Gravely model L motorcycle day dreams...

silverbear · Sep 6, 2013

Earlier today I saw a picture Ricks Rides posted of a grungy old Gravely Model L. It sure has a nice old time look to it. Mr. B says it put out 8 hsp. I've had that image in my wee little brain all day bouncing around in all the empty space up there and then got to thinking about the remains of a Harley Davidson Sprint a friend gave me earlier this summer. Too far gone to restore unless somebody had a lot of money. (not me). I have it sitting under a tarp. It reminds me a little of 1940's or 50's motorcycles. I like it. Then I started thinking that instead of restoration simply put something together from this and that. Upholster a tractor seat...

So I was trying to picture that Gravely with a different motor mount on the Harley and was remembering a beefy three speed transmission fasteddy has which had sprockets on it for roller chain and a stick shift with a wooden ball on the end. Can't get it all to fit together in me wee brain but it seems like something might be possible. What do you think? I also have an extra long Triple tree front fork from some kind of Suzuki motorcycle.

Here's the Harley Sprint which originally had a 250cc four stroke.
SB (cont)

silverbear · Sep 6, 2013

And a couple more pictures of the Harley with one of the Gravely model L.
SB

silverbear · Sep 6, 2013

I wonder how big the Gravely Model L is? Wonder if it could be tilted some.

Maybe this is all just a brain fart, a mis-firing of dying brain cells. Ha.
SB

RicksRides · Sep 8, 2013

SB,
29cubic inches go .030 over bore and you ve got 30 cubic inches

If youre talking physical size from bottom of motor to tip of plug 20 inches, the head is 9 inches wide, the widest at the bottom of the motor is 10 inches . The cases are around 6 inches deep and tip of crank to outer edge of starter assymbly is 13 inches.
ya you can tilt it some, it has an oil pump. But remember these take some mods to run as bike motors.
OH and there is an overhead cam kit for them that really polish off the look, exposed rockers, pushrods, etc...

silverbear · Sep 8, 2013

I'll be looking forward to your build, Rick. You mentioned doing an early Harley tribute. Will that be belt drive? And you already have an original early Harley 2 speed tranny for it. How cool is that?

What kind of mods are needed so the Gravely can be used as a motorcycle engine?... aside from the overhead cam kit? Do you have more photos of the engine?
SB

fasteddy · Sep 9, 2013

Silverbear,

I was wondering if you have a rear wheel for it. If you do I'd put it in and take the motor and transmission out and see how much room you have to play with. With the wheel in place you will be able to gauge how far the bottom of the motor will be from the ground. If it fits I'm thinking two pieces of tubing running from the front of the frame down to a bend then back to where the rear of the motor and trans mounts. The tubing will have to flair out from each other so that the motor is supplied with a place for a strong mount.

You might be able to run a belt drive with a tension lever. The possibility's are endless.

Steve.

RicksRides · Sep 9, 2013

silverbear said:
I'll be looking forward to your build, Rick. You mentioned doing an early Harley tribute. Will that be belt drive? And you already have an original early Harley 2 speed tranny for it. How cool is that?

What kind of mods are needed so the Gravely can be used as a motorcycle engine?... aside from the overhead cam kit? Do you have more photos of the engine?
SB

SB,
The original thought was to do a tribute of the 1909 model 7e which was a belt drive. However after getting a deal on the 2 speed tranny we are shifting gears ( pun intended) to the 1913? single with a 2 speed chain drive.
The Gravely requires the following mods (minimal) to be used:
1- tranny side has no bearring just a bronze bushing The cases need machined to except sealed bearring.
2- tractor drive gear on crank gets turned off by lathe, leaving out put shaft of crank @ .750 inches so a drive sprocket can be installed.
3- Oil, 2 ways to tackle this. First is the best (IMO) and more costly Have a gearbox/oil sump made. This allows for burped oil from the crankcase to gather and return to the cases. Also makes it easier to fine tune gear ratios.
Second way would be to plug the 2 burp holes ( tranny side)as well as the small oil return holes at the bottom. Install some type of crankcase venalation. Then route the oil lines like you would on a bike with an external oil tank

RicksRides · Sep 9, 2013

Heres pix's of the oil lines

RicksRides · Sep 9, 2013

heres a look @ piston and valve sizes This is why they are torque monsters

RicksRides · Sep 9, 2013

the 1st picture is a gravely with an overhead kit but not the one I want.
that twin would make one heck of a bike engine it is overhead valve as well

silverbear · Sep 10, 2013

Steve & Rick,
Thanks for the input and photos. It gives a lot to think about and dream on. That Gravely twin would also make a very cool engine for a three wheeled velo car modeled after a Morgan three wheeler. Can you picture that up front exposed for all the world to see? Woohoo! You could do it, Steve!

