1964 Li150 S3- Has Some Issues...

[kurtminus]

Hey Everyone,

Just bought a 1964 Li150 Series 3 off some guy in Texas and had it shipped to California. I have always been wary of buying any old bike with a freshly rebuilt engine-- typically the seller has just put it together good enough to start and sell, leaving the new owners to get it working RIGHT-- and I'm feeling like I broke my own rule here, because it looks like that's what I've got. Talked to the guy on the phone about it before purchase so it wasn't totally sight un-seen and he sent me some videos and what not of it running. The bike originally came from a barn in Indiana where it sat and collected quite a bit of surface rust in certain areas. The guy in Texas has been building scooters for decades and is British (got to count for something right?) and seemed to know his stuff.



Seller said he bored out the cylinder from 150 to 175, don't know what top end though. He said he did not replace crank or do anything to engine internals such as transmission as far as I know.
Installed a new CDI stator (I don't know which).
Has a Jetex SH2/22. 110 main, 50 idle, 50 pilot. Dunno which slide or atomizer. I've got the mix screw 2 turns out.
No battery (AC)
Stock Exhaust

So it has some issues...

1. Runs poorly. It starts up pretty good on 2 or 3 kick, but even with the choke on, you've got to wait a while before it will take you anywhere. You've got to give it a good 1-2 minutes otherwise it just bogs to a halt right off the line. Even after it fully warms up it really bogs from lift-off until you hit the pipe. It feels like lean bogging. I don't think I've got an air leak because it actually feels a bit rich and even 4-strokes once you've hit the pipe and are cruising at 1/2 to full throttle. At the same time, based on looking around at jetting settings online, it seems like my jetting isn't too far off-- despite the fact that I don't know which atomizer I've got. Could it be a timing issue even?

Photo of new B7ES after 5 miles or so of riding.


2. Some issues with the lighting. When it came to be it was blowing headlights as if there was no voltage regulator. I replaced the voltage regulator and that seemed to solve my problem, however, this morning it seemed to blow a headlight bulb again. I'm going to guess this is due to improper ground or possibly vibration? Any advice here? What could be causing headlights to blow even with a good voltage regulator? I know the voltage regulator is good because even with my headlight blown my tail lights and pilot lights are still okay.

3. Lots of rattling and some vibration. I realize Lammys tend to vibrate quite a bit anyways (esp compared to Vespas). I'm experiencing what feels like body parts rattling, esp at high rpms in 1st and 2nd gear. I'm feeling some vibration that sounds like it's from rich 4-stroking at high rpms. I'm NOT feeling vibration at speed, in fact it cruises at speed somewhat comfortably, which suggests that my motor mounts, I mean, I think they're referred to as "silent mounts" are possibly ok, even though they don't quite look it. Any advice here would be great.

[kurtminus]

Sorry, here's the images that didn't work above:

[Warkton Tornado No.1]

Looking on the bright side, that is a nice looking machine.

The sad thing is, having owned it for such a short time, there are issues with it.

We can speculate forever what the problems are down to, but the best course of action is take the engine apart & see what you have got.

I know that's probably the last thing you'd want to do, but the process will make the engine 'your own' & if you are methodical, will virtually eliminate any further problems just waiting to rear their heads;

If you discover that the seller was good, then you can celebrate.

If you discover that the seller was bad, then you can call on the Peaky Blinders......

[wintermod65]

think of it as an opportunity to get to know your machine ,
id buy the Stickys spanners manual if not already got it as will be invaluable for home maintenance
i wouldnt take for granted certain matenance tasks have been done or done well unless can be backed up by bills for work/ parts .

an engine strip new bearings seals gaskets an replacement of worn parts as necessary can only help improve reliability .

ive not used a jetex carb but know of others that seem to have problems with these stting them up .
a dellorto maybe a better option or the dellorto copies made by Scootopia in the UK .

trying to fault find on old lambretta electrics can be really time consuming lots of poor connections earths an chafed wires giving shorts (handlebar mounted light switch )

new looms and switchgear is relatively cheap again Scootopia do these .

not sure how far away from San Diego you are but theres a scooter shop there "Vespa Motorsport/ Scooterwest.com primarily a vespa agent but they may have some contacts in the American scooter scene .

