Sat Jul 24, 2021 4:33 pm

Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
 
Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
Sat Jul 24, 2021 4:33 pm linkquote
Hi. So I’m
Going through the infamous indiana burgundy glitch in the matrix p200 frankenfender double seat twin tail light special. One of a kind.

I was having a hard time shifting into gear but I replaced the clutch cable and adjusted the slack on the gear selector and
Now I can get it in all
Gears easily.It goes into first a little hard. But it was rainy so I stopped there. (I work outside)

But here’s where it gets weird.

It starts first kick ( as long as I don’t flood it over night doh! )

But after idling for a while it starts sucking a lot of fuel and goes into super high rpms. On one occasion the key kill switch wouldn’t stop it. I opened the air mix screw til it died. The next time the key killed it

So two things

What would cause that high rpm issue

And is that a faulty kill switch wire ? Or some other issue like it became sentient?

Thanks In advance!
Sat Jul 24, 2021 5:59 pm

Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8448
Location: Atlanta, GA
 
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8448
Location: Atlanta, GA
Sat Jul 24, 2021 5:59 pm linkquote
Air leak. It's sucking too much air.

The ignition can continue without the spark when it really gets roaring.

The kill switch and key circuit are probably fine (although the wiring of the kill switch is notorious for going bad).

By cranking the mix screw out all the way you were able to enrich the circuit enough to stop the perpetual motion machine.

Most likely the flyside seal, but there's also a clutchside (I need to do mine) and potential air leaks at the carb base and cylinder head if they got warped from over-tightening (chances are not, though - the seals have a life span and that's my bet)

For sanity it is worth checking the carb throttle slide is moving smoothly and returning ok (another sign of warped carb).

Your bike is super old and the previous owner probably ran into these issues and then ran away. But it's "normal" fixable stuff and now is a time to poke around like you were doing and find those gremlins
Sat Jul 24, 2021 9:08 pm

Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
 
Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
Sat Jul 24, 2021 9:08 pm linkquote
Thanks Xantufrog!

I did notice the slide looked like it wasn’t closing all the way. And the throttle return spring (?) is worn out.

I’ll go through the seals and see where that gets me. Thanks so much.
xantufrog wrote:
Air leak. It's sucking too much air.

The ignition can continue without the spark when it really gets roaring.

The kill switch and key circuit are probably fine (although the wiring of the kill switch is notorious for going bad).

By cranking the mix screw out all the way you were able to enrich the circuit enough to stop the perpetual motion machine.

Most likely the flyside seal, but there's also a clutchside (I need to do mine) and potential air leaks at the carb base and cylinder head if they got warped from over-tightening (chances are not, though - the seals have a life span and that's my bet)

For sanity it is worth checking the carb throttle slide is moving smoothly and returning ok (another sign of warped carb).

Your bike is super old and the previous owner probably ran into these issues and then ran away. But it's "normal" fixable stuff and now is a time to poke around like you were doing and find those gremlins
Sun Jul 25, 2021 4:47 am

Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8448
Location: Atlanta, GA
 
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8448
Location: Atlanta, GA
Sun Jul 25, 2021 4:47 am linkquote
You're welcome.

Just to make sure we're using the same lingo, though: The slide isn't going to close all the way with the throttle screw properly adjusted. It is normal to sit a little open. So the comment was really to make sure it returns to its natural stop point, on its own/by spring - not to be literally closed.

I might start with making sure the throttle moment is not hitching and is returning to its stop before chasing an air leak, so that it doesn't complicated things if it is sticking. Also, if it's sticking you may have found your air leak - at the carb base
Sun Jul 25, 2021 6:10 am

Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
 
Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
Sun Jul 25, 2021 6:10 am linkquote
Ok thanks for clarifying. Either way sounds like I’m gonna need to replace a bunch of old gaskets and seals eventually. The notch in the slide looks kinda big to me but my only previous carb experience is with cb750 carbs. But I noticed the spring is not super tense and there’s play in the arm after I close the throttle by hand.
xantufrog wrote:
You're welcome.

Just to make sure we're using the same lingo, though: The slide isn't going to close all the way with the throttle screw properly adjusted. It is normal to sit a little open. So the comment was really to make sure it returns to its natural stop point, on its own/by spring - not to be literally closed.

I might start with making sure the throttle moment is not hitching and is returning to its stop before chasing an air leak, so that it doesn't complicated things if it is sticking. Also, if it's sticking you may have found your air leak - at the carb base
Sun Jul 25, 2021 7:03 pm

Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
 
Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
Sun Jul 25, 2021 7:03 pm linkquote
So I got I to the air is today and the slide wouldn’t close more than half an inch. I took out the air mixture screw, closed the slide all the way and screwed it in until I could see it just open. Started it and blipped the throttle a few times and it idled fine. Then I decided to shut it off and see what the wires in the junction box look like. The yellow one was a little crumbly and when I touched it the connector broke off. I do t know if that would prevent it from starting, but while that was happening I left the gas on and it got busy flooding the engine 🙃.
xantufrog wrote:
You're welcome.

