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@mdchanic avatar
UTC

Hooked
GS 160 /4
Joined: UTC
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Location: Maine, USA
 
Hooked
@mdchanic avatar
GS 160 /4
Joined: UTC
Posts: 402
Location: Maine, USA
UTC quote
I have asked this question of others, and gotten some good answers, which I deeply appreciate, but none that really seem to "click." I figured I'd try it here as well to see whether I could collect any more grist for my slow-grinding brain...

My 160 GS is dead stock, has 26,000km, and sat in a dry barn for the past 15 years or so.

I've gone through it, had the cylinder off, found the rings were clean, combustion chamber in good condition, and wear minimal.

I filed the points, but did not replace them because they looked better than the replacements and had perfect continuity. It has a new condenser, there is no points sparking when running. I carry the old condenser (there has been some condenser swapping back and forth while troubleshooting at different points).

I rebuilt the carb. - new float, needle, gaskets, all cleaned and blown through.

The fuel tank was sloshed and recoated years ago. New fuel tap. No problems with the tank lining peeling.
New black rubber fuel line.

I cleaned the original muffler with Drano, then left it to cook on the charcoal grille.

I replaced all cables. All are working well, no binding.

New plug (B6ES, if I remember).

I resealed the original coil into the original can, on the advice of Gene from S.O.

All rubber parts and the spark plug wire were replaced.

Gas tank was full, mixed 2 1/2 gallons to 16 oz of generic 2-cycle oil.

It's a Euro battery bike - all electrics working well. All contacts have been cleaned with Dremel wire brush attachment, including inside of headlight / ignition switch.

6v / 12ah maint. free lead-acid burglar alarm battery.


The bike had been starting 1-2 kicks over the past 2 months.
A few days ago, I turned on the fuel, pulled the choke, 2 kicks, started right up after about a week not running.
I rode about ten miles, at average 40-50mph, at an ambient temp of about 80 deg F.
I turned off the bike. I think I did NOT turn off the fuel
After about 10 minutes, I tried to start it - nothing. Maybe an almost-pop once or twice.
I kept trying to start - choke on , choke off, throttle open, throttle closed. Repeat.
I started taking stuff apart - changed plugs back and forth, checked spark [good], moved fuel tap to R, pulled and pushed on fuel line through body. Plugs were getting wet.
I pulled the air cleaner, found good fuel spray on kick.
I tried starting fluid (ouch) - nothing.
I pulled the flywheel to check for a sheared key - perfectly fine, all electrical connections good, no sparking at points when kicked, still a good spark at the plug.
A thunderstorm started. Everything got soaked, including me.
I put all back together.
I turned the ignition switch on, put the fuel valve to Run, choke off, gave a kick, instant start, smooth idle.
I rode home in the rain, no problems.

So, why, after months of running great, did it decide not to start for that one time, and then behave perfectly well again afterwards?

I can categorize them as follows, within my own framework:

Possible problems with any motor -

-- Compression - N/A here

-- Timing - Checked, hadn't changed, N/A here

-- Electrical - Spark looked identical throughout this experience, and the same as it always had before. This s not conclusive evidence that all was fine, but it sure looked okay.
----Within Electrical: Coil heat intermittent, Condenser heat intermittent
----Discounted within electrical - leakage from wire or plug cap, bad plug, bad primary wiring.

-- Fuel - Vapor lock or flooding.
I saw normal-appearing spray from the spigot in the carb while kicking and the plugs DID get wet, making fuel starvation seem unlikely.
No improvement after I put in a new plug, making flooding seem unlikely.

Well, does this ring a bell for anyone?
Or is it just a "quirk" I'll have to get used to dealing with now and then?

Thanks,

- Eric
UTC

Member
px200 efl SH300i
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Location: cambridge uk
 
Member
px200 efl SH300i
Joined: UTC
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Location: cambridge uk
UTC quote
Here is a thought. Is the coil on the way out? A quick test is to reduce the plug gap to say half normal & try it.
If it seems ok now it is the coil breaking down.

8)
@rover_eric avatar
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Moderator
1965 Vespa SS180, 1963 Lambretta LI150
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Posts: 6980
Location: Detroit, Michigan
 
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@rover_eric avatar
1965 Vespa SS180, 1963 Lambretta LI150
Joined: UTC
Posts: 6980
Location: Detroit, Michigan
UTC quote
I posted this reply in the other thread, but i'm pasting it here to keep shit tidy.

OK... after reading that whole thread....

I honestly think it was something stupid, like it was flooded or something.

