Modern Vespa

Chris is right, my bad. NTN is a good option!

SKF and NTN also list the code as 98305. That looks to have 8 balls, though.

Finally stopped putting off my rotary pad repair. Used the old crank and 2 layers of waxed paper bolted into the case until the JB weld set up. Enlarged the id/reduced the od of the old bearing to make it easier to get the crank in and out.

Swapped the old bearing race onto the new crank and checked clearance with the pad. No issues. The fit of the old crank was pretty sloppy compared to the new one.

Bearings arrive Tuesday. Glad I ordered a set as I don't want to reuse the old bearing race on the new crank. Pretty sure you're not supposed to do that.

Also chamfered the ports on the new cylinder.

Boring and tedious work, but I think the pad repair came out better than last time. From this point it should be a straightforward reassembly. Then I can finally finish the 200.

New crank and bearings are in and everything is turning smoothly with case halves test fitted.

Thought I was getting near the finish line, but when putting together the gear stack with the new short forth, the endplay is really tight. I could barely shove a couple .005" feeler gauges in there. Should be .006"-.016". I wouldn't sweat it, but it feels tight. The new short 4th is 1mm wider.

Shim is 1.9mm, the ones available are all thicker.

Thinking of taking the shim down a little on the surface plate with some fine grit sandpaper. This would fix the end play but I'm not sure if the thicker fourth will cause problems. I imagine this has happened before.

I just finished fitting mine and I don't think I have any fingerprints left. 😝 It was a bitch to do.

Sounds perfect. If the gears spin freely, it's enough to run in the new cog.

Thanks,

For a minute I considered skipping the short fourth.

I will check it again, but it feels a little on the tight side. I will sand the shim until the cogs spin freely and check how they mesh with the X-mas tree. If everything lines up as it should then I'll button it up and check shifting by spinning the wheel and shifting with the batwing on the selector box.

Hopefully all goes better this time; new crank, P and C, rings, wrist pin and a better job on the rotary pad. And the autolube works fine. Having a crank with straight stumps should help with the vibration.

Corrected the end play and got the gear box together.

Do these look like they are lining up properly with the x-mass tree?

Your gear stack looks great. They don't need to be perfectly centered. What matters most is where the cruciform ends up at each shift point.

Thanks. They never seem to end up centered. I'm just gonna button it up. Confirmed the shaft is bottomed out. Phone camera is the best thing that ever happened to engine builders with bad eyesight.

Buttoned up the case last night and measured my new cylinder just out of curiosity. I thought my old cylinder was wearing out with the piston bore clearance measuring something like .0085" or so, but the new one measures about the same. I guess they were designed to run with a lot of clearance.

I'm not sure if I have a 12HP version. According to FMP, the difference is the height of the exhaust port; 39mm (for the 12HP) vs 41 to the top of the cylinder. Mine measures 38.5mm.

I have a lot of respect for the stock design. It's almost as if it was engineered with the expectation that things would not be perfect; a little air leak, some oil sucking or dripping and ballpark timing. A couple soft seizes wouldn't kill it. They knew that some people would run it wide open all day long, but they would never be able to spin it fast enough to break it. It seems pretty insensitive to small changes in jetting. The genius of a cheap and sloppy mass produced engine.

Hoping to finish it up today and bolt it into the p200 this weekend. This project has taken way longer than expected with unexpected setbacks and juggling another scooter, a bus and the rest of life.

I'm still really enjoying it though, which is how I know I should keep going.

And *that* is why you always have to do your own measurement versus trusting what the promised port timings are.

I agree on how various design decisions accounted for poor manufacturing or maintenance quality, along with expected poor treatment by the owners.

A lot of tuning is just wiping away those buffers, producing a more efficient/powerful motor, but with the resulting loss of resilience.

I liked your tuning overview a lot. A certain level of tune doesn't have to be unreliable, but more details have to be just right and stay that way. Air leaks for starters. A tight engine is critical. And just because it was tight on the bench, doesn't mean it will stay that way as I have learned more than once. Cheaper parts and materials that will hold up forever on a stock engine just won't cut it when the HP and heat go up. And it's all in the combo.

Not to hi-jack here - apologies to Orwell - but this is why I asked the question awhile back about the "O-tune". It may be that I get into the engine during the cold months as I don't expect the 1980 P200 seals of my new to me scoot to last forever. If it happens, a soft rebuild would be order with checking and shimming stuff along the way. But the ability to tweak the engine for efficiency remaining in stock form (no aftermarket top ends, reed setup, etc...) would be desirable while the engine is taken apart. Until then, I'll just keep taking notes. Who knows, I may ever learn something with this old brain of mine.

