Modern Vespa

The sensor socket is a great solution. Much better than needle nosed pliers.

Before I figured out the socket, I used a 12mm wrench held vertically like a screwdriver. Still not great, but definitely better than pliers.

The compressor threw a belt. It looks original, so the compressor is the next project!

Bought a gasket kit and new belt. I'll clean it up minimally and pull the jugs off and inspect. Hopefully it'll be just putting it back together, with RTV of course

Well, the sensor is 14~15mm long. I drilled the hole to around 17mm~ish deep. For myself, i'm not concerned about about the tip of the sensor making direct contact with the head. I'm not familiar at all with the design of the Koso sensor, so i have no idea just where exactly the internal temp sensing circuity is located in the sensor's aluminum body. Maybe the sensing is exactly at the tip?...or maybe the sensing is located in the midsection of the senor? I figure that since the whole durn thing is threaded deep into the dead center of a cylinder head that it won't make a lick of difference if it's just the tip.

Hindsight it seemed the socket design was an obvious solution, but the truth of it is, it took me a at least a day for the simplistic epiphany to pop up in my head. No doubt there are similar spark plug sockets that exist, but i somehow forgot that they did.

The sensor is located at the tip of the probe. It looks like maybe a 2mm bulge on the tip of the wires.

If it's not touching the metal, it's going to be both slow to register and inaccurate when it does, because it's measuring the air temperature of the cavity, not the head temperature.

I'll dig out an example K-Type Thermocoupler which is functionally different but visually identical to the Thermoresistor that is in these sensors.

I will definitely be making a dedicated cht sensor socket.

One thing I noticed about my CHT setup is that the under plug sensor and screw in sensor are actual pretty close in their readings. Sometimes one may react more quickly, but they tend to end up in the same neighborhood once the engine is really heat soaked. Eventually I get to a point where I know what a normal range of readings should be and don't look at them much. On air cooled engines in general, CHT's, oil pressure and oil temp are all over the place compared to water cooled engines, which keep these values within a more narrow range. Eventually, I will add an EGT to both my scooter and my bus and an AFR gauge to my bus. It's been in the original box for almost 10 years.

Perfect weather for filler. Dry and not so hot it kicks off in seconds.

Boring work though. Skim the panel, sand it flat. Repeat.

Yep, not the most glamorous job but definitely stress free compared to shooting the final paint. Great progress!

Funny you should mention this...

I just did this comparison today. Under-plug reads a lot more slowly and has a significant sensor lag compared to the in-head. Reads a lot cooler, too.

A few notable points:
- From zero to 1:10 I was just letting the motor idle and warm up
- From 7:30 to 9:00, I was WOT in fourth gear.
- I shut off the motor at 15:20 and temps converged and fell about 5 degrees/minute from there.

The under-plug readings were so delayed (almost 90 seconds) versus the in-head that they would be effectively worthless other than as a long-term trend indicator that something needed looking at. The in-head sensor response was good enough that I think it might actually save you from any but the most catastrophic failure, so long as you knew what normal was for your motor.

Coincidentally to Orwell's post earlier, today was the day I finally got around to making the "Under-plug vs. in-head CHT" video I've been thinking about since my trip to Kentucky and uneventful 420F CHT readings.

Someone sent me a diagram ages ago that showed temps are generally higher at the top of the cylinder head, closest to the top of the piston dome. My VMC head uses a center mount plug. The screw in sensor is right beside it, so it makes sense that the readings are pretty close.

If so, that could explain the temperature differences, but not the 90+ seconds of latency of the under-plug gauge's readings.

For you Piper Cub lovers out there (me, not so much) I broke in a new engine today. No dramas and got a decent pick of the Ventura Pier and Fairgrounds. Couldn't fit a scoot in this one and I think it's too slow as a parts runner.

how come nobody is at the controls?

Pilot flies from the backseat. 😆 That does look weird though. Guess I'm used to it.

I would LOVE a Piper Cub.

That picture brings back good memories Rob!

