how big of a tranny gear to run?

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scooter65
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how big of a tranny gear to run?

#1

Post by scooter65 » Sat Apr 11, 2009 2:30 pm

I've got a inclosed belt and a 23 stock tranny gear on my 65 but it seem to top out at about 80mph ????



51Hog
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Re: how big of a tranny gear to run?

#2

Post by 51Hog » Sat Apr 11, 2009 4:10 pm

I also have an enclosed belt.
I am running a 25 tooth, and also top out at 80 mph.
1st gear is pretty steep.
can't run around town in 4th.
Don't like running around in the whining third gear.
I will probably go back to 23 or 24 tooth.
Dale

lockdoc
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Re: how big of a tranny gear to run?

#3

Post by lockdoc » Sun Apr 12, 2009 4:50 am

A little off topic but I'm curious so I will ask. Never had a Pan before what I have now and I have no one in my area with one so I can't compare or ask questions. You both mentioned you top out at 80mph which took me by suprise. My question is, is that the norm for a Panhead? I have a 65 drivetrain with a 23T sprocket with enclosed belt as well. Before I even rode mine when I got it I had the top end done by flo works. Shovel valves, minor porting, dual plugs, top end oiling mods, etc. Plus I put in Wiseco pistons cut down from 9 to 8.5 compression and a crane 260 cam. I have nothing to compare it to. From 80 I can pull to well over a hundred though I never really go over 65 due to the fact that my hands and feet will go numb with vibration. Looking back I could have left it bone stock and been happy since I don't go fast with it.

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Re: how big of a tranny gear to run?

#4

Post by Cotten » Sun Apr 12, 2009 2:26 pm

lockdoc wrote: You both mentioned you top out at 80mph which took me by suprise. My question is, is that the norm for a Panhead?
LD!

My wife's zillion-mile oil-burning '65 warhorse tops out at about eighty,...
with a fully loaded sidehack.
(and no headwind!)

Or at least I think it can do it one more time, but a hack is little fun at that speed anyway.

And that's with a 22T engine sprocket and a 22T tranny sprocket: as low as you can go.

If you are geared too high, you can't get past the bad vibration range.
Geared down low, its somewhere in second or third gear instead of cruising speed.

....Cotten
PS: I never topped out my '65 stroker: too timid.

john HD
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Re: how big of a tranny gear to run?

#5

Post by john HD » Sun Apr 12, 2009 2:39 pm

i run out of courage at about 70!

i saw a guy on the interstate lose a front spoked wheel, it was a big puff of rust then ground sky ground sky ground sky then the big slide!

i know my bike will do over 80 with the stock gearing due to the ported heads and the flh cam.

switching back to a linkert only made it go faster! go figure!

john

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Re: how big of a tranny gear to run?

#6

Post by Kuda » Mon Apr 13, 2009 1:39 pm

scooter65 wrote:I've got a inclosed belt and a 23 stock tranny gear on my 65 but it seem to top out at about 80mph ????
Running a mostly stock (FLH cam, 8.5 - 1 pistons) '49 pan with an open belt drive (Supermax) and a 24 tooth trans sprocket it'll pull verywell up to 90 mph. At 80+ it's still pulling pretty hard but the motor sounds like it's gonna come apart and the vibrations get pretty bad, so common sense has me staying below 80. Since I'm doing a few longer weeklong trips this year (4K plus each), I put on a 25 tooth trans sproket just to see if highway riding is a little easier on the motor. If it doesn't kill off-the-line enjoyment, I'll leave it on there for good. If it does kill around town riding, I'll swap it back after the trip. But either way, a good healthy pan should do 80+ without breaking a sweat...

-Kuda
'49 panchop

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Re: how big of a tranny gear to run?

#7

Post by steinauge » Mon Apr 13, 2009 1:56 pm

My stock engine 49 FL tops out about 90 with my 300 pounds on it.I am geared 23-23.In my experience most stockers with stock gearing and non worn out engines will run around 100 mph.As Cotten says overgearing is the cause of a lot of problems.

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Re: how big of a tranny gear to run?

#8

Post by Kuda » Mon Apr 13, 2009 4:20 pm

steinauge wrote:My stock engine 49 FL tops out about 90 with my 300 pounds on it.I am geared 23-23.In my experience most stockers with stock gearing and non worn out engines will run around 100 mph.As Cotten says overgearing is the cause of a lot of problems.
So you think a 25T is too high? Huh. I'm always worried about over-reving, especially since I don't have a tach. Now that I'm going back to the stock timer (from a mag) I guess I could run one. But on some of these trips if I need to make time I'll run 80mph for 16-18 hours, stopping only to gas and pi...er...go. She gets pretty darn hot running like that so I was thinking lowering the revs a bit might help out. I'm certainly open to suggestions tho'...

-Kuda
'49 panchop

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Re: how big of a tranny gear to run?

#9

Post by 51Hog » Mon Apr 13, 2009 5:12 pm

Kuda--
I have a fresh engine with about 5K on it.
I run an 11mm belt that gears the bike up a little.
I run a 25 tooth sprocket and a linkert.
I also have a full windshield.
When my speedo indicates 60, I am actually doing 68.
In My case, I am finding out that the 25 tooth sprocket is definitely too much for my Pan.
You will find that you will be running around in third gear a lot---If you put in the 25.
I can ride at 55 mph in third.
If I do not down shift to third running up an over pass, I will loose 5mph.
She does not have the torque to overcome the wind resistance and a small hill at the higher speeds.
I think she will actually run cooler and work less with the smaller sprocket. Might even save a little fuel.
I am going to gear back down to a 24 or maybe even the 23 tooth.
Dale

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Re: how big of a tranny gear to run?

#10

Post by Kuda » Mon Apr 13, 2009 6:01 pm

51Hog wrote:Kuda--
You will find that you will be running around in third gear a lot---If you put in the 25.
I can ride at 55 mph in third.
If I do not down shift to third running up an over pass, I will loose 5mph.
She does not have the torque to overcome the wind resistance and a small hill at the higher speeds.
I think she will actually run cooler and work less with the smaller sprocket. Might even save a little fuel.
I am going to gear back down to a 24 or maybe even the 23 tooth.
Dale
Interesting. I guess that begs the age old question: what's a safe max operating RPM for a small bottom-end pan (early smaller bearing)? 4K? 4.5K? I'm sure one of you oldtimer experts out there knows. I just don't want to blow these original cases apart by pushing it too hard...

-Kuda
'49 panchop

indianut
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Re: how big of a tranny gear to run?

#11

Post by indianut » Tue Apr 14, 2009 2:28 am

First time I rode my stock '61 Duo-Glide out West (from Florida) I had a 24 trans sprocket on it. I changed it in the Black Hills because it was sluggish and I wanted to cross the Rockies. I went with a 23 and never looked back! Now I find myself cruising FASTER than before (about 68-70) even here in Fl. where it is Flat. I think what I did was to put the bike's Powerband back where it is the most efficient! I don't think a Stock Pan has the Horsepower to efficiently pull a larger sprocket.

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Re: how big of a tranny gear to run?

#12

Post by steinauge » Tue Apr 14, 2009 7:01 pm

Theoretically ideal gearing for top speed would allow the engine to pull 2-300 RPM past the redline in high gear on a flat road with no wind.I can say,after having watched literally hundreds of big twins on one of our dynos that a stocker is all done making power past 5-5200 RPM .If you live where the roads are flat run all the gear you want,just realize you wont be able to pull redline in high gear.

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