and theres Jet200/ Casa lambretta usa based in denver .

good luck

[Cav]

I think the guys are right on with their advice. Otherwise you will forever be chasing shadows. The really good news is that it starts easily and reliably. There are some obvious and simple checks, and maybe you've already done them. I didn't see any reference to your exhaust, so it's worth checking it out. On a pretty standard set up like yours it should really be pop, pop, popping out at the tail pipe and you should be able to feel quite a bit of force in the exhaust stream. Any blockage in your exhaust could cause the symptoms described. The other obvious one is the choke set up. Make sure it is off when it's meant to be. But really it could be any number of things and you should take the head and cylinder off, check the piston and rings, squish setting, gaskets, ignition timing, etc, etc.

The bulb blowing issue will drive you mad if you cant sort it. I have been having the same problem on and off for 18 months on my current ride. Just the headlight bulb. I have checked everything. I've been chasing ghosts on this one, even to the point of thinking the bulbs are poor quality as sometimes they last for a short while. So I hope you at least solve that one and post the answer Good luck with your journey..............

[Cav]

Sorry I forgot to add the other obvious check. And that's air flow to your carb

[kurtminus]

Hey Folka,

Thanks for all the advice so far. Honestly it doesn’t run that bad and I don’t yet suspect and air leak or bearing problem or anything. I’d like to see if I can clean up the low end bog and see how it runs properly jetted before I tear into it.

It’s got a Jetex Sh2/22 with the following:
Main - 112
Slide - 7895-2
Atomizer - 5899-4
Pilot - 50
Idle - 50

The bog is right after kick off before it hits the pipe. So like 1/8 to 1/2 throttle or so? It’s low rpm bog.

When you’re warming up it pulls great with the choke on. Once it’s warm you have to turn the choke off and it idles find with choke off and cruises fine with choke off it’s just this low end bog off the line.

What jet controls that part of the progression? Is it the pilot? Atomizer? Slide? It feels like it needs to be a bit richer right there.

Any advice would be great.

Thanks!!

[dragoonpvw]

Did you break it in yet. Makes a difference. Find out about the stator and ignition. The main jet for that carb with a gp 150 and 200 is 118 main and 45 pilot. Your slide and atomiser are right for a 150, but who knows . If you are on facebook, Lambretta Club USA has a good public group and I know there are a few guys in Calfornia and maybe someone close. If the builder is trustworthy, then cool. I bought my first (perfect rebuilt) lambretta 2.5 years ago here in Florida from an English guy ( I am an English guy too) and came on here after it blew its main bearings after 40 miles. I learned how to rebuild it and now have three more of my own (2 engines complete rebuilt and one in the works) and have rebuilt 2 others for Florida owners. I agree with WT, I always take the cylinder off and case to find out what I have. Good luck, I am in Florida so a bit far to help.

[kurtminus]

Thanks for the advice everyone.

I am getting it sorted!

I ordered a richer pilot jet (55, up from a 50) and also got a richer atomizer (really interesting how those change the tuning mostly of the lower rpm spectrum) and it has almost totally cleared up my low end bogging problem.

Now I need to go a bit leaner on the main jet (I think). It was 4 stroking at high rpm pretty bad with a 115 main jet and is still 4 stroking with a 112. I ordered a 110 and should get that this week.

From there I think I’ll be tuned about as well as I can with this Jetex carb.

For those curious why my jetting seems odd. It’s a 150 jug bored out to 175 so I’m kinda in between 150 and 200. It’s got a bgm stator/ignition. I can’t seem to ID the exhaust but I think It’s stock. It looks like photos of stock and has innocenti stamps on it.

The engine is very clean looking and there is no leaking from the top end, exhaust or intake. Shifts very very smoothly.

I am sensing a vibration at high rpms that is hard to place but I think it’s 4 stroking from being too rich. I’ll try leaner and feel that out a bit. Otherwise it feels like maybe something rattling from someplace.

Aside from that the headlight is a bit wild in terms of brightness depending on rpms but doesn’t seem to blow anymore. It’s pretty consistent at running rpms. Can’t quite figure that out. My grounds seem fine. Maybe that’s just how they are when you convert to ac and run with a regulator?

Enjoying the bike so far!