ignition advance on SEM

Taffy · Oct 16, 2008

did a '03 501 yesterday.

on start up with the mark in the middle it was at 5D BTDC. it then, on the touch of the throttle shot out of sight to my left (advancing) to something like 45d BTDC. it then settled back to about 26d BTDC at far higher revs and also had that line to the left and line to the right look which means it was doing both at the same time!

when decelerating the line would come back in to view from the right????????????????

anyway, i advanced it twice. the idle degrees went to 6d BTDC and then oddly enough to 4dBTDC. the advance was similar pattern to that mentioned and the full advacnce was still only 28d.

for the first two runs i had glowing headers at low to mediumn revs. only on the furthest advance i ran did it stop.

so i wnet back and settled on just 1mm of advacne (as seen at the M5 screws).

i'd laugh if it wsn't serious!

regards

Taffy

sparks · Oct 16, 2008

Taffy said:
did a '03 501 yesterday.

on start up with the mark in the middle it was at 5D BTDC. it then, on the touch of the throttle shot out of sight to my left (advancing) to something like 45d BTDC. it then settled back to about 26d BTDC at far higher revs and also had that line to the left and line to the right look which means it was doing both at the same time!

when decelerating the line would come back in to view from the right????????????????

anyway, i advanced it twice. the idle degrees went to 6d BTDC and then oddly enough to 4dBTDC. the advance was similar pattern to that mentioned and the full advacnce was still only 28d.

for the first two runs i had glowing headers at low to mediumn revs. only on the furthest advance i ran did it stop.

so i wnet back and settled on just 1mm of advacne (as seen at the M5 screws).

i'd laugh if it wsn't serious!

regards

Taffy

Well Taffy I have to say I don't why it is doing this, all the advance is done in the box nothing to do with the stator.
The part number you should have for the cdi 501 is 250-293-01. Have you got good suppression of the plug cap, if not it can cause all sorts of problems.

I will see if I have a good cdi and I'll send it across so you can do back to back testing.
Like I said before I have never experienced any of bazaar results you are getting, and I don't know how many ignitions I have tested, they either do as they should or not spark at all.
Your strobe couldn't be faulty by any chance.

Regards

Sparks.

Taffy · Oct 16, 2008

i don't think we can blame the strobe because every run on a particular bike is consistantly the same. it's the bikes that change.

i'm kinda goading folk to have a look at their own and maybe something will come out in the wash you know?

tell me more about what you think the cap does?

i know that the least resistant used to have .5ohm resistance. hope i've got that right? some use hard plastic (or ceramic?) others the floppy rubber, sometimes red, sometimes black. this one had a floppy rubber black on it/

i guess the first question is "what was the OEM?"

BTW, i haven't had an ignition go to 'double' on me for ages? so how come? all you'll get are questions from me steve, i'm dopie with electrics!

regards

Taffy

sparks · Oct 17, 2008

Taffy said:
i don't think we can blame the strobe because every run on a particular bike is consistantly the same. it's the bikes that change.

i'm kinda goading folk to have a look at their own and maybe something will come out in the wash you know?

tell me more about what you think the cap does?

i know that the least resistant used to have .5ohm resistance. hope i've got that right? some use hard plastic (or ceramic?) others the floppy rubber, sometimes red, sometimes black. this one had a floppy rubber black on it/

i guess the first question is "what was the OEM?"

BTW, i haven't had an ignition go to 'double' on me for ages? so how come? all you'll get are questions from me steve, i'm dopie with electrics!

regards

Taffy

Hi Taffy,

Yes getting people to strobe there ignitions would be a good idea, would be interesting to read the results, especially for me.

The resistor cap is there to do one thing stop interference (harmonics), many years ago before the electronic ignition the suppressed cap was to stop car engines interfering with televisions etc, but now we are in the electronic world these harmonics will run rife in electronic equipment especially the ignition box, but having had one of these boxes apart the main components are well shielded.
It's the same with radio transmiters certain circuits are shrouded in steel boxes to stop unwanted harmonics getting in.

The general resistance of a HT cap is 5000 Ohms (5K).

Regards

Steve.

Taffy · May 19, 2009

RE: Re: RE: Re: RE: ignition advance on SEM

did a sidecarx'er today.

funny or what? ok to be fair it's a heath robinson of an ignition system but everything appears to be ok.

anyway, i noted the line midway across the window and decided to get it running but it just wouldn't start so i advanced it 1mm and sure enough it started. lovely jovely!

set the strobe on it hoping for 6d of advance at idle but i got 10, full advance was 38 so i thought; 'no problem, back/****** 1mm and that'll be good.

suitably ******** the new ignition timing was 11 at tickover and 39 at max.

so i went another1mm and this time the line is 1-2mm right of centre which i haven't seen for years....

12d advance at idle and 42d at full.

i have had this soooooo many times. magnusson/mats if you are still mates with "conny", please ask him WTF?

in the end i stopped in the middle frightened to go either way

to the left and i might be over advancing it and to the right where apparently i WAS over advancing it!

regards

Taffy

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