Early, or late? A flywheel conundrum

[The Drach Man]

My FXS shovelhead was built in March 1980. I rebuilt it from a wreck and originally used the Keihin it came with, but despite repeated attempts I could never get it to run right. So I swapped it out for a Super e, and all was lovely. For about a thousand miles.

When I rebuilt the engine, I timed it to a compufire electronic ignition pack, and used the 'early' timing mark to do so. As I say, it ran ok, but not great, so when I replaced the Keihin with the S&S carb, I retimed the engine.

Now at this point I had a bit of a brain fart and looking at the diagrams, felt I had a 'late' flywheel and so timed it accordingly. I even checked the date of my bike's manufacture, and thought, March, is that late? Who knows? They only went to 1984, so maybe....

Well, it isn't. For anybody else doing this, the diagram below is the clearest one I could find and it makes the point that you can have a vertical timing mark, or a drilled mark, or a 'lazy 8', but not all three on the same flywheel. I should've really thought this through.



Anyway, a thousand smoky miles later, my bike finally said, f##k this, I'm off, and after a little bit (!) of rebuilding, retiming to the correct mark, and retuning, it finally runs like it did with that crappy Keihin. The price of progress

 

[Ron]

Clymer Shovel manual M420, page 84 says that the vertical line is the advance timing mark for early 1980 engines up to engine number 1480-128-001. After this the mark is a single drilled dot for the front cylinder advance position. A pair of drilled dots is the mark for the rear cylinder advance mark.

 

[Oldguy]

And just to confuse matters, my HD FLT/FXR manual for '80 to '83 shows the following.
I think I need to lay off the booze ---

 

[watchman]

Handy to know for sure usually with a compufire or crane and s+s ist type ignition the timing is done only on the front pot marks the crane used to run a rear cylinder offset trim pot but you only needed to turn the trim pot while while idling to hear the difference on street motors there was not a lot of gain by buggering about with it think i still have the idiot guides if anyone needs em

 

[The Drach Man]

And just to confuse matters, my HD FLT/FXR manual for '80 to '83 shows the following.
I think I need to lay off the booze

I think that illustration, which I have read and re- read, is one of the more confusing out there

 

[The Drach Man]

Clymer Shovel manual M420, page 84 says that the vertical line is the advance timing mark for early 1980 engines up to engine number 1480-128-001. After this the mark is a single drilled dot for the front cylinder advance position. A pair of drilled dots is the mark for the rear cylinder advance mark.

My engine was manufactured before that cut off point, so I have even less excuse, as I used that info to time it the first time I did it.....why I dumped my brain the second time is a question I'll take opinions on, mine being that I am old and easily confused. But in my partial defence, the Clymer illustration that accompanies that text is THE most confusing one out there....

 

[Ron]

I am old and easily confused.

Ain't it fun getting old...NOT. Mind you I wouldn't want to be young again either, mid 30's would do, still had bounce in my knees.

 

[SJC69]

Am I being too simple here?
Reverse engineering, it is easy to determine TDC on the front cylinder, then see which timing mark aligns and work from there as to which marks you have!

 

[jayzedkay]

i've always taken timing marks as 'indication only'.
not a bad thing to confirm exactly where tdc is, timing-marks have known to be stamped slightly off on more than one ocassion.
time it where it runs best, not necessarily where 'marks' dictate.

regardingn carb, you can't go wrong with a keihin-CV?
if it won't run great with one of those you have problems elsewhere or the carb is shot?

i have a couple of proven CV's, that i ran on my shovel engines for many many thousands of miles. faultless.
if you want to borrow one/them to confirm/eliminate carb issues, message me.

 

[peter1450]

Never timed any of my shovels with a light back in my youth! Stactic mark in window then start her up and find the sweet spot by ear, not very technical but worked for me .

 

[The Drach Man]

Thanks all. Actually the Super e is running fine now, it was only my own stupidity thst got in the way. Hindsight is a wonderful thing

 

[SJC69]

Never timed any of my shovels with a light back in my youth! Stactic mark in window then start her up and find the sweet spot by ear, not very technical but worked for me .

If you did you would have got covered in oil....... Those little plastic, supposedly see through screw in plugs are next to useless even with a mains power strobe light! Evos were better , with less oil... but not much!

Mark the alternator rotor & time through the primary adjustment hole was far less messy!

Some company made a nice little timing indicator that fitted on two of the inner primary case bolts just for that purpose!

They still do...

E-bay link

 

[jayzedkay]

you never used the timing-hole.
my own diy timing marks. definitely the way forward.
at the very least a dab of correction fluid after establishing tdc.

 

[Oldguy]

I see there is an unopened bottle of appropriate fluid to hand