Sprocket Change for Highway Speed

[40 Nuck]

I'm thinking of changing my motor sprocket to get a little more top end. I'd like the experience of others in the effect of changing one or two or three teeth ... obviously giving up accelleration for top-end, but can someone give me a feel for how much acceleration is compromised for the increase in top end? My 40 EL gives me quick acceleration and 65 to 70mph top end without too strain, but I'd like to get another 5 to 10 mph. Will I give up a lot of acceleration for that gain? Should I go up one or two or three teeth?

Thanks!

[Rubone]

Pretty hard to answer Vic with no knowledge of what is on it now! And what transmission and transmission sprocket is on it? That all affects the characteristics of gearing changes. But just as an answer of sorts, three teeth on the engine is HUGE!
Robbie

[Chris Haynes]

I like to run a 25 or 26 tooth transmission sprocket.

[Matt McManus]

The biggest engine sprocket that I am aware of is a 24 tooth. A 24 engine -24 trans -stock 51 rear is a pretty good combo for riding in my opinion. If you dont care about having a chain in the primay get a belt drive it will have a slightly higher ration than the 24 tooth engine sprocket, if that is still not high enough put a 25 on the trans with the belt drive. If you do that I am sure you will have to move the splash guard on the back of the primary to accomodate the large trans sprocket. It will slow your 61 down a good bit accelerating but you will be able to run 80 mph or faster if that is what you are in to. Then you will just need better brakes to slow down.

[Steve Little]

Years ago "that would be about 30 years" I went from a 23 tooth trans to a 25 tooth sprocket.
I was looking for a higher cruising speed and more reach out of my tanks.
At that time I lived in a area where the road curved tightly through the hills, and I knew it like the back of my hand.
I knew my entry speed for every corner and could roll off the throttle for the breaking effect and then barrell out the other end.
I had changed the setup at a mates place and the first night I came barreling back through those mountains with this 25 tooth was nearly my last.
The de-accelaration I was used too when I rolled off the throttle, was gone.... and I proceded into the corner at the same speed.
Dinner plate eyes and some exhaust gouging manouvers got me through that first corner.

In the end I think I settled on a 24 tooth sprocket. I had a 3 inch Primo belt drive so I dont remember the ratio of that.

[Sargehere]

...My 40 EL gives me quick acceleration and 65 to 70mph top end without too strain, but I'd like to get another 5 to 10 mph. Will I give up a lot of acceleration for that gain? Should I go up one or two or three teeth?
Thanks!

Vic, Everything depends on the "grunt" in your motor and the size of your ass. It's a 61 to start with. If everything else is stock (and 22t and 22t and 51t) and you don't weigh 250 lbs., put a 24t on the motor and try it. You'll learn quick if it will give you what you want.
I've run 23t for years, pulling a sidecar most of the time, on an otherwise stock UL (designed for torque, not HP) with no ill effects on the drivetrain. Harley's Service manual told me to drop to 20t for sidecar with a 4 sp, or 18t with 3+R. They must have thought if you wanted to back up your sidecar you'd never leave the center of a city, but it's not a parade bike.
I guess it's not the fastest thing off the blocks, but cruises in a "sweet spot" on the interstate that I can live with (65-70 "all day" when I want to) solo, and with the hack, no ill effects and I don't push it.
Obtain one or two sprockets and experiment. Your EL will soon tell you at what speed it sings on the interstate, or wherever you want to set it up to cruise, and adjust accordingly.

[40 Nuck]

Thanks all ... It's looking like I'lltry the 24T and see how it goes. Sounds like 25 may be too much. May also consider the belt drive and 25 Tranny sprocket. Good useable info Sarge, Chris, Steve, Matt & Rub ... the kind of info that will help me "triangulate" a decision ... or a couple of good alternatives to try out.

[Steve Slocombe]

Dear Vic, the VLs have the same drive sprocket as the knucks, with a 28 tooth countershaft sprocket and the same 51 tooth rear. With a 3-speed gearbox the solo bikes were originally specified with a 23t drive sprocket, then a 22t in 1934 with the more powerful motor (why?), with a 25t for 'speed work' or the 1936 four speed gearbox. I've always thought the VLs were undergeared for paved roads, and usually run a 25t sprocket with the three speed box. This topped out at 99 mph on my 1934 speed bike, so I made a few 27 tooth sprockets and took it up to 103 mph, but you sure feel the gap between second and third. I sold a 27 tooth drive sprocket to a Florida customer with a 1936 VLH and a 3-speed box, who said you had you do 70 on the Interstate or the trucks would run right over you. Last time I spoke to him he'd done 11,000 miles that way. So, depending on how hilly it is your way, I'd suggest a 25 tooth drive sprocket, then trim it either way based on experience. These are not big big dollar items so you could have a touring sprocket and an about town one. Best regards.

[40 Nuck]

Many thanks, Steve ... more great info. Appreciate the time and detailed responses.