Page 1 of 1

help

PostPosted: Tue Jul 15, 2014 5:21 pm
by matt horton
Hello, Ive just changed the points on my li150(175) I took off the stator which had been marked on the magneto housing, reassembled using same marks, good spark but would not start, checked and remarked tdc and 19degrees btdc mark, used rollup paper to find opening point the original marks however do not match up, even when I turn the stator plate the most i can get is a firing point 26 degrees before tdc, the point at which the points are opening is also not to easy locate as points are moving out of view of the slots on the flywheel, have a feeling missing something really basic but god knows what, any help would be much appreciated

Re: help

PostPosted: Tue Jul 15, 2014 5:31 pm
by coaster
Is the woodruff key still in place?

Re: help

PostPosted: Tue Jul 15, 2014 5:51 pm
by matt horton
Yes Key is still in place, I had the flywheel off initally because two of the grub screws holding magnets in place had come out and prevented the bike being kicked over, electrics aren't my strong point and Im at a loss to know where I'm going wrong.

Re: help

PostPosted: Tue Jul 15, 2014 6:05 pm
by Wack
Set points at 15 thou with piston at TDC. If the gap is incorrectly set the timing alters and explains why your stator no longer lined up. If I remember rightly , too big a gap - timing advanced. Too small - retarded. A fag paper is ok but better to use a battery and bulb on the green stator wire and watch when the bulb dims as the points open.

Re: help

PostPosted: Tue Jul 15, 2014 6:11 pm
by MK Monty
am I missing something here but you have replaced the points, so the cam follower will be unworn eg longer. So your opening point and timing will net be in the same place. long time since I did points so shoot me if Im wrong

Re: help

PostPosted: Tue Jul 15, 2014 6:23 pm
by matt horton
MK Monty wrote:am I missing something here but you have replaced the points, so the cam follower will be unworn eg longer. So your opening point and timing will net be in the same place. long time since I did points so shoot me if Im wrong



This did enter my mind but putting side by side they are identical

Thanks

Matt

Re: help

PostPosted: Tue Jul 15, 2014 6:32 pm
by matt horton
Wack wrote:Set points at 15 thou with piston at TDC. If the gap is incorrectly set the timing alters and explains why your stator no longer lined up. If I remember rightly , too big a gap - timing advanced. Too small - retarded. A fag paper is ok but better to use a battery and bulb on the green stator wire and watch when the bulb dims as the points open.


Hello yes gap is set to 0.4mm however when points loose contact firing point is 30 degrees btdc with stator in same position as it was previously and even if i turn stator the best i can get is around 25

Matt

Re: help

PostPosted: Wed Jul 16, 2014 6:12 pm
by matt horton
Anyone got any ideas ?

Re: help

PostPosted: Wed Jul 16, 2014 6:24 pm
by Wack
Are you sure they are proper Lambretta points as some Vespa ones fit but won't work correctly? Why not clean the old points up to retry and eliminate the new ones as the problem?

Re: help

PostPosted: Wed Jul 16, 2014 6:30 pm
by matt horton
Wack wrote:Are you sure they are proper Lambretta points as some Vespa ones fit but won't work correctly? Why not clean the old points up to retry and eliminate the new ones as the problem?



I'll double check but just bought from scooter restorations, I know for cerain the cam heel is identical not sure about base

Re: help

PostPosted: Wed Jul 16, 2014 9:13 pm
by Nigel. S
I also changed points the other night, from SR.

Turned flywheel until points at their widest opening then set 0.4mm gap. (pretty much as per the book) As you say, not easy to see but laying on the floor with a torch was ok. mine's a 3 slot flywheel. When I stripped mine originally the stator was at the extreme end of slots, from memory I think I moved it back just beyond centre closer to the other extreme of slots when I rebuilt to achieve 19 degs.

Are the original marks yours?

Re: help

PostPosted: Fri Jul 25, 2014 8:55 pm
by Ivor the engine
Hi all,

What ignition do you have, Ducati or Dansi? The Points for these two are different. Ensure you have the correct make for your ignition.
Keep us posted.
Cheers,

Ivor.