Engine Sprocket Change?

Post Reply
tdewalt
Posts: 8
Joined: Tue Nov 14, 2006 8:23 pm

Engine Sprocket Change?

#1

Post by tdewalt » Mon Mar 24, 2008 3:39 pm

I have a 50 Pan that likes to run at about 50mph. 60's ok for short periods but I don't like to run it like that for very long. I always feel like I'm in the way on local roads where everyone seems to feel the need to go 65+. If I go from the stock 23t engine sprocket to a 25t what can I expect. Mathmaticaly it only looks like about a 13% increase in speed at the same engine RPM (55 = 62). What can I expect as far as problems go? How much does that affect take off and top end power? Is there a better alternative? I figureed this was the most econnomical choice and it would not affect the speedometer reading but I'm looking for some advice before I change anything.

Tad



Pantony
Posts: 149
Joined: Sun Sep 10, 2006 3:23 pm
Location: Milwaukee Wisconsin
Been thanked: 1 time

#2

Post by Pantony » Mon Mar 24, 2008 4:42 pm

24T on the engine; 24t on the ouput of the tranny, That will give you PERFECT RPM on the freeway

tdewalt
Posts: 8
Joined: Tue Nov 14, 2006 8:23 pm

#3

Post by tdewalt » Mon Mar 24, 2008 6:49 pm

Thanks, I just spent about an hour with the rear wheel calculator in the Knowledge base and reading post. 24-24 gives me a 3.28 final ratio, and I had picked out 23-25, also a 3.28 ratio, either way seems like it will work.

Thanks,

Tad

Guest

#4

Post by Guest » Mon Mar 24, 2008 9:23 pm

Go with 24-24, it's easyer to kick. My 48 would just "Sing" at 65mph (62 indicated), I'll never forget how that thing purred going at that speed.

Cotten
Posts: 6911
Joined: Mon Aug 26, 2002 9:09 am
Location: Central Illinois
Has thanked: 100 times
Been thanked: 268 times

#5

Post by Cotten » Tue Mar 25, 2008 12:50 am

Methinks you all like to lug yer motors.

The powerband is higher than your ears might be comfortable with.

My '65s would run tirelessly at Interstate speeds with 22/22 sprockets, and a hack!

....Cotten

51Hog
Posts: 664
Joined: Fri May 20, 2005 7:29 pm
Bikes: 1951 Fl
Location: Wasilla, Alaska
Has thanked: 1 time
Been thanked: 5 times

#6

Post by 51Hog » Tue Mar 25, 2008 1:47 am

Where exactly is the power band on the 1200?
What is red line on an old pan engine?

What RPM is the engine doing with stock sprockets, wheels and tranny gears at 60 mph?
What rpm gets the best fuel economy on flat ground, 4th gear, no wind,
properly inflated tires, properly tuned engine, 250 lb person, windshield,
on a stock 51 FL?
I currently get about 18-21 mpg around town. with 25 tooth sprockets.
I have no power above 65 mph and max out at 80 mph.
I am thinking I may go to a 24 tooth on the tranny output--Since my rear chain almost cut the clutch lever in half (The 25 tooth sprocket does not leave much room and when the rear chain needs adjusting, you back off the throttle the chain raises at the top of the sprocket and hits the clutch lever crossover bar.)

fourthgear
Posts: 1391
Joined: Mon Apr 11, 2005 1:12 pm
Location: north florida
Been thanked: 4 times

#7

Post by fourthgear » Tue Mar 25, 2008 2:08 am

51hog
What carb and type of ignition are you running ? Your gearing(sprockets ), cam, may have some thing to do with your gas mileage and your top end.(among other things)

mbskeam
Posts: 1006
Joined: Tue Mar 16, 2004 5:52 am
Location: Sultan, WASH
Been thanked: 2 times
Contact:

#8

Post by mbskeam » Tue Mar 25, 2008 2:25 am

I ran 24/24 for years and liked it. then when I went to belt drive I changed the T to 25T. about the same ratio....
I currently get about 18-21 mpg around town. with 25 tooth sprockets.
I have no power above 65 mph and max out at 80 mph.
ummm...I was getting 35-40mpg and it would do 100+ when it was a 1200, not trying to brag, but max at 80 is a bit slow and 18-21mpg is a bit on the low side. might be runnin a bit rich. this will also drop off your top end mph...


mbskeam

Pantony
Posts: 149
Joined: Sun Sep 10, 2006 3:23 pm
Location: Milwaukee Wisconsin
Been thanked: 1 time

#9

Post by Pantony » Tue Mar 25, 2008 2:37 am

"Methinks you all like to lug yer motors.

The powerband is higher than your ears might be comfortable with.
My '65s would run tirelessly at Interstate speeds with 22/22 sprockets, and a hack! "

No Cotten Mine wasn't lugging at all, was running just fine right on the begining of the powerband at 62. Remmeber the 65 pan compared to my 48 had a little weight differance. Gas Mileage I would get 35 on average with the Linkert I had on it (with one of Cottens floats). I guess I could have gotten more if I leaned it out on the highway but didn't want to chance it (never drove it much on the interstate) I could have gotten 40 I guess.

51Hog
Posts: 664
Joined: Fri May 20, 2005 7:29 pm
Bikes: 1951 Fl
Location: Wasilla, Alaska
Has thanked: 1 time
Been thanked: 5 times

#10

Post by 51Hog » Tue Mar 25, 2008 4:32 am

I am running a J grind cam.
Ignition is 6v single points original setup with later model round coil.
Linkert carb--
Plugs looked a little dark. I just leaned the hi-speed needle 2 clicks.
We will see what the plugs look like later tomorrow.
25 tooth engine
25 tooth tranny out put
Stock clutch basket gear
stock rear drum gear.
(Pressure test on the intake and pan cover screws is good)
You do not have the required permissions to view the files attached to this post.

51Hog
Posts: 664
Joined: Fri May 20, 2005 7:29 pm
Bikes: 1951 Fl
Location: Wasilla, Alaska
Has thanked: 1 time
Been thanked: 5 times

#11

Post by 51Hog » Wed Mar 26, 2008 7:09 pm

After running 50 miles, The plugs are about the same color---A little rich.
Going to lean out another couple of clicks on the hi-speed needle. I will need to fill up today and should be able to tell if leaning made any difference.
What is red line on the 51 1200 pan engine?
Where is the power band?
I think I may go back to a 24 tooth on the rear drive sprocket. See if that helps with the top end and fuel consumption.
I am not after more speed, Just need to be able to pull the hills at 65-70mph without slowing down. Drivers in Alaska are not looking for Bikes, so I need to be able to move.
Thanks
Dale

Post Reply

Return to “Sprockets”