Author Topic: Screw securing contact breaker body bent, could this cause misfire ?  (Read 1091 times)

Offline chicago

  • Valued Contributor
  • ****
  • Join Date: Apr 2012
  • Posts: 271
  • Karma: 6
  • North west manchester,
Hi folks, I've had a problem for ages with the left hand/drive side spark plug fouling with petrol from cold, when the bike warms a little (after say 1-2 minutes) the plug seems to sort it's self out and the bike then runs on both cylinders, although it still miss fires a little, I have tried most things ( well the stuff I can afford) new pickups, new good quality pickup brushes, new leads, new caps, new plugs, new magneto earth brush, new contact breaker body brush, new contact breaker points, ect. Well today after a brief ride I had another look at the points ect and decided to take the points body out again. I put the centre bolt from the middle of the points body in a drill and found it was bent, see video...
http://youtu.be/mYrA1lW-TNs
I could be barking up the wrong tree here but could this be the cause for the fouling from cold and misfire ?.
Cheers in advance fella's, chicago
Location: north west madchester.
Preferred location: somewhere warm and dry.
Bike: 1953 plunger Longstroke engine.

Offline KenF

  • A's Best Friend
  • ***
  • Join Date: Feb 2012
  • Posts: 36
  • Karma: 6
I doubt it, but on the other hand oddities in the contact breaker assembly can have effects which it's difficult to explain.

You could of course try a different screw. If you don't have a spare (and I know I'll be accused of heresy for saying this), you could make do, just for a trial, with an M4 x 40mm screw that you might be able to get from B&Q or Screwfix. If you've got a cut-out brush fitted, then take it out temporarily so that the screw head doesn't grind the brush away to nothing in a jiffy.

Cheers,

Ken
www.brightsparkmagnetos.com



Online bsa-bill

  • Wise & Enlightened
  • *
  • Join Date: Mar 2006
  • Posts: 5440
  • Karma: 62
Not a lot of bend on it Chicago tbh.
You've changed a lot of stuff tho, I'd be inclined to think something new is to blame, I'd start at the plugs and work back ( you may not have to go much further)
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline chicago

  • Valued Contributor
  • ****
  • Join Date: Apr 2012
  • Posts: 271
  • Karma: 6
  • North west manchester,
Cheers bill and kenf, shame I thought I might have cracked it, I'm going to see Brian at lightning spares today and see about some new plugs and a new screw, think I might try some ngk plugs this time though as I've read on here about people having trouble with champions, there again there's also people who've had trouble with ngk plugs but as I've not tried ngk yet I think I'll give them a go. When I've changed the plugs in the past the problem does go but returns after a short while, I'll update my post if the ngk do the trick. All the best fella's, chicago
Location: north west madchester.
Preferred location: somewhere warm and dry.
Bike: 1953 plunger Longstroke engine.

Offline chicago

  • Valued Contributor
  • ****
  • Join Date: Apr 2012
  • Posts: 271
  • Karma: 6
  • North west manchester,
Once again cheers bill and kenf, just by way of a update, going to order some new ngk plugs from the green spark plug company today, and Brian at lightning spares is ordering me a new points body securing screw. Last night I went over a few things again and decided to try running the bike with the advance/retard lever pulled almost all the way back and it does seem to run a bit better, a bit quicker and sound a bit less rattlely and tick over more evenly with the ignition set retarded. So timing could be set to far advanced maybe. I'm going to have to get my head around learning how to set the timing I think.
I do remember when I had the timing side cover off when I was doing the dynamo belt conversion I did check to see if the nut that holds the fibre timing gear on was tight, when I tried tightening it it did move/tighten a little, I don't know if the magneto shaft has a keyway on it but if it hasn't then I might have upset the timing then ?. What do you think ?. All the best fella's, chicago
Location: north west madchester.
Preferred location: somewhere warm and dry.
Bike: 1953 plunger Longstroke engine.

Online metalflake11

  • Resident Legend
  • *****
  • Join Date: Aug 2012
  • Posts: 579
  • Karma: 9
Hello Chicago, set the pistons at the correct b.t.d.c. for your bike. Then put a fag paper between the points, if the timing is ok they will grip the paper at retard and let go at fully advanced.
                                     mf
England N.W
1960 A10
England

Online bsa-bill

  • Wise & Enlightened
  • *
  • Join Date: Mar 2006
  • Posts: 5440
  • Karma: 62
Quote
I don't know if the magneto shaft has a keyway on it

taper only so you can move it to set timing. which should be set so the points just open at the btdc setting with magneto at full advance as mf has said, does your bike have automatic advance and retard unit or is it handlebar lever ( not familiar with long stroke) , either way full advance (auto unit jam the bob weights out with something big enough you wont forget it's there)
Would someone like to correct me if longstroke is different
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline chicago

  • Valued Contributor
  • ****
  • Join Date: Apr 2012
  • Posts: 271
  • Karma: 6
  • North west manchester,
Hello Chicago, set the pistons at the correct b.t.d.c. for your bike. Then put a fag paper between the points, if the timing is ok they will grip the paper at retard and let go at fully advanced.
                                     mf
Hi metalflake, cheers for the help and advice fella,  but I feel like it might be a bit wasted on me at this stage until I can study all the ins and outs of setting the timing because at the risk of making myself seem like a complete and utter dumbo (I prob will any way, and won't be the first time *red*), all I really understood was the bit about the fag paper, the things I'm not 100% sure about is, how do you establish that you have attained so many degree's before tdc, how many degree's btdc for my bike, how would I stop the magneto shaft from moving/rotating when I went to tighten the nut up, I'll have to burn some midnight oil tonight on the forum cramming it all in. All the best metalflake, Chicago.
Location: north west madchester.
Preferred location: somewhere warm and dry.
Bike: 1953 plunger Longstroke engine.

Offline chicago

  • Valued Contributor
  • ****
  • Join Date: Apr 2012
  • Posts: 271
  • Karma: 6
  • North west manchester,
Hi there bill,
Quote
I don't know if the magneto shaft has a keyway on it

taper only so you can move it to set timing.
Bugger, that means I've prob disturb the timing with my half witted attempt to tighten the nut then.

"does your bike have automatic advance and retard unit or is it handlebar lever"
It has a handlebar lever, but it's funny because I'm sure the fibre timing wheel looks like the type that's supposed to have an auto advance retard unit on it ?. I'll try and find a photo of it and add it to this post.

What do you think?. Cheers bill, take it easy fella, chicago

Location: north west madchester.
Preferred location: somewhere warm and dry.
Bike: 1953 plunger Longstroke engine.

Offline gavinoz

  • A's Best Friend
  • ***
  • Join Date: Apr 2012
  • Posts: 140
  • Karma: 3
  • Dogs & Sheep hate smokers worse than Hondas.
Hi Chicago,

Yourr photo is manual, (Automatic has a centrifugal arrangement on top of the fibrewheel.
Th groove in the other steel pinion i think where your arrow is is for valve timing not ignition,
good luck, gav
Rigid A7S, 57 A10 in pieces
Australia

Offline chicago

  • Valued Contributor
  • ****
  • Join Date: Apr 2012
  • Posts: 271
  • Karma: 6
  • North west manchester,
Hi there gavinoz, cheers for the reply fella, I thought maybe with the fibre wheel being very thick and the middle nut being resessed it might have been the type that had the auto advance unit on it but somebody had taken it off, the photo was one that I used on a previous post about should there be a cork washer between the two arrows, I should have explained when I posted the photo, still got to cram up about setting timing, not had time yet. Cheers anyway for your help. All the best fella, chicago
Location: north west madchester.
Preferred location: somewhere warm and dry.
Bike: 1953 plunger Longstroke engine.