Modern Vespa

I get exactly the same. Inlet slightly shorter than spec. However, I'd leave it. 140 is pushing it. See how much blow back there is first. Exhaust might be a bit low too. Can fix in round 2.

Round 2 say what? Hopefully not if it runs I anticipate it will be better than ever and hopefully good enough for parades. For now I'll leave it.

I kept trying to visualize my previous squish calculations in my mind and things weren't adding up so I made a sketch to give the brain cells a break. Think I made an error and this looks more sense. Think I'll need only 2.7 mm under the head to get to 1.2 space. Look good?

Yeah, I got the same, 2.70. Looks like that's all good. Power will be comfortable to ride. Will putter about at 50mph really solid.
If not quite enough there's always a round 2. See how it goes. Piston port, no reed, is not the best. Piston port with reed is the best. There's going to be blow back. The issue will be if it's too easy to flood on a missed start. Could be great, we'll see. Just having it running will be pretty cool.

Thanks for checking my math Jack! I hope 50 is not top speed I thought stock set up was closer to 60.

I think I'm going to use a 23T on the clutch original is 22/67.

Made some progress on the GS that had me stumped for a few days. Piston seemed to hang up on rotation turned out to be the connecting rod interfering with the cylinder skirt maybe because it's a 60mm crank. There was a cut out on ONE side of the cylinder skirt but not on the other. Finally I separated the cases put crank and cylinder on 1/2 case so I could see what was going on and duh that's the problem. A smile returned to my face just knowing what was wrong.

Took cylinder to machine shop to cut other side of cylinder skirt and to enlarge the original cut wanted more clearance for the rod. The original slot was 6mm wide and the rod was 6mm I wanted an 8mm wide track. Machinist had trouble he started to enlarge the first side and had some of the nikasil chip fortunately it's not on the bore and on the bottom edge of the skirt. He made a quick cut mark on the opposite side but got too nervous and put it on the shelf. Ended up picking it up as is still needing the 2nd slot cut. Spent a few hours cleaning up the damage so the piston could move freely again in the cylinder something happened could not see or feel lots of working with Emory paper rolled on a small steel rod seemed to get it back into shape.

Checked marks again with crank on both sides 1/2 case assembly and went at it with a stone bit in the dremel. Think it's good now after more sanding with the steel dowel.

After finishing the grinding and checking clearance I asked myself why didn't I grind the rod instead? Still can't answer maybe I could do a little to make more room?

Going to start working on exhaust Polini box needs a few changes to fit.

Waiting on parts to move this along. Had the exhaust modifications made to a Polini box. Bollag offers an optional slip collar with an internal o-ring so the clamp can be eliminated. I added two spring hoops to keep it tight. Removed pipe hangers, captive nut welded both tabs together and re-attached. Removed rear hanger patch so it looks like it was never there. Fits like a glove.

Had the exhaust ceramic coated. Chose burnt bronze to mimic the color on Mauro Pascoli exhausts. Might not be everyone's cup of tea but I'm jazzed.

this carb would be right at home on this build.

https://www.ebay.com/itm/145832766710?mkevt=1&mkpid=0&emsid=e11021.m43.l1120&mkcid=7&ch=osgood&euid=1ecc24678a2443d490a2364fdd8fd540&bu=43109903675&ut=RU&osub=-1%7E1&crd=20240615030047&segname=11021

Wow ok so this is the carby you mentioned before I still had no idea. Got a little sticker shock when I reviewed the link. If anyone has one laying around please let me know maybe we can work something out. I'm not expecting too much performance increase but I'm not sure what to expect. The bore is actually slightly smaller than original old piston is 57.5mm new piston is 55.9mm. Old stroke is 57mm new stroke is 60mm. Both old and new come in at 147cc's. Expect some advantage with the aluminum cylinder, better piston, ring and wrist pin roller bearing. Looking forward to running 2% oil mix big savings on that. 20 years ago I rode a VS5 with a custom expansion chamber and could not believe how much it improved.

Had the exhaust ceramic coated. Chose burnt bronze to mimic the color on Mauro Pascoli exhausts. Might not be everyone's cup of tea but I'm jazzed.
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That pipe should look good on the GS. I like it better than the Pascoli. They did a nice job on the coating.

I've heard that it's not difficult to up the ponies on the GS engine but don't ask me how it's done. After mine is running I'll have you take a spin and you can tell me if it's better than stock. Curious how my newer style pipe performs.

