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Lambretta advance and retard

Posted: Tue Mar 05, 2013 12:23 am
by Bren
Any one have ideas why an Augusto and an M-tech would not retard fully?

Have tried both on my ts1 with different stators and CDI's and they both will not fully retard. For example the M-tech set at 19 degrees BTDC will only retard to 17/16 degrees on its full retard setting.

I have also tried different flywheels :?:

Re: Lambretta advance and retard

Posted: Tue Mar 05, 2013 2:59 am
by corrado
Aren't you supposed to set the M Tech at 25 degrees and then choose the switch position to suit?

http://www.lambrettaspares.com/info/fit ... s+184.html

Re: Lambretta advance and retard

Posted: Tue Mar 05, 2013 8:46 am
by fishi
you have tried this, works perfecly:


http://www.lambretta-teile.de/CDI-Zuend ... etta-Vespa

Re: Lambretta advance and retard

Posted: Tue Mar 05, 2013 10:29 am
by Minority
Bren wrote:Any one have ideas why an Augusto and an M-tech would not retard fully?

Have tried both on my ts1 with different stators and CDI's and they both will not fully retard. For example the M-tech set at 19 degrees BTDC will only retard to 17/16 degrees on its full retard setting.

I have also tried different flywheels :?:
That's really interesting. I have an Mtech unit that I think is doing exactly the same!

I fitted it after a rebuild and seemed to be getting minimal retardation even on the maximum setting. As I was running in, I set it to a conservative initial advance and was going to revisit the ignition timing scenario with a few more miles on the clock.

I must admit I haven't asked Martin at Chiselspeed about it which I should have maybe initially, my bad! Maybe both you and I should drop him a line.

My setup is basically a SIL 12v electronic ignition which has given me no problems.

Re: Lambretta advance and retard

Posted: Tue Mar 05, 2013 7:05 pm
by giankx
My mtech did the same too, only retarded from 23 to 17 in the fully retard position.
I initially tought it was due to a bad earth contact, but the unit didn't worked well even on other earth points.
Now i've bought another unit with 2 earth wires. Hope it works!
I have a bgm stator with a Beedspeed midweight flywheel and blue Ducati CDI.

Re: Lambretta advance and retard

Posted: Tue Mar 05, 2013 7:30 pm
by Bren
I made sure earth is good to frame and engine. I wondered if it could be the loom earthing out or the ignition switch however this wouldn't explain the consistent movement. It just will not retard past 3 or 4 degrees. Augusto was the same so I am guessing its something on the bike!!

Re: Lambretta advance and retard

Posted: Tue Mar 05, 2013 8:24 pm
by jason frost
Have you run it with the green from the loom unplugged from the coil ?

Re: Lambretta advance and retard

Posted: Tue Mar 05, 2013 8:55 pm
by Bren
Jason, Yes we did that when fitting it so that's the ignition eliminated!

Re: Lambretta advance and retard

Posted: Tue Mar 05, 2013 9:04 pm
by giankx
Which stators, flywheel and CDI did you tried with?

Re: Lambretta advance and retard

Posted: Tue Mar 05, 2013 11:18 pm
by Bren
New BGM stator and a new sil one form Scooter restorations. Two different Ducati CDI's, An elmec flywheel and my original Ducati electronic flywheel. Mixed and matched for my other bike..