300 hours - clean combustion chamber, clean and lap valve seat surface

[WinterDeere]

Machine: Deere 757 ZTrak
Engine: Kawasaki 25 hp V-twin

Okay, most of us have (or have had) these ubiquitous Kawi V-twins on our mowers, we all know this engine. We all know it's good to check and/or adjust the valve clearance every few years, Deere happens to recommend 300 hours... all good. It's a clean and easy operation, no problem.

But they also recommend cleaning the combustion chambers and cleaning and lapping valve seat surfaces every 300 hours. Am I alone in thinking that's just insane? What are the rest of you doing?

 

[Racer4]

No experience with this particular engine, but I would not be tearing off the heads for any reason every 300 hours. That’s ridiculous.

Dad had a JD 325 with over 1000 hours on a 17hp Kawa single. Never had an issue. Tractor is now run by my FIL at his house. Still going.

I’ve got 600 hours on my Wheel Horse 314-8 and never pulled the head for cleaning.

 

[ericm979]

But they also recommend cleaning the combustion chambers and cleaning and lapping valve seat surfaces every 300 hours.

The 1940s called and wants their maintenance schedule back.

I'd check/adjust the valves and run it. What do new heads cost for it? A new head for the single cