Modern Vespa

Hi, just picked my first scooter as a restoration project. Engine rebuild etc. The chassis is in great condition and the underneath all in tact, so pleased about that.

I thought it was a 2-stroke so I was looking for the oil tank refill cap which isn't there! Turns out it's a 50cc 4-stroke

I really wanted a 2-stroke so a little bit gutted now. What is this 4 Tempi engine like? Is it the same one in the more modern vespa's that gets less than positive reviews? Pressumbly, it's not the hardest thing in the world to get the 2 stroke engine and swap it out?

Check this link out maybe of use to you
ET4 to ET2 Swap

Thanks, I need to get a list together and then price it up.

How about this 4 Tempi engine?

I did not know that a ET2 came with a 4 stroke engine. Learn something new everyday.

I'm guessing that the OP is from the UK where they would've gotten 4T 50's in the very last ET2's before the switch to the LX platform.

Don't know about the tempi but what year is it. Is it the ET4 engine and is the tempi just the model name or does the 4 tempi mean it might not be a 2 valve model but the later 4 valve model. Pics of it would be good and the engine number which is at the back of the transmission casing. Does the reg doc state it's a ET2?
I had same problem once bought et2 off eBay but got there numpty didn't know it was meant to be a 2stroke and just assumed it was. Still had it was still a good price though.

Yes, my first time buying a scooter so my fault for not checking! The seller had it in a barn for the last 15 years and didn't have much knowledge of it. I never realised there was a 4-stroke 50cc in the ET2 either.

It's a 2003 and yes I'm UK based. Hopefully the pics help.

Ah it's the model range and the engine is the 2 valve model. Not as fast tuned up but should be capable of a true 40 mph maybe more. I am sure others will chime in.
Main tunable bits is transmission side and a 70cc cylinder kit and maybe re jet of the carb or a larger one. I think most people just re jet it from what I remember.
High lift camshaft also, which if you go down that route I have a new one somewhere I never used you can have.
Research eBay, ped parts and racing planet for 70 or 80cc cylinder kit.
For 2 stroke a complete engine, oil tank top panel where it fits by battery, wiring loom, CDI. That's it from memory. The handlebar end switch gear and headlight etc the same and tail light end will all plug into the main new harness and won't need changing.
Good luck which ever way you go.

4 tempi just translates to 4 stroke

Thanks for all the info, Graham. Thanks for the offer of the part, really appreicated. The plan is to get it running as it currently doesn't start and see how I feel about it. I will probably swap to 2-stroke though. Will all be a good learning curve!

The fuel filter and pipes to it were in a bad state so have changed those today along with the spark plug and battery but still no joy starting. It does turn over just fine though and I do get a spark.

One thing that might be odd is that I dont get the red warning lamp on the dash when ignition turned on and I also dont get the little LCD showing anything. The low petrol light does work as I've only put in a litre of fresh fuel. Indicators also working....

Any tips welcome before I start researching and trying things!

Being a 50 they don't have a immobilizer fitted so could be a instrument panel from a 125 how many miles an hour does the Speedo go up to that would tell you then.
(Just looked online and 50cc Speedo goes up to 60 mph the 125 80 mph)
Have you tried easy start down carb just to see if it will fire up . You could squirt some down the vacuum line into the inlet manifold to see.
Anything else just ask away.

I haven't got any easy start to hand so will get some tomorrow.

Speedo goes up to 50mph.

Forgot that Toolstation was open until 8 so just got some but still no joy

Check if you have a good spark if that's ok remove the air filter and see if there's any blockage with the foam disintegrating and blocking carb and with air removed see what results again you get with easy start. Once it's fired the carb is going to need to be stripped and cleaned after all those years of standing. Check manifold also for age related deterioration cracks etc.

Yeah spark seems ok and already removed air filter and no blockages. Will take the carb out today and clean out. Will also check manifold, cheers.

Removed the carb and cleaned. Manifold has seen better days so will get one ordered. Still can't get it to start, even with easy start. Wondering if ignition coil is struggling under compression? How does it look to you while testing?

https://youtube.com/shorts/xjeYz6FZByI?feature=share

Looks good but could be breaking down under compression. What state is the HT lead and cap in. May want replacing.

All looks decent but I'm wondering about the voltage regulator putting out the correct voltage to the igniton coil. I'm only measuring around 8v on the volant/cdi pin with 13.5v being supplied. I've taken the voltage regulator out and tested it on a bench power supply. How often do these fail? Could be a red herring....?

The volanti/CDI is AC, not DC. It's the main unregulated AC output of the stator. Use this LX50 4T circuit diagram:
https://manuals.wotmeworry.org.uk/Vespa/LX50/LX50%204%20Stroke/

Ahh, ok. Thanks Jim. More work on it tomorrow. Still a bit stumped…

Got her started and running Electrics seemed all ok so had a look at the carb again and (embarrassingly) I had not cleaned the fuel filler to float area properly. Blocked solid at the float end! She runs dog rough but probably lots of reasons for this so will report back soon 👍

Well found - and well done owning up to some forgetfulness - we've all BTDT.

Cheers Forgetfulness and lack of knowledge

In the meantime, I've been looking at 2-Stroke engines.

I've found a cheap one and as far as I can tell I will need:

Engine + Carb
Air Intake Box
Wiring Loom
CDI
VR
Rear Shock
2-Stroke Oil Tank + Plastic Surround

Sound about right? Anything I've forgotten?

so while I know I'd rather have a 2 stroke than a 4 (like you), I'm really wondering what you hope to gain by changing it. the HP ratings of the 50cc 2 stroke and 4 stroke are almost the same.

why not swap for a bigger 4T motor? you'd get so much more out of the swap.

The 2-Stroke is quicker, more tuneable and smells better

sure, if I were looking at 2 ET's I'd choose the 2 stroke. but you're still stuck going like 30 MPH max whereas the 150 4 stroke will double that. but if you don't need that then that's cool too. just wondering what your motivation is. it's your scooter, of course.

Yeah, just a bit of fun cruising around, modding etc and something to work on for myself and son. No need for 125 at the moment.

Bit of an update for the rough running / not running at all!

Checked everything over again and had the bike sometimes starting and sometimes not at all

Had the carb out again and double checked everything but still no joy and couldn't find anything wrong. I then went back and started the checks from the beginning, Air, Fuel, Spark. Couldn't believe it but I had either no spark or spark for just a few seconds and then it died.

I looked through the workshop manual and electrical schematics again and tested the stator and picked resistance and voltages coming out of them. All good and the ignition pin is not shorting to ground when ignition is on so everything checks out. Got continuity between all cables and CDI plug as well + HT lead checks out.

Seems to be the CDI at fault unless I'm missing something?

Strange thing is that this CDI and whole bike has only done 4500 miles but is 20 years old so maybe age can kill a CDI not just miles?

Replacement CDI came today and fixes the issue of either not starting/running

Starts ok with a little throttle and revs ok until I go WOT then struggles and would stall if I kept the throttle open. Looking in to that now so any tips welcome

Edit: All seems to working well now, bit of A/F adjustment and a good run to blow out the cobwebs