Flywheel timing marks

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65 Eric
Posts: 59
Joined: Fri Jul 13, 2007 10:35 am

Flywheel timing marks

#1

Post by 65 Eric » Tue May 08, 2007 4:46 pm

Description: Flywheel timing marks

Gentlemen,
While checking (static timing) my timing after installing a Andrews "B" grind to help get rid of my "pinging" problem (by lowering the compression) I removed the plugs and turned the motor over until my front intake valve just closes and I can feel compression coming out of the front spark plug hole. I then continued to turn the motor over while looking thru the timing hole until the timing mark appears in the window. The mark is a single line but is not perfectly straight up and down but is actually slanted a little to the right. I put the mark in the center of the timing hole and when I looked at the mark on the circuit breaker cam lobe which should line up with the "thing" on the points that rides on the cam lobe I saw it was off by one tooth. I lifted up the circuit breaker, turned it one tooth (clockwise) and dropped it back in,attached a test light to the points and when I turn the circuit breaker cam to full advance the test light comes on. The bike starts in 1 or 2 kicks and runs great, my question is why did I have to reposition the circuit breaker drive gear to line up my marks (when held fully advanced) after changing the cam from an "A" grind to a "B"? does the"A" cam gear itself have a different number of teeth than the "B" grind? or was I off the whole time I was running the "A"? one more question and I'll leave you guys alone (yeah, right), as I continue to rotate the flywheel I see a pair of timing marks that are straight up and down and close to each other, about an 1/8 in. apart, what are these for? Is this a stock flywheel for a '65 FLH? And for those of you wondering if I solved my "pinging, clacking" problem....I don't know yet. I just fired it up last night after work and haven't had a chance to put some miles on it. If this doesn't do it I'll be ordering those low compression pistons that Skip speaks so highly of. I thought I'd try the cam first because it's easier to do and doesn't require a break-in all over again as with new pistons.
I think I'll go for a ride at lunch time, it should be about 90deg. outside by then and if it doesn't ping after that I'm gonna call it good. I'll let you know when I get back.
wish me luck,
Eric



65 Eric
Posts: 59
Joined: Fri Jul 13, 2007 10:35 am

Re: Flywheel timing marks

#2

Post by 65 Eric » Tue May 08, 2007 8:23 pm

Well..........I took a 20 mile ride in 94deg. heat and while rolling along at 60-65 I whacked the throttle and the pinging is still there. If I roll it on slowly there is no noise. I can also pull away from a stop rather briskly without any noise but if I really get on it, it pings. What to do? ride like a sensible sane person? I think not. It may be time to order those low-comp. pistons.

Eric

Skip
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Re: Flywheel timing marks

#3

Post by Skip » Wed May 09, 2007 1:03 am

Hey Eric...I don't know if pistons are the problem...how are your push rods set???...may try and start there...???...just a hunch...Skip

65 Eric
Posts: 59
Joined: Fri Jul 13, 2007 10:35 am

Re: Flywheel timing marks

#4

Post by 65 Eric » Wed May 09, 2007 1:40 am

Hey Skip, I set'em by rotating the cam to the lowest spot starting with the rear exhaust, btw, does it matter which pushrod you start with? and I adjusted them "snug". Two fingers can spin them but you have to squeeze "a little". Sound 'bout right? They're aluminum after market (Colony I think) solids. I'll go back and check'em again 'cause I'm about out of ideas other than the pistons or going with an electronic ign. Oh, on my earlier post asking about the flywheel marks, there's also a "dot" on the flywheel along with the single diagonal line and the two straight ones. Thanks for the support Skip, we are going to get this dialed in, no doubt in my mind of that.
back to the drawing board,
Eric

flattrackfan
Posts: 1
Joined: Sat Jul 14, 2007 1:59 pm

Re: Flywheel timing marks

#5

Post by flattrackfan » Wed May 09, 2007 3:44 am

Eric,

I think you are on the right timing mark, but you should time it with a light when it is running also.
Pinging is very bad news, tends to make holes in the pistons.
First thing I would try is retarding the timing a couple of degrees.
If I recall correctly (always doubtful) the pinging is caused by the flame travelling thru the combustion chamber too quick, so you are getting the power of the burning mixture peaking before the piston is at TDC. So the piston is getting hammered in the wrong direction. Retarding the timing should get your power happening a little later.
High compression pistons make for a smaller combustion area, so the flame doesnt hafta travel as far as in a low compression motor. Another reason to retard the timing a little bit.
Retard it till it doesn't ping any more.
Once it's broke in, you can try advancing it a little, till it starts to ping again then back it off a CH.
High octane gas burns slower than low octane, so get the highest octane you can.

King
Posts: 387
Joined: Fri Apr 02, 2004 5:05 pm

Re: Flywheel timing marks

#6

Post by King » Wed May 09, 2007 11:56 am

Eric

You might be chasing your tail with this one. When I was a kid an old timer told me that one should set timing so that the motor just pinged under the most extreme condition one would experience on a regular basis. For me that has always been pulling the Rte 250 grade going over the Blue Ridge.
My 51FL with STD heads and 8.5/1 pistons probably has about the same compression characteristics as your motor. I pull the aforementioned grade with no pinging but when the motor is hot it WILL ping in 3rd and 4th when I do a full crank-on. As you observed no pinging under normal acceleration.
From your descriptions you have conducted a very careful analysis of the problem and done about all you can do to correct it. Dynamic timing might revel something but I think it may be"as good as it gets".
Good Luck

King

65 Eric
Posts: 59
Joined: Fri Jul 13, 2007 10:35 am

Re: Flywheel timing marks

#7

Post by 65 Eric » Wed May 09, 2007 1:57 pm

Thx to all you guys,
I'm going to play with the timing a little more and see what happens, this actually may be as good as it gets without throwing a bunch more money at it. We'll know more after this week-end when I can adjust, test ride, adjust, test ride, etc., etc.

thx again,
Eric

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