65 FL Sprocket Combinations

[JSB55]

Hi, Guys

I'm looking for some expert input on sprocket sizes as I put my newest project together.

65 FL rebuilt .020 over, 3 speed w/ reverse transmission, 66 HD sidecar will be permanently attached, but mostly run without passenger.

Primary travel will be 25-50 mph around town at 6500 ft elevation, but I have a 1.5 mile 5%+ grade to climb getting home to 7000 ft.

Sprockets I have now are Motor 23T, Trans 25T, Rear wheel 51T.

Does this sound about right, or should I consider a sprocket change before buttoning things up?

Thanks in advance!

John

[T. Cotten]

Is there any way to change the rear wheel, John?

My '65 with hack started 23/23, but after a season or two or three experimenting, 22/22 proved far better, avoiding lugging and knocking away from stop signs, accelerating onto Interstates better, etc.

Highway speeds to follow the pack of Evos in the '80s was no problem, as cruising at seventy achieved an "aircraft whine" where it seemed to be in a better powerband, with more left over.

I seriously think everybody is afraid to let them wind out.

....Cotten

[JSB55]

Hmm. I thought the rears were all 51T, and you seem to be referring to Engine/Trans sprocket combos, Tom. I could get a different drum and rear sprocket aftermarket, I suppose, but changing something in the primary would be a ton easier.

I'm most interested in pulling power to get up the hill to my home base. Also, being in the mountains means any highway riding will involve some serious altitude changes of up to 3000 feet.

[T. Cotten]

Hmm. I thought the rears were all 51T, and you seem to be referring to Engine/Trans sprocket combos, Tom. I could get a different drum and rear sprocket aftermarket, I suppose, but changing something in the primary would be a ton easier.

I'm most interested in pulling power to get up the hill to my home base. Also, being in the mountains means any highway riding will involve some serious altitude changes of up to 3000 feet.

If there was something other than 51T available, John,

It would still be more trouble and money than its worth. I had to ask just in case.

And if there were smaller sprockets than 22T for the others, they might already be on my hack (Too long ago to remember).

My point is to gear as low as possible, and take advantage of RPM.

....Cotten
PS: You're going have to pull the whole primary to get at that super-tall 25T tranny sprocket.
Come to think of it, you'll want a shorter primary chain, and maybe take a link out of the drive chain.

[Rubone]

Standard sprocket for a 74ci H-D trans is 22 tooth. Rears are fixed at 51.Engine for a sidecar is anywhere from 20-22 depending on whether it is an FL or FLH, etc. It is tough with a 3&R as in most cases 3rd is too high and 2nd is too low. But they function just fine with a bit of RPM even though most owners panic after about 3500....

[JSB55]

If there was something other than 51T available, John,

It would still be more trouble and money than its worth. I had to ask just in case.

And if there were smaller sprockets than 22T for the others, they might already be on my hack (Too long ago to remember).

My point is to gear as low as possible, and take advantage of RPM.

....Cotten
PS: You're going have to pull the whole primary to get at that super-tall 25T tranny sprocket.
Come to think of it, you'll want a shorter primary chain, and maybe take a link out of the drive chain.

=========
Thanks, Cotten
As of now, it's just a rolling chassis with engine and wheels installed, so I can do whatever on the engine and trans sprockets and chains.
Deciphering as best I can what you and Robbie have said, I'm thinking a 22T on both the Engine and Trans would give me the torque I need.
I'm less interested in chasing Evos than I am in getting up the hills around here.
And as old as the chains may be, I don't mind replacing them if I have to.

[JSB55]

Standard sprocket for a 74ci H-D trans is 22 tooth. Rears are fixed at 51.Engine for a sidecar is anywhere from 20-22 depending on whether it is an FL or FLH, etc. It is tough with a 3&R as in most cases 3rd is too high and 2nd is too low. But they function just fine with a bit of RPM even though most owners panic after about 3500....

Hi, Robby
It's an FL, only engine mod being bored over .020 when rebuilt.
The previous owner was running the 23/25 sprocket combo I've seen suggested on other forums, but he had no sidecar and was in pancake flat Florida.
I'm planning on the sidecar being a permanent fixture, and I have big hills to contend with.
Based on your input along with Cotten's, I'm thinking both engine and trans should be 22T.
Does that sound right to you?
Thanks.

P.S. ... RPMs don't bother me. I routinely run my Evo and Shovel up over 4k briefly, and judging by sound, I get there on my other 65 FLH, too. And the Servi Car I just finished has to scream to get up the hill to my house in 2nd gear!

[JSB55]

Actually, the parts book calls for a 19T motor sprocket (NON compensating sprocket) for a sidecar bike, and a 22T trans sprocket. Maybe I should just go with the original setup?

UPDATE: So the 22T Transmission sprocket is a no brainer, and they are available all over the place. Got one on order.

Engine sprocket is a different story. The book calls for 19T, but the smallest I can find listed for sale are 22T. I'll put an ad in the "wanted" section here on the forum and try to scare up that rare 19T (#40206-55). Worst case, I can put in a 22T and keep hunting for the original.

Thanks for all the input!

John

[T. Cotten]

Actually, the parts book calls for a 19T motor sprocket (NON compensating sprocket) for a sidecar bike, and a 22T trans sprocket. Maybe I should just go with the original setup?

