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no spark. cut out whilst driving.
Posted: Wed May 20, 2015 10:53 pm
by olliewtf
as above, cut out whilst overtaking, that was fun. no spark. all connections still tight. running old vespa conversion, with scootopia regulator and reedspeed cdi. Lights still working (ofcourse) disconnected green at headset to rule out cut out, still nothing. took green from cdi put me finger on it and got a little shock, so presuming thats stator ruled out. gonna try new ht lead tomorrow, tried different plugs, took cap off and put me finger on lead and nothing. after that im thinking its the cdi which is annoying as i bought it off of ebay, so doubt reedspeed will do anything.
Will try and swap cdi tomorrow if i can get hold of one.
Is there anything else i can try or look out for before spending money?
also, new loom and good earths....
help!
Re: no spark. cut out whilst driving.
Posted: Wed May 20, 2015 11:11 pm
by Norrie Bodge
If the CDI was a cheepo off ebay m8?
id suspect that could be your issue?
IMO always best buying Ducati CDI units
Re: no spark. cut out whilst driving.
Posted: Wed May 20, 2015 11:21 pm
by olliewtf
as stated its a reedspeed adjustable cdi (advance retard). ta
Re: no spark. cut out whilst driving.
Posted: Thu May 21, 2015 6:14 am
by Toddy
I would still test your stator with a multimeter , it may not show on the readings but sounds like staor breaking down when warm / under load
Re: no spark. cut out whilst driving.
Posted: Thu May 21, 2015 7:38 am
by Daggs
Your fault description suggest CDi to me.
Re: no spark. cut out whilst driving.
Posted: Thu May 21, 2015 9:47 am
by olliewtf
cheers all. stator or cdi, i will find out inabit. not convinced its the stator breaking down under load as it has been fine on many a longer run over the last 2 months, and still no spark later on when all was cool. will test it before changing cdi. Does anyone think i have a leg to stand on with reedspeed? It is their own product made by them. I have no proof of purchase but it is unmistakeably their product and im sure they will be interested that one of their units has failed. I will call them anyway once im certain its the cdi, but i think i may be told to f@@k off...
also for anyone else with this problem, this is the best guide i have found to diagnose this fault:
http://www.afrayspeed.co.uk/index.php?page=Per_nospark
apart from at the bottom where ti says take it to a dealer!

Re: no spark. cut out whilst driving.
Posted: Thu May 21, 2015 2:14 pm
by rosscla
You can only ask
Re: no spark. cut out whilst driving.
Posted: Thu May 21, 2015 8:56 pm
by coaster
Get hold of a multimeter and check the resistance readings from the green and red stator wires to earth and also that there is minimal resistance in the white earth wire when measured to earth. CDI wise, you can but Indian CDI's off ebay for as £5.99 which are perfectly good for using as a temporary substitute when you want to eliminate the CDI from your investigations....also good as a get you home spare. I have one wrapped in bubble wrap in the toolbox. Thyis highlights a possible downside to the Readspeed CDI as with the other units on the market, they are separate units and can be by-passed quickly as a check.
Re: no spark. cut out whilst driving.
Posted: Thu May 21, 2015 9:52 pm
by olliewtf
turns out it was the p1551ing stator. bit miffed as i bought a cdi as id convinced myself it was that. oh well, at least i have a spare!
in terms of that being a downside, if you bypass a retard unit on most units it will leave your timing advanced, whereas the readspeed unit advances after tickover then retards again. i will be positive about it until it proves me wrong!
i have now rounded off the flywheel nut and am rather pissed off. going to order a stator from sr, then repair mine so i have spares for everything.
i do love my lambretta.
Re: no spark. cut out whilst driving.
Posted: Fri May 22, 2015 9:32 am
by HxPaul
olliewtf wrote:turns out it was the p1551ing stator. bit miffed as i bought a cdi as id convinced myself it was that. oh well, at least i have a spare!
in terms of that being a downside, if you bypass a retard unit on most units it will leave your timing advanced, whereas the readspeed unit advances after tickover then retards again. i will be positive about it until it proves me wrong!
i have now rounded off the flywheel nut and am rather pissed off. going to order a stator from sr, then repair mine so i have spares for everything.
i do love my lambretta.
You can get a walldrive 17mm socket that grips the flats of the flywheel nut.