So the main bearing on the block is trashed. John Deere doesn't sell the bearing separately and wants me to buy the entire block for over $1000! None of the small engine places I've called has the bearing or any way to order it, its not even listed as a separate part in the Kawasaki service manual. It is a pressed in bearing so I don't understand why it's not available. My question is, does anyone know if there is a bearing available from another model that will work? Having to pay over $1000 for a $15 bearing failure is ridiculous.
John Deere Ztrak 737 main crank bearings. FH680D-AS04 engine
- Thread starter evers310
- Start date
StarTech
Lawn Royalty
- Joined
- Feb 19, 2020
- Threads
- 80
- Messages
- 10,296
As far as I know these are not separate bushings but just crankcase and cover material used as the bearings. There is a manufactured step in the aluminum so they hone them to the correct size only.
Never seen any from Kawasaki either. They would have to be custom made. I wish there was but then you need reamers to install them.
Never seen any from Kawasaki either. They would have to be custom made. I wish there was but then you need reamers to install them.
I thought that at first as well, but if you zoom in on the pictures you will see that it is actually a separate bearing. On the one picture at the top in the keyway you can see the line separating the bearing from the case. And on the other picture you can see that it is separate all the way around. i’m hoping that there is another similar model that does not belong to John Deere that maybe actually has a part number for their bearing and that I could use that.
bertsmobile1
Lawn Royalty
- Joined
- Nov 29, 2014
- Threads
- 64
- Messages
- 24,705
Star is correct, there is no bush
What you are seeing is a casting fin caused by an insert that is put in the mould to make that slot and machining marks
If you take a photograph square on to the chunk that has broken off you will see that the grain pattern is continious and there is no joint line
I have used a speedy sleeve on the crankshaft then honed the bushing area once & I won't do that again.
It was not particularly easy to do but it was a old pensioners mower & I do these type of silly things .
If you have the jigs & fixtures to recut the bushing then it is a simple job but if you haven't then there is a good 4 to 5 hours in it which will cost more than a new block
The hole has to be in alignment with the top hole +/- 0.00005" and to size within +/- 0.0001" because it is running directly on the case without any bushing or rolling element bearing
There is a reason why a vertical shaft engine is only 2/3 the price of a horizontal shaft engine of identical capacity & power rating .
What you are seeing is a casting fin caused by an insert that is put in the mould to make that slot and machining marks
If you take a photograph square on to the chunk that has broken off you will see that the grain pattern is continious and there is no joint line
I have used a speedy sleeve on the crankshaft then honed the bushing area once & I won't do that again.
It was not particularly easy to do but it was a old pensioners mower & I do these type of silly things .
If you have the jigs & fixtures to recut the bushing then it is a simple job but if you haven't then there is a good 4 to 5 hours in it which will cost more than a new block
The hole has to be in alignment with the top hole +/- 0.00005" and to size within +/- 0.0001" because it is running directly on the case without any bushing or rolling element bearing
There is a reason why a vertical shaft engine is only 2/3 the price of a horizontal shaft engine of identical capacity & power rating .
Last edited:
Well crap, do you happen to know what speedi sleeve would fit on this engine? I have the service manual and it has all of the specs except for the bearing diameter and the clearance between it and the crank. Why that would be the one spec they leave out beats me.
bertsmobile1
Lawn Royalty
- Joined
- Nov 29, 2014
- Threads
- 64
- Messages
- 24,705
The sleeve is for the crank
SO the first part is to clean the crank & make the surface good
Then chase up a sleeve that fits the crank
The bush should be around 0.0001" to 0.00025" bigger than the crank as the alloy expands much faster and more than the steel crank so the running clearance gets bigger as the engine gets hotter .
Can you accurately measure down to tenths & hundreths of a thou ?
My gear only goes down to tenths of a thou
SO the first part is to clean the crank & make the surface good
Then chase up a sleeve that fits the crank
The bush should be around 0.0001" to 0.00025" bigger than the crank as the alloy expands much faster and more than the steel crank so the running clearance gets bigger as the engine gets hotter .
Can you accurately measure down to tenths & hundreths of a thou ?
My gear only goes down to tenths of a thou