Help setting points in the "F" range

[cmyoch]

Guess what? I left off my top motor mount so when I did my initial run to seat the rings, I could easily retorque the head bolts. Guess what is bolted to that motor mount? I wondered why there was a double plug at the coils but only one wire available to plug into them.

Hopefully this solves my issue!! I'll be bolting the mount on later tonight.

 

[5twins]

So that's what happens when you run without the condensers, lol.

 

[cmyoch]

No top mount meant that I didn't even have my condensers installed. I installed them and rechecked my timing statically. Both sides are firing right at the "F" which is dead center of the range. The bike started and idled with minimum hesitation. I assume a tweak of the mixture screws will smooth things out. I have yet to purchase a timing light and plan to do so. When using the strobe to set the timing, what exactly am I looking for?

1. Both cylinders firing at exactly the same point?
2. Cylinders firing dead center at that F mark?
3. Firing more towards the advance side of the range?

I believe I am at the fine tuning stage of this rebuild. That is after I put on a few initial miles to seat the rings.

BTW, thanks guys for mentioning the condensers. You probed and asked enough questions to help me find the issue. I doubt I would have found that right away and would have chased this issue for quite some time, never finding a solution. I greatly appreciate it.

 

[5twins]

1. Yes
2. Not necessarily. Where the idle timing ends up will depend on where you have the advance timing. Make sure the advance timing does not go past it's slash mark (to the left of it). If that means placing the idle timing more towards the right side (retarded) of it's range, then so be it.
3. See above

You have to understand a little about what your advance unit does and how it operates. It is built to advance the timing a set number of degrees (when new), something like 25. That means that where ever you have the idle timing set, full advance will be 25° from there. Like I said, this is when the unit is new. As it gets old and wear sets in, the amount it turns and advances grows. Instead of changing your timing by 25°, it will move it like 26°, 27°, eventually maybe even more. That 3° or 4° range for the idle timing allows you to compensate for this wear for a while. Eventually, the wear will become too great and you won't be able to get both advanced and idle timing at their specs anymore. Then you need a new advance unit.

 

[cmyoch]

Those instructions are easy to understand, I get it. Thanks a ton! I'll need to pick up a timing light. Are the ones at Harbor Freight good enough? It will get minimal use.

 

[5twins]

I've heard the HF lights work OK but I've never tried one.

 

[1974jh5]

Yeah, a bad or missing condenser will drive you nuts and glad you found it. The HF timing lights are OK for light duty use.

Back in da day, we used to check timing this way: turn the engine over till the points are open. Slide a piece of thin cellophane from a cigarette pack (anything thicker or softer won't work, some CD's etc have that thin stuff too though) between them, turn the engine over till the points trap the cellophane. Now pull gently on the cellophane, turn the engine over by hand and watch the timing marks. When the points let go of the cellophane, there's your firing point.

Something else which will make an engine run crappy at low RPM is valves too tight. I run mine a smidge (.001-.002) loose, as valves wear the setting will close up.

 

[5twins]

If you insist on keeping points then I highly recommend you acquire a dwell meter to set the gaps. It is the most accurate method and really the only accurate way to set used ones.

 

[XSLeo]

My old timing light got so it would only read at idle and a bit above. The clamp part where you hook it to the plug wire has had a rough life, but then again I got it from a pawn shop in the 70's.
I picked up Harbor Freights item #03343 timing light. It works well. Not quite as bright as my old one.
The wires to the battery clips and to the clamp are fairly light. With a little care they should hold up ok. They won't take touching the exhaust pipe even a little bit.
Leo

 

[cmyoch]

Eventually I will upgrade to electronic ignition when my budget permits. I'm just pleased as pie to have the bike running and back on the road. Most likely, I'll make that upgrade this winter. I read some reviews that the HF lights are a little dim but does the job. I may spend a few bucks more for a nicer one from say Sears just to have in my arsenal of tools.

 

[5twins]

I've had a Craftsman one for years. Watch for a good sale and you can get it cheap. They recently had all their clicker torque wrenches on sale for half price. I bought two more as back-ups/replacements for the ones I already have.

 

[cmyoch]

I remember my father having a Sears timing kit which were items (light, dwell meter, etc) in individual boxes neatly packaged into one nice big box. I wish I could find something like that. I plan on converting the XS to electronic eventually as well as my GL1000 and finally my old Camaro.

 

[5twins]

I still have points on a couple of my old Beemers and I tune a lot of points equipped 650s for guys. I need the light and the dwell meter. Even when you convert to electronic, you will need the timing light to initially set it up. And then in the future, it's a good idea to check your setting occasionally. Electronic ignitions aren't supposed to change their setting but sometimes they do a little after new parts all settle in.