Do you know where the timing mark is?

 

Nada as yet - haven't opened my buddy up yet. Or, do you mean do I know how to find it? I can't cite procedure off the top of my head, but I have a manual, a veteran rider / mechanic, and a buddy with an earlier ironhead sportster all as tools at my disposal.

As I recollect when I last read through timing adjustment (assuming that it's out of adjustment) it wasn't a difficult or trying task at all.

BTW - do '83 XLH's come with electronic ignition? My cover is riveted over, which I thought was odd enough. Guess I have to drill out them rivets to get to the gooey screw-filled center.

- Al

 

1. It may not be overheating, but is a different problem. Your description is the classic symptom of a bad ignition coil. You can test the coil - the procedure is in the manuals and your buddy will know how. But the test is not conclusive. The only real way to know is to replace it with a known good coil.

It must be a coil for electronic ignition. A points coil has different characteristics.

Other possibilities include mis-functioning gas cap, fuel filter getting clogged up. But sounds like the coil to me.

2. The VOES was not used on IronHeads until 1984. The S&S carb is not the stock carb and may not have a VOES port. This is a metal nipple to which you attach a small diameter black rubber hose, which comes from the VOES. If the carb does have a port it will [should!] be blocked with a black rubber cap.

3. Here is the S&S WebSite http://www.sscycle.com/ Browse around it and you will find the tuning instructions for the carb.

4. Using a different heat range spark plug is not a valid tuneup option. If the bike has correct plugs now then find the real problem and solve it. Changing to a different heat range plug may make the symptom go away but will not solve the problem. There are specific uses for heat range changes, but they are rare and apply to engines that are running well.

5. The front rocker cover gasket is relatively easy to replace as you do not need to remove the cylinder head [as you do with the rear]. I suggest that you do not attempt to do this until you have the factory service manual [part number 99484-85] in hand. eBay, J&P Cycles, HD Dealer, etc.

6. Here are my Ignition Timing notes ...

Setting The Ignition Timing on Your IronHead

1. Checking vs Setting the Ignition Timing

You can check the timing without changing anything. Changing the timing can be done by one person but is easier with two. The ignition module or points is on the right side of the bike, the timing hole is on the left side. Easier with one person on each side than to go back and forth. Standard advance for the 1980 XL is 40`. I have mine set at about 35`. At 38` i get pinging.

2. Equipment That You Need

You need an induction timing light which you can buy at any auto supply store. Best to get the "dial back" type. These allow you to set a number [like 35`] into the timing light and then adjust the ignition module/points backplate until you are there.

If you have very well insulated spark plug wires the timing light may not sense the signal thru the wire. If this is the case then open the gap on the spark plug to 050 or more. Reset it to your normal gap [030 for points or 040 for electronic] when done with this procedure.

It also helps to have a throttle lock as the timing should be checked/set with the engine at 2500 to 3000 RPM.

You will need a piece of rubber oil line hose about 1 inch long. Press one end up against the side of a stone grinding wheel [or whatever] to make sure it is perfectly flat.

3. Front Cylinder: TDC Mark vs Advance Timing Mark

The TDC [Top Dead Center] mark is used with a dial back timing light to check the timing, or to set the timing at a specific degree, such as 37`. The advance timing mark is used to set the timing to the factory setting, such as 40`. Best is to use a dial back timing light to check or set timing.

4. To Identify Your Front Cylinder TDC Timing Mark

Remove spark plugs. Rear wheel off the ground, shift to 2nd gear, rotate wheel until it clicks, repeat until you get to top gear. Now by rotating the rear wheel you are rotating the engine. Almost impossible with the plugs in; very difficult in lower gears.

You want the front cyl to be at TDC. You can see in thru the spark plug hole, especially with a flash light; you can try inserting something soft like a pencil and watch it rise and fall as you rotate the engine with the back wheel but be careful it does not break or get stuck! You will have to hang on to the pencil with left hand while rotating the rear wheel with the right. Helps to have a good wingspan, or an extra person.

With the piston at precisely TDC look in thru the timing hole. You should see a drilled dot or a line. That is your front cylinder TDC mark. Once you know for certain what the TDC mark looks like you can check the timing.

5. Procedure, Checking The Timing

Begin with the engine at operating temperature. Remove the timing plug from the left side of the engine. Insert the 1" hose smooth end first, right tight up against the flywheel. I use a needle nose plier and twist it in there as firmly as i can. If it is not smooth and tight against the flywheel oil will spray out while you are working.

Start the engine, have it at about 2500 to 3000 RPM [it will be extra noisy with the timing plug out], set the timing light at 40`, aim it into the timing hole thru the hose. Click it down one degree at a time while you look for the timing mark. If you don't find it you may have to work up from 40`.

If it is in the 35` to 40` range and there is no pinging then you may wish to leave it as is. With pinging on acceleration you may want to retard it by about 1/16 of an inch or less [see Math below].

6. Procedure, Setting the Timing

Remove the points cover from the right side. You will be rotating the back plate so first mark it so you can get back to the current position if needed. Make a scratch mark or use a permanent magic marker, or better still a small bright red or whatever color paint mark.

To change the timing loosen the two standoffs holding the points/ignition module and rotate the backplate. Clockwise advances [larger degree number] counter-clockwise retards [smaller degree number].

7. Some Math, How Much to Rotate

The backplate has a 3" diameter = 1.5" radius.
The circumference = 2 * pi * radius = 2 * 3.14 * 1.5 inches = 9.42 inches
The circumference = 9.42 * 16 ~= 151 sixteenths of an inch.

