Modern Vespa

Dear Vespisti,

So far so good I had finished a restoration project of a PX200E, model year 1985. On last saturday I had cleaned fuel tank, lines, carburettor, adjusted mixture and idling, controlled sparks, oiled piston, cables correctly connected. The I kickstarted and it started, wow, engine run for 45 seconds then died. At least 10 kick starts; nothing.

When you kick start, instrument panel lights up, lights come, spark is there. During kick start fuel is being sprayed in the carburettor, lines clean. But no sound of igniton. Even no cough.

Yesterday, I had reopened flywheel, inspected timing, it was on "A" sign. Kickstarted again, no sound, reopend sparkplug, saw the sparks, fuel is inside the carburettor, recleaned the floating member case. NONE.

I am thinking to do a timing adjustment. Would that be correct or systematically I need to control other things in sequence ?

Can you verify the cylinder is getting fuel dripping in? Is your exhaust old and possibly clogged?

Turrider,
A 2 cycle is an extremely simple machine; so long as it has good fuel in the proper ratio and a spark, it'll run. Perhaps not *well*, but it'll run.
I'd recommend not adjusting the timing until you've got it running.

Step #1: Shoot some starting fluid in there and see if it responds.
If so, then you know you have spark. If not, then you know you don't have spark.
If you have spark, then you either have bad gas or your mixture is way out of whack. You can tell by smell if your gas is stale. If you're too lean, pulling the choke will get a response. If too rich, opening the throttle will get a response. One of the two should get it to do something, which will guide you on how to proceed.

If it doesn't respond to starting fluid, then you don't have spark even though you've confirmed that your coil is good. Your plug is probably fouled. Try it with a new plug. If it runs for a while and then dies, pull the plug and see if it's wet. If so, you're flooding it because it's too rich.

HTHs,
-Slashy

Dear MJRally,

I did controlled the exhaust. Not clogged. Carburettor is wet, see the picture below.

Dear GolSlash27,

I did smell and poured out the fuel mixture throw it to the oldlawnmover. It is functioning on lawnmover, so anyway I took it out of the vespa;

1) fuel tank cleaned
2) fuel pipes are cleaned
3) carburettor cleaned
4) new fuel mixture from petrol station
5) cleaned the spark plugs
5) kickstart 10 times, no reply, pull the plug out, kickstart, fires, I ser the sparks
7) since I don,t have starterfluid, sprayed gasoline inside the plug hole, kickstart, nothing
8) changed the sparkplug with NGK b6es, saw sparks outside, plugged in, kickstart, nothing, even no cough.

I had noted that at each 5 kickstart, kickstart is very hard. Do you suggest something else ? As soon as I will purchase a starterfluid. I will try again.

Will that make sense to measure vacuum ?

Turrider,
I'd begin with the starting fluid before anything else. Open the throttle, shoot some right down the intake, close the throttle, and kickstart it.
If it tries to run, you have a fuel problem. If it doesn't, you have an ignition problem.

Best,
-Slashy

Good Evening,

Starter fluid let the engine run smoothly till I shut it off. Without starter fluid it run as soon as kickstarted when the engine was hot. But after 15 mins it did not run. Again as soon as the starter fluid is in, it run well again.

So I had decided to check cables up to magneto cables. Replaced the spark plug cable, replaced all magneto cables ( see the pictures) It all went well. I will assemble it this week and kick start again. Pictures are clear there was a series of burns, improper cable connections.

It's too late now, since you started working on the stator - but I doubt you need to work on the stator. It sounds like you have a perfectly good spark.


Are you using the choke when you try to start it?

^ This. It's a mixture problem, not an ignition problem. Sounds like your choke isn't working properly.
Now that you've had the stator out, it's important to degree the engine and use a timing light to set the ignition advance. Don't rely on that "A" index. Torque your flywheel to spec every time you put it back on during this process.
Once you have the timing set, replace the lockwasher on the flywheel.

Best,
-Slashy

Slash, are you saying not to use the lockwasher early on, but still torque the nut up?

V oodoo,
I'm saying it's okay to reuse the old lock washer while setting the timing, but torque it to spec every time. Once the timing is set, replace the lock washer with a new one and torque.

Best,
-Slashy

I don't know as much as most of you about these things but I had a P that would not run when warm and after I replaced everything else in the ignition system it turned out to be weak flywheel magnets. Just sayin'

Good Evening,

Back to work. I had replaced magneto plate cables since I noticed that there were burned cables and improperly connected cables.

Now I had assembled everything this evening. Placed the plate exactly at the same position. Kickstarted, no sound of ignition. Sprayed a starter fluid, it is perfectly running, smoother running noise compared to previous run. Choke closed or open does not change the start.

Then I had measured compression, see below. I do not know the ideal value. Gasoline is new.

Is it time to adjust timing ? Or I should do smt else ? [/img]

By the way after I shut the engine off. Status of the spark plug is attached

Slow down, don't mess with too many variables at once! It's rule #1 of engine troubleshooting.

Did you set the electronic ignition at the factory timing marks? If so, this should be "good enough" for now. Instead, take a step back and look at the facts:

You have a scooter that will not start on a cold engine, with- or without- using the choke.

You have a scooter that seems to run "fine" if you can get it started (using starter fluid)

You have a scooter that seems to start ok if the engine is already warm.

It sure sounds like you have something that is primarily a cold-start issue. Before messing around with the electrics more, a few things should be checked.

