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Discussion Starter · #1 ·
Due to 20 years of use but only 760 hours of run time I found the mower deck was showing its age. The front wheels on the ZTR mower deck needed replacing. They were foam filled from the start but deteriorated and flopped around like two flat tires. So, I bought two replacement wheels with foam filled tires for $120. When I installed the new, correct size and specification diameter tires and rims the tires rubbed the mower deck. (expletives deleted) I studied the problem and there is no adjustment to pull the "wheel lift assembly" forward because slop had developed in the linkages and floating mounting locations. Geeze, what to do. After taking it all apart and looking at all the component the solution is simple if you have the tools and talent to execute the fabrication or modification to the Deck fork. I needed to reduce the caster angle (backward rake) that's built into the Deck fork. So, I decided to give each fork a "wedgie" cut.

I modified the fork using a power hacksaw to cut out a wedge shape on each side and drove it nearly closed to provide more clearance. There is a optimum amount of material to be cut out of the fork. Too much moves the wheel and tire too close to the bottom of deck fork. It requires a "just right" amount of modification.

BELOW IS THE BEFORE PICTURE


BELOW IS THE POST MODIFICATION OF THE FORK (but now yet welded)


LAYING OUT THE CUT AND ONE SIDE CUT (Dead blow hammer in background)


FINAL POSITION THAT PROVIDES NO RUBBING AGAINST MOWER DECK AND NO RUBBING AGAINST BOTTOM OF FORK (not shown)


FINAL POSITION which also requires grinding down some protrusions in the bottom of the fork (not shown)


Next step is to do the same on the right side, weld, paint and reassemble. Then on to the camshaft replacement.

Bill
 

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Nice work! It seems like a design that should have come from the factory.
 

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Discussion Starter · #3 ·
Nice work! It seems like a design that should have come from the factory.
I have concluded the design engineers did not consider deterioration and wear with use. I don't picture Woods or Grasshopper spending a great deal of money on engineering for reliability and maintainability. The hard welded steel sleeves wore internally because the bolts were selected such that the threads on the bolt which were riding inside the steel tube sleeve and acted like a file and ground the holes egg shaped like a file would do. And I don't know of any of these mower companies are any better. Maybe Honda. I still use a 1983 Honda single stage which has only required one repair (carb rebuild) when I let my Dad keep it and he left the same fuel in it without Stabil for 3 years. Things got a bit gummed up. 33 years and it starts first pull.

Bill
 

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Discussion Starter · #6 ·
More maintenance on mower deck fork

I examined the deck fork shaft and saw there were two small O-rings on the shaft that sat in a machine groove. One was totally worn down (top one) and the other was sitting in the groove and had more material left on the o-ring. I popped both of them out and replaced them with the correct thickness (1/16") and diameter (11/16"). I am lucky enough to have a newly outfitted real hardware store which has racks of Hillman products and it even has a knowledgeable person to help you find what you want. I went in with my specifications for the O-rings and she went right to the correct box. Sure, they cost me a $.25 each but geeze, they had them. I am going to continue to patronize them over big box stores.

Anyway, below is a picture of the new O-rings on the shaft that fits into Fork Mount.


The grease fitting in the fork mount shoots grease into the sleeve mid way between the two O-rings.

Below is the gap between the mounted tire and deck fork base. This gap is equal to the design without modifying the fork. It should have been designed with more gap as it came from the factory.

 

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Wow, a real hardware store...with what you need in stock...and a person who knew the product! All under one roof! How rare is that these days?! You should give tours of that place and charge admission.

Does the narrowness of that gap between the tire and fork cause any problems with catching debris the tire might pick up?
 

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Discussion Starter · #8 ·
Wow, a real hardware store...with what you need in stock...and a person who knew the product! All under one roof! How rare is that these days?! You should give tours of that place and charge admission.

Does the narrowness of that gap between the tire and fork cause any problems with catching debris the tire might pick up?
No tours planned but it sure is nice to have a real hardware store nearby.

The tight clearance hasn't caused any specific problems in its 19 years other than in the last few the tires both "flattened" when the foam fill softened and the tire flopped around. I am sure the minimal clearance contributed to the destruction of the front mower deck tires. I am just writing it off as a another dumb design from the clown car engineers at Woods or Grasshopper. I may have to splice in some pieces (i.e., cut and weld) to lengthen the forks. I don't think I have any steel of that thickness as home. I will have to pick up a couple of pieces at work.

