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@thegreatvolare avatar
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@thegreatvolare avatar
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Hello!
I am looking to purchase an old Vespa and I have found one that looks like a pretty good deal. Being a bit of a newb my self, I wanted to ask some advice. The scooter I am looking at is a 1979 P200e. I have been in contact with the seller and he has been pretty up front with the problems present in the scooter. The seller lives a decently far distance from me and I want to see if it is worth checking out before I go all the way to examine the scooter in person.

According to him, the paint and body is in reasonably good condition, a few minor scratches and dings but nothing serious. He had to replace the front fender. It doesn't start on the first kick but it only takes one or two extra kicks apparently. The scooter idles well but it dies when he tries to run it unless he keeps the choke out. The seller along with a couple of other people to whom I have described the problem to seem to agree that it is a problem with the carb. That seems to be the biggest issue. I also made sure to ask and the scoot has never been any where near Vietnam, which, I understand, is a good thing. The seller is asking $1500 for it.

Thats pretty much all I know at this point. Here I appeal to your knowledge, Oh scooter gurus. Does this seem like a good deal? Does the mechanical issue seem like an issue with the carburetor or is it something more sinister? Roughly how much would it cost to replace or repair the carb? Is there anything else I should check or ask about it when I go and check out the scooter? I would really appreciate any advice you may have. Thanks so much!

(P.S. I don't call it vintage because of the debate as to whether or not the P series can truly be called vintage)
@rover_eric avatar
UTC

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1965 Vespa SS180, 1963 Lambretta LI150
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@rover_eric avatar
1965 Vespa SS180, 1963 Lambretta LI150
Joined: UTC
Posts: 6980
Location: Detroit, Michigan
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haha. ignore the old debates. The P-series uses the same basic engine as they used in 1946, drum brakes and bicycle cables for operation,... so i've got no problem calling it vintage...even if you just bought it from the store.

Now, the problem your describing sounds an awful lot like a flyside seal leak. Fear not, though, as that's exceptionally easy to fix on a P-series engine. You'll just need a flywheel puller tool ( 20 bucks at most scooter shops, and a replacement flyside seal for it ) and you should be ok.

Everyone always thinks that's a carb problem ... but it's an airleak from somewhere. Hopefully the carb isn't warped... but it could be a few other things besides it and the flyside seal ( loose spark plug, loose head, improperly torqued down carb box or carb, bad gaskets, etc ).

Anyways, it's not a dealbreaker to me.

-Eric
@cooper avatar
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Hooked
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Hooked
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Is there anything more you can pass on about changing out the flyside seal? I have been told its pretty easy and can be changed out without dropping the motor. I have to get around to it sooner or later as well.
@rover_eric avatar
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1965 Vespa SS180, 1963 Lambretta LI150
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@rover_eric avatar
1965 Vespa SS180, 1963 Lambretta LI150
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Location: Detroit, Michigan
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you pull the flywheel off, you undo the stator and swing it out of the way, and then you pry out the existing flyside seal. It's just press-fit around the crankshaft, and you can get it out with a small pick.

then you just press in the new one, reassemble and you're done.

i'm simplifying ...but, it's one of the easiest engine repairs you could be asked to do.
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Hooked
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Hooked
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Brilliant, thanks dude. Doesn't get much easier than that.
@masala avatar
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Veni, Vidi, Posti
946
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Veni, Vidi, Posti
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Hey Volare,
Did you get the P? If so, please post some pictures!
OP
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Thanks so much for the help! I am going out to look at it tomorrow. If I decide to get it I will definitely post some pics. Thanks again!
@woodenhead avatar
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Molto Verboso
GT60
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Molto Verboso
@woodenhead avatar
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cooper wrote:
Brilliant, thanks dude. Doesn't get much easier than that.
Hey Eric,

Correct me if I'm wrong.

Bad seal on fly-side causes revving. Easy change.

Bad clutch-side seal will only run with the choke out. More involved.

cheers

Edit: diagnosis for a bad seal
UTC

Hooked
1974 Rally 200, 2009 Yamaha C3, 2010 Honda SH150i
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Location: san francisco
 
Hooked
1974 Rally 200, 2009 Yamaha C3, 2010 Honda SH150i
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Location: san francisco
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woodenhead wrote:
cooper wrote:
Brilliant, thanks dude. Doesn't get much easier than that.
Hey Eric,

Correct me if I'm wrong.

Bad seal on fly-side causes revving. Easy change.

Bad clutch-side seal will only run with the choke out. More involved.

cheers

Edit: diagnosis for a bad seal
either or, same difference. both seals do the same job of keeping it airtight in the crank. only diff is clutch side seal also keeps case oil out.
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Location: Detroit, Michigan
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With respect to Greasy on that post, i have to disagree.

I'll explain the mechanics to justify my reasoning.


1) The Flyside seal leak :

In this instance, since your flywheel side opens to the air, you're getting the same symptoms as a generic airleak. Your bike is pulling in air which is leaning out your mixture, causing your bike to run hot ...potentially rev to the moon ... OR, if it's severe enough, your bike won't run at all unless the choke is out. Why? Because you've leaned out the mixture so much that there's not enough gas in the charge for it to burn. When you pull out the choke, you've suddenly given it the amount of gas that makes it run again... you've richened the mixture enough to make it combustable again.

