Ah crap. what did I do wrong here

Alright, you guys saw my post about my coil install.

I started the bike today. It fires up quick, but it's running awful. It's puffing black smoke out of the exhaust and running really rough. To be honest, it sounds like it's only firing every other revolution.

It ran for about 30 seconds and shut off...I'm guessing the plugs got fouled out.

If I screwed up something when I changed the points, would it cause this? Or could it be something with the coil install?

Getting really frustrated with this thing...especially because the starter clutch that I just put new springs in is not working any better than it was before....argh

edit: OK, I just pulled the cover off the points. It looked like the actuator had backed off, so I readjusted it to a .3 mm gap and made sure everything was tight. But, I started it again and it's still running the same. Took the cover off and it hasn't backed off again. So now I dunno.

Hi I'm no expert but my guess is when you did the points you reversed the cam for the points take it out and turn it 180 degrees and see if the bike starts.

What do you mean reversed the cam?

I've done timing belts and whatnot on cars before and I know you can get them "180 degrees out" but I guess I don't really see how you could do that with this setup. Also I've never messed with points before.

"Re:Ah crap. what did I do wrong here"

The title made me laugh :laugh:.

As Spudbuddy said;
The rotor for the points can go on two ways on the four cylinder bikes. If it can go on two ways on the twin as well, there is a chance you are firing before BDC instead of TDC. That would make the bike barely run and backfire through the exhaust I would guess.

This would only happen if you dissasembled the advancer mechanism and put the points cam on backwards.

Yep, the 750 twin points cam/rotor will go back on 180 degrees out, I don't know if there is a twin owner who has disassembled the advancer and not put it back on wrong at least once.

Never seen one run that way though, usually just shoots fire out of the carbs

Personally, I think the timing is retarded.

Well I didn't disassemble the advancer...I just swapped out the points and condenser, and put everything back on the same way.

How can I check to see if the timing is in the ballpark with the engine not running? I don't think I could get it to run long enough to hook up a timing light and do all that stuff.

Static timing is how you do it with a non-running motor. The following link has good instruction on how to do it, although it's written for cars, bikes work the same.

custompistols.com/cars/articles/ignition_timing.htm

I suppose a couple questions I should have asked before I even started messing with this...

First off, which cylinder is the timing set off of on a twin? Left or right?

When you're turning the stator to change the timing...is it clockwise to advance timing and counter clockwise to retard it, or is it the other way around? The bike fired right up the first time I went to work on it today (as it has been doing, but running really rough and blowing black smoke), and it stayed running long enough for me to shoot it with the timing light. The "F" mark was wayyy to the right of the timing pointer. Dunno if that means advanced or retarded since this thing has no marks.

Also how the hell are you supposed to get the advancer off? My maintenance manual says to grip the 17mm hex so the shaft doesn't turn, and loosen the smaller (13mm) hex. However when you put a 17mm wrench on the larger hex you can't even adequately get a wrench on the 13mm hex. I wanted to at least take the advancer off and clean it up and lube it but i can't even do that.

I feel like this thing hates me.

On top of all that, some previous idiot owner rounded out half the screws on...well, everything on this bike, which makes working on stuff just all kinds of fun.

Sears sell some thin wrenches called "tappet wrenches" that are about 1/2 the thicness of regular wrenches I believe they come also in metric sizes.

And if you're going to sears get a set of stud and bolt removal tools(not ez-outs) one set used used with a drill in reverse to help remove stubborn fasteners.

Well I have three sets of metric wrenches so maybe I'll just grind down one of the 17mm wrenches from one of the cheaper sets.


No answer to my questions about timing? Anyone?