Bill
 

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Discussion Starter · #9 ·
Fork material specifications

Since I don't like the potential rubbing of the tire circumference on the base of the fork I need to not only change the fork angle but lengthen it as well. So, I need some more steel that is that's 2" wide by 3/8" thick.

What is somewhat funny, if not pathetic, is I called Woods product support regarding removing PTO off the back of the Kawasaki so I can remove and replace the camshaft in the motor. I also talked to tech rep at Woods regarding the mower deck tire rub clearance problem and suggested I replace a couple of the parts. He couldn't specify which but it was obvious he had no idea about how the front wheel lift assembly wears out with use. My fork revision (i.e., reduced caster and lengthening) accounts for all the wear that has happened on wheel lift assembly to date and it protects for future wear out of mounting holes and brackets.

Below is a picture that specifies the quantity, width and thickness of material needed.
 

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Discussion Starter · #10 ·
3/8" plate steel purchased -- ready to modify

I picked up the 3/8" thick plate steel and need to cut off 4 pieces 2" long by 3/4" wide pieces. Also 4 diamond or triangular pieces need to reinforce the weld areas. The picture below is the weld prep requirements. You don't just butt weld these together. You use a double bevel weld. Then, you top it off with diamond on triangular shaped reinforcement of the welds created to added 3/4" to the forks. See picture below:

 

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Thanks for the updates and explaining the steps! That's good that you brought up this issue with one of the reps.
 

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Discussion Starter · #12 ·
Thanks for the updates and explaining the steps! That's good that you brought up this issue with one of the reps.
I am glad you appreciate the steps with pictures. It is mutually beneficial.

Any lessons learned are probably lost by Woods since whomever designed it probably works elsewhere, retired or dead. I don't think Woods will do much to revise the design.

The final fork dimension will be longer but the final ride height of the front of the mower deck should be more like what it was when I bought the machine 19 years ago. Wear and tear resulted in more caster that angled the wheel and tire into the mower deck.

Today I had limited time to work on the mower so I decided to remove the carb in preparation for pulling the manifold and heads. Nothing is straightforward on this engine.I t took more time studying the manual to figure out what to remove first. The Kawasaki has aluminum heads and block. Removing the heads is NOT a impact wrench task. There is a procedure for removing cylinder heads. Below is a screen grab from the JDeere technical manual section for the Kawasaki FD620D engine. See below for a screen grab from the technical manual for the engine.


Tomorrow I am off from work and I should have time to make some headway on modifying the forks if I don't get diverted by wanting to teardown the engine.
 

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Discussion Starter · #13 ·
Beveling to weld fork

Here is the double sided bevel that will be used on each welded area.


The below gives you the sense of the final fork angle when finished.
 

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Discussion Starter · #14 ·
No progress on the fabrication and welding. Now that I know what I need to do it is just time. I have the design, the tools and talent. Time to work on the mower has shifted to the engine.

The engine repair and reassembly is now in the reassembly phase once I clean all gasket surfaces. All parts have been received except for some studs to install the muffler and heat shield. Belts are on order for the PTO which is removed to work on the engine. The heads had the valves lapped and all surfaces cleaned. New valve springs were installed. My focus now is swapping out the camshaft to a steel geared one, lapping the valves, changing valve springs, and the rest of what is old will be new when finished. In other words, getting the engine running again. Once it runs again I will modify the front forks.

Bill
 

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That's quite the procedure for removal. I've seen those sort of steps for installation on engines I've worked on, but never for taking something off.
 

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Discussion Starter · #16 ·
That's quite the procedure for removal. I've seen those sort of steps for installation on engines I've worked on, but never for taking something off.
Yes, I agree, that was unusual to see a "de-torqueing" cylinder head bolt removal procedure.
 

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Discussion Starter · #17 ·
Tire rub on left side is fixed

I never showed the final modification to the front fork. One the left fork needed to be modified. Here is the modified fork which prevents the tire from rubbing the mower deck. It required changing the angle and lengthening the fork. The triangular piece on the outside is for extra strength and load transfer.


 

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Looks like that's doing the job for you. Has the change in the original angle and addition of length effected the tracking of the wheels?
 

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Discussion Starter · #19 ·
Looks like that's doing the job for you. Has the change in the original angle and addition of length effected the tracking of the wheels?
Tracking is just fine. The original deck caster angle worked fine. The rubbing wheel caster angle was far greater and the fork modification returned it to the original angle. It is simply a design prone to wear as it came from the factory.

Bill
 
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