Rear Sprocket position/chain alignment

[hammerweight]

Hey Guys
Had a look around on previous posts and couldn't find an answer to my quandary.
Here's the deal...
My build is a 79 fxe frame with a 79 ratchet top 4 speed and a 67 to 72 rear swing arm and drum etc.
The issue is that the rear sprocket is 3/16" to 1/4" inboard of the trans sprocket.
Nothing bent etc, everything squared up.
Anyone else had this issue when converting to a juice rear drum from a previous disc brake setup?

Thanks!

[govmule84]

I think your ratchet top might be earlier... last year for those is '78 1/2, I believe. But that's neither here nor there.

I have had this problem before. I just used a dished (offset) rear sprocky.

[hammerweight]

No can do....drum brake
Sprocket is integral to drum.
Thanks all the same

[govmule84]

Ah, I thought you were going the other way around. Readers are leaders.

You need to swap your trans mainshaft, then, I believe.

You may find this useful: https://www.jockeyjournal.com/forum/...d.php?t=114746

I would think, too, there must be a factory axle spacer setup that should work, as a ratchet top and a juice drum was a factory combo.

Or do you actually have a rotary top?

[Dan Boy]

Can you not off set the hub by re-spacing and then off set you rim via the spokes to compensate and have your wheel run central?

[hammerweight]

Main shaft length doesn't alter the sprocket position.
Ratchet top for sure.....

[govmule84]

Ah, of course. So since the trans sprocket didn't move at all... good news! Everything lines up!

I'ma take one more crack and see how strong my Google-Fu is today. If this doesn't help, fuck it, I'm going to bed.

http://www.hydra-glide.com/phpBB3/viewtopic.php?t=6185

[hammerweight]

Hey Dan boy,

Afraid you have no side to side adjustment with the drum brake setup....
The spacers are the spacers.

[govmule84]

Check that link I wrote up there... I think Dan Boy nailed it. Apparently the manual tells you to kick the rim over; guy in the link had the exact same problem you do.

Do you have a manual? I think I have a Pan manual at home if you don't; I can scan the relevant info for you if you need.

[joe49]

The spacer on the main direct changed in early '77 it fit '37-E'77 P/N 35171-37.
Late '77 to '79 P/N 35070-77
'80 to '81 P/N 35070-80
'82 to '85 chain drive P/N 35079-82A or 35079-84
'82 to '86 belt drive P/N 35070-82A or 35070-84
You need the early one, you will need the seal too for the change out. Early '37 to E'79 is P/N 35230-39 or late'79 to '81 P/N 37741-67
Also in'80 there was a sprocket spacer added P/N 35079-80 and a sprocket change.
If your's has the spacer, deleting it maybe enough.

[hammerweight]

Hey Guys,
Found the problem...
You would never think, but I guess if these parts could talk!
Drum rivet flange had been “narrowed” to adjust the sprocket at some time in the past. Check the pic.
Installed a non-muckedwith drum and voila.....perfect alignment.
Thanks for the input.

[JAWS]

I wouldn’t have guessed that ever...
Who does that kinda mod to a drum?

[hammerweight]

Originally Posted by JAWS

I wouldn’t have guessed that ever...
Who does that kinda mod to a drum?

I don’t know man...I figure some kinda modified bike where the guy had major alignment problems...lol.

[FredoTwoWheels]

Wow, nice find, I would have never noticed.

[rhysmort]

Originally Posted by hammerweight

Hey Guys,
Found the problem...
You would never think, but I guess if these parts could talk!
Drum rivet flange had been “narrowed” to adjust the sprocket at some time in the past. Check the pic.
Installed a non-muckedwith drum and voila.....perfect alignment.
Thanks for the input.

You must have eyes like a shit house rat to notice that! Who said size doesn't matter aye?!