Sprockets

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BEK

Sprockets

#1

Post by BEK » Sat Jan 10, 2004 1:41 pm

I've got a '48 Pan that I've been restoring for the past couple of years that I hope to have finished this spring.
The manual says that the motor sprocket should be 23 teeth and the tranny sprocket 22 teeth. By the way it's a 74" FL Pan. Is this a good combination for highway driving: RPM's, vibration etc.? Just wondering what everybody else is using.



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Re: Sprockets

#2

Post by Sidecar » Mon Jan 12, 2004 2:30 pm

Do a search through this section and you will find a lot of combinations. Check the subjects, "Belt primary's & chain vs belts". I think you'll find what you are looking for.
I'm running 23 teeth on the motor and 25 on the tranny. I don't think I'd go to 26 on the tranny unless I was on the highway all of the time.
I would recommend the 25 tooth tranny sprocket. If you are not sure, start with 24, but no lower. I started with 23 teeth on the tranny and it was too low.

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Re: Sprockets

#3

Post by dereborn » Mon Jan 12, 2004 4:39 pm

I've got a primo belt setup for the primary, and a 26 on the tranny. I want my rpm:s even lower at hightway speeds, so I'm now fiddling with the rear sprocket, trying to fabricate one with fewer teeth (48?).
I echo sidecars advice; use the search function on this site - lot's of valuable info!

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Re: Sprockets

#4

Post by Sidecar » Tue Jan 13, 2004 1:41 pm

Dereborn,

When you're crusing around in 3rd, what is the speed that you are running. I haven't ridden my bike in a few months, but if I can remember correctly, below 45 mph it starts to get sluggish in 3rd.

I'm starting to think that I'm an old fart !!!!
You guys running 26 teeth on the tranny and looking to smaller rear sprockets must be ridding a lot faster than me !!!!!
Maybe it's these lousy roads in Pa.
My rear tire comes off the ground quite frequently with the rigid frame. 3 or 4 inches of daylight under the rear tire is not uncommon !!!!!

Ride safe
Randy

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Re: Sprockets

#5

Post by VintageTwin » Tue Jan 13, 2004 4:32 pm

For chain primary, a 24T motor sprocket and a 25T transmission sprocket will allow the motor to run at a comfortable low RPM at 63 mph on the highway. Stetttler told me that using the 24T motor sprocket and 26T transmission sprocket will even further "blow your mind" in a good way, if you want low highway RPMs. Most definitely run a 26T trans sprocket if you belt your primary. I'm looking at also getting a clutch drum with one less belt-tooth in it from BDL and a 26T tranny sprocket. You can run a 26T trans sprocket on any Big Twin 1936-64. On a '65 Pan the 24T tranny sprocket is the biggest that will fit.

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Re: Sprockets

#6

Post by dereborn » Tue Jan 13, 2004 5:06 pm

Sidecar: I don't have a speedo, but I estimate that i usually use 3rd gear between 25-30 mph in LOW rpm city traffic, and when passing a truck on the highway it stretches above 55 mph too! I guess my cruising speed on the highway is around 75 mph, and I'd like to get the rpm:s a little lower doing that. If i manage to get the rear sprocket down in size a bit, it will also mean i can stretch the 3rd gear a bit longer, making truck-passing even easier! I almost always ride solo, and no sidecar.

Vintage Twin: You must promise to let me know if you get your hands on the smaller belt drum!

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Re: Sprockets

#7

Post by Sidecar » Tue Jan 13, 2004 9:39 pm

Dereborn,

You're runnin faster than me on the highway.
I can see why you estimate the speeds !!!!!
I don't spend a lot of time on the interstates myself. I try to stay off of them. Most of my riding is done at 50 mph and below.
I've clocked my bike at 66 mph actual when the speedo is reading 60. So I would guess that my highway speed is 60 to 65 (on the speedo) and 66 to 71 actual. Good for this slow old fart !!!!

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Re: Sprockets

#8

Post by DuoDave » Tue Jan 13, 2004 10:31 pm

Interstates? We call them motorways here in the U.K. Who the hell wants to ride on them? They just get you from A to Z. The roads that Panhead riders like take in the other 24 letters of the alphabet. Maybe we should start a "Slow Old Farts Club". We may not get there in a hurry, but at least we get to see what the heck is going on.
"What is this life, if full of care, we have no time to stand, and stare."

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Re: Sprockets

#9

Post by dereborn » Tue Jan 13, 2004 11:50 pm

You're absolutely right! Of course highways are chosen only if no other choices are available! However I'd rather ride my pan to wherever I'm heading, than put myself in a 4-wheeler. And every now and then time tends to get short, so it happens that I ride the ol' girl at 75 for an hour to team up with my buddies and then go for the REAL ride of the day, on the scenic roads, in appropriate tempo.
The wonderful thing is that the Pan performs wonderfully in both situations! That's why I haven't got more than this one bike, she can be both effective and cultural!

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Re: Sprockets

#10

Post by VintageTwin » Thu Jan 15, 2004 12:36 am

I ask Bob at BDL about the one less tooth clutch drum, having heard that BDL made one. He answered that they nor Primo did not. So, if you want the lowest possible rpm's in 4th gear at 63-65 MPH on a Knuckle or '48-64 Pan, you will need to run a 26T transmission sprocket. I think we Knuckle and Panners should give our business to Primo or BDL. They are equally as good. And whenever you get a chance, tell people about this site. It's for the Replicators and Bobber-minded individualist of our century.
Here's BDL's reply:

SORRY NO, BOTH PRIMO AND US MAKE ONLY THE 31 / 47 COMBINATION.
BOB G

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Re: Sprockets

#11

Post by dereborn » Thu Jan 15, 2004 4:12 am

OK, i thought so... Well, I've already got the 26 tooth, so I'll just have to get on with my "smaller rear sprocket project", and see what it can do...

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Re: Sprockets

#12

Post by mbskeam » Sun Feb 01, 2004 6:11 am

hello, for years i had run a 24 motor and 24 trany sprocket. I now have a belt drive and went to a 25 trany sprocket. It cruises at 75 - 80 all day MB

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Re: Sprockets

#13

Post by Jack_Hester » Sun Feb 01, 2004 9:41 pm

I have a program on one of my web pages that will let you calculate your rear wheel speed for all the variables mentioned in this post (sprockets, rpms, tranny gear, tire size). There are two programs on the page. Get the one that says OH_DAT14.exe, as it has this speed calculator on the menu. It is an old format, but runs well on any Windows version up through WinXP. You'll just have to click on the upper right hand corner, to close the window.

http://www.terra-glide.net/harley_tech.html

Jack

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Re: Sprockets

#14

Post by DuoDave » Mon Feb 02, 2004 9:49 am

I had a bit of a rant here the other day on the subject of interstates. I do hate them, but I should have stopped to consider that some of you guys have the misfortune to live in congested areas and have to use these highways to hell. So, apologies to anybody I offended. (again!). :

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Re: Sprockets

#15

Post by haggis » Tue Feb 03, 2004 3:22 am

I'm no lover of interstates either, way too much heavy metal!
But.............there is a nice 20 mile or so stretch of The Maine Turnpike .between Lewiston and Augusta..that on a nice summers day at the right time is almost empty of everyone including the boys in blue.....
some high speed,straight line, flies in the teeth fun makes a pleasant change now and again. ;D ROLL ON SPRING! Haggis

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