The Gravely is probably beyond my means, but who knows, maybe a bit at a time...
Steve, regarding the Harley Sprint, I was thinking along the same lines, picturing something like the (can't think of the name of it... Simplex? The one made in New Orleans.) That was belt drive, I believe, and pretty simple in design and operation. A big old Wisconsin or Briggs might work, too. Mr. B. would probably have a suggestion. I'm not interested in going real fast... just something fun that might ride me to town & back on the local highway. It is fun to stare at the Harley and think about it. A sidecar would be nice.
SB

fasteddy · Sep 10, 2013

Silverbear,

I was adding up the cost of the motor and then the cost of doing all the modifications to the motor and it put it out of the realm of anything I could do. It would be great if you could the work yourself or had a friend who could do it.

I hadn't thought of a velocar/Morgan with the V twin. Oh the possibilities that brings to mind. That motor would have all the car buffs scratching their heads would it not.

I think with the Harley a smaller large engine would be a better choice and an accompanying sidecar would be a classic. Placing a wee doggie in the sidecar would finish off the image and would make the menfolk look on in envy and the womenfolk look on with desire.

Steve.

silverbear · Sep 10, 2013

Steve,
The more I think about it, something in the spirit of the Simplex, but using the Harley Sprint frame is starting to ring my bells. I'm not interested in any particular "look", just a simple, straightforward and fun to ride light motorcycle. The Simplex was belt drive, 125CC 2 stroke with a variable speed transmission (the later ones). Sounds good. No shifting. Tractor seat with a big spring under it like the Simplex. The frame would need to be altered as you said. What engine, I wonder. I would want to be able to go 55mph in order to keep up with traffic to town. No desire to go real fast. Dumb not to consider a motorcycle engine... maybe from something wrecked. Anything that works. Low budget is paramount. Open to suggestions...
SB

Mr.B. · Sep 11, 2013

Perhaps a big Briggs matched with a CVT?

Pretty common (inexpensive) and reliable engine.

I was given a old wood chipper with a 9hp F-head and I’m saving it for some like project- As soon as I figure out how to get the damn chipper blade off, Ha!

On a side note I have a line on a old Italian made Harley “Rapido” complete less the gas tank, I believe I’ll get and make a little cafe racer out of it for resale.

Sorry for the OT, back to your build now!

-Kirk

silverbear · Sep 11, 2013

Mr.B. said:
Perhaps a big Briggs matched with a CVT?

Pretty common (inexpensive) and reliable engine.

I was given a old wood chipper with a 9hp F-head and I’m saving it for some like project- As soon as I figure out how to get the damn chipper blade off, Ha!

On a side note I have a line on a old Italian made Harley “Rapido” complete less the gas tank, I believe I’ll get and make a little cafe racer out of it for resale.

Sorry for the OT, back to your build now!

-Kirk

One like this?
Not off topic at all. I'd say right on topic as you are thinking of a similar kind of make it go again project. Thank you, sir!
SB

Mr.B. · Sep 11, 2013

I think that would be a good economical choice. It must have nearly the same cc’s if not more than the original Harley engine.

Because of width you may have to rig a jackshaft, but that just makes it easier to adjust your “to be determined” gear ratios. Or better yet, a heavy duty CVT.

-Kirk

silverbear · Sep 11, 2013

Thanks, Kirk.
It does look like a good option and I might very well find one around here. The chances are also good in finding a heavy duty CVT up this way, maybe from an old snowmobile. Economical is the bottom line for this old Harley. It is a not even an on the back burner build at this point. I have other things I want and need to finish up first, so it may be a couple of years away. But if I know what stuff I'm looking for then I can start setting things aside for when it gets put on the front burner. I have no wish to go faster than the 55 mph limit on the road between here and town and would go slower if it weren't for wanting to keep up with traffic. It would be fun and economical in the warm months, especially with a sidecar for hauling dog and groceries. Each trip is 25 miles which adds up with my 3/4 ton truck. Who knows what gas will cost in a couple of years? Thanks for the input, my friend.
SB

RicksRides · Sep 11, 2013

I was thinking more along these lines
even have a foot starter

chainmaker · Sep 11, 2013

I'm thinking an old Briggs flathead as well they made probably millions of them, they are cheap and reliable and easy to work on.

silverbear · Sep 11, 2013

Yes, the Briggs flatheads are as American as apple pie, which is appropriate for an American brand of motorcycle (even if it was made by Amerchi of Italy). Less easy to find are the Clinton motors, but also an American Icon. I do like that Clinton and a kick start would be way cool. How many hsp is the one in the photo... is it 2 or 4 stroke? I imagine that is a collector item.

Gravely model L motorcycle day dreams...

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