The Cross, the Holiday Inn and it's parking structure (skateboarding and general hooligan behavior in days gone by) the Ventura Pier, the bike path through and around the fairgrounds. Hobo junction, etc, etc.

Thanks for that - awesome picture!

So cool. Nearly 30 years ago I built a 76 inch Piper cub. In the exact same colour. Italian nitro engine. Flew it for several years. Crashed it once. Still in my attic. Give the prop a turn whenever I'm up there.

I picked up a new Tach+CHT for the Lammy and installed it tonight.

, since you asked, here's a shot of the Lambretta's Quattrini TV210 head after I carved a giant effing hole in the top and then drilled and tapped in order to install an in-head CHT sensor.

While it should have been a pretty simple install, because you have to pull a body panel and remove the exhaust in order to get the cylinder shroud off. I have a solution to this problem in my head, but it will take a little more execution that I was going to sign up for at 8:30 at night.

Nice! I have a Koso CHT gauge, but still use the Runleader for tach. It's hard to see and eats batteries since I can't see it at all without the backlight.

Not a gauge, but I found a cheap phone mount that fits easily on the mirror bracket. I have given up trying to fix my Stella speedo. Reads 60 at 50 or above or bounces all over.

I have that same Koso CHT on the Boo-Badge, but it's discontinued, so I had to go with something different this time. Right now, I use an old handheld GPS from my sailing days as the speedo, but I have the RPM's for common speeds pretty well memorized so I don't need to run the GPS most of the time.

I killed a phone when it popped out of the mount on me once upon a time when I hit a bump, so I don't use cell phone mounts in general. (And that was about the high point of that day, if you can believe that)

(Yesterday) … Put in a new fuel system (tank, cleaned carb, new lines, tap) in my friends Stella.

Then stared at the ET3 for a spell and pleaded to the scooter lords for a fast and easy shift-dog/gear swap.

3rd time opening the cases is the charm?

Ffffff.

I put a new clutch and pinion plunger for the Lammy tonight.

The existing FA Italia clutch just wouldn't quit slipping, even with uprated springs, so I went to a LTH Liedolsheim. 7 CR-80 plates, but if it still slips, I can add another five springs to it.

It's kind've a cool design in that it uses the same pressure plate as a Vespa. I happened to have a spare ball bearing plate, so I put that in it and while I just gave it a tiny bit of test riding, initial results seem good.

And now that is more-or-less complete, the Lammy should be set for a while so I can get back to the Vespas.

This weekend, I think I'm going to kick off a motor swap between my VBB and SprintV. The SprintV's motor has been in the VBB, but it needs a new cruciform, which is not really an in-frame task since it's not a two piece fly side bearing. I'll see what else it needs while it's on the bench, like maybe some new clutch plates, then it's going back in the Sprint.

As for the Sprint's current motor, it's a P200 that I put a Malossi 210 on and did just the port matching and cleaned up the intake but didn't extend it. It'll get the 8" conversion kit and I'm going to put a tank in the glovebox to keep it autolube. Eventually, I'll get a 24t clutch cog, too, but will probably just ride it short geared to start.

The last time I opened the cases on it, I tore a base gasket and rebuilt it without that gasket, so the port timings have been too low for like two years. I'm going to revisit the port timings while it's on the bench, but not mess with it other than that.

And the GL's M1XL is still stuck in SIP Shipping Hell. Latest was that FedEx sent the box back to SIP because the customs declaration was wrong for the fact I ordered ball bearings.

And after all that...I'm still scheming to add a third port to my VBB's OG motor because...why not?

You're an inspiration Chandler - keep up the good work and scooter shenanigans

Oh you are still a new Lambretta owner…..

I can't wait to see you add the 3rd port on the VBB!

And the GL's M1XL is still stuck in SIP Shipping Hell. Latest was that FedEx sent the box back to SIP because the customs declaration was wrong for the fact I ordered ball bearings.

I quit using FedEx just for that reason. I pay a little extra but UPS gets to CA in a week or less with no drama. Just stay below $700 and no surprises.

