Timing Question
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Tourer
Joined: Dec 2007
Posts: 388
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From: West Tennessee
Timing Question
Okay first off. I'm sorry for starting all kind of threads with all these questions but I'm also trying to help out other people so when they search they find the info they need.
I have a question on static timing. I'm geting close to getting the bike started again and I wanted to clarify a little bit on the static timing method. So here are the steps that I know.
1. Raise bike or rear wheel
2. Put bike in 4th gear
3. Remove spark plugs (to make it easier to rotate the rear wheel)
4. Remove the timing cover plug
5. Gap the points correctly
6. Put the vertical timing mark in the timing window, making sure that the timing mark is there on the compression stroke of the first piston.
7. Pull the points cam to the fully advanced posistion
8. Move the points plate to the point where the points just begin to open and tighten them.
9. Move the crank to the alternate firing mark.
10. The points should just be opening on this mark as well
My question is with step 6, 7, and 9.
On question 6. How would you determine that the bikes front cylinder is in the compression stroke? I mean there is the obvious way which is to put your thumb over the spark plug hole and wait for it to push your thumb away, but on my bike I need two hands to rotate the rear wheel. And then this sort of leads into question 9. If the fly wheels vertical timing mark is in the window in one rotation and then I rotate the fly wheel 360 degrees and the vertical timing mark is back in the window again would this put the rear cylinder in the firing posistion or just put the first cylinder in the intake stroke? Would I need to use the two dot mark on the fly wheel for step 9?
On question 7. Does this mean to literally rotate the circuit breaker cam (picture below)? And if so what part of that CAM is the advanced location? The straight sided narrow sides or the widest part which is rounded?
Thanks again and please don't get frustrated with me. I just want to make sure I get everything right.
[IMG]local://upfiles/49728/3568CB1A52D84C14A9902CCF77A0BF52.jpg[/IMG]
I have a question on static timing. I'm geting close to getting the bike started again and I wanted to clarify a little bit on the static timing method. So here are the steps that I know.
1. Raise bike or rear wheel
2. Put bike in 4th gear
3. Remove spark plugs (to make it easier to rotate the rear wheel)
4. Remove the timing cover plug
5. Gap the points correctly
6. Put the vertical timing mark in the timing window, making sure that the timing mark is there on the compression stroke of the first piston.
7. Pull the points cam to the fully advanced posistion
8. Move the points plate to the point where the points just begin to open and tighten them.
9. Move the crank to the alternate firing mark.
10. The points should just be opening on this mark as well
My question is with step 6, 7, and 9.
On question 6. How would you determine that the bikes front cylinder is in the compression stroke? I mean there is the obvious way which is to put your thumb over the spark plug hole and wait for it to push your thumb away, but on my bike I need two hands to rotate the rear wheel. And then this sort of leads into question 9. If the fly wheels vertical timing mark is in the window in one rotation and then I rotate the fly wheel 360 degrees and the vertical timing mark is back in the window again would this put the rear cylinder in the firing posistion or just put the first cylinder in the intake stroke? Would I need to use the two dot mark on the fly wheel for step 9?
On question 7. Does this mean to literally rotate the circuit breaker cam (picture below)? And if so what part of that CAM is the advanced location? The straight sided narrow sides or the widest part which is rounded?
Thanks again and please don't get frustrated with me. I just want to make sure I get everything right.
[IMG]local://upfiles/49728/3568CB1A52D84C14A9902CCF77A0BF52.jpg[/IMG]
Stellar HDF Member
Joined: Feb 2006
Posts: 3,035
Likes: 17
From: Houston Texas
RE: Timing Question
My question is with step 6, 7, and 9.
On question 6. How would you determine that the bikes front cylinder is in the compression stroke? I mean there is the obvious way which is to put your thumb over the spark plug hole and wait for it to push your thumb away, but on my bike I need two hands to rotate the rear wheel.
Raise the pushrod covers and hold them up (collasped) with rubber bands and bent paper clips.
When the front piston is coming up to the top the pushrods on the front cylinder should not be moving (valves are closed because this is the compression stroke) BUT....see next comment...
And then this sort of leads into question 9. If the fly wheels vertical timing mark is in the window in one rotation and then I rotate the fly wheel 360 degrees and the vertical timing mark is back in the window again would this put the rear cylinder in the firing posistion or just put the first cylinder in the intake stroke? Would I need to use the two dot mark on the fly wheel for step 9?
Remember the pushrod movement? If the front cylinder P/Rs were not moving, the rear cylinder P/Rs were. That was on the overlap stroke for the rear. The next forward revolution shouhd have the rear cylinder on the compression stroke. (Note: I think I have stated it correctly here)
And yes, the DOT would be used on step 9 because it is the mark for the rear cylinder.
On question 7. Does this mean to literally rotate the circuit breaker cam (picture below)? And if so what part of that CAM is the advanced location? The straight sided narrow sides or the widest part which is rounded?
