Stator or Not?

[Granty]

Troops -- running a Lambretta Series 2 - Stage 4 200cc, set up as
30mm Delly - Open Mouthed
42mm AF Clubman
2 1/4 turns out
50 pilot
70 choke
40 slide
AV264 atomiser
X7 needle with clip at top
123 main jet

The problem is that after c 6-10 miles or so at at 3/4 throttle the scooter splutters as if running rich, plug is good choccy colour and dry. No difference when I go down to 122 main jet and go up to 125 main jet the same thing happens, have changed atomizer, needle onto 2nd from top etc and issue always the same - after constant driving at a good pace the engine starts to splutter and feels like its cutting out.

This issue started Oct last year and I thought it was a jetting issue but maybe not now. Spent all day today trying to jet this bike, plug chops at every change - scoot pulls well and plug good choccy brown up to 1/2 throttle and then the same again. Now wondering if this is now a stator issue, I have another 30mm delly jetted exactly the same but with a 125 main. Will swap them over tomorrow to see of there's any improvement but wonder if anyone else has sorted this with a new stator?

[Hat]

I’d try working from the plug back; cap, ht lead, cdi before going for the stator. Does it still rev when its spluttering or will it not go at all?

[MickYork]

check flow rate from tank
check breather hole in cap
might be worth stripping carb and checking float moves freely

change stator

[CHRIS in MARGATE]

You know what it is.... it's the stator. Classic fault.

[Granty]

I’d try working from the plug back; cap, ht lead, cdi before going for the stator. Does it still rev when its spluttering or will it not go at all?

I've replaced the plug, cap, HT lead, only the cdi & stator to go Yes it still revs through the splutter and goes in a fashion but just spluttering & not revving through as it should. As I've said I've been up and down with the clip on the needle, if I move it to the bottom it just bogs down as it should do if too rich -- this spluttering is different.

Thanks for taking the time to reply -- G

[Granty]

check flow rate from tank
check breather hole in cap
might be worth stripping carb and checking float moves freely

change stator

Hi Mick

Checked the flow and no problem with that and checked the breather hole in cap, that's OK and stripped the carb today -- the float is moving freely in the bowl no problem. I have another 30mm dellorto on another bike, was going to swap them over tomorrow and see if the spluttering starts at the same time ie between 6-8 miles along the road

[Granty]

You know what it is.... it's the stator. Classic fault.

That's what I'm coming to realize - bought the scoter in 2015 and never changed the stator -- I just think this has to be the issue -- G

[gaz_powell]

I've had a stator that checked out on readings and sparked but would not start the bike....
I went through spark plug onwards...ending at stator!
Note to self!

[Granty]

I’d try working from the plug back; cap, ht lead, cdi before going for the stator. Does it still rev when its spluttering or will it not go at all?

I've replaced the plug, cap, HT lead, only the cdi & stator to go Yes it still revs through the splutter and goes in a fashion but just spluttering & not revving through as it should. As I've said I've been up and down with the clip on the needle, if I move it to the bottom it just bogs down as it should do if too rich -- this spluttering is different.

Thanks for taking the time to reply -- G

OK -- tale of the tape today, CDI changed, HT cable, cap & plug changed. Off I go and same again -- it then really starts coughing, spluttering a little back fire and stop! No spark, then I get a spark ---- change the cap again but spark intermittent. New stator it is and that will be everything new from stator to the barrel. G

[St George]

Let us know which stator you chose, so many out there. I had a brand new one in storage for ages, when it was fitted, same issues as yours.

[Granty]

Let us know which stator you chose, so many out there. I had a brand new one in storage for ages, when it was fitted, same issues as yours.

just going for the new BGM one Buddy, put one on my Special a few years ago and never missed a beat since.

Seriously this has been driving me nuts -- even checked the fuel flow & fuel cap for the 10th time this morning, changed everything I can change -- 6hrs of plug chops and found faulty HT caps the lot -- it can only be the stator now

[St George]

Also make sure that you have a good earth on engine to frame. Regards.

[Granty]

Also make sure that you have a good earth on engine to frame. Regards.

Just done that recently too -- goo earth from flywheel cover to frame -- stator purchased -- Keep everyone posted and thanks for the help

[CHRIS in MARGATE]

You will find that it will still fire with that earth missing with electronic ignition.

[rossclark]

You will find that it will still fire with that earth missing with electronic ignition.

If the white from the stator is connected to the CDI and that is in turn earthed

[Warkton Tornado No.1]

You will find that it will still fire with that earth missing with electronic ignition.

If the white from the stator is connected to the CDI and that is in turn earthed

The white from the stator to the CDI serves to earth it allowing a spark to be generated even with the CDI hanging in fresh air. Obviously, 'best practice' means the earth lead should be attached, but it is not an absolute necessity. (I always fit it, but I also mount the things with AV mounts as well, as should be the case with such electronics, even if one of the purpose made brackets is on the bike)

I reminded myself of this recently as only one out of my four working CDI's 'works' with a brand new AFR lightweight ignition & stator. They all sparked but only one CDI would allow the engine to run.

The owner was going to have a moan @ AF as the CDI supplied does not allow the ignition kit to work.

I like what AF do a lot. They have been creative & they don't claim to have invented the wheel, like one particular 'Legend in his own Lunchtime' we can all surely think of......

But AF really should have this particular kit fully sorted by now

[Granty]

You know what it is.... it's the stator. Classic fault.

And the prize goes to .............
New BGM stator in, 1st shake down ride yesterday, problem solved. Year's I've been messing about with this.

[St George]

Which model BGM Stator did you get please. Glad it's sorted.

[CHRIS in MARGATE]

Well done. That will be 21 guineas.
Always good to hear the outcome whatever the reason.

[Granty]

Which model BGM Stator did you get please. Glad it's sorted.

BGM AC Version 4 Buddy - G