Just to make sure we're using the same lingo, though: The slide isn't going to close all the way with the throttle screw properly adjusted. It is normal to sit a little open. So the comment was really to make sure it returns to its natural stop point, on its own/by spring - not to be literally closed.

I might start with making sure the throttle moment is not hitching and is returning to its stop before chasing an air leak, so that it doesn't complicated things if it is sticking. Also, if it's sticking you may have found your air leak - at the carb base
Mon Jul 26, 2021 5:02 am

Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8448
Location: Atlanta, GA
 
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8448
Location: Atlanta, GA
Mon Jul 26, 2021 5:02 am linkquote
Bizibetiko wrote:
So I got I to the air is today and the slide wouldn’t close more than half an inch. I took out the air mixture screw, closed the slide all the way and screwed it in until I could see it just open. Started it and blipped the throttle a few times and it idled fine. Then I decided to shut it off and see what the wires in the junction box look like. The yellow one was a little crumbly and when I touched it the connector broke off. I do t know if that would prevent it from starting, but while that was happening I left the gas on and it got busy flooding the engine 🙃.
Hm, I think you may be mixing (ha!) the idle and mixture screw up. The mixture screw is a small screw on the back of the carb that has no impact on the slide position. The tall screw down from the top is the idle adjust - it physically blocks the slide from closing to different degrees.

This is important because it changes my hypothesis about what is wrong a bit.

Revisiting your original post, if you killed the scooter by turning the idle screw out all the way (rather than the mixture screw), then it sounds like you simply killed it by snuffing it out. Moreover, if it was adjusted to sit that far open then yeah - the engine will race like crazy at "idle" (it's not really at idle at that point).

New hypothesis: you don't have an air leak; your seals are fine; the idle was just way out of adjustment and there is something dodgy about your kill switch wiring.

But I don't want to speculate too much over the internet and have you whiplashing around - I would go about it really methodically.

First, I'd familiarize yourself with the dell'orto SI carb, if you haven't already, to make sure we're all using the same lingo

Then, I'd confirm the slide moves freely - this is a quick and easy test and it sounds like it has already passed: you turn throttle open and let go and should see the slide down the venturi snap back into its resting position (as set by the idle screw) without snagging up/dragging.

Then, I'd clean the jets and give it some fresh gaskets: http://vespamaintenance.com/fuel/carbrebuild/index.html

Then, I'd start the scoot and tune the carb: http://vespamaintenance.com/fuel/carbtune/

At that stage, if it won't dial in and you are having persistent engine racing problems, then I'd revisit the idea that there's an air leak. Changing the clutchside seal is a major pain, so I wouldn't go hunting for a seal change unless signs of a leak force you to

I wouldn't turn the scooter off via the killswitch in daily use, because they are fragile and prone to breaking (and the replacements aren't good quality that I have seen). I would save the killswitch for emergencies, and turn the scooter off via the headset key. That being said - both should effectively kill the scooter, and you obviously want to know that they are working correctly. So it does sound like there's some wiring touch-ups to do since there's now a broken wire. Fortunately there is a junction box under your horncast, so running a new wire isn't a huge pain provided you can limit the chore to be running one from the switch to the junction box (rather than running a wire from the junction box through the scooter body back to the engine, which is no fun).

I hope this helps
Mon Jul 26, 2021 5:11 am

Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
 
Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
Mon Jul 26, 2021 5:11 am linkquote
Ok. My terminology was wrong. I originally shut the engine racing down issuing the idle adjust screw and I adjusted the slide opening yesterday with the same screw.

I have the air mix screw 1.5 turns out

Im not sure how many turns the slide adjusting screw is out. I just opened it til I could see a small gap.

One issue I’m having is when I open throttle it doesn’t return on its own. What’s causing that?

Also I am calling the key the kill switch. Do I have another kill switch?! It’s not apparent if I do.

Edit: found it. Doh!

I’m opening the carb up today to look at Jets but it seems super clean at a glance.

I’ll read that tuning guide you sent.

Thanks again!
xantufrog wrote:
Hm, I think you may be mixing (ha!) the idle and mixture screw up. The mixture screw is a small screw on the back of the carb that has no impact on the slide position. The tall screw down from the top is the idle adjust - it physically blocks the slide from closing to different degrees.

This is important because it changes my hypothesis about what is wrong a bit.

