Help! Dyna S timing marks question

[t3rmin]

Ok I've thoroughly searched through the archives and can't seem to get any clarity on this...

I've got a Dyna S installed with my factory mechanical advance and the timing mark plate is still intact. With my adjustable timing light set to 0, the clip on #4 wire, and the bike "idling" at 3000 RPM (to make darn sure it's advanced all the way), which mark should line up with the mark on the plate? I've got these markings on the advance:
|T F| t

The little 't' is like a line with a short line on top. Below the "|T F|" is a "1-4".

If I line the mark on the plate up with the 't', then turn the timing light dial to 40 degrees, then I'm lined up with the 'T', which makes me think that's the one, since the book says the advance should go 40 degrees BTC.

But I've got even more confusing markings visible through the window when I clip onto the #3 wire which has me totally lost. It looks like:
345

...above a "2-3". I don't see any lines or t's like in the 1-4 section. How do I know whether I've got the 2-3 cyls timed right? The pickup coils are individually adjustable.

To sum it up: can somebody please state clearly what mark on the advance to line up with for the 1-4 cyls and what mark to line up with for the 2-3 cyls?

Thanks!!!

[t3rmin]

It's like 80 degrees today and I couldn't ride it to work 'cause I tried to re-adjust the timing and got stumped. *sniff* We don't have weather like this in September in WA State very often!

I'm pretty sure I got it wrong when I first installed the Dyna S. I've had crappy gas mileage, fouled plugs, and a noisy/vibrating motor at high RPM. I realized I was never really sure which mark to line up with *and* sorta forgot my timing light was adjustable, so who knows where that dial was set...

[t3rmin]

After further thought, I think I've deciphered the 1-4 timing marks. Let me know if I've got it right:
T = TDC
F = Fire without advance (10 deg BTDC according to my manual)
t = Fire with advance (40 deg BTDC according to my manual)

Now what about 2-3? There are markings, but nothing like for 1-4. Now that I've messed with the allen screws and the individual pickup coil adjustments, I'm worried I'll have 2-3 off. Any advice?

[tomcat24551]

I'm "winging it" with this reply 'cause I don't have time to go out and check my '79 850 which has a Dyna S and mechanical advance, too.

I would back the idle back down to 1000 RPM or so and adjust cyl 1-4 so that it fires on the "F" mark. I don't know the timing specs on the 650 but I'd guess there's probably about 20 degrees difference between idling and full advance--or probably about the distance between the "T" and "F" marks on the rotor. You can see if the timing appears to advance that much. Sombody else will probably write in and give you the exact timing specs and procedure for this engine.

Then, put the clamp on cyl wire #2 or 3, and I think you oughta see the marks for those cylinders.

Sorry, all the above is for a standard timing light! I've never used a timing lite that has the advance dials, etc. and displays that I think you're describing.

Also, make sure the plug wires are going to the correct cylinders!

Hope this helps.

[t3rmin]

I'm "winging it" with this reply 'cause I don't have time to go out and check my '79 850 which has a Dyna S and mechanical advance, too.

I would back the idle back down to 1000 RPM or so and adjust cyl 1-4 so that it fires on the "F" mark. I don't know the timing specs on the 650 but I'd guess there's probably about 20 degrees difference between idling and full advance--or probably about the distance between the "T" and "F" marks on the rotor. You can see if the timing appears to advance that much. Sombody else will probably write in and give you the exact timing specs and procedure for this engine.

Then, put the clamp on cyl wire #2 or 3, and I think you oughta see the marks for those cylinders.

Sorry, all the above is for a standard timing light! I've never used a timing lite that has the advance dials, etc. and displays that I think you're describing.

Also, make sure the plug wires are going to the correct cylinders!

Hope this helps.

Well I'm actually pretty sure of my understanding of the T F t marks now. I think my marks are different than yours since my bike had stock electronic ignition. My Suzuki shop manual states 10 deg BTDC at idle and 40 BTDC full advance (30 deg difference). The spacing from T to F looks to be about 10 degrees and from T to t is further (looks like about 30 deg), so it all adds up.

The 2-3 side does NOT have marks like that, though. I'll probably just have to give it a best guess. I think I can orient with the advance weight bolt, since the 1-4 full advance mark is right close to that.

Plugs are going to the right cyls; I've ridden the bike over 100 miles like this. I just realized today that I'd set the timing way off which explains perfectly the issues I've been having.

[BadBillyB]

Set the timing for 1 and 4 at the F mark with the engine idling below 1200. Do the same for 2 and 3 at the F mark.....When the RPM's are raised above 3K RPM you should be seeing the mark that is to the right of the F mark, on both the 1-4 and the 2-3 , This is the total advance mark....The only difference between the marks for 1-4 and 2-3 is there is no TDC mark for 2 and 3. You are not concerned with this though as the ignition is not fired at TDC...Hope this helps....BadBillyB

[t3rmin]

Yeah I got it timed right last night and WOW. I'm pretty sure I had the timing 20 deg or more off. I'm surprised it ran at all. And I thought it was fast/running well before. Sheesh. All three of my buddies who test drove it after that had two things to say: 1) "WOW. You're going to kill yourself with that thing." and 2) "You know your seat really does suck."

Got the 't' mark aligning at full advance (past 3500 RPM according to my manual) and the 'F' mark aligning at idle. My advance plate does NOT have T or F marks on the 2-3 side, so I eyeballed it and am confident it's pretty much right on because I had a good frame of reference with the weight anchor screw. Now my plugs come out looking just right instead of sooty black. This solves a lot of problems.

[uudfourty]

what is the difference between a timing light and a test light?

[t3rmin]

The test light the Dyna "static timing" instructions refer to is just a continuity tester. A multimeter with an audible continuity setting (or just watch the resistance change, but a light or buzzer is easier) would work just as well. Continuity means that the two contacts are connected electrically.

A timing light is a device that detects magnetic induction. You clip it on a spark plug wire, and it flashes a light every time it detects a spark. When the bike is on this creates a strobe effect which causes the rotating timing advance wheel to appear to stand still. (If you've ever messed with a strobe light, you've seen this effect in action.) As you adjust the timing, the wheel will appear to rotate slightly; then you just line up a mark on the wheel with another mark (stationary, not on the wheel) and you're done! A timing light is easier and more accurate than "static timing" with a test light or multimeter.

Here's a Wikipedia article on timing lights for further reading:

http://en.wikipedia.org/wiki/Timing_light

[uudfourty]

much thanks