Right.
I established a TDC with the positive stop method.
Gapped my points as prescribed by sticky, and marked off 19 degree BTDC.
Wouldn`t start.
Closed the gap to 025 and it fires up first time.
Strobed the feker, and it was firing at around 25 degrees btdc, so moved the stator clockwise and it started but was backfireing.
So I then moved the stator plate anti-clockwise a touch and held the revs to around 5000rpm. from around 4000rpm the firing mark was flickering between 18 and 28 degrees.
I take it that it means that my points are buggerd/worn, or is there another explination?
Points Timing
-
bristolmod
- registered user
- Posts: 1741
- Joined: Wed Jan 07, 2009 8:42 am
- Main scooter: Lambretta TV175 S3- what else!
- Location: Bali-Hai bar, Locarno Ballroom Bristol, 1967!- mines a Brown Split!!
- Contact:
whats the points gap measured in? Metric or Imperial?
The old WSM recommends "15 thou" (Imperial) although its not laid down in concrete- you can alter the gap slightly to ensure the timing is correct.
Chris
The old WSM recommends "15 thou" (Imperial) although its not laid down in concrete- you can alter the gap slightly to ensure the timing is correct.
Chris
Scootering since 1968.
-
Adam_Winstone
- registered user
- Posts: 1693
- Joined: Tue Jan 31, 2012 8:54 pm
- Main scooter: Lambretta GP
- Contact:
It does suggest that something is not right... but there are a number of factors that could give you such issues. Missing/backfiring is often a symptom of the condenser breaking down but it might be something as simple as contamination of the points. If the points are new, they often come with a light coating to protect the faces and it is very common for an over-oiled felt pad to discharge oil, which can find its way onto the points faces and contaminate them. Points bounce would not be an issue at those revs, unless the spring is damaged.
First thing to do with points is to cut a thin strip of very fine wet and dry sandpaper and use this to clean the points faces. You do this by looking in through the flywheel holes and rotating the flywheel clockwise until you see the points gap open, then slip the strip of wet and dry in between the open points, then rotate the flywheel anti-clockwise until it grips onto the wet and dry (W&D), then pull the W&D out towards you so that it pulls flat between the points. Do this a number of times until you are happy that both points faces are clean. Note, you are not trying to sand then down... just give them a light clean to remove any crap that might be in there.
If the spark will not jump a normal spec/distance points gap then it might also indicate the flywheel magnetism is down... but I would look to ensure that all is well with the stator first.
Points take a bit of getting used to but they are pretty simple when you get the hang of it.
Adam
First thing to do with points is to cut a thin strip of very fine wet and dry sandpaper and use this to clean the points faces. You do this by looking in through the flywheel holes and rotating the flywheel clockwise until you see the points gap open, then slip the strip of wet and dry in between the open points, then rotate the flywheel anti-clockwise until it grips onto the wet and dry (W&D), then pull the W&D out towards you so that it pulls flat between the points. Do this a number of times until you are happy that both points faces are clean. Note, you are not trying to sand then down... just give them a light clean to remove any crap that might be in there.
If the spark will not jump a normal spec/distance points gap then it might also indicate the flywheel magnetism is down... but I would look to ensure that all is well with the stator first.
Points take a bit of getting used to but they are pretty simple when you get the hang of it.
Adam
-
Fux
- registered user
- Posts: 501
- Joined: Mon Aug 17, 2009 9:42 pm
- Main scooter: li150 S2
- Location: Norway
- Contact:
Ok, thanks I`ll give the point a clean and try again.
I tried to advance my timing again by moving the stator and it wouldn`t start at all.
Double checked my TDC and that is bang on. Moved the stator back to where it was and it fired right up. I`m a bit worried about using it at 25 degrees, so I`ll investigate further.
I tried to advance my timing again by moving the stator and it wouldn`t start at all.
Double checked my TDC and that is bang on. Moved the stator back to where it was and it fired right up. I`m a bit worried about using it at 25 degrees, so I`ll investigate further.