Yup. For eight bucks more, Scooter-Center and UPS took the order on Sunday night and had it to me yesterday. I was over $700 this time, but screwing up bearing import paperwork that should be completely automated is just pathetic.

It may be my most pointless project yet, so why not?

The motor only needs a new top end. The rest was rebuilt with a P-cone crank back during early COVID and I killed it as the project was nearing completion, so should be relatively easy (as major project like that go).

I've had it five months now and it's sucked up almost 100% of my scooter time and money. Now, though, so long as it all holds together...

Had to remove a crank bearing. I already had this HF inexpensive kit so with a little grinding to the bigger puller it worked like a dream. Just tightening down the end bolts pulled it most of the way off but installing the pulling shaft gets it done pretty quick. No need to buy the expensive puller if you can do some light profiling to this one. Still retains the original function for other bearings. This is a bearing for a GS 150 but fits a P as well.

Can you show what had to be profiled?

First time I've seen the tin worm attack brass.

Bike sat for the past year, took it out for a ride and it would bog at anything more than idle. End of the main jet as well as the bore are pitted beyond belief.

I opened up the radius to match the bearing better and thinned the edge to get under the bearing easier.

Yeesh. Was it just that main, or were the other brass parts also impacted?

Just the main (and just the end and bore of the main), nothing else touched, and a goldish residue in the bottom of the bowl that cleaned out with carb cleaner.

I recently threw a carb away due to ethanol corrosion. 2019 dirtbike that sat for 3 years without draining the fuel. Ate up the jets and some of the aluminum. The bowl was a putty matrix of aluminum and brass. Never seen that before. The fuel also ate the rubber seals. I'm a big fan of biobor for anything that sits for awhile. Works great in my boat.

Outside temps are finally down a good 10-15F over summer, so it's possible to do some extended wrenching sessions again.

Fought with my buddy's Zuma a bit today. Been chasing intermittent spark and fuel issues. It had last been started in November 2023. Had 16 m.o. Cali gas in the tank and some weird silt. Fuel tap screen had crumbled. Pulled and cleaned the tank. Buddy got a replacement tap off of Amazon...

Gauges and farkles, fine. Critical components should never be Happy Flying Monkey brand. Of course the new tap leaked like a sieve. Ordering the OEM part since it's still available. Grrr.

Even with fresh gas in the carb, it refuses to run. Spark is good. Stator key isn't sheared. Borescope inspection looks good. I get 85psi on the compression gauge while kicking it, but I know the gauge's hose length is a considerable volume compared to a 70cc cylinder. Probably going to fab a leak down tester.

Got annoyed enough to switch efforts over to the Scarabeo. It did struggle on Catalina Highway a few months back and it had some annoying flat spots in the CVT operation.

Greasy and SaFiS, my cooking tip on these is a Polini 243.077 torque spring and 245.080 clutch springs. I used the green ones. Kept the stock weight (12gr) rollers. Doesn't seem to impact top speed, but does wonders for off-the-line performance and makes a marked improvement in powering up grades.

I'll take that win for now. Working on my Majesty's forks to convert it from a crappy unicycle back into a two-wheeler this week after work and then sending two friend's scoots home in better shape than they arrived.

Need to get back on a NSM project.

All the beer can shims in the world won't fix this. Looks like it might have cracked first, then stripped the splines. I've noticed that if I have to kick the scooter for a long time, it catches, then slips abruptly. It's like ever xx# of kicks. I don't remember my kickstarter gear looking stripped. Hmmmm…

The kickstart shaft is steel. The kickstart lever is aluminum, which means a lot less energy to be absorbed when the lever returns.

Plus, if they get in a fight like yours did, the expensive and hard-to-replace part wins every time.

Yup. Someone thought it through.

Reminds me when this happened to me in the late 80's. Nearest replacement was a long ride across town and funds were scarce. Ended up bump starting it for a long time. I think that's why the cruciform ended up breaking apart months later.