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Timing Advance Weights

Started by rbabos, July 19, 2018, 11:22:48 AM

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rbabos

Got a shovel I'm having a bitch of a time setting idle to the normal rpms of 800-1000. If I move the screw a hair, timing advance kicks in and idle moves into a too high rpm once the advance kicks in. Idle will hang high as well and takes a while to drop to drop back . If I move the screw to prevent this higher rpm hang,  idle is too low and causes issues with the E carb, like a spit and die sometimes no matter how the idle mixture is set. All jets are correct.  I'm looking at different springs for the weights but not sure which is the best approach as in have the advance kick in sooner or have it start kicking it at around 12-1500 rpm. I'm thinking latter but thought I'd ask. Ignition is Dyna S from what I recall and the cams are new and free to move.
Ron

rigidthumper

Ignorance is bliss, and accuracy expensive. How much of either can you afford?

rbabos

Quote from: rigidthumper on July 19, 2018, 01:19:02 PM
Not sure if this is the replacement for the Revira 1106-0014 kit, looks like it. That kit always served me well.
https://www.ebay.com/itm/American-Prime-Advance-Unit-Rebuild-Kit-1106-0014/192548716603?rt=nc&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D52935%26meid%3D00477599646648b3a3371e84c544af20%26pid%3D100005%26rk%3D1%26rkt%3D1%26sd%3D401542058151%26itm%3D192548716603&_trksid=p2047675.c100005.m1851
Thanks for the link. It is a new advance weight system but I don't feel it's working in the right rpms. I can tweak what rpm it should with springs and weight alterations but don't know for sure if the advance should kick in right after the engine starts or have it come in later, past any rpms over the set 800-1000 at idle. What's best? All I know for sure is sometimes the idle will quickly drop if I rev it up and other times it hangs with a high idle. When it hangs, putting finger pressure on the spinning inner reluctor or whatever that 2 magnet deal is in the center it will instantly pull the weights back to a more retarded timing and drop back to what rpm the screw is set for, which is too low. 5-600 rpm roughly. The hang rpm or if I move the idle speed screw slightly to bring the rpm up a tad, the weights move to a higher advance and rpms seem to run close to 1200 -  1500 ish. Hell of a lot or rpm variation between having the cams in retarded position or full advance.
Ron

guppymech

I tried a aftermarket advance unit and it hung up at idle like yours so I installed a NOS Harley unit I have and no more hanging idle speed.  I found this small how-to on the Dyna S from a guy who posts up a lot of Shovel stuff.
http://tearitupfixitrepeat.blogspot.com/2013/05/goodbye-hi-4-hello-dyna-s.html
'84 FXE, '02 883R

rbabos

Quote from: guppymech on July 19, 2018, 04:00:06 PM
I tried a aftermarket advance unit and it hung up at idle like yours so I installed a NOS Harley unit I have and no more hanging idle speed.  I found this small how-to on the Dyna S from a guy who posts up a lot of Shovel stuff.
http://tearitupfixitrepeat.blogspot.com/2013/05/goodbye-hi-4-hello-dyna-s.html
Yes, thats the ignition system that the Indy replaced the Compufire unit with but the cams on neighbors shovel are grey not yellow zinc, so I suspect OEM.
Am I to understand there are likely three different springs available from my basic research? All in at 1400 rpm, 2000 and 2600. Maybe I need the one that's all in at 2000? I'm thinking the one jerking me around is the all in at 1400 rpms , making it hard to set a correct idle speed.
The advance system is free and new as far as I can tell, just right on the edge of in and out of advance at idle. Tach is crappy on the bike, like about 400 rpm off but it sure looks like advance is all in at around that 1400 rpm spring deal.
Ron

