Modern Vespa

Thanks. I'm pretty sure that's what it did but I will listen for it more closely before going to a smaller jet.

After I get the main jet right, what direction do I go in to get the 4 stroking under control?

To follow up on Jack's point, the splutter test is not about how fast you open the throttle. It is about putting the scoot in 2d, opening the throttle all the way and just holding it there for 10, 15, 20 seconds.

One cross-check is how fast are you going when the throttle is pinned like that? I forget the details of your setup, but a cast iron Polini 177 on stock 21/68 gearing should be pretty close to 40 mph gps if it is revving out cleanly in 2d.

Thank you, that helps. I tend to not stay at full throttle too long because it's screaming and it feels like I'll break it, but I know that's not the case. I will try it that way.

It's a 2 stroke, they will stay at max rpm all day........when not too lean. As Kowalski said , hold it out at max, feel it, listen to it, try different jets. When set perfect it will still feel slightly spluttery but rev out too.

For the paint, I was able to find it surprisingly easy.

There was a PPG website (that I can't find now) that you could search the code.

But I had to find a local dealer that mixed PPG paint. There's only one in the Bay Area, a classic car shop.

But they had the code, and mixed it.

The blue is called Piaggio Blu Marina 275. Or just Piag 275.

PPG paint is expensive, but the quality is very high.

Mine was in the computer as Piaggio Biancospino 715 (the same white they used for many years).

This website is great. It has photos of all the colors.
https://www.vespafarben.de/suchfilter/blu-marina-275/


Blu Marina 275. Beautiful color. Was also used on Rallys and ET3s.

Thank you hjo. I have seen that site too and I did provide that code at the paint shop. I think the color ended up quite close to the original. My first scooter was white with black trim. White doesn't look great on many cars, but very sharp on a scooter.

Jack 221: After years of being careful not to over-rev my VW bus, I have to change my mindset. Yes, 2 strokes will rev to their limit and be fine with enough lube.

I get what to shoot for in choosing a main jet is: Settled and smooth at full throttle with some intermittent splutter as it's held open. Just on the edge of too rich. 1/4 throttle splutter is less of a concern as long as it clears as the throttle is opened. Too lean idle = seize rolling off throttle.

It was a nice surprise hitting 60 yesterday. I wasn't really thinking about it and just glanced at the speedo and there I was.

and so is their primer (and its own catalyst), reducer, surfacer (and its own catalyst), color (and its own catalyst), clear (and its own catalyst)! I need to paint a panel on one of my scooters and all the PPG products will probably add up to around $500!

I paid $200 for 2 quarts of single stage urethane with reducer and catalyst (Ppg Omni). I didn't think that was too bad. I found a body shop that will spray it and just charge the hourly rate. I just have to wait until April or so.

I've quirted a fair amount of Omni over the years. Though it gets the job done, i've always been unimpressed with both their colors and clears products. For anything nice, i do like to take the big step up to PPG.

Another crack at jetting…30* out but dry roads. Same jets: 40-130, 140/be5/119.

I tried the unscrew the idle screw test. It did kill the engine.

Found a long straight road and held second at WOT for a good stretch. It did sputter, but revved out. Hit almost 50 indicated though probably not that fast. 8500 rpm.

Adjusted the clutch cable and still having issues. I think it's called grabbing. I have to let out the clutch very carefully and feel for the friction point, otherwise it jumps when moving off with a scuffing sound. I'm going to pull the clutch and have a look. Possible I assembled it wrong; spring not seated, holes not aligned, etc. I thought it was my lack of practice, but Vespa shifting is usually pretty forgiving.

I'm thinking I need to come down more on the main jet. Changing the idle jet, or adjusting the screw doesn't seem to do all that much. It's crap until I'm in on the main. Then it will pull nicely. Hello 4th gear!

When I was running the 160/be3/MJ combo, 4 stroking was confined to 1/4 throttle and the mixture screw seemed to have a bigger effect. It just wouldn't pull 4th very well.

The clutch grabbing like that is often caused by a worn clutch bushing. Easy enough to check, just a bit of a pain to do so since you have to pull the clutch.

If you're running a box exhaust, it's just a few minutes to pull the clutch.

Probably time to pull the it and replace that bushing before it turns into premature cruciform wear.

I did replace the bushing and the thrust washer. Memory is fuzzy but I feel like the old bushing pulled right off and the new one plopped right on. I think it is supposed to be tighter…not as tight as the crank bearing race, but enough to require a little tapping. I also missed the part about the alignment holes in the plates. It's worth a look either way. Cold as balls here, so now's the time to tinker.

Grabbing you describe is either the thrust washer worn, internal brass thrust bearing or incompatible parts creating excessive cog clearance. If disengaging correctly it's always this.

Be sure before reducing main jet. Expensive mistake if wrong. Can't do anything about 4 stroking until the main jet is done.

Thanks!

The 119 might just be the one. I wouldn't go richer. The splutter at WOT comes in a little after it's stayed at WOT a bit. It doesn't feel like it's too rich to not rev out. I would rather err on the side of a bit rich.

Do a sound recording on your phone. Thinking it might still be slightly too rich.

Will do!

Gonna pull the clutch this weekend. I'm pretty sure my assembly was sloppy. Completely missed the part about aligning the holes in the clutch basket and pretty sure I didn't click the springs into place. They were in the cups but I missed the part about moving the springs into the ridges on the next plate. I will also check the thrust washer and bushing. I'm pretty sure the 22 t gear meshes correctly. It worked fine before I rebuilt the clutch.

The part I dread the most is that stupid castle nut. A flanged nut is in my next SM order.

