OP
@starreem avatar
UTC

Ossessionato
07 GTS250(RIP), 13 GTS300, Several Lambrettas
Joined: UTC
Posts: 2801
Location: Raleigh, NC
 
Ossessionato
@starreem avatar
07 GTS250(RIP), 13 GTS300, Several Lambrettas
Joined: UTC
Posts: 2801
Location: Raleigh, NC
UTC quote
Before I slice into a perfectly good CDI, Can anyone confirm or deny this modification applies to US spec scooters?
doniq wrote:
Vespa LX 4T ignition test points.

Only two wires come from the stator. The engine to earth connection is very important.
Battery voltage at idle = 13 v (Battery charged) max will be 14.5 volts at high revs. Meter between battery neg. & pos.
Battery charge at idle = 1.5 - 2 amps (lights off). max will be >5 amps at high revs with all lights on. Meter between red wire and battery pos.
Test 1: Brown - earth = ~170 ohm To test pick up coil. Stator un-pluged
Test 2: Black - earth = ~1 ohm To test charging coils. Stator un-pluged
Test 3: Blue / Grey - earth = 25 - 35 v ac @ 2000 rpm with regulator disconnected. To test charging coils.
Test 4: White - Black = ~8 M ohm. If the resistance is low it could cause the fuse to blow.

External inline image provided by member with no explanatory text
Original thread here:

cdi swap
@baudler avatar
UTC

Foiled
Racing 60's Sprint
Joined: UTC
Posts: 1301
Location: Matthews, NC
 
Foiled
@baudler avatar
Racing 60's Sprint
Joined: UTC
Posts: 1301
Location: Matthews, NC
UTC quote
Yep, that is exactly what we had at our dealer. I never had done it though.
@motovista avatar
UTC

Veni, Vidi, Posti
GT 2.4
Joined: UTC
Posts: 8850
Location: Watts, Cherokee Nation
 
Veni, Vidi, Posti
@motovista avatar
GT 2.4
Joined: UTC
Posts: 8850
Location: Watts, Cherokee Nation
UTC quote
If your scooter is in perfect working order, and is going a bit under 30 mph, you have a restricted cdi. If not, you don't. If the bike is going 35 mph, you don't have a restricted cdi, and I can tell you from experience that if you cut into it like the diagram says, you will end up with a cdi you cut into and one that works that you ordered after the one you cut into stopped working. Was there a washer over the bushing, between the variator plates? I haven't seen the restricted cdi on US market Piaggio or Vespa scooters.
@baudler avatar
UTC

Foiled
Racing 60's Sprint
Joined: UTC
Posts: 1301
Location: Matthews, NC
 
Foiled
@baudler avatar
Racing 60's Sprint
Joined: UTC
Posts: 1301
Location: Matthews, NC
UTC quote
De-restrict a LX50?

Or the CVT can be changed.
⚠️ Last edited by Baudler on UTC; edited 1 time
@jimc avatar
UTC

Moderaptor
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: UTC
Posts: 43417
Location: Pleasant Hill, CA
 
Moderaptor
@jimc avatar
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: UTC
Posts: 43417
Location: Pleasant Hill, CA
UTC quote
Motovista wrote:
If your scooter is in perfect working order, and is going a bit under 30 mph, you have a restricted cdi. If not, you don't. If the bike is going 35 mph, you don't have a restricted cdi, and I can tell you from experience that if you cut into it like the diagram says, you will end up with a cdi you cut into and one that works that you ordered after the one you cut into stopped working. Was there a washer over the bushing, between the variator plates? I haven't seen the restricted cdi on US market Piaggio or Vespa scooters.
Agreed. I'm pretty confident that the restriction only applies in those EU countries where there is a separate category of 'Moped' <ugh> that is <50 cc and is restricted to <30mph / <50kph, and can be ridden by those otherwise too young to ride anything faster or more powerful.
OP
@starreem avatar
UTC

Ossessionato
07 GTS250(RIP), 13 GTS300, Several Lambrettas
Joined: UTC
Posts: 2801
Location: Raleigh, NC
 
Ossessionato
@starreem avatar
07 GTS250(RIP), 13 GTS300, Several Lambrettas
Joined: UTC
Posts: 2801
Location: Raleigh, NC
UTC quote
I'm 99% sure there is no washer between the variator halves, but it has been a while since I went into the transmission. The CDI in there is a Ducati ac17 639069 so maybe it is not restricted? I can maintain 35-40 mph on level ground.

I stumbled upon the previous thread when researching a new CDI for intermittent spark issues. I believe the spark issues were a result of corrosion on the negative battery terminal, since CDIs usually work, or they don't.
@motovista avatar
UTC

Veni, Vidi, Posti
GT 2.4
Joined: UTC
Posts: 8850
Location: Watts, Cherokee Nation
 
Veni, Vidi, Posti
@motovista avatar
GT 2.4
Joined: UTC
Posts: 8850
Location: Watts, Cherokee Nation
UTC quote
starreem wrote:
I'm 99% sure there is no washer between the variator halves, but it has been a while since I went into the transmission. The CDI in there is a Ducati ac17 639069 so maybe it is not restricted? I can maintain 35-40 mph on level ground.