guppymech

I'm posting a link to the section on ignition curves from a book I have, I've posted this before and got some negative feedback on the info but I find it valuable.  The things I think to take away from it is that the ignition curve numbers presented are from the WOT curve of a ignition with VOES (the curve that is most like the one centrifugal advance unit provides).  The other thing of note is that the Author lists the full advance with the centrifugal unit taking place at 2400 rpm.  Personally I agree with everything he says and wish the stock unit reached full advance closer to 3k rpms but Harley certainly had their reasons for using 2400 rpm.  Hopefully the link will work, Please read through it a few times to soak up all the info provided.
https://books.google.com/books?id=8UOSTJf-N9wC&pg=PA65&lpg=PA65&dq=shovelhead+points+ignition+advance+curve&source=bl&ots=SSKa6xic9o&sig=nk3nn_3VvuWFkhQ_1KAwHZFw4Ew&hl=en&sa=X&ved=0ahUKEwi8w4-q9szbAhWn8YMKHWc9B_o4FBDoAQhSMAI#v=onepage&q=shovelhead%20points%20ignition%20advance%20curve&f=false
'84 FXE, '02 883R

rbabos

I will look that over . Thanks.
Ron

tmwmoose

Ron, I used to play with the springs and all that stuff back in the day. And I had a selection of different springs. I'm sure there still someone selling them I use to get them from CCI and Rivera. I also took the skimpy Taiwan springs and rebend them to stiffen them up .Been so long I don't remember what I did but I believe I tweaked the end that fit in the weight. Idle problems seemed more of an issue on the 74" motors with S&S Es on them

rbabos

Quote from: tmwmoose on July 19, 2018, 06:10:42 PM
Ron, I used to play with the springs and all that stuff back in the day. And I had a selection of different springs. I'm sure there still someone selling them I use to get them from CCI and Rivera. I also took the skimpy Taiwan springs and rebend them to stiffen them up .Been so long I don't remember what I did but I believe I tweaked the end that fit in the weight. Idle problems seemed more of an issue on the 74" motors with S&S Es on them
This an 80" but yes the E is touchy. Until I get that idle up to where it should, without that over run from timing, I can't really set the low speed mixture right either. Sometimes it will just spit and die. Nice to know I'm not the only one on the planet that found their way toward the advance curve and the need to modify it. Is all in timing at 2000 the best route to take?
Ron

PoorUB

Remove one of the springs and wire the advance down, adjust the idle then put the spring back in and work on the timing.
I am an adult?? When did that happen, and how do I make it stop?!

rbabos

Quote from: PoorUB on July 20, 2018, 10:55:22 AM
Remove one of the springs and wire the advance down, adjust the idle then put the spring back in and work on the timing.
That makes no sense to me what so ever. :scratch: He ordered a couple different springs so I can alter the timing curve and keep it from advancing while at idle.
Ron

dirtymike

ditch the electronics and get a set of points and a timing light.

rbabos

Quote from: dirtymike on July 22, 2018, 07:08:51 AM
ditch the electronics and get a set of points and a timing light.
That would not change the advance curve caused by the weights or springs.
Ron

turboprop

Quote from: dirtymike on July 22, 2018, 07:08:51 AM
ditch the electronics and get a set of points and a timing light.

Or go the other way and ditch the flyweights and springs. The old trouble head I built for Johnny Bo (Double leg amputee) had a DTT nose cone module and a Super E. Watching Johnny kick it over was pretty cool. Usually fired on first kick and was as maintenance free as on old shovel could be.
'We' like this' - Said by the one man operation.

dirtymike

Advance weights were designed for points.

Ohio HD

The type of advance really doesn't make a difference to electronic ignition. Advance weights are a simple poor way to advance a distributor. But they work the same with points or a magnetic pickup.


