Modern Vespa

honestly if you were able to fix the gears with a bit of sanding, I'd say still a good deal despite the few snags in the other parts.

Mind the metallurgy of the Indian gears. Ever see what happens when the kickstart gear welds welds itself to the primary? The best case scenario is the cases explode...the worst case is the cases explode AND the rider gets free high side frequent flyer miles.

Interesting experiment none the less.

Here come some additions to the flaws discovered so far:

Kickstart quadrant - Gear teeth were so rough that the mechanism was very janky and sometimes had to be lifted up manually. This even though the spring cup was welded on wrong position resulting in more pre-tension on the kickstarter spring.

Xmas tree shaft - Slightly coarser thread on the end, original nut does not fit. Neck for ball bearing too tight, has to be hammered inside the side cluster gear bearing. Other end seating into a cup on the flywheel side case is too thick, has to be lightly hammered in.

Gear selector rod - Slot for gear selector arm is 0,5mm too wide. Adds unnecessary play to gear selection.

Cluster gear springs - Only thick springs come with the kit altough it's for 200 engine. The tensions is higher than on original piaggio though so might be +-0.

The value keeps decreasing…

Everything I've heard about the lack of quality for Vespa parts from India confirmed in this thread. You don't even know if the gears are going to explode or crumble under normal use.

It was worth a try.

Maybe.

Updating on this one.

Budget big-block build has been running happy with this gearbox for this summer without any woes. Also went on a dyno and clocked in at 15hp with old Malossi (feat. welded piston) and Polini box.

This is the Bajai engine right?

Engine is originally from a spanish PX200 Iris and currently mounted to the orange Vespa 150. It will go to the Bajaj though after the VR-One is ready.

I'm glad it worked out well. I would bet that the quality of Indian gears would probably be pretty decent in something like an original LML motor, as poor fitting parts would be rejected during manufacturing.

Buying Indian gears as parts is probably more risky, but it seems like you did the quality control part yourself by modifying and hand fitting these parts. It makes sense that it would work out. This kind of hand fitting/blueprinting is not unusual in building other types of vintage engines with aftermarket parts. You can't just assemble it like LEGOs and expect it to work. Good work!

I still had a small little nagging doubt that the transmission I received was somehow one-off defective. Call me bull-headed, but I went ahead and bought another set


Inspecting the package revealed, that the oil deflector thingy and the spacer that goes between the crankshaft bearing and clutch are missing - again


Second off the bat, the kickstarter spring was no good at all, since it had a straight section where it is supposed to be arched. Not sitting right in it's place and never will.


Gear selector rod gap too wide - again


Kickstarter shaft was better this time. It worked like it should unlike the last one which was so rough that the return spring was not able to pull it up after turning the engine over along gear grinding noises. The cup for return spring though was welded to the wrong angle - again


And the exact same thing with the main shaft - again


These things were enough to throw the little doubt about the first set being one-off defective out of the window for good. I was still baffled by the fact that the parts are made to rather good tolerances. It's a shame that the tolerances are just wrong

While packing the parts for return, I spotted a phone-number on the GR Gears box. Added that to my contacts and chatted them up using Whatsapp. It came apparent that GR Gears manufactures only the stuff that comes in their boxes and the little accessories like kickstarter shaft, shims and circlips are from another manufacturer(s) and packaged together by the eBay seller. I sent the same pictures to them about the assembled shaft with no room for spacer under the lock ring. As a response I got instructions to leave out the bottom spacer and only use a lock ring there.

I disagreed with this advice and threw them a little curveball. I asked why the design has been changed from the original along a picture of my Bajaj and stating that it's original shaft had spacers on both sides. They immediately pointed out that the original shaft on Bajaj has a solid collar on the bottom and only one lock ring, so they clearly have some knowledge on these engines and are not just manufacturing parts that they know nothing about. They also stated that the gear parts are for Vespa, not Bajaj. Lucky me who were always intending to use them in a Vespa engine We did not reach an agreement regarding the tolerances. They said that "there is no need to put spacer on the bottom side" and in response I voiced my concern about the lock ring being softer material than the spacer and pointed out the risk of the ring spinning in the groove.

After failing to resolve the problem with the seller, I opened a defective item dispute on eBay - again. After stating that I can not use these defective parts they threatened me with contacting eBay abuse, since I bought this item once before and disputed that too for refund. I stated that I bought it again because I genuinely thought that maybe the first one was one-off defective and have no reason to be a dick if the parts would fit. This time the seller supplied a shipping label on the return case which I printed out and taped on to the box. I left the box outside and couple days later it was picked up. All ends well, right?

Nope. A week later I got a reminder from eBay to ship my item back before date nn. I checked the return case tracking and it still showed up as "not shipped". Used the tracking number on ParcelABC tracking page and it did not find anything. Checked the shipping label and it had the tracking number with one dash in it that the return case number did not have. Using the tracking number with the dash on ParcelABC site showed that the item has been collected and is on it's way. Problem was that the seller supplied the number on the case and there was no way for me to correct it. I contacted the seller about this but got no answer back. I had no other option than to wait until the timeframe for return closed. The seller contacted eBay about the item not being shipped back and eBay closed the return request based on this and did not issue a refund. I shortly appealed this resolution, sent picture of the package, screenshot of the ParcelABC tracking page and image from my CCTV where the package is being collected. Couple hours later the appeal went through and I got a message stating that eBay has reviewed the case and will issue my refund.

A minor ending sidenote to the whole saga is that the returned package is still stuck on UPS warehouse in Finland for a reason unknown

That's annoying.

Was really hoping it at least fits. Even if longevity isn't happening.

Well, you gave it a shot…Very informative thread. The aftermarket parts world is hit and miss. I have never bought anything off eBay, but I would probably take a chance on some things.

Within the last couple years, I have rebuilt an LML engine and a 70's P200 engine. The LML engine is reasonably well made, but the old Piaggio stuff seems obviously better for fit and finish, materials quality, etc. Fastener's don't rust as quickly, edges are mostly smooth…you get the idea.

Shot was given and information gathered for everyone else to see. Now if anyone asks about these gearboxes, they can be slapped with info package on what they are getting into. For some people sanding down the cogs and finishing the parts themselves might actually be worth it.

And also the longevity testing part of the first gearbox continues on after I swap the Budget Big-block to the Bajaj frame