Here is where we get into a problem using the so-called static timing.
The timing mark(s) on the flywheel are where the engine is at 40° BTDC (1971 and later).
This is where the points just start to open when the ignition unit is in the advanced position due to centrifugal rotational force.
Being at 40° is going to make reading the pushrod movement (or lack of) difficult to determine.
The ignition cam has 2 lobes, each with a different shape. When the engine is stopped, the ignition advance is retarded by 30°. Have I confused you yet?
Rather than blather on, I will just post a section out of the manual for you to carefully read.
Notice the last paragraph in particular.
The only way to time the engine is with a light. Period. Nowhere in the entire manual will you see mention of static timing the engine!
As it suggests, you can set the points plate in the middle of the slot and this is going to be close enough for any Sportster to start. Then time it with a light. Forget the static timing exercise, unless you just want to endure much frustration and extra work.
This is an ironhead engine (a.k.a. tractor technology) not a Swiss watch.........pg
On question 6. How would you determine that the bikes front cylinder is in the compression stroke? I mean there is the obvious way which is to put your thumb over the spark plug hole and wait for it to push your thumb away, but on my bike I need two hands to rotate the rear wheel.
Raise the pushrod covers and hold them up (collasped) with rubber bands and bent paper clips.
When the front piston is coming up to the top the pushrods on the front cylinder should not be moving (valves are closed because this is the compression stroke) BUT....see next comment...
And then this sort of leads into question 9. If the fly wheels vertical timing mark is in the window in one rotation and then I rotate the fly wheel 360 degrees and the vertical timing mark is back in the window again would this put the rear cylinder in the firing posistion or just put the first cylinder in the intake stroke? Would I need to use the two dot mark on the fly wheel for step 9?
Remember the pushrod movement? If the front cylinder P/Rs were not moving, the rear cylinder P/Rs were. That was on the overlap stroke for the rear. The next forward revolution shouhd have the rear cylinder on the compression stroke. (Note: I think I have stated it correctly here)
And yes, the DOT would be used on step 9 because it is the mark for the rear cylinder.
On question 7. Does this mean to literally rotate the circuit breaker cam (picture below)? And if so what part of that CAM is the advanced location? The straight sided narrow sides or the widest part which is rounded?
Here is where we get into a problem using the so-called static timing.
The timing mark(s) on the flywheel are where the engine is at 40° BTDC (1971 and later).
This is where the points just start to open when the ignition unit is in the advanced position due to centrifugal rotational force.
Being at 40° is going to make reading the pushrod movement (or lack of) difficult to determine.
The ignition cam has 2 lobes, each with a different shape. When the engine is stopped, the ignition advance is retarded by 30°. Have I confused you yet?
Rather than blather on, I will just post a section out of the manual for you to carefully read.
Notice the last paragraph in particular.
The only way to time the engine is with a light. Period. Nowhere in the entire manual will you see mention of static timing the engine!
As it suggests, you can set the points plate in the middle of the slot and this is going to be close enough for any Sportster to start. Then time it with a light. Forget the static timing exercise, unless you just want to endure much frustration and extra work.
This is an ironhead engine (a.k.a. tractor technology) not a Swiss watch.........pg
[IMG]local://upfiles/8331/E6534C82FB954079A42C5EBA3862AB12.jpg[/IMG]
Tourer
Joined: Nov 2005
Posts: 282
Likes: 0
From: Georgia
RE: Timing Question
I'm sure you have seen me say it before, but I'll mention again, recheck your point gap after each time you turn the timing plate. There is enough slop in the slots to throw the point gap off several thousands and I'm sure this is enough to mess with your timing. Good luck.
Rich
Rich
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Joined: Mar 2008
Posts: 96
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RE: Timing Question
Im sure this is a dumb question, but I want to be sure im doing it right, and my manual has not come in the mail yet for me to confirm. Ok, so when you are checking the points gap with a feeler gauge, its suposed to be .018 right? next question, where in the rotation am I suposed to check, do I check the gap asthe pointsjust begin to open, when full open, full closed? I hope you get what im asking, but certianly understand if not.
Thread Starter
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Tourer
Joined: Dec 2007
Posts: 388
Likes: 0
From: West Tennessee
RE: Timing Question
ORIGINAL: csd4682
Im sure this is a dumb question, but I want to be sure im doing it right, and my manual has not come in the mail yet for me to confirm. Ok, so when you are checking the points gap with a feeler gauge, its suposed to be .018 right? next question, where in the rotation am I suposed to check, do I check the gap asthe pointsjust begin to open, when full open, full closed? I hope you get what im asking, but certianly understand if not.
Im sure this is a dumb question, but I want to be sure im doing it right, and my manual has not come in the mail yet for me to confirm. Ok, so when you are checking the points gap with a feeler gauge, its suposed to be .018 right? next question, where in the rotation am I suposed to check, do I check the gap asthe pointsjust begin to open, when full open, full closed? I hope you get what im asking, but certianly understand if not.
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