We'll I thought I had her wired right

[xscorex]

I've never wired up a bike before. I think I have it all wired up right but when I kick her over all I get is a big fireball out the tailpipe like one big backfire. I also noticed a small jet of flame come out of my pipe at the head so it must not be seated well at all. Where should I start looking? It's not trying to turn over, it's like kick kick burp!

 

[TwoManyXS1Bs]

Maybe the ignition is crossed over. If you're running the stock 2-coil, 2-point setup, you could swap the points wires where they plug into the harness above the top motor mount, see if that helps...

 

[xscorex]

So it matters which points goes to which coil?

 

[TwoManyXS1Bs]

Oh, yeah! The upper/right point fires the right cylinder, the lower/left point (mounted on that sub-plate) fires the left cylinder.

It 'IS' possible to install the advance rod parts 180° out, so that relationship could be reversed, but that's the book setup anyway.

You may want to ensure that its setup correctly, by viewing the points cam when you rotate the engine. As you approach Compression TDC on the right cylinder, the upper/right point cam follower should be in the cutout/dip of the points cam (such that the point is closed and grounding the right coil). And, continuing to turn, the 'bump' in the cam should just start to open the upper/right point when you get into the idle fire zone (those two little hash marks just before TDC).

The spark occurs when the point 'breaks' contact to ground. That's how we time these things...

 

[xscorex]

Well if I just swapped plug boots from one side to the other, would that be an easy way to test it or am I missing something

 

[TwoManyXS1Bs]

Sure! That's the easiest test, assuming the plug leads are long enuff...

 

[xscorex]

Awesome. Ill try that out tonight. Hopefully its just that easy

 

[xscorex]

I just swapped the cables and she fired up! Thanks guys!!

 

[azman857]

I did the same thing to a 850cc Norton Commando. MAN it bellowed loud out those Dunstall replicas...

 

[gggGary]

Now put em back and swap the points leads at the coil/points/condenser junction. Nothing sweeter than when they come to life!