1) are you sure the choke is actually "choking" - is the cable connected?
2) is the pilot jet, and the channels leading to it, actually clear of any debris?
3) how many turns out is your idle set at; how many turns out is your mixture screw set at (and is it the fine-threaded spaco screw or the coarse threaded one)?
4) that compression read is WAY off - either it is wrong, or you have very very poor compression. 70PSI isn't workable. I suspect the reading is just wrong. Can you tell us exactly what you did you get that reading? Did you kick more than once? Did you hold the throttle open? Is this a read with a warm or a cold engine?

IMO, you don't have an electrical problem.

I'm gonna say it again... it doesn't matter if you have the throttle open or closed when you check compression. Just kick til the gauge stops moving.

Low compression, wrong spark plug and very wet. I would start from the cylinder / piston and move to carb / fuel delivery...

That compression reading could easily be not correct. A B6ES is fine and is not causing their scooter to have trouble cold-starting. Seriously, we need to know more about their testing methods and the situation before stators get rewired and cylinders get pulled for rehoning and rings.

The spark plug pictured last is definitely not a B6ES. It has a protruding electrode so it's not the correct one. About the compression, I would agree with SoCalGuy. Stator wise, from the pictures he posted, I see a rotten wire on the left picture, so a rewire wasn't a bad idea...

You're right, the electrode is protruding far and it's got the black metal. The OP said they switched over to a B6ES above - I guess they switched back.

As far as the compression, I am not talking about the throttle position (but that should help the gauge fill faster) - we have no idea what procedure the OP followed. Did they kick once and stop? We don't know.

Rewire is done and couldn't hurt - that rotten wire is nasty. But for the cold-start problem, the bike ran fine beforehand (once started ).

I just think the OP can get to the bottom of this - and we can give them good advice - faster if we know everything that has been done.

Good afternoon gentlemen,

Let me restate what I have done so far.

1) I had to rewire because there were lot's of broken cables or burnouts.
The windings were fine, cables had to be replaced as far as our electrician has already stated. After all the work, we see that the sparks are healthy and brighter.
2) all fuel lines and carburetor is clean.
3) fuel mixture is replaced with a fresh one.
4) choke is working fine. Controlled the system. Petcock and fuel filter is changed.
5) reading from the pressure gauge is done as the heighest one after both choke is open and closed. It does not change, max. reading is that one.
6) magneto table is at "A", ideal position.

Now, today. I had set idle to 1.5 turns, mixture to 2.5 turns. Kick started 5 times, no reply. Sprayed a starter fluid, it did run. Idle sound is fine, back firing after each ~ 1 min.

Shut the engine off after 5 min. No sign of running after several kick starts.

This is the situation. Any systematic suggestions ?

thank you for your patience with my anal retentive questioning.

I am with SaFis. That compression is way too low if that is the max you can get. You should be seeing something in the range of 110-130 on that scooter with a decent condition top end.

You should use the correct NGK spark plug, and your scooter definitely should not be backfiring. Can you snap a picture of your stator plate's position on the scooter?

turrider,
I don't think your choke is working properly. It should have a dramatic effect on the engine, even when using starting fluid.
I agree with xantufrog; everything points to the choke.

Best,
-Slashy

Good Afternoon,

Following up the lead for the compression value, I had removed the cylinder head to ser inside. Strangely, I had observed that cylinder head gasket is missing. This has an effect ?

Cylinder bore is clean, without scratches, piston looks fine.

It resulted to me the cylinder diameter is 68.5 is this a correct reading ?

See the pictures...

By the way, ı had adjusted the choke cable for a verification it is working.

There is no head gasket, only a base gasket between the cylinder and case.

You have to take out the piston rings and check them for wear. Put them in the cylinder and check their gap. Just mark which ring was on the top and which was on the bottom...

Dear Vespisti,

Further notice,

I did removed cylinder, piston etc and realised that piston rings are worn out, cylinder is rectified to the last end scratches in lower portion (69 mm !).

So, I had started to rectify everything (even gaskets bearings everything on the engine).

Today parts have been delivered, most probably I will be posting some nice photos within next week.

Thank you to all.

Maybe it's my eyesight or the photo, but the brass nozzle into the venturi looks bent in your shot of the carb with filter removed.

Too many issues here...try another stator,new or remade and see results.THERE IS NO GUSKET BETWEEN HEAD AND CYLINDER ON vespa PX.

If there's one thing on my '79 P200E that's finicky, it's the carb. Yours sounds like it's doing what mine does.

Most of the time she's a second kicker, but every once in a while I'll try starting her and 30 kicks later nothing. The carb rebuild helped tremendously. I'ts like $20 and an hour's work.

Mine floods easily. Once I get it started it runs like a champ and after it's warm it restarts without an issue.

My process for starting it when this happens is just to push the choke all the way in, grab the throttle and open it all the way up and kick until it fires. That opens the slide all the way up and sucks in as much air as possible. Usually after about 10 kicks she'll catch and smoke like crazy until the excess fuel is burned off, but normally I'm good the rest of the day.

it certainly sounds like you have a fuel problem. Try shutting off your fuel tap at night, too. If it's leaky this will keep excess fuel from bleeding through.

Will you use same piston, hone the cylinder and install new rings
or
new next oversize piston & rings then rebore the cylinder?

Be sure to check cylinder bore for excessive out of round or taper along the bore before you decide to hone only.


Hard to tell here, but bore maybe looks to be getting big for that piston.

Look again & think reflection.