Scott (QAScooter) did this on one of his P200's and added like 5 MPH of top end and noticeable acceleration/power compared to stock, yet he's still able to ride it WOT all over the Oregon coast without issues.

And he didn't even do anything particularly aggressive (e.g. no adjusting port heights or the like).

When I put the Malossi 210 on my P200 motor, all I did was clean up the intake and match the ports. No intake timing mods or anything and that was enough to get me from stock to about 16 or 17 HP.

With the P200's in particular, there's SOOOOO much easy performance to be gained from just improving the overall build quality and tweaking the port timings within the massive squish of a stock crank.

I have read thru the thread by Scott (QAScooter) about all the work he did on Ruby and have it bookmarked so I can find it again easily. Lots of good stuff there and I am so appreciative of that write up. Any work that may happen is months out as there are too many things going on here now, but that's alright as have time to compile all these ideas. The only mod I may do now is find a 24/24 carb to replace the 20/20. Whether it will make any difference, I don't know. SDjohn did not seem to think so with a stock engine. Thanks for your reply, Chandlerman.

maybe you will notice the 24.24 if you o-tune it? on mine I could not notice anything. it's probably marginally better, but based on my butt-dyno, not worth the money to go replace it unless you are going further. I'd spend $ on an exhaust any day before I'd worry about going from 20.20 to 24.24.

On a stock 200, the 24/24 really only becomes necessary if you're getting up past 6,000 RPM's for your power peak.

I have a 24/24 on my P200 because it's a Malossi 210 and it puts out peak power at about 7,200 RPM's.

Can only compare carbs that are jetted well. 20/20 carbs jet easier. 26/26 difficult. Performance comes from being on the lean side of too rich.

Thanks guys, good stuff here, but this is still Orwell's thread. When I feel good enough again to get back on the scoot project, I'll start my own thread and not Hi-jack someone else's who is actually making progress.

No worries. Chime in anytime.

Thank you. Been following you build and learning and relearning as I go here.

Relearning is the right word. Second time I've had this engine apart. Almost a re-build as I've replaced the top end, crank and crank bearings. The old crank flywheel stump had excessive runout. Big end bearing play I only noticed when the engine was last assembled. I could feel it with a light touch on the flywheel. Stella engine with everything rebuilt didn't have the same looseness there. I couldn't feel it doing the push-pull with the crank out.

When I rebuilt my last bus engine, I took it to an older experienced friend and dry-built the shortblock in front of him to learn how to feel…how loose is loose. How tight is tight. I had gone full mental micrometer on the whole thing, but feel is the ultimate check that it's right. Check feel of every part separately in the case, all together, and as you're torquing it all up. Eventually you start to trust yourself.

Got the top end on last night and let it sit on the bench overnight to let the goo set up. Re-check torque, pressure test and it goes in the bike for the first time since I brought it home in December of 2021. That should give this whole project a needed boost.

It's in!

Congrats! That is one good looking P.

Looking great! Nice work!

Jumpin Jesus on a pogo stick, she's in!

How about BunGeeZus....

Dude that came up with that is going to Hell, for sure.

Perfection!

Maybe. But it'll only last until his Bungie takes up.

Hiya Satan! Yoink!

Sometimes Jesus on a bungee and finishing this scooter have seemed like equally likely events. For sure, on some days my money's on bungee Jesus.

The shift cables I installed ended up being too short. Definitely the inner cables as an old one from the Stella was a few inches longer. Not sure how I ended up with them, I don't know what kind of scooter they would go on.

I could cut down the outer cables, but would probably be easier to replace the inners. I was able to connect them to the selector box, but they are difficult to work with.

It seems like every time I ever ordered a outer and inner cable set they were not right. That is, the outers were too long and there would be a fairly good bend in them translating to a lousy feel when shifting. I just heat the ferrule ends, remove and cut the excess off the outers. Then heat and install the ferrules again. Plenty of inner cable length then.

^^^ This!

Thanks! Good to know.

+1

Let the run define the cable length and not the other way around.

Definitely outlers have some excess because I have to push them back into the tunnel.

Runleader gauge I spent an hour routing through the tunnel is DOA.

Slooooow….