I stumbled upon the previous thread when researching a new CDI for intermittent spark issues. I believe the spark issues were a result of corrosion on the negative battery terminal, since CDIs usually work, or they don't.
Not with this one, especially if the CDI has an orange terminal where it plugs into the harness.

Here's something I put on our site about this...

Does your Vespa LX 50 cut off after ten to twenty minutes and then start up and run briefly? We've seen a lot of Early US market Vespa LX 50 4T models that will run fine for about ten to twenty minutes then cut out, Wait a while, and they start again. We did the usual r&r fuel lines, check the fuel for contaminants, Poke a hole in the gas cap, check the compression, etc. All fine. Then we hooked up a device that will show if the plug is getting spark while you are riding, and found out that there were intermittent losses of spark. One guy had two Lx50s, and they both quit within about ten feet of each other after we rode the piss out of them. It's the sort of problem that often presents in bikes that have been sitting for years and are suddenly back on the road .
To diagnose this, you need to ride the bike for about ten miles, let it idle, ride it hard, let it idle, and so on until it dies. Then when you try to start it, it may start up and run briefly, then shut down again. It will start, run briefly, cut off, and then start, run, cut off sooner, then not start until it sits and cools down.
When this happens, switch out the CDI and that will usually solve the problem.
This is a tough problem to solve at home, because the only way to really diagnose it is to put in a known good cdi and see if that fixes it. Electrical parts purchases are final, the CDI is expensive, and if that's not the problem, you now own two good CDIs, and a Vespa that dies.
If the bike is idling rough and dying at stop signs right after it gets warm, it can also be an exhaust valve that is too tight, but that shows up a lot sooner than the intermittent CDI issue

That said, I did find an aftermarket cdi that gives the bike a good 4-7 mph.
OP
@starreem avatar
UTC

Ossessionato
07 GTS250(RIP), 13 GTS300, Several Lambrettas
Joined: UTC
Posts: 2801
Location: Raleigh, NC
 
Ossessionato
@starreem avatar
07 GTS250(RIP), 13 GTS300, Several Lambrettas
Joined: UTC
Posts: 2801
Location: Raleigh, NC
UTC quote
Thanks for that info, I did see that on your website. But that is not my problem, The problem here is it works one day just fine, then it doesn't another. I have replaced the plug wire and HT cap. Have tested the stator as in the other thread, and some days there just is no spark.

It ran just fine for a few weeks after I cleaned the acid corrosion from the negative terminal. I thought that was the problem. I just cleaned it up again, and now there is no spark again. Very frustrating to figure out. I don't have another CDI to test with.
@motovista avatar
UTC

Veni, Vidi, Posti
GT 2.4
Joined: UTC
Posts: 8850
Location: Watts, Cherokee Nation
 
Veni, Vidi, Posti
@motovista avatar
GT 2.4
Joined: UTC
Posts: 8850
Location: Watts, Cherokee Nation
UTC quote
There has to be someone here in your area with a Fly, LX, or SR 4 Stroke that will let you switch out and see if that fixes the problem. I would be surprised if it's anything else. On a day when it starts and runs fine, ride it for about 20 minutes and see if it shuts down again.
OP
@starreem avatar
UTC

Ossessionato
07 GTS250(RIP), 13 GTS300, Several Lambrettas
Joined: UTC
Posts: 2801
Location: Raleigh, NC
 
Ossessionato
@starreem avatar
07 GTS250(RIP), 13 GTS300, Several Lambrettas
Joined: UTC
Posts: 2801
Location: Raleigh, NC
UTC quote
Thanks, I might have a spare lined up from a shop I work with. I have been caning it for the last three weeks, for hours on end. I'm not experiencing those exact same symptoms, but I can't figure anything else is causing the lack of spark but the CDI. The stator wires test OK.
@baudler avatar
UTC

Foiled
Racing 60's Sprint
Joined: UTC
Posts: 1301
Location: Matthews, NC
 
Foiled
@baudler avatar
Racing 60's Sprint
Joined: UTC
Posts: 1301
Location: Matthews, NC
UTC quote
My connecting wires were not making contact where they connect to the HT. It was driving me mad. It started perfectly fine and would go okay. As soon as it warmed up, it would start sputtering. I thought it was fueling issues but reading MV I decided to look at the HT. Sure enough it was loose. Just simply made them clamp on tighter and BINGO all was fixed. I don't know if this helps, just throwing it out there.

But I see you just replaced it as mine was replaced as well before I bought my ET. I bet the previous owner replaced it because they thought it was bad. In fact I bet the connection was just poor in the first place. Here I go rambling on and on.........
The two little prongs sitting out in the open is where it connects to the wiring harness.
The two little prongs sitting out in the open is where it connects to the wiring harness.
DoubleGood Design banner

Modern Vespa is the premier site for modern Vespa and Piaggio scooters. Vespa GTS300, GTS250, GTV, GT200, LX150, LXS, ET4, ET2, MP3, Fuoco, Elettrica and more.

Buy Me A Coffee
 

Shop on Amazon with Modern Vespa

Modern Vespa is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com


All Content Copyright 2005-2024 by Modern Vespa.
All Rights Reserved.


[ Time: 0.0271s ][ Queries: 4 (0.0069s) ][ Debug on ][ 313 ][ Thing One ]