Mon Jul 26, 2021 6:42 am

Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8448
Location: Atlanta, GA
 
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8448
Location: Atlanta, GA
Mon Jul 26, 2021 6:42 am linkquote
No problem! More than happy to help.

The slide sticking open like that could be a cable/handlebar problem or at the carb. If it's only sticking at wide-open-throttle my guess would be it's the handlebar and/or cable are just sticky and need some grease. Someone else could weigh in, but the warped carb I had resulted in sticking towards the middle of the sliding process.

You could disconnect the throttle cable from the hook on the carb and just give it some pulls+snap-backs by hand down at the carb to take grimy/worn cables out of the equation

i think the recommendation for the idle is to start 2.5-3 turns out, but my memory is hazy - to some extent it'll wind up being what works best on your own unique scoot of course.

Keep us posted
Mon Jul 26, 2021 8:29 am

Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
 
Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
Mon Jul 26, 2021 8:29 am linkquote
xantufrog wrote:
No problem! More than happy to help.
Keep us posted
Update


Carb is tuned and running great. Shifting great. I sorted out the yellow wire problem (for now) it’s being held together in that friction slot in the j box.

But when I looked at the kill switch it was in the off position.

Now this is strange because it starts first kick. So I did an experiment. I kickstarted it with the key AND kill switch both set to off. Guess what? Fired right up. So- is this a ground thing OR did someone maybe bypass the switches? Either way I’m thinking new harness. Regarding the throttle return- it just doesn’t. It operates like a moped. So I’ll be digging into that next.

This is turning out to be a way easier project than I thought it would be for what I paid for it. Gotta love that.
Mon Jul 26, 2021 9:28 am

bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6105
Location: So Cal
 
bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6105
Location: So Cal
Mon Jul 26, 2021 9:28 am linkquote
Enjoy. These are not complicated machines.
Mon Jul 26, 2021 9:34 am

Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8448
Location: Atlanta, GA
 
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8448
Location: Atlanta, GA
Mon Jul 26, 2021 9:34 am linkquote
Bizibetiko wrote:
This is turning out to be a way easier project than I thought it would be for what I paid for it. Gotta love that.
Nice! The beauty of these old things is they are so simple in design. There really isn't that much to wade through when sorting them.

That being said...
Quote:
But when I looked at the kill switch it was in the off position.

Now this is strange because it starts first kick. So I did an experiment. I kickstarted it with the key AND kill switch both set to off. Guess what? Fired right up. So- is this a ground thing OR did someone maybe bypass the switches? Either way I’m thinking new harness.
...I'm not a big "electricals" guy so I don't have a ready answer on this one. The only thing I'll add right now is you can download the wiring diagram from scooterhelp.com and start to poke around it that way. New harness is a PITA because getting stuff through the body is no fun - so I'd be inclined to try to change upper harness bits (north of the junction box) first to see if you can fix it. The key+switch share wiring, so it may be something silly and boring like a single bad connection or grounded out point (can't recall how the kill circuit works)

I'm sure someone on here has an "ah it's probably just the __" (pics are always worth a lot too if you pull the headlamp and show our crew what you're working with)
Mon Jul 26, 2021 10:58 am

Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
 
Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
Mon Jul 26, 2021 10:58 am linkquote
xantufrog wrote:
New harness is a PITA because getting stuff through the body is no fun - so I'd be inclined to try to change upper harness bits (north of the junction box) first to see if you can fix it. The key+switch share wiring, so it may be something silly and boring like a single bad connection or grounded out point (can't recall how the kill circuit works)

I'm sure someone on here has an "ah it's probably just the __" (pics are always worth a lot too if you pull the headlamp and show our crew what you're working with)
I just rode around Chicago for about an hour. It’s lovely. But it took about fifteen minutes for all of the lights to just stop working lol. And it needs some fine tuning but all in all



ITS ALIVE!!!!!!!!


Formal garden

Wed Aug 18, 2021 7:54 am

Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
 
Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
Wed Aug 18, 2021 7:54 am linkquote
So after my reworking of the electrical/ignition system, removing all rust from the gas tank and installing new fuel and oil lines and a new petcock lever the bike starts and runs and rides great BUT doesn't idle very well. Taking bets on- clogged idle jet, vacuum leak, other?

What do y'all think?
Wed Aug 18, 2021 8:32 am

Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8448
Location: Atlanta, GA
 
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8448
Location: Atlanta, GA
Wed Aug 18, 2021 8:32 am linkquote
have you adjusted the mixture screw? simple and likely source of meh idle
Wed Aug 18, 2021 8:52 am

Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
 
Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
Wed Aug 18, 2021 8:52 am linkquote
xantufrog wrote:
have you adjusted the mixture screw? simple and likely source of meh idle
I did but I'm gonna go through the carb easy stuff later today again. Mixture screw, idle screw etc. There's no visible vacuum leak, compression is great, but it's running a little lean. Lean is a mixture issue right?
Wed Aug 18, 2021 9:11 am

Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8448
Location: Atlanta, GA
 
Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
Joined: 12 Jun 2008
Posts: 8448
Location: Atlanta, GA
Wed Aug 18, 2021 9:11 am linkquote
Bizibetiko wrote:
it's running a little lean. Lean is a mixture issue right?
Yes, although just to confirm: how do you know it is running lean?

