Kubota D722, belt driven, 7500 watt, generator project…

[keith71]

Have a D722 from a onan 7500 watt generator. The flywheel on this engine has no way to incorporate a stub shaft. As the generator rotor is casted as one piece with the flyheel. The part numbers I have are for the Z482 engine. Hopefully they should be the same for the D722.                                                                                        Part numbers I am looking for are-  Thanks to Henry for posting the z482 parts book..

From the June 2006 parts book  Z482-E2B-DGDE-4

Flywheel 16851-2501-5
starter housing plate 15847-0461-2
      OR

From the 1994 parts book  Z482-BBs engine

Flywheel 16851-2501-0
starter pate housing 19666-0462-0

Thanks, Keith.

[keith71]

More pics of D722 Onan style.. Even the starter is on the wrong side.

[mobile_bob]

if it was me, and fwiw

i would look to making a stub shaft by cutting out and machining a round plate that would
register with the 3 bolt pattern, and then inset a stub shaft into the plate

i would look at maybe a half inch plate, maybe a bit thicker if you like
and machine it to register in the recess of the oem flywheel, drill the three holes to bolt it up
and then chuck it up in the lathe and bore for a stub shaft of whatever size you like, maybe 1.25" or so
press it in and weld it in place,

alternatively with the machining process

rough cut out the round larger than what the finished size would be, chuck it up and bore the hole for the stub shaft
then press in the stub and weld... then chuck up the stub shaft and turn the OD of the plate to fit the flywheel register lip
and then fit it up to the flywheel, use a little slow drying paint of whatever transfer media you like to illustrate the hole pattern, drill and bolt it up.. the holes would not need to be perfectly aligned, just close enough to allow the bolts to mount the plate as the OD would provide for the perfect alignment.

i think that would work very well in my opinion.

about how large is the diameter of the flywheel 3 bolt register on the ID needed to mount the OD of a plate?  looks like maybe ~8" or so?

bob g

[Tom Reed]

+1 on what Bob suggested.

[keith71]

Bob and Tom.. Thank you for the reply.  I like the way you guy's think.
                                                                                                                                                                                                                                                     I will post a few more pictures. Bob those three bolt holes are there for a plastic fan that cooled the radiator. They are only M6 size bolts. Do you think they will be strong enough? It looks like their might be some room to drill and tap for an M8 size bolt.                                                                                                                            

Also this rotor is deeper than it looks.  With a 3-4 inch shaft, the end of the shaft where the pulley will be mounted will be 9-10 inches from the face of the flywheel.            Should I be concerned that it might be to much sideload on the crankshaft and bearings? Also, the register where the 3 bolt holes are 5-9/16'' and the flywheel OD is 10-5/8''..  Anyway I will let the pics explain more.

[keith71]

A few more

[keith71]

Look what I came up with.. Pulley is a perfect fit inside the register of the rotor.. If I could thru bolt it with maybe some threaded rod, would it hold tight enough to keep from spinning?

[Tom Reed]

Look what I came up with.. Pulley is a perfect fit inside the register of the rotor.. If I could thru bolt it with maybe some threaded rod, would it hold tight enough to keep from spinning?

I think the flanges of that pulley are to weak. A 3/8 or 1/2" plate with a stub shaft should work well.

[veggie]

This is where I got the stub shaft adapter for my Kubotoa.
Hayes manufacturing in the USA.
Give them a try.

See the attached .pdf

[keith71]

Look what I came up with.. Pulley is a perfect fit inside the register of the rotor.. If I could thru bolt it with maybe some threaded rod, would it hold tight enough to keep from spinning?

I think the flanges of that pulley are to weak. A 3/8 or 1/2" plate with a stub shaft should work well.

