Introduction and help please (Another D750 -> D850 swap)

TheH

New member

Equipment
B7100D
Jul 15, 2020
2
0
1
UK
Hello,

My name is Howard and a month or two ago in a moment of lockdown weakness/madness/clarity* (*Delete as appropriate) I decided that it was time to invest in a big boys tractor and buy a Kubota compact. A B7100D to be precise. The machine in question has an engine issue and I was aware of this at the time of purchase and this was reflected in the price, putting the machine within reach. A good price for a machine in the UK, and enough to make you squirm and recoil in the US etc I expect? They seem to be relatively cheap to own across the pond? I received the tractor partially dismantled (again with full knowledge of this) with all its parts as the prev. owner didn't have time to fix it and had purchased a replacement. This being the case I had not heard the tractor run of course. I stripped down the engine having been made aware that cylinder number 2 in the D750 was unwell. It soon became apparent that the problem had been a bad case of rod knock.
20200709_164429.jpg

On making some enquiries I was informed that this crank was no more an beyond a grind. Having looked into a replacement crank and some other components to rebuild it seemed that this was not the way to go due to the eye watering cost, and the search for a replacement engine commenced. I found a welder generator with a running (only by word not action) D850. I have started to change out the various elements from it, such as the oversized oil pan and the bell housing and flywheel, with a view to swapping in the components from the D750 and at this point I reach my question. I believe that the flywheel should be attached to the crank end in a particular orientation, but I am struggling to find exactly how to achieve this. Any help would be gratefully received.

Thanks

H
 

kubotasam

Well-known member

Equipment
B2410, B7100dt, B7500,Woods BH750,Landpride 2660RFM, Tiller, B2781 Snowblower
Apr 26, 2010
1,200
125
63
Alfred Maine
The bolt holes have a slight difference in the spacing. It looks like you can just put the flywheel on and tighten the bolts. What you need to do is make sure that the bolts will thread easily into the crank just by hand. If not find out why and fix it. Next place the flywheel on the end of the crank and try putting the bolts in. If they all thread easily all the way in by hand then you got lucky. If not then remove the bolts and turn the flywheel one hole and try the bolts by hand again. Repeat as necessary till you find the correct position. Remember thread bolts only by hand till they will all go in easily then use a torque wrench to fully tighten them.
 
  • Like
Reactions: 1 user

TheH

New member

Equipment
B7100D
Jul 15, 2020
2
0
1
UK
The bolt holes have a slight difference in the spacing. It looks like you can just put the flywheel on and tighten the bolts. What you need to do is make sure that the bolts will thread easily into the crank just by hand. If not find out why and fix it. Next place the flywheel on the end of the crank and try putting the bolts in. If they all thread easily all the way in by hand then you got lucky. If not then remove the bolts and turn the flywheel one hole and try the bolts by hand again. Repeat as necessary till you find the correct position. Remember thread bolts only by hand till they will all go in easily then use a torque wrench to fully tighten them.
Thank you, great information to have before I got the impact out and broke something