Did you try bump-starting it? I never read that you did, and it's something i ALWAYS do. If i can't get a bike running after 5 minutes of bumpstarting ( and the corresponding cardiac arrest i give myself ) then something is SERIOUSLY wrong with it ( like, my timing is way the hell off ).

And, i'm in agreement with Gene that the GS original coils, though some people hate them because eventually the housing cracks and lets water in and then they get unreliable, i think they are super reliable... and, well, they're original so i'm more likely to want to keep it on my bike. I've got the repop and it's certainly nicer than the repop.

So... i'm not inclined to read into this too far. If it happens again with the same symptoms, i'd be concerned... but i think i'd just let this one slide... and try bumpstarting the next time it happens.

I honestly think you just flooded it. Sometimes i'll take out the spark plug and hold a lighter to the hole and kick the bike ( don't sit too close, it's like a momentary flame thrower ) ....or bumpstarting will clear out those floods.
OP
@mdchanic avatar
UTC

Hooked
GS 160 /4
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Location: Maine, USA
 
Hooked
@mdchanic avatar
GS 160 /4
Joined: UTC
Posts: 402
Location: Maine, USA
UTC quote
Well, Eric, I tell you, I did NOT try to bump start it.

I thought of it, but I guess with my airhead BMW experience, I just assume that if it doesn't start on the first or second kick, then there's something wrong, and I need to start taking things apart.

I DID kick it a few dozen times, though (way easier to kick 160cc than 900cc).

Funny thing is, I made the same ride under the same conditions today, was all ready for trouble, and it started right up, first kick.

Bastard.

So you may be exactly right - it's something that happened once and won't happen again. I hope so, because I've got an obsession about reliability with my antique vehicles - if I'm going to use them at all, they've GOT to start every time. You are way cool if you give it a casual kick and it just starts kicking over. You look like a fool if you're kicking it like crazy and it's not even sputtering. Call it Vanity.

Thanks,

- Eric
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not-so-normal
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UTC quote
sometime we forget trivial things... I have experienced with kill button stuck... didn't return to position initially
@joshzingzing avatar
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Veni, Vidi, Posti
px200 cutdown,px180,px150. Puch SR. Puch scooterette
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Location: west aus
 
Veni, Vidi, Posti
@joshzingzing avatar
px200 cutdown,px180,px150. Puch SR. Puch scooterette
Joined: UTC
Posts: 5109
Location: west aus
UTC quote
yeh id have to agree with eric--- might have just been flooded
like if it was parked up on a bit of an angle itll flood. kicking it over might not work enough to clear out the extra crud
so go the push start

im lucky ive got the option of holding the throttle wide open and just hitting the starter button till it starts revn like an old deisel tractor then give it a few twists an off i go



but still, sometimes the push start is better
@starreem avatar
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Ossessionato
07 GTS250(RIP), 07 LX150, Several Lambrettas
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Location: Raleigh, NC
 
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@starreem avatar
07 GTS250(RIP), 07 LX150, Several Lambrettas
Joined: UTC
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Location: Raleigh, NC
UTC quote
Re: GS 160 Hot-start Problem (collecting more opinions...)
Is this a typo? Unless my math is way off, that's more like 7%.
MDchanic wrote:
...
Gas tank was full, mixed 2 1/2 gallons to 16 oz of generic 2-cycle oil....
OP
@mdchanic avatar
UTC

Hooked
GS 160 /4
Joined: UTC
Posts: 402
Location: Maine, USA
 
Hooked
@mdchanic avatar
GS 160 /4
Joined: UTC
Posts: 402
Location: Maine, USA
UTC quote
Re: GS 160 Hot-start Problem (collecting more opinions...)
starreem wrote:
Is this a typo? Unless my math is way off, that's more like 7%.
MDchanic wrote:
...
Gas tank was full, mixed 2 1/2 gallons to 16 oz of generic 2-cycle oil....
Not by my figgerin'...

