exhaust. No reason to spend money on an not permanent intermediate step.
Top speed on gps with this setup is 42mph on a flat. It's still 14/69 primaries on a 3 speed pk transmission and factory 3.0-10 tires. Wow. That calculates to over 9k rpms. I'd happily trade some of those rpms for some better torque.

Best way to test if you have Improved the torque is to see how it runs with two people on it

Assuming you can't dyno it

If it pulls the same speed with two people on it, you are safe to assume you have loads of torque and could also safely up gear it some more

I was chatting to a friend in Germany who told me the pk from 1989 and onwards is actually the exhaust the sito plus is. He said if I cut it open that I'll see that there are no internal restrictions and that it's actually a decent exhaust. Well I found a pic on this site of a pre 1989 pk muffler insides. I also baked my muffler out on the grill in prep to cut the bottom off? Not sure why some Italian guy cut the stinger off and punched holes into it? Possibly because it clogged up? It smoked heavily on the grill at 650 degrees for 1.5 hours

Well I wouldn't call it "not restrictive" , but it's extremely simple. I wonder how this could be improved without causing it to make less power?

I'd drill a few more holes on the in pipe and replace the exhaust pipe to a bigger diameter…

I would just cut the crimped end off to improve the flow

Probably remove that baffle plate, or make it more free flowing

This is for a Sip Road for largeframe compared to original, but do you have room to fit a cone in there? Perhaps by removing one of the baffles?

All great ideas. I really don't want to spend toooo much time on this muffler adventure, so I stuck a bar into the end of the crimp and hammered it open, found a piece of 1/2" conduit (17mm id vs the 13mm id of the original) to make into a new stinger, drilled a couple more holes in the baffle and started welding. I'll finish up welding tomorrow. Not pretty but it was going to be binned sooooo….

Great !!

I couldn't sleep with a partially welded muffler so I finished it up. Excuse the ugly welds. I only have a tiny flux core welder at home.

Here's the custom muffler. Accidentally left the choke out.

https://youtube.com/shorts/2dGtttH_QmI?si=6ZC8YDNC8iTeuHd5

What's the experience now with the modified exhaust?

Better than when it was stock but lost high rpm power due to no expansion. I'm going to chop up proma, old piaggio muffler, and old ktm expansion and try to make something work. My mad scientist is coming out.

Getting closer to something

Ooh nice.

Hmm

Oh it's ugly. Haha

https://youtube.com/shorts/GC6PGF6E2Jw?si=lNdv8RuAbthmamjD

And for my next mad scientist experiment, I'll fab a new intake manifold out of a square washer, some 1 inch tube and bends and a 21mm phbg

Cut out and fabbed the flange and started on the bends

Finished, blended flange and filed flat

Seems to have more response. I need a cable end to attach to my throttle

https://youtube.com/shorts/iOkAZezk69s?si=_wWgDAyQmTf6E2Et

Took a while to get the jetting, needle, and slide right. But it ended up using a 45 idle jet, 50 slide, w9 needle 2nd groove, and 78 main.
It rips harrrrd for a 85 dr kit. I don't think they intended it to be used like this. I'll have to get my action cam working and I'll record a ride. This is about the limit that a 3 speed pk50 can do. Next is a real build because it fails a pressure test at the clutch seal. I'm not stripping the motor apart unless I'm kitting it to 20hp and 4 speed.

Well done.

enquiring minds want to see

finished in place exhaust
sound of it
top speed runs


you name it

I guess I forgot the pics!!!

Hmm what's this?

is there some EGIG parts or just sticker?

Doesn't the sticker make it go faster? Like stripes on a car?

I can't keep teasing myself right now because I don't have time to build yet!

Congrats! It will be nice time during the assembling and absolutely joyful riding!

I'd done two 170 engines - one for myself and one for a friend.

Is it Mamba or Unisex curly?
The only one thing that disappointed me is the Unisex exhaust which hits the ground on the left turns too early😓. And it is even with 3.50" tyres.

Thank you, I look forward to it. My engine is very worn and has 25k+km on it and has not been opened. I hope the cases are okay.

I read all of your builds, it's an inspiration!

The exhaust is a unisex curly. I wanted the torque as I'm in a hilly area. I will have to cut out the wall behind the panel because it's a PK. Erich told me that with the unisex curly i should use the 29/68 and will have no problems with steep hills and he told me 120km/h is no issue. I trust him since he is in the mountains.

On the other hand I'm thinking of becoming a distributor for his parts here in the USA. I'll build this engine and take it to some meets and rally and tell people. Very few people here on the left coast of USA know anything about vintage vespa modification

My VERY HUMBLE opinion after few thousands km on my EGIG.
My setup standard PK gearbox, 29/68, 3.50 tyres. My friend have same but with long 1st gear and 3.00 tyres.
And I think that for me will be better 28/68 and long 1st. Or 29/68 and short 4th.

I have 29/68 and short 4th.

I went to my shop to grab my small motorcycle stand but I guess someone needed it more than me. All I had was an atv lift and that's way too big. So I went back home and hacked together something out of scrap lumber. Works well and plenty of space to work.

Say bye bye to my home made expansion. It worked well but I'm 99.9% sure my clutch side seal is really bad and I can't get it to run right without soft seizing. I then disconnected all wires and cables.

Engine out and on the bench. Output shaft makes that weird noise and what a tiny primary pinion!

https://youtube.com/shorts/RT5trWrirsg?si=yu7lVdQapOUiL-lM

Aaaand cases split. Seal is just as I thought. Completely smoked! Rotary pad is perfection. Too bad I'm going reed. Not sure what's going on with this cone washer and clip. Seems messed up. Video has noises of all bad bearings and gear noise. Yikes!

https://youtube.com/shorts/LU591ySl28g?si=m5b1UG5TTLlyqwzY

I couldn't sleep so I built the output shaft. Say bye to the 3 speed! With the supplied shims from Erich I had .3mm clearance! I didn't have anything larger than the 1.3mm so I swapped the .8mm on the bottom for a 1mm and now the clearance is .1mm.