One rotation of the backplate corresponds to two rotations of the engine, so it is like a circle that has 2 * 360 = 720 degrees. 720 / 151 ~= 5

Therefore a rotation of the backplate by about 1/16 of an inch results in a timing change of almost 5 degrees!

 

Thanks for the info Mick. So these coil-packs actually flake out over longer trips? I never thought a static component / electrical component would function like that, but I'm definitely going to check now.

Also, the S&S does have appear to have a port for the VOES - matches your description with the metal nipple fitting perfectly. It presently has a rubber hose attached to it, and isn't attached to anything on the other end. That was what made me curious.

Already cleaned the fuel filter, drained some grit out of the float bowl, hosed a little carb cleaner in the carb, etc., so this coil idea is look pretty optimistic for me. Never would have thought to check that. I'll get back to you on this.

Thanks much.


- Al

 

They tend to fail after they get hot. That takes some run time. Condensers will fail the same way. You can try heating the coil with a hair dryer and see if you can recreate the symptoms with a 'cold' engine.

That VOES tube had better be plugged...

 

Plug the VOES tube and do a test ride before you change anything else.

It is very important when looking for a tuneup problem to change only one thing at a time. The VOES tube is first choice here.

 

Update:
Had a busy day today, and my bike is like an entirely different animal. So, for whatever his reasons may have been, the first owner (I'm owner 3, owner 2 is me mum's boyfriend and easy to get in touch with) actually replaced the EI with points / condensers. I found this out this morning when I drilled the rivets out of the timing coverplate and found all this hardware hidden inside. A quick call to owner #2 confirmed this.

I took things in stride. Tested the coilpack's resistance, and it failed with flying colors. But even more importantly, the points may as well have been glued down. When the bike was turning over, wasn't budging a bit. The buddy and the veteran rider were both amazed the bike would run at all. Gapped it accordingly, did a check on the timing (I don't think it's quite right yet. Advance mark shows up once in a while at circa 1300 rpms, but it's jumpy and I don't think it's how I want it yet) which ultimately turned up O-K, and went for a sixty mile test ride.

Amazing what a difference properly gapped points will do. Easily kept up with my buddy's bored out sporty, almost no trouble from the carb, etc. Hit up my local parts dealer, snagged NEW points / condenser / coil pack, even BETTER now. I was careful to make sure, when I purchased the coil, that it was a coil meant for POINTS, and not the stock EI that usually comes with the bike.

So, as far as I can tell, that's it. This whole time, I've had points and didn't know it. Maybe in the distant future I'll undo this evil deed and port it back over to EI, but for now I'm just happy to have a smooth ride.

Next up, timing troubleshooting. Right now, a physical observation of the adjustment plate made it appear that it had rattled and walked on me; the plate was turned as far clockwise as it would go. Which, to me, seemed pretty indicative of years of vibration catching up to the sporty. Maybe not though - single "o" front advance timing mark does make an appearance once in a while. But it sure isn't solid. This can be improved - I have the technology.

Thoughts before I tinker my poor bike to death? I have time to mull it over. No more wrenching until I get a bit of backlogged work taken care of.


- Al

 

With the ignition timing procedure you need to have the RPM up above 2500. I usually try for about 3000 RPM then the mark will stay steady in the window.

Also it is a dual fire system - both plugs fire together so you can get two images - the timing mark and whatever happens to be on the flywheel when the other one fires.

 

Dual fire as in they both fire at roughly the same time, on the downstroke? Sort of like a loping double-tap, yes?

I don't have access to a dial-back light, just a regular inductive timing light, so I'm tuning for the factory advance settings. I can tinker from there with the math you provided (thanks!) if I would like. But yes, there are two marks, a single circle for the front cylinder timing advance, and a double-circle for the rear cylinder timing advance.

For whatever reason, Hayne's tells me to keep it at 1,350 for this test. I thought that sounded MIGHTY low, too - so I'm going to give it a re-read, and also just take your advice and try in the 3000 range to see what consequence it brings. It doesn't necessarily help that I didn't read the manual myself (the veteran rider was flipping through it, but his eyes aren't as good as they once were. I'll take a peek myself for continuity's sake).

So, if there isn't a VOES equipped on the bike, how does the advance actually work? I imagine there must be a mechanism elsewhere in the bike that compensates for this instead. In any event, I'll be plugging up that port - I did a trial seeing if stopping it up / opening it back up made a difference at idle by pinching it off with a pair of needlenose, and it did not.

I DO have some kind of breather tube running from the right side of the case into the S&S carb. Is this some kind of oil pressure relief, or what?

I know, I'm just FULL of questions - sorry about that. I just like knowing how to work on my bike. Way I see it is, if I'm going to ride, I'm going to fix it. And if I'm going to fix it, I'm going to make it run reliable, and run right.

Thanks again for feedback.


- Al

 

Dual fire vs single fire: A single fire ignition fires only one plug at a time, and that is the one for the piston that is approaching TDC. Dual fire is also referred to as wasted spark - it fires both simultaneously; the spark for cylinder that is on the exhaust stroke is wasted.

HD motorcycles have been traditionally dual fire - but changed to single fire in recent years. A problem with dual fire occurs when there is unburned fuel in that cylinder. This burns and to a certain extent the engine works against itself.

All of the modern electronic ignitions [Crane, Ultima, etc] are [capable of] single fire.

I do not recall what year is your bike or what ignition [points or electronic] it has; or if it had a VOES when new. Sportsters had a VOES starting in 1983. Must have electronic ignition to use a VOES. Without one the weights in the points setup take care of the advance/retard.

Does the breather tube run from the 10:00 oclock position, at the right side end of the generator? That should run up into the back of the air cleaner, and enter the A/C by-passing the filter.