1 gal. = 128oz (in the US)
(ie: 1 cup = 8oz, 1 pint = 16oz, 1 qt = 32 oz, 1/2 gal = 64 oz)

128 oz x 2.5 = 320oz

320 x 5% (or 320 x 0.05) = 16

so, 16 oz is 5% of 320oz (which is to say 2.5 US gallons)

-- OR --

5% = a 20:1 mixture, so 16oz x 20 = 320oz

- Eric

ps: no, it never makes any visible smoke.
UTC

Addicted
1974 Rally 200, 1974 Rally 200 with sidecar, Vespacross bike
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Location: Atlanta
 
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1974 Rally 200, 1974 Rally 200 with sidecar, Vespacross bike
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Location: Atlanta
UTC quote
If you have 2.5 gals in your tank you have a problem. The brass breather on the fuel tap is not long enough to sit above the gas and you will get vapor lock in the fuel line. I would look to see if you can see the tube. If you can't drain some gas and try again.
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GTS, PX125E, P200
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Posts: 997
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GTS, PX125E, P200
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UTC quote
Re: GS 160 Hot-start Problem (collecting more opinions...)
starreem wrote:
Is this a typo? Unless my math is way off, that's more like 7%.
MDchanic wrote:
...
Gas tank was full, mixed 2 1/2 gallons to 16 oz of generic 2-cycle oil....
5%
1 Gallon = 128 oz
2.5 * 128 = 320
16/320 = .05
@rover_eric avatar
UTC

Moderator
1965 Vespa SS180, 1963 Lambretta LI150
Joined: UTC
Posts: 6980
Location: Detroit, Michigan
 
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@rover_eric avatar
1965 Vespa SS180, 1963 Lambretta LI150
Joined: UTC
Posts: 6980
Location: Detroit, Michigan
UTC quote
i don't remember what the capacity of the GS / SS / Rally tanks are, but remember that they are larger capacity than any of the other vespa gas tanks.
OP
@mdchanic avatar
UTC

Hooked
GS 160 /4
Joined: UTC
Posts: 402
Location: Maine, USA
 
Hooked
@mdchanic avatar
GS 160 /4
Joined: UTC
Posts: 402
Location: Maine, USA
UTC quote
No, I don't put 2 1/2 gallons in the tank (I think it's supposed to hold something like 2.4??) - I buy 2 1/2 gallons at the gas station, pour 16oz into the gas can, then pour into the tank as needed. So long as I don't go too low, I never have to worry about refilling, as I just do local riding.

HOWEVER... I DID fill it quite full IMMEDIATELY BEFORE that ONE time that I had a problem (more full than usual, very nearly to the top), so I wonder whether blockage of the breather tube could have been all or part of the problem...

This is the first promising explanation for my problem that I've heard.

Can anyone explain the exact routing / function of the breather tube?
I've blown through them, but never really sat down to try to figure out exactly where everything goes (I guess I could grab an old one and figure it out myself, but, hey, I'm lazy, and besides, I'm at work now).

Thanks,

- Eric
@rover_eric avatar
UTC

Moderator
1965 Vespa SS180, 1963 Lambretta LI150
Joined: UTC
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Location: Detroit, Michigan
 
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@rover_eric avatar
1965 Vespa SS180, 1963 Lambretta LI150
Joined: UTC
Posts: 6980
Location: Detroit, Michigan
UTC quote
IIRC, the breather tube ( that long brass pole ) is supposed to let the air in so that your gas can drain properly.

Why does it need it? I don't know. Lambrettas don't have one of those and they drain just fine.
@cooper avatar
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Hooked
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Hooked
@cooper avatar
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UTC quote
I really don't think thats it. I bought a scoot that was running. My first task (after changing tires and gear oil) was replacing the tap for a few reasons. One of the reasons was that the breather tube was broken right off. It stil ran fine though. I didn't think it let air in I thought it let air out. So it just made bubbles in the tank.
OP
@mdchanic avatar
UTC

Hooked
GS 160 /4
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Location: Maine, USA
 
Hooked
@mdchanic avatar
GS 160 /4
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Location: Maine, USA
UTC quote
Hmmmmmm...

I've got to check out an old one when I get home and figure this out.

- Eric
UTC

Addicted
1974 Rally 200, 1974 Rally 200 with sidecar, Vespacross bike
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Location: Atlanta
 
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1974 Rally 200, 1974 Rally 200 with sidecar, Vespacross bike
Joined: UTC
Posts: 609
Location: Atlanta
UTC quote
I have a rally tank and if I put more than 2 gallons in it the brass tube is covered. I have had the brass tube fall off before and the bike would run for about 10-15 min and would stall. It would start right up afterwards but would stall after 10-15min again. At one time it didn't restart. I fixed the brass tube and it always started after that and ran fine. Joe Casala has had the same problem before too. He restored a bike for a guy and they overfilled the tank. It would run fine for a little while then stall. The older fuel taps flow less fuel but the air release channel is larger. The repro fuel taps have a larger fuel channel but a smaller air channel.
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