Author Topic: Fh721D  (Read 1288 times)

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Offline bighead9007

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Fh721D
« on: January 09, 2017, 05:34:09 PM »
On cam there are two ball's that moves, can I take them out or leave them in.


johnny

Offline bighead9007

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Re: Fh721D
« Reply #1 on: January 09, 2017, 05:54:00 PM »
Any help would be great.
johnny

Offline Kokamo

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Re: Fh721D
« Reply #2 on: January 09, 2017, 09:53:22 PM »
On cam there are two ball's that moves, can I take them out or leave them in.

On the parts diagram, there should be 6 balls on the govoner....assuming that's what you're talking about (as that's the only ball located in the entire motor that I can see), they are to limit the top speed of the engine. It is critical they stay in there for safety reasons.You can take them out, but unless you have a billet flywheel or billet rods, you run a high risk of the engine coming apart and possibly injuring you or someone.

~Joe
"Mow" Joe Hopkins
Liberty Hill, Tx


Offline Kokamo

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Re: Fh721D
« Reply #3 on: January 10, 2017, 09:49:04 AM »
Ok, I see what you're saying now. There are 2 balls in the camshaft itself. Those are there for the ACR (auto compression release). They release a bit of compression at a low RPM (cranking speed) by opening the exhaust valve just a tiny bit at the right time. This makes it easy on the starting components for longer life. You really should keep these installed and in working order, especially if you make any sort of compression changes or timing advances.

~Joe
"Mow" Joe Hopkins
Liberty Hill, Tx

Offline bighead9007

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Re: Fh721D
« Reply #4 on: January 10, 2017, 01:08:49 PM »
Any know if a fh770d cam will fit a fh721d block.im trying to get a little more lift and duration.
johnny

Offline Kokamo

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Re: Fh721D
« Reply #5 on: January 11, 2017, 08:14:43 AM »
Any know if a fh770d cam will fit a fh721d block.im trying to get a little more lift and duration.

They are the same part number, so yes it will fit, but it's exactly the same cam. Best thing to do is call Precision Cams and ask if they can re-grind your stock camshaft into whatever you want.

As far as I know, there isn't much of any performance parts for the Kawasaki motors except for the big single (FC420 I think)....if you look deep enough here, there's someone out there making rods and flywheels....I don't know who it is tho.

All I know is that if I had the chance to build a Kawasaki, that would be my motor of choice....the way the heads are built, they seem like it would have so much more potential. I'm not sure why there's a lack of performance parts for them.....they are great motors!!

~Joe
"Mow" Joe Hopkins
Liberty Hill, Tx

Offline Jeff McKelroy

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Re: Fh721D
« Reply #6 on: January 13, 2017, 07:55:05 PM »
Same here Kokamo, I've recently had by horizons broadened with Kawi Twin engines. I think if someone worked these it would raise the bar considerably.


Offline Kokamo

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Re: Fh721D
« Reply #7 on: January 13, 2017, 11:34:27 PM »
Same here Kokamo, I've recently had by horizons broadened with Kawi Twin engines. I think if someone worked these it would raise the bar considerably.

You are right Jeff. I sell new riding mowers for a living and I get to experience how different new twin engines run being brand new. I sell Briggs, Kohler and Kawasaki. The Kohler motors are your typical twins...they do what they are supposed to do...they start, they run good, they mow grass. The Briggs motors are the same as Kohler, but they seem to be a tad smoother and don't make as much noise. The Kawasaki motors....they are an entirely different animal. They start up quick, they don't make any clicking or clattering noises, you can't hear the pre-ignition ping you hear in the Kohler motors, they have impressive throttle response, they have an impressive amount of torque as they don't bog down when turning on a 50+ inch deck....and they are dead smooth with almost ZERO vibration. Now you take all that from a Kawasaki and take in the advantage of the canted valves they have, slap in some ARC rods, an ARC flywheel, a precision cam, a little port work along with a bit of carb work, I would think that would be an almost bulletproof motor!

On the brand new mower I just bought only to tear apart to build a racer (CUB XT2), it had an FR600V 18hp Kawasaki. I've been saving this motor that has less than 5 min run time on it, in hopes someone will make performance parts for it, but I'm not holding my breath! I took the valve cover off and I'm impressed with the valve angles and they look like they could benefit a performance application. Kawasaki shows a max torque of 32.4 ft lb's at only 2200rpm....this is why it has awesome throttle response, but looking at the dyno graph, the torque curve is relatively flat across the full RPM range.....that gives me hope of a great running motor all around under a performance build with one of these motors.

I can't wait for go-fast parts!!

~Joe
"Mow" Joe Hopkins
Liberty Hill, Tx

 

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