no spark on one cylinder mid 70's doo 440 everest

[Bull Elk]

headed down to norcal in a week or so and my dad wants to help him out with one of the 2 sleds we got a long time ago. my brother was riding it a few years ago and lost spark to one cylinder. IIRC i tried swapping the coils and had no luck with the side that was bad. do these old sleds have points or a stator or should i look at something else? any help is greatly appreciated.

thanks ryan

 

[tlb]

no spark

look at the polar fire ignition box mounted right behind carb on engine block

 

[brushwolf]

Doo used points later than most so I would look there first. Doo also used an alternate firing system on some machines back then so it stands to reason that one side may fire and the other may not.

If you have points in your machine the all it takes is a little grease or carbin in a point set to cause a no spark condition. Take a clean white piece of thick paper ( a business card cut into 1/4" wide strips works really well) dip it in laquer thinner and drag it throug the points thru the window in the flywheel. Note: if you don't have a window in the flywheel it is likely that you also do not have points.

Try this first as it is a cheap and simple place to start.

 

[brushwolf]

p.s. repeat this until the paper comes out clean.