I'm wondering whether I should keep the 22t gear or just go back to the stock 21. Looking at the gearing calculator, it seems to only add about 2 mph. There must be some other advantage that I'm not understanding since so many people upgear. 2 mph doesn't seem worth bothering with.

People (and by "people," I mean "me" ) frequently swap to a 65t primary at the same time. That way, if you don't want the full P200 23t, you can dial the gearing back a little for better alignment of the power band by changing out the clutch.

Dropping the speed even a couple MPH can make a big difference when you're talking about in or out of the power band at a certain speed. Or, for example, to align 4th to your preferred cruising speed, traffic on a commute, not needing to downshift every time you want to accelerate, etc.

That makes sense and kind of where I was going. I was thinking that the stock gear might actually shift the power band in a way that works a little better. It also alters shift points and throttle position.

I get what you mean about the 200 gearing. It's kind of luggy and cruisey, hitting 60 mph under 6000 rpm. I like it, but the quickness of the 187 is growing on me, especially as it gets closer to being dialed in. It feels pretty smooth at 60.

If the motor revs out clean for a bit and then starts to splutter continuously, I would still consider that spluttering and try a smaller main jet. Sometimes, the motor will oscillate back and forth between clean and splutter. I would consider that acceptable as long as it's only happening in 2nd and revs out cleanly and continuously in 3rd. I wouldn't sweat too much about perfection right now anyway because you will need to revisit the main jet again when the weather gets warmer.

Next time you test, bring a gps for a little cross-check on your top speed and max rpm.

Will do. I know the speedo is lying and possibly the rev counter.

Yes, the splutter at WOT in second is kind of in and out. It does pull cleanly in 3rd and 4th. No harm in giving a 118 a try.

I would really like to make some progress on the 4 stroking at the first 1/3-1/2 throttle. It's just awful. The first 1/4 throttle doesn't really worry me.

I'm not sure what direction to go in next. Am I looking at finding the right idle jet, atomizer or both? Could the main jet be making the first 1/3 throttle too rich?


Thanks

Worry about the main jet first bud. Don't fret about with the idle until the main is sorted. You're just chasing your tail otherwise.

As someone who literally tried to do this before winter. Just relax and get the main jet dialed. Then move on to the other jets.

I pulled apart the clutch this afternoon. The bushing and thrust washer looked fine. The holes in the basket and back plate were also aligned. Can't tell about how the springs were.

There was some scoring on the boss where the brass pushy thing sits and on the lever that pushes the brass thingy as well as some debris.

Edit: Actually that's not scoring on the lever.

That looks like no wear at all. The scoring looks like it's supposed to be there?

Is that scoring?

I replaced the knuckle thing and it doesn't have that, but it's like an aftermarket part.

I think it's machined like that. I found a pic from a manual that looks exactly the same.

Really does seem like the main jet is still too rich. Main jet first, then other issues. Is the clutch the same scooter?
The grabbing is the gap between the clutch cog and the thrust washer. Supposed to be 0.5mm max. If nothing is worn, it's incompatible parts in the clutch. Can be adjusted with the thickness of the flat brass ring inside the clutch.

Thanks. It's the same scooter. I will go one down on the MJ and record.

I think this is the measurement you were referring to. Pic is from a manual. I will check.

Thanks.

Just eyeballing it, it looks about right.

Spare clutch with 21t cog on left, grabby clutch with 22t cog on right.

This clutch worked fine with this cog before I rebuilt it, lol. I will measure it for realz just to make sure. Plates are flat and not shiny or scored.

Only other thing I can think of is misaligned springs.

Just gonna measure it, lube it up and reinstall. Probably would go easier if I pulled the shock bolt and let the engine hang.

I get the jetting thing. Main has to be right first and can also contribute to the idle circuit performance. Leaner main might start to improve idle through mid range.

Messing with the other jets doesn't change much if the main is contributing too much to the equation, either by being too rich or lean. The finer adjustments of the other jets just won't make up for it.

Tabs on the cork plates are a little mushroomed. They were new when I rebuilt the engine in the fall.

That's what the lurching into gear does, which is why you have to get on top of that sort of thing ASAP.

Ideally, the cush drive protected your cruciform from too much of the same.

Yeah, that's why I pulled it. It's not gonna get better by itself. I haven't put many miles on this engine since the rebuild and very little since the grabbing started. Just long enough to rule out the easy and obvious.

The gear cog is for a 6 spring clutch and the backing plate is smaller. The PO ran it like this without issues as others have. I'm not sure if this is causing the problem.


22t as I was running above. Stock 21t from spare LML clutch.

One other thing I have to check is possible scoring on the oil drive gear spacer. I'm away from home but I grabbed this pic.

I put both the 22t clutch and the 21t spare back together. Just going to measure it, check the spacer and give the 22t another try and the 21 if things haven't improved. I may have adjusted the cable too tight.

Not sure what else to do.


Not sure if clutch has been rubbing on the spacer. Will take a closer look.

The thrust washer is the autolube cog. And that one in the picture is worn out.

I thought it might be and I think it was when I rebuilt the engine. I found a pic of my engine rebuild and the teeth were shiny. I didn't catch it as wear at the time. I have some spares that might be in better condition.


Thrust washer when I rebuilt the engine.

Jack 221:

To save you some splainin' time and me searching time trying to find it again, I'm linking this thread. Exact same issue.

First full restoration project.. 1980 P200E (Page 10)

Always nice to find the smoking gun.

It's not the teeth, it's the face that the clutch sits against.

Thanks. I see it now. I will have a closer look and see how my spares look.

Closer look at the gear. It's marked but not scored. Nothing I can catch with a fingernail.

I will look at my spares and measure them up against the clutch bushing.

Also noticed that one side was chamfered. Which way should the chamfer face, or does it matter.




Which way does the chamfered side go?