Help setting points in the "F" range

[cmyoch]

Correct me if I'm wrong, when setting points, Do you set the point of opening to the mark right at the left of the "F" or to the mark about a quarter inch before the "F"? I have my rebuilt engine installed and it's running but very poorly. I'm popping and it dies when I touch the throttle. My points gaps are set to spec and everything is fully functional. I know the issue lies in timing. I searched the forum and didn't really see any images of the marks showing where to set the opening of the points to. Can anyone help? Once I have her firing correctly, I'm on the home stretch.

Oh, and before anyone chimes in and says "Toss the points, go Pamco". That is not in the cards right now, that will happen later on. The budget is blown on this bike at this point so I have to make due with what I have.

Anyway, please let me know what I'm possibly missing. Thanks!

 

[hobodictator]

The F should be between two line. at idle you want it to be set between those two lines. I've read that its best to err on the side of retarded rather than advances if you can get it exact.

 

[cmyoch]

That's what I thought. I have them opening dead on at the line left of the "F" which would be on the retarded side. The bike runs but only at idle, pops periodically, and dies when I bump the throttle. I failed to mention that I have new advance springs from Mikes XS also. Maybe I'll move the points to open dead center in the "F" range.

 

[hobodictator]

to the left of the F would be advanced ever so slightly. But that should be close enough to where it would run. Make sure you check your tappet clearances as well as making sure the advance assembly isn't sticking. If its at normal idle rpms when it should be then that should be ok. I may be wrong on this, but i believe that it dosent start advancing till around 3k rpms. Other issues could also cause the popping and things you described such as vacuum leaks or a leaky exhaust gasket. But make sure to get the timing set correctly before setting that.

I'm sure others that know more than I do will chime in as well

 

[TwoManyXS1Bs]

If you set the idle timing to the right mark, it'll be a little retarded, forcing you to open the carb idle a little, maybe improving the fuel delivery.

Here's an old tech bulletin...

 

[XSLeo]

Very interesting bulletin, but it applies to the XS1, I think the op has a 78, so that won't really apply.
If you have both sets of points between the two marks each side of the "F" and it won't rev, I don't think it's timing. Have you thoroughly cleaned your carbs?
On your advancer, it starts advancing a bit above idle and is completely open at around 3000 rpms. Being springs it advances gradually. They can't hold the weights in until 3000 rpms then just open.
The tension of the spring controls when the weights start to move and when they reach fully open. To loose and it advances too soon and reaches full advance too soon. To tight and it won't advance soon enough and won't reach full until to late.
With a timing light you can watch the timing marks move as rpms increase. You can also use the timing light to watch the weights. Both the marks and weights should move smoothly. No jumping around.
Leo

 

[cmyoch]

I took a picture this morning and want you guys to clarify if I'm looking at this correctly. I set the static timing right at the "F" mark which I think is the middle of the range. Is this right? Setting it here, I'm idling but popping and barely running when I touch the throttle.

Should I retard or advance the timing?

 

[XSLeo]

Any where in that range is good. If you have it there and it isn't running well then it's not timing. Are the points clean?
Are the carbs clean?
Leo

 

[cmyoch]

It runs, just not that well and it's popping. Carbs were gone through to a "T" so I know they are clean. I set the air/fuel mixture screws at the factory spec.

Do you think I should move the timing more to the advance or retard side?

 

[5twins]

It may still be timing related. Maybe the advance is stuck in the retarded position and won't advance as you rev the bike up. Easy enough to check, just pop the advance cover off and insure the advance rod is turning freely, and snapping back smartly when released.

You're really not done setting the timing yet. You must check it at full advance as well as at idle. Where it falls at full advance will determine where between the "F" marks the idle timing needs to be. You want full advance to be at that unmarked slash to the far left in your pic, and not go beyond it. Set your timing to achieve that and at idle, it will be where it will be. Just as long as it is somewhere in the "F" range, it's good. If you can't achieve this then your advance unit is worn out, advancing too much.

 

[cmyoch]

I'll double check that tonight. I greased the advance rod very well when installing it and I bought new advance springs from Mikes XS. If the rod snaps back and appears to be functioning, what do you suggest I do next?

 

[5twins]

Well, I would verify timing with a timing light. Static timing isn't always that accurate. If that checks out then I would revisit the carbs. Your symptoms sound like a plugged pilot circuit. I know you said you cleaned the carbs but sometimes it takes several tries to get it right. Besides cleaning the pilot jet, you must make sure the passageways through the carb that feed the pilot mix in are clear. There are 4 tiny holes in the main bore that feed the pilot fuel/air mix in. They must all be clear .....

 

[cmyoch]

Worth a look. I will revisit the carbs this weekend.

 

[5twins]

This is the pilot inlet on the bottom of the carb body. This is how the fuel/air mix from the pilot jet goes through the carb body on it's way out those 4 holes. Spray some WD40 (to test) through this and watch the four holes in the main bore to see if it's getting through. Remove the mix screw and cover it's hole with a finger during this process. The screw tip will partially block that 4th hole. Also, if you use carb cleaner, it can destroy the o-ring on the mix screw.

As I said, test first with WD40. If blockage is found, use carb cleaner. A compressor and blow gun with a tapered rubber tip are best for blowing these passageways clear.

 

[cmyoch]

easy enough. I hit the carbs pretty good before installing but just like everything else, I could have easily missed that part.

 

[TwoManyXS1Bs]

Also check for arcing of the points...

 

[cmyoch]

I turned the lights out last night and there is strong arcing all over them. I cleaned the points after adjusting them.

 

[5twins]

Well, that could indicate your condensers are bad. That could cause the symptoms you're having as well.

 

[cmyoch]

blue arcing (looked like mini sparklers) between the points. I thought that was correct?

When I say sparklers, i mean that sparks are strictly between the points. They do not arc anywhere else.

 

[TwoManyXS1Bs]

Yeah, the sparkles should be only just barely visible, if at all, in the darkness. Check condensers, their plugins, good ground mount, ...etc.