*insertion* I know this goes against what i said the other day about how it's the air that is burning in your engine, not the gas... but you gotta think of the jet numbers as a line... say from 75 to 150. Now, you've got a span of about 10 numbers in there where your bike will run. Say you need a 116 main jet, and that's optimal for you. Your bike will run with +/- 10 points from 116 ( i'm guessing, it may be only +/- 8 ). On the upper end of that scale, you're going to run really rich and foul plugs, and your engine will suffer in performance...boggy, unresponsive, etc. On the lower end of that scale, you're running too lean, and your bike will run AWESOME right up until the point you either blow a hole in your piston or soft / hard seize it (more likely ). OUTSIDE of that range of 10 numbers, your bike won't run at all.... it's either got way too much gas and not enough air, or way too much air and not enough gas. (YES, i realize that i'm using the main jet range as an example, where the idle jet is probably the one we're concerned about in this instance, but i think most people are most familiar with their main jet number as the one they most frequently need to change out, so i used that as the example. )

So, in the case of a bad flyside seal, your bike might be sucking in SO MUCH AIR that it's leaned out the mixture akin to you putting in a jet that's like 20 points too small. In pulling out the clutch, you're overcompensating, bringing it back up into the range where it will run ( but, still not ideally ... you may be running too rich or too lean in that condition while you limp it along. ) It's not a situation you want it to stay in long term.


2) Clutchside oil seal leak :

Realize the very different nature of the clutchside versus the flyside on vespa and lambretta engines. The Flyside keeps the air from leaking into the sealed off crankshaft area. The Clutchside opens to the inside of the engine case, where it's full of case oil. The same suction / leaking principles apply, but in this instance now you have case oil getting sucked up into the gas / air mix. That's not good, as it burns about as good as a wet cigar.... and why should it? It's not supposed to ever burn! So, you'll start pulling the engine case oil into your top end, where it's burnt (poorly) and you'll get white smoke pouring out of the exhaust. Don't confuse this with the smoke that comes out of your engine after it's flooded and finally kicks over... this is like James Bond smokescreen kinda white. It hangs in the air and doesn't dissipate the same as the 2stroke smoke.

So, that's no good, as you're losing power. Your bike won't idle properly. Frequently you'll try to combat this by turning your idle screw all the way in, and setting your base idle setting really far open, relying on a huge influx of air to lean out the mixture enough to keep it running. If you try to drive it, apart from fogging out all the mosquitoes on the street, it will run like an absolute dog...slow, nonreactive, boggy, etc. That said, pulling your choke out, as was asked earlier, will NOT make this situation any better, as all you're doing is further richening the mixture... making it more likely the bike will just stall out from too much fuel.

At the same time all that thick case oil is getting sucked into your gas / air mix in the top end, your gas is also spurting into your engine cases. In there, it proceeds to thin out your remaining case oil, and basically ruin it as a lubricant. So, you're rear axle bearing and all your engine innards are now being lubricated by a shitty gasoline mix that's rapidly becoming MORE gasoline and LESS case oil. If you rode like this, you might lock up the rear bearing on your axle... which, if you survive the inherent crash, will absolutely ruin your engine cases in the process.

This aspect DOES give us a nice way of diagnosing a bad clutchside seal, though - drain the oil. Is it thin? Does it smell like gas? Is there a TON of it ( pouring out like water! )? Then you've got a bad clutchside seal, friend.

Hope all this helps.

-Eric
@woodenhead avatar
UTC

Molto Verboso
GT60
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Location: Fraser Valley, BC
 
Molto Verboso
@woodenhead avatar
GT60
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Posts: 1381
Location: Fraser Valley, BC
UTC quote
Cool. The only problem now is getting rid of that little morsel of information I had tucked away somewhere in my little brain. Probably right next to something from a Gilligan's Island episode, or the name of my neighbor's kids. Great.

cheers
@rover_eric avatar
UTC

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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
Try using a mnemonic device

"If you have to pull the choke, you've got a bad clutchside seal"

If
You
Happen
To
Picnic
Today,
Cindy
You'll
Gag.
Avoid
Bad
Cucumber
Salad


There you go. Now you'll never forget!
@phaetn avatar
UTC

Addicted
'78 Super 150 Mk II ported DR177, banded clutch, ASC Big Bore
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Posts: 664
Location: Ottawa, ON, Canada
 
Addicted
@phaetn avatar
'78 Super 150 Mk II ported DR177, banded clutch, ASC Big Bore
Joined: UTC
Posts: 664
Location: Ottawa, ON, Canada
UTC quote
Rover Eric wrote:
Try using a mnemonic device

"If you have to pull the choke, you've got a bad clutchside seal"

If
You
Happen
To
Picnic
Today,
Cindy
You'll
Gag.
Avoid
Bad
Cucumber
Salad

There you go. Now you'll never forget!
He he he. Thumbs up for creativity. However, I thought your diagnosis was a FLYwheel side seal....

Consider:
If
You
Happen
To
Picnic
Today,
Cindy
You'll
Gag.
Avoid
Bad
F**kin'
Salad

Nerd emoticon

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