Yes I agree. I was just throwing it out there. I got over excited because it fit the flange register so well..                                                                                            

How about the three M6 bolts? Pretty small diameter bolts to hold a 1/2'' plate and a 2 groove pulley with 4L belts driving a 7500 watt head. Those three bolts were just holding a plastic cooling fan to the flywheel hub..  Not doubting anyone's expertise here, just double checking..                                                              

Kubota used the super mini series in alot of different applications. There are 3-4 different size flywheels, starter plates, bellhousings, starter on left or right side etc depending on what they were installed in.   Thank you..

[Tom Reed]

Looks like there is plenty of beef in the cast bosses to easily go up a bolt size. How deep is the step in the flywheel. The reason I'm asking is that if you're uncomfortable with the 3 bolts holding, you could machine a step in the adapter plate and add some new/extra bolts to the surface of the flywheel. If it was mine, I'd just upsize the 3 bolts and go with it.

[mobile_bob]

giving this a bit more thought, and from what i can see in your pictures

i would think that one could make a stub shaft machined to fit the bore of the flywheel, and make it long enough
to go out through the plate that registers to the 3 bolt flange

then the flange need not be more than maybe 1/4" plate,  fit it all up, tighten the 3 bolts, tack weld the stub to the plate
then remove and weld it up from the inside

then turn the shaft plate assembly to clear off the tack welds on the outside so the pulley can slide up as close to the plate as possible, and i would think it would be  good to go... just use some high strength m6 bolts and it should last forever.

the shaft would not flex the plate under load either, even with a 1/4" plate.

fwiw

bob g

[keith71]

There are a few ways to skin this cat.. But I have found a flywheel and starter mount plate for the D722. And have also found a stub shaft that is made to fit this engine.. For a very reasonable price as well. Thanks for the good idea's Bob.. As I was probably gonna do what you suggested had I not found these parts.. More pics to come soon.. Thanks everyone.

[Henry W]

Bob and Tom.. Thank you for the reply.  I like the way you guy's think.
                                                                                                                                                                                                                                                      I will post a few more pictures. Bob those three bolt holes are there for a plastic fan that cooled the radiator. They are only M6 size bolts. Do you think they will be strong enough? It looks like their might be some room to drill and tap for an M8 size bolt.                                                                                                                           

Also this rotor is deeper than it looks.  With a 3-4 inch shaft, the end of the shaft where the pulley will be mounted will be 9-10 inches from the face of the flywheel.            Should I be concerned that it might be to much sideload on the crankshaft and bearings? Also, the register where the 3 bolt holes are 5-9/16'' and the flywheel OD is 10-5/8''..  Anyway I will let the pics explain more.

I would be concerned some about side load. 9" to 10" from the face of the flywheel is way too much.

There is a flat D722 flywheel from a grasshopper mower for sale on eBay. I might have a left over starter plate from a Kubota z482. I'll have to get in the garage and look. The starter plate should fit the D722.

China makes a Kubota clone starter that will work. No reason to spend lots of money on an oem starter. The Chinese starters worked fine on my projects.

Henry

[keith71]

Bob and Tom.. Thank you for the reply.  I like the way you guy's think.
                                                                                                                                                                                                                                                      I will post a few more pictures. Bob those three bolt holes are there for a plastic fan that cooled the radiator. They are only M6 size bolts. Do you think they will be strong enough? It looks like their might be some room to drill and tap for an M8 size bolt.                                                                                                                           

Also this rotor is deeper than it looks.  With a 3-4 inch shaft, the end of the shaft where the pulley will be mounted will be 9-10 inches from the face of the flywheel.            Should I be concerned that it might be to much sideload on the crankshaft and bearings? Also, the register where the 3 bolt holes are 5-9/16'' and the flywheel OD is 10-5/8''..  Anyway I will let the pics explain more.

I would be concerned some about side load. 9" to 10" from the face of the flywheel is way too much.

There is a flat D722 flywheel from a grasshopper mower for sale on eBay. I might have a left over starter plate from a Kubota z482. I'll have to get in the garage and look. The starter plate should fit the D722.

China makes a Kubota clone starter that will work. No reason to spend lots of money on an oem starter. The Chinese starters worked fine on my projects.

Henry

See post #12 Thanks.