ATTN: ALL BTR Builders (Gravely Model L)

Well , it didnt take as long as I thought, son and his friends helped, only took 7 hours to catologue the motors and parts. Have a dozen I'll part with 5hp, 6.6hp and 7.6hp available.Im selling them @ $250 for the 5hp, $275 for the 6.6hp & $300 for the 7.6hp add $50 for starter +shipping. complete with carb (oil bath only on 5hp), mag, exhaust flange.
 
Back to your twin idea and intake manifold.
Looking at the symetrical design of these engines, it looks to me that it would be possible to turn the rear cylinder 180 deg,
switch the cams around, and then only need a a short "T intake manifold, sorta like a Harley twin.
 
I got 3 of these off the tractors today wow what an experience. was out at a place this morning and ran across this seat on a ole boardtracker frame, not enough of the bike left to positivally ID,half a frame and a seat but shaped like a merkel, gave me the seat he thought it'd be nice to see it used after all these years,he couldnt remember much about it. it had been there along time and the motor had been cut off of it back in the 50's. Ill redo it in leather and put it on my 1913 tribute
 

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Looking at these motors today I realized they have 2 holes in the pto side of the engine think freeze plugs should be perfect cure. The more I look at them the better I think theyll look in BTR and vintage builds. These engines have style.
 

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Wayne, I opened up all 3 different hp models all have 3.25 bore and 3.50 stroke heads are different for the 7.6 (smaller combustion chamber) but everything else appears the same. Leaving me to beleive that the different hp rating must be due to external parts. A neighbor down the road has one of these tiller with a carb off a 500cc 4 stroke thumper installed says after putting it on it had more power and quicker throttle response and thought even a few more rpm
 
RicksRides said:
Looking at these motors today I realized they have 2 holes in the pto side of the engine think freeze plugs should be perfect cure. The more I look at them the better I think theyll look in BTR and vintage builds. These engines have style.
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Hadn't thought about freeze plugs, I was considering tapping and using pipe plugs. They do have bolt in freeze plugs that tighten and expand with a nut.
 
Wayne I just got off the phone with the Gravely guy at GT enterprizes. Best bet instead of freeze plugs is to machine a disc the same size and heli arc it in place. He's also checking with WICO about cost of a ccw direction mags, engines run in cw direction. Reversing the jug is doable. spin jug,swap cams and seals reset timing and use ccw mag.
 
RicksRides said:
Wayne I just got off the phone with the Gravely guy at GT enterprizes. Best bet instead of freeze plugs is to machine a disc the same size and heli arc it in place. He's also checking with WICO about cost of a ccw direction mags, engines run in cw direction. Reversing the jug is doable. spin jug,swap cams and seals reset timing and use ccw mag.
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they have interal oil pumps as well. These engines are well suited for these types of builds, Im stoked!!!!! side note top rpm @ wot 2600-2800rpm
 
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Hey, I just realised that those holes are for crankcase breathing, and one lungers need to breathe a lot, or there'll be oil leaking out everywhere. They breathed into the large transmisson case.

The original crankcase breather was on the transmisson. The breather cap is where you put the oil in, and the transmisson case is also the oil resivoir. There's no oil level in the seperate crankcase.

In fact, if there's no second oil pump for scavenge, like Harlrys, triumphs ect. then the holes may also be there for the engine to cough the oil pump emitted oil back into the transmisson resivoir. If that's the case we might hafta build a resivoil/breatherbox to fit there.

If they do have a scavenge pump, then all we need is a breather and an oil tank. Ya need to ask your Gravely buddy about this stuff.
 
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wayne z said:
Hey, I just realised that those holes are for crankcase breathing, and one lungers need to breathe a lot, or there'll be oil leaking out everywhere. They breathed into the large transmisson case.

The original crankcase breather was on the transmisson. The breather cap is where you put the oil in, and the transmisson case is also the oil resivoir. There's no oil level in the seperate crankcase.

In fact, if there's no second oil pump for scavenge, like Harlrys, triumphs ect. then the holes may also be there for the engine to cough the oil pump emitted oil back into the transmisson resivoir. If that's the case we might hafta build a resivoil/breatherbox to fit there.

If they do have a scavenge pump, then all we need is a breather and an oil tank. Ya need to ask your Gravely buddy about this stuff.
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This was actually one of the topics of conversation all that needs done, lol, cap em by heli arc a plug in place tap a oil port in the crankcase re-route the oil lines using an oil tank with vented cap. problem solved he is sending me a diagram to make sure all is done proper I will post it when I receive it. He said there was going to be some mods required to use these engines for this application , But well worth it in the end. They are capable (when built right) of more then 12 hp goverened. Lots of old school hop ups and mods if you want to take the time or spend the money.
 
if it needs to breath use a npt cap with a barbed hose fitting. that would look old style and easy to do. good luck dennis
 
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