Keeps Cutting Out

[Strummer10]

Guys, I gotta look at a mate's GP 200 tomorrow. He was on a ride out a few weeks back and it just suddenly stalled, after which he kept starting and it stalled again a few hundred yards down the road. We changed the spark plug and cleaned out the carb and he got home on it (15 miles) then tonight he was on he's way round to me and it cut out again within a mile (same as before).

Any suggestions to consider ?

[Adam_Winstone]

Indian stator plate failing?

[Muttley McLadd]

Ignition switch is a cheap check.

[Toddy]

Start with the easy checks Wiring , Ignition switch, , plug , cap , lead , CDI and work back to stator (which it probably is as Adam says)

[Chris in Margate]

So it ran ok for 15 miles after plug change and carb clean.
Petrol cap breather blocked ?.
More muck dragging into carb ?
Cut ends of HT lead back 1/2 inch and refit.
CDI swap

Easy things first.

[Strummer10]

Cheers ALL for your thoughts. Gonna pop round today with the electrical tester and check the stator, look at HT cap and lead. Is there anyway of testing the CDI (coil) unit ? OR is the thought just change over for a new unit ?

I know last time it kept cutting out we stuck a new coil on it and it was fine and he said to me yesterday, 'surely it can't be that cos it's new' and I said yes but even new parts are dubious nowadays........its not the good old 1980s I said lol

[mick1]

Stator looks a good call, CDI units are best swapped to check.

No "waterproofs" under the seat blocking the air scoop ?

Might be worth checking the flow rate from the tank as well.............

[Monty]

I had the same problem. Replaced everything but had changed the CDI for one of the red BGM ones. It can't be that so I went stator pickups and coils then complete stator. It would be OK for weeks then blaaa. Swapped the CDI for a Ducatti one on my other bike and it ran perfectly. Unfortunately so did the other bike with the BGM.
So at that point you put it down to bloody Lambretta's till it went on the other bike. It was months later but I ride my series 1 a lot more. At least once it had gone I was actually happy to have a definitive answer. Check your stator readings and do the CDI sooner than later once you have removed your loom green from the CDI.

[philz]

Just had a similar issue would fire but not run. Turned out it was a broken wire behind the rubber cover on the ignition switch. Every days a school day with a Lambretta.

[Strummer10]

Cheers Guys for all the suggestions....ok we did this today

1/ Used an electrical tester on the indian stator plate and readings seemed ok .....with one wire being within the tolerances Sticky mentions and another at 93 (against Sticky's 95) and another 170 (against Sticky's) 180, but he does say indian readings are lower than Italian so we presumed the stator was ok, albeit readings marginally lower.

then

2/ Swapped the red BGM CDI for a new blue one (Ducati written on it) and cut the lead ends and run it......still cut out after a few miles.

then

3/ Switched the ignition to setting 3 (with lights switched on) and it seemed to run fine, but after 8 miles conked out.

Wondering if it's now the stator is at fault on a coil, like the post above, so borrowed a BGM supercharged stator to try tomorrow and see I guess, but agree it's a pain in the arse lol

then