For the mixture screw, start ~1.5 turns out (unless your carb is stamped spaco and the mix screw has very fine threads, then the story goes it should be ~2.5 turns out), and the idle screw ~2.5 turns out. Warm engine. See how turning the mixture screw half turn out and waiting a bit for the motor to adjust to the new mix affects the idling. Normally it should start to thump and chug a little more. Patience is important - wait a bit after each adjustment to perceive what really happens to the motor in response to that idle mixture change.

My first thought when you said it was idling rough was that it would be too far out, and you'd need to lean it up a bit with 1/4 turn in. But the mixture at idle and the mixture and WOT are different, so bear that in mind when jetting.
Wed Aug 18, 2021 11:44 am

Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
 
Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
Wed Aug 18, 2021 11:44 am linkquote
It idles with choke pulled out like 1/4 inch

I started with those specs and it idled great until the cdi/stator wiring failed.

When I did the electrical I cleaned the gas tank and ran new fuel lines. Now it seems to not be getting enough fuel.

That reads as running lean to me. But maybe I'm mixed up?


It's a dellorto carb
xantufrog wrote:
Yes, although just to confirm: how do you know it is running lean?



For the mixture screw, start ~1.5 turns out (unless your carb is stamped spaco and the mix screw has very fine threads, then the story goes it should be ~2.5 turns out), and the idle screw ~2.5 turns out. Warm engine. See how turning the mixture screw half turn out and waiting a bit for the motor to adjust to the new mix affects the idling. Normally it should start to thump and chug a little more. Patience is important - wait a bit after each adjustment to perceive what really happens to the motor in response to that idle mixture change.

My first thought when you said it was idling rough was that it would be too far out, and you'd need to lean it up a bit with 1/4 turn in. But the mixture at idle and the mixture and WOT are different, so bear that in mind when jetting.
Wed Aug 18, 2021 3:58 pm

Addicted
63 Lambretta LI 125 series 3, 71 Sprint Veloce , 2005 Vespa PX150, 1979 P200E
Joined: 04 Jul 2011
Posts: 972
Location: Tucson, AZ
 
Addicted
63 Lambretta LI 125 series 3, 71 Sprint Veloce , 2005 Vespa PX150, 1979 P200E
Joined: 04 Jul 2011
Posts: 972
Location: Tucson, AZ
Wed Aug 18, 2021 3:58 pm linkquote
A couple of years ago when I did a double engine swap I noticed that one of my scooters (PX150 with malossi 210) had a crazy high idle and it had other RPMS issues. I swapped carburetors with my identical engine running P200E with malossi(210 cc).

The carb was running good on the other scooter. Long history short, during the process of removing , installing the carburetor with the 11mm hollow carburator nuts I slightly stripped one. When I called scooter west to order them I realized that the engine studs that my scooter previously had were short.

So in summary, my short studs were not allowing the carburetor 11mm hollow nuts to properly tighten and press down to make a good seal. Once the studs were replaced with the proper lengths studs the problem went away.

Most high revving problems have to do with improper jetting, improper air mixture calibration and small air leaks like the one that I just described.
Mon Aug 23, 2021 9:46 am

Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
 
Member
1980 p200e
Joined: 15 Jul 2021
Posts: 29
Location: Chicago
Mon Aug 23, 2021 9:46 am linkquote
Update on the fuel delivery situation with my 1980 p200

New fuel and oil lines - right length and size, fuel tap is working fine
I went through the carb piece by piece. All stock Jets and everything works as it should. There wasn't much bad on it but I removed what there was. Just a little silty rust lol in the float bowl.

Two things I noticed- PO had filled the idle jet air passage with solder - I was able to dig that out easily with a pick tool. Why tho?

The slide doesn't slide very easily coming out of the slide track. It slide fine with regular action but it sticks coming out. It doesn't appear to be bent but neither does the carb body. This makes me worry that it's been over tightened in the past and warped. ☹️

Everything else is clean and working as it should.

Now it will only idle with like 1/4 of choke. Otherwise it runs fine. Is there a good way to test to see if the carb is warped? I suppose just lie it on a flat surface and look at it? Lol. Anyway, didn't stop me from hitting mikos for a line and coconut ice



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