UPDATE: So the 22T Transmission sprocket is a no brainer, and they are available all over the place. Got one on order.

Engine sprocket is a different story. The book calls for 19T, but the smallest I can find listed for sale are 22T. I'll put an ad in the "wanted" section here on the forum and try to scare up that rare 19T (#40206-55). Worst case, I can put in a 22T and keep hunting for the original.

Thanks for all the input!

John

Got out my '65 Parts Catalog, John,..

But I don't see sidecar designation anywhere; Am I on the wrong page?

Notice how there is a 19T, but no 20T, then 21T, etc.
The 21T carries a -30 part number, superseded by a 22T also with a -30 number, which fits "41 to * - FL, FLH"
(The asterisk means '65, as it is a '65 book.)

So there is a sprocket blueprinted in 1930, which would naturally fit '41 to '54, but fits '55 to '65, too?
It suggests a very special application, as well as for the 19T -55 splined sprocket.

Notice also the 'double repair links' for front chains (specific to Diamond or Duckworth); You may need one to go lower, as I believe even the 22T requires the shortest available intact chains (80 as opposed to 82 links I think?).

Compensators were invented for hacks.

...Cotten
PS: I just noticed that a 22T countershaft (tranny) sprocket is all they listed!
(I mistakenly thought production was 23T, as that's what I always found. And I did a few.)

[JSB55]

COTTEN ... I'm using the 58 to 68 parts catalog published by Antique Cycle Supply out of Michigan. On Page 50, there are 6 motor sprockets listed. The 19T says "(sidecar)" as part of the listing. I got a bit of an education on all this today. The -30 21T sprocket listed for use 1955-64 is splined, but has a raised part on the back that would probably misalign the primary chain by acting as a spacer. The 23T that was on the bike is splined, but flat on the back side.

There are plenty of repop 19T sprockets out there, but they are tapered and use a key, and fit sprocket shafts dated up through 1954. The 19T splined sprocket is so far nowhere for me to find, but I have some "feelers" out to people I know who hoard old parts.

To make things more interesting, for once the Clymer book is more illustrative than the HD manual. Clymer has a table showing the various motor sprockets used on FL and FLH from 1948 through 65. The table shows that a 65 FL ridden solo uses a 23 tooth motor sprocket, but used with sidecar, it's the 19T that I'm hunting for.

And yes, my book shows only a 22T transmission sprocket, as Robbie pointed out yesterday. Already located a Drag Specialties version and ordered it. Worst case, there are splined 22 tooth repop motor sprockets out there if I can't find the 19T. Or maybe I should consider a compensator?

I bought this thing at Panhead City almost 20 years ago, and it has sat in my garage since, until i finally found a 66 sidecar a few years ago. When I bought the bike, Chuck said it was originally a Police sidecar bike, and it had the Police speedo, 3 speed w/reverse and sidecar attachments on it when I bought it. The previous owner had trashed the paint, but my painter was careful to uncover the original color, which was Birch White. I mainly want to ride it as a novelty grocery getter, but I like to make them as original as I reasonably can, even while I'm no candidate for any AMCA judged points winner.

[T. Cotten]

... . Or maybe I should consider a compensator?...

Without any hesitation, John.

....Cotten

[dukekleman]

I apologize for the poor picture, however here's the factory information if you don't already have this...
IMG_20241125_045926017.jpg
You'll note that the 1965 and newer FLH models used 22 tooth engine sprocket on the 3 speed w/reverse transmission.

Lugging the engine due to load is not a good thing. As a long time technician I've seen some very bad scenarios.
You could also consider a 21 tooth sprocket on the transmission final drive.

Hope this helps,
Duke Kleman

[JSB55]

I apologize for the poor picture, however here's the factory information if you don't already have this...
IMG_20241125_045926017.jpg
You'll note that the 1965 and newer FLH models used 22 tooth engine sprocket on the 3 speed w/reverse transmission.

Lugging the engine due to load is not a good thing. As a long time technician I've seen some very bad scenarios.
You could also consider a 21 tooth sprocket on the transmission final drive.

Hope this helps,
Duke Kleman

Yes, I have that, Duke, but thanks for sending it along. Everybody says 22T on the motor sprocket (I ordered one online). The confusion, however, seems to be around what engine I have. This is an FL, not an FLH, and that table says 19T for the FL motor. With 19T not for sale anywhere, 22T is going to be my default setup to start.

[Rubone]

Cute..
"RPMs don't bother me. I routinely run my Evo and Shovel up over 4k briefly", I regularly bounced my strokers off 7000 according to the mechanical tachs I used...

My sidecar has a 20 on it but it is a UL so only 35 HP or so. And at 7000ft a bit less than that. Here it is at the top of Lizard Head Pass. Carrying a passenger and all our stuff for a 1200 mi 6 day round trip on an AMCA Road Run in 1990.

[JSB55]

[QUOTE=Rubone;n330386]Cute..

My sidecar has a 20 on it but it is a UL so only 35 HP or so. And at 7000ft a bit less than that. Here it is at the top of Lizard Head Pass. Carrying a passenger and all our stuff for a 1200 mi 6 day round trip on an AMCA Road Run in 1990.

===

Killer outfit, Robbie *LOL* ... I took your advice and ordered a 22. If you topped Lizard Head in that rig + passenger, I'm sure I'll be fine.

35+ years on the old iron is impressive. No wonder your knowledge is encyclopedic!