GM used advance weights on HEI ignitions for years.


https://st.hotrod.com/uploads/sites/21/2013/02/ccrp-1302-05-hei-distrubtor-tune-up-heat-sink.jpg

rbabos

Ok, so a spring change allowed me to bring the idle up without advance kicking in too soon. I do have another issue that's been ongoing and so far nobody has found the cause. At idle, every once in a while it will spit back through the carb and almost die or actually die. No intake leaks in normal testing and the manifold was actually changed when the Indy rebuilt it, likely assuming this was the cause.
It has an E carb and no amount of fiddling with the idle mixture screw stops it whether you adjust it richer or leaner. I could not detect any play in the throttle shaft and the carb was also rebuilt to try and eliminate the spit problem. I'm almost 100% sure there is some form of mixture disruption from an intermittent intake leak of some form or a suction issue within the carb, again intermittent. Key word here is intermittent, as it can idle for the longest time, then spit out of the blue. Open to suggestions. Oh, this has had 2 different coils, run single and dual fire, Compufire, Mikuni, and currently Dyna S installed. Several different plugs, wires  and all the normal "Potty mouth" replace but the issue remains. I'm thinking the carb itself and even though it's been cleaned and rebuilt, the problem remains.
Ron

guppymech

My stock 80" with a Super E did the same thing and I'm trying to remember what cured it.  I changed the intake rubber bands and went to aircraft style clamps.  Make sure your float bowl overflow hose is clear by blowing through it.  The one provided by S&S looked good but it was shrunk down inside, it's not the bowl vent but it made a difference.   Where did you get the stronger advance weight springs?
'84 FXE, '02 883R

rbabos

Quote from: guppymech on July 26, 2018, 06:34:18 AM
My stock 80" with a Super E did the same thing and I'm trying to remember what cured it.  I changed the intake rubber bands and went to aircraft style clamps.  Make sure your float bowl overflow hose is clear by blowing through it.  The one provided by S&S looked good but it was shrunk down inside, it's not the bowl vent but it made a difference.   Where did you get the stronger advance weight springs?
Preston Cycle. They may only sell to dealers or indys however.  I measured the old ones and were .019. These were .025. I fully expect it's fueling related in some form due to some other traits I've seen. Sometimes it gives the impression it runs out of fuel to the point the accel pump won't squirt. Possibly float hanging up or needle lowering the fuel level but then it magically recovers, takes quick throttle, idles and you can see the accel fuel stream on rapid throttle. It can also shoot a 3' flame from a lean spit out of the blue with just a slight opening of the throttle. All point to lean at this point but when you adjust the mixture screw for idle it keeps ending up in the same middle point for when it seems to be running good.  As you say, venting could do this also but it will haul ass down the road, never skip a beat all day long which tends to rule that out. It's something simple, yet elusive so far.
Ron

DRN

Hello,
I too have been experiencing the same issues. I have a '68 FLH and after going through the Super E carb a couple times, I came to the conclusion my issue was the timing or the flyweight springs. I see that for the '70 and newer shovels you can get three different replacement spring: stock, HD, and extreme duty. These correspond to what has been mentioned with what was noted with regards to them working at different rpm. Sadly, mine being a '68 there is only stock replacement springs available and I purchased a set and found them very light gauge and did not have any expectation of them resolving my issue. I have thought about trying the HD or extreme duty springs for '70 and up, but was concerned they may be different physically in shape and would not work on my '68. I wish someone could tell me they are identical, except for some reason have a different part number. Can you tell me the year of your shovel and if the stronger springs resolved your issue. Thanks. Darren.

Dogbone45ACP

Teds V Twin has several weights of springs. Never used his. I got a set years ago from a shop in PA. The shop is long gone.

Dogbone45ACP

I looked in my notes. V Twin PN 13-9247 Gold Advance at 2600
                                13-9246 Silver in at 2000
                                13-0121 Black (stock)  in at 1400
I have no experience with these springs.

DRN

Thanks for your thoughts, but those springs are for '70 and up; my bike is a '68. I have a suspicion that the '70 and up spring would likely work on my earlier '68...even though the part numbers are different and my bike runs a distributor rather than the nose cone of the '70 and up.

JSD

They make reverse drive gear to rotate timer Antilock wise then I use a 70/99 cone module. No springs just tune it yourself. Also can use the Voes . Makes a Genny great to tune for ignition. 

DRN

Hello, thanks for your thoughts. Can you tell me more about this reverse drive gear? Also, can you tell me if you have ever compared the flyweight springs for a '67-'69 to the springs for a '70 and up? I know they are a different part number, but sometimes you get lucky and they work.