Got a few tasks completed on the GS. Sent the cush gear with a new DRT rebuild kit to BajaRob after seeing his impressive rivet skills. Rob did his magic lickety split and it's relieving being rebuilt and back in my hands. I wasn't going to rebuild it but Rob convinced me and he also replaced the FAG bearing with a new SKF! Thanks Rob you ROCK!

I replaced the motor mounts. I was dreading doing this job because it's always been a pain in the ass on my large frame scoots. Have to say wide frame might be easier the bushings are tapered and went together pretty easily. I'm glad I did it, doesn't look like they've ever been replaced. Had to chisel one side out and the other popped out easily. The one that came out whole was soft as a marshmallow compared to the new hard ones. Getting the new ones IN and the shaft peened to the washer went as good as I could expect.

Have the kickstart segment and drive axle sent out for fixing up with new oversized bushings. When those are back engine assembly will commence.

Good on ya, Rob! That's tidy work!

Looking sharp, Hibbert! Those steps all add up. Your GS is going to be quite the looker with that sort of attention to detail.

My V90 project has been a class in checking everything. It's a stocker, but when when you want a collection of chingered-up old parts to run and ride decently and you can't always get new parts, I'm finding value in checking the parts fit of subassemblies, doing repeated dry builds and knowing a good machinist

Took a page from the SaFiS playbook again and added an o-ring to the clutch lever. The GS150 doesn't have one originally they have a flat rubber washer that compresses at the bottom. Not quite a double maybe 1 and 1/2 now.

Mmmmmm, I'm jealous! On my list.

Just wanted to say hibbert had mentioned doing this mod to me recently. He said that was a troublesome leak spot on the GS. Thanks to him after this mod I should have a much cleaner scoot. Thanks bro!

Made more progress on the GS thanks to Jonathan Gick at Gickspeed. The kickstart was extremely worn and wobbly. Looked into replacing parts but later decided to refurbish the original parts. The kickstart segment was worn down that rotates in a bushing pressed into the casing. So much so a new bushing would probably maintain a sloppy fit. Bought an OVERSIZED DRT bushing so the segment could be trued to match the new bushing.

Also some noticeable wobble in the output shaft and end bushing/bearing. Bought an oversized bushing and had Gickspeed match the output shaft to the oversized bushing now it's back to tolerance.

Finally the castle nut wasn't threading on the axle as good as it should. Jonathan fixed the axle thread and provided a fresh nut.

I'm pleased with the results and Gickspeed was the perfect choice to rescue the original parts. I have confidence it will be better than ever.

GickSpeed making it happen again with quality work!👍

Made some progress after a few delays partially my fault. I purchased a set of BGM main bearings which were specially MACHINED for the GS 150 to use with BGM VITON main seals. When I got the bearings 3 years ago there was metal shavings in them I made a mental note I needed to clean them before installing them. I forgot and 3 years later tried putting the engine together without cleaning the bearings. After I set a bearing into the case it was locked up and wouldn't rotate. Then I probably made things worse and tried to force rotation. Probably embedded the shavings and made things worse. Knocked the bearing out and thought I got them clean but destroyed the seal taking bearing out. Waited a month for a new seal to arrive. Tried again with the now cleaned bearing. Same problem bearing is jammed and not turning. Ordered a new set of bearings and seals which came in much better condition maybe BGM got their act together. Took a trip up to BajaRob's for his aero mechanic expertise and married the cases together. Worth the trip. Engine is back in the frame and running. Going to begin tuning the carb.

Can't wait for the ride report on that top end and exhaust.

We require a video from the first start Great job you did

The GS is running really good. Settled with a 112 main jet after finding sputter pulling out of a low speed in 3rd and 4th gear with a 115. Pilot seems to like a 55 tried a 52 but couldn't loose a bewhaa bog with 1-4 turns out on the mixture screw. Plug probably has some color to check now with 120 miles.

You need a model next to your scoot for the calendar! 😉 Nice setting.

The Giro Ultimo is doing very good no complaints! But the onkle Mike ddog Honda CR80 clutch wasn't working. First problem was pretty bad clutch sprawl from the get go and never improved. Then I noticed it was slipping in 3rd and 4th gear when power was applied. Bit the bullet and changed it to a VMC MOLLE.