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Old 12-23-2008, 08:20 PM   post #1 of 9
FD611V
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Default Intake/Exhaust valve adjustment on JD 345

The following information comes from. John Deere 235,335,345 Technical Manual.

NOTE: Valve Clearance Check And Adjustment on Kawasaki 20hp V-twin
IMPORTANT: Make adjustments when engine is cold.

PROCEDURE: Turn crankshaft until piston is visible, or at Top Dead Center of the COMPRESSION stroke...Both INTAKE and EXHAUST valves will be CLOSED.

Question: Does the above procedure make sense?

How in the world will a engine run correctly when both "intake and exhaust" valves are "opens and closes" at the same time? This don't sense at all.
I learned a long time ago when working on gas engines, that intake and exhaust valves have to be adjusted when one is closed and one is open.

So, is there anyone here that has adjusted the valves on a John Deere V-twin...different than what the procedure states above?


Follow-UP... Here is my thinking on how these valves should be adjusted.

Move crank pulley so piston is TDC..Compression stroke. One valve..intake or exhaust should be fully depressed (open). Make .010 gauge measurement to the other valve. Move crank pulley so the cam rotated again to TDC, the valve that was open before now can be adjusted the same way..010. Repeat to the other side of engine. Will this be the correct way?

Last edited by FD611V; 12-23-2008 at 08:40 PM.
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Old 12-23-2008, 08:48 PM   post #2 of 9
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Default Re: Intake/Exhaust valve adjustment on JD 345

Both valves will be closed when the piston is at the top on a compression stroke. On a twin cylinder engine you adjust one cylinder at a time.
The manual ,at least for me, is easy to understand. It is saying to adjust only one cylinder at a time.
Dave
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Old 12-23-2008, 10:10 PM   post #3 of 9
Walt 2002
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Default Re: Intake/Exhaust valve adjustment on JD 345

DLF above is right.

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Old 12-23-2008, 11:55 PM   post #4 of 9
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Default Re: Intake/Exhaust valve adjustment on JD 345

Yep - on the compression stroke in a four-stroke engine, all valves for the cylinder in question have to be closed. If they were not all closed, you'd have no compression.
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Old 12-24-2008, 07:42 AM   post #5 of 9
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Default Re: Intake/Exhaust valve adjustment on JD 345

I agree too. No compression, no big bang, tractor make no noise.........

Merry Christmas!!!!
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Old 12-24-2008, 08:41 AM   post #6 of 9
FD611V
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Default Re: Intake/Exhaust valve adjustment on JD 345

Gentlemen, I just might be from the old school on valve adjustments.

Some of you may follow what the "new books" says. There's the old way, and there's the new way, so to speak. I'll take the sure way, as it's the best way to insure proper valve clearance.

So here's two versions on how it can be done.

1) In written form... as you have stated in your posts here.

2) In a video form... the old way... the sure way.

Results: Probably come out the same on valve clearance.





Adjusting Overhead Valves the modern way according to John Deere's bible.

Turn the flywheel to close both valves.

Insert a narrow screwdriver into the spark plug hole and touch the piston. Turn the flywheel clockwise past top dead center until the piston has moved down 1/4". Use the screwdriver to gauge the piston's range of motion. PLEASE NOTE: This procedure must be performed for each cylinder on V-Twin engines.

Check the valve clearance by placing a feeler gauge between the valve head and the rocker arm. Clearances differ for the two valves and typically range from .002 - .004" to .005 - .007". Valve clearance specifications for your engine series are available by viewing our Engine Specifications Chart.

Adjust the clearances as required by turning the rocker screw. Once adjustments are completed, tighten the rocker nut.

Install the valve cover, using new gaskets, as required, and make sure the cover is secure.



The Old Way. Less headache and accurate.

Clink on Video link here. Scroll down to Rider Repair. Valve Adjustment on V-Twin.

http://www.smalleng.com/Repairvideos.html

Last edited by FD611V; 12-24-2008 at 10:01 AM.
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Old 12-24-2008, 09:43 AM   post #7 of 9
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Default Re: Intake/Exhaust valve adjustment on JD 345

I just have a couple of things to mention on this subject.

Anyone that uses the new method has never set 48 valves on a V-12 engine.

Whom ever wrote the manual that said to put a slim screwdriver in the plug hole as an indicator of TDC is an idiot. After breaking a wooden dowel in a 17HP single Briggs, because of the piston to plug hole geometry, I'll never put anything in the plug hole except a drink straw.
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Old 12-24-2008, 10:16 AM   post #8 of 9
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Default Re: Intake/Exhaust valve adjustment on JD 345

Maybar, there are many that don't know what Compression Stroke means. Like here is a true description. You are correct about the screwdriver effect. Surely would be a disaster when one really don't know how to use a screwdriver.
--------------------------
Valve design for the four-stroke small engine includes one intake valve and one exhaust valve per cylinder.
Intake valves open to allow the air-fuel mixture to enter the combustion chamber. Exhaust valves open to allow spent fuel gases to leave the engine. Both valves close to seal the combustion chamber for the piston's compression stroke.

Valve springs push the valves toward the closed position, so that they open only at precisely timed intervals. The valves are pushed open by tappets that ride on the lobes of the camshaft. The camshaft turns along with the crankshaft; both are driven by the movement of the piston. This synchronizes the actions of the vales with those of the piston.

In L-head engines, the valves are located to one side of the cylinder. The valve stems run through the cylinder block, parallel to the piston.

In overhead valve engines, the valves are located in a cylinder head that is much larger than that found in an L-head engine. Overhead valves are pushed open by pivoting rocker arms, operated by push rods. The push rods, in turn, are pushed toward the rocker arms by the tappets. The slightly more complex design yields greater power.
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Old 12-27-2008, 08:53 PM   post #9 of 9
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Default Re: Intake/Exhaust valve adjustment on JD 345

FD611V,
Now that you have impressed us all with your knowedge of internal combustion engines, what is your point? The instructons you sited in your first post simply tells you to set both intake and exhaust valve lash at TDC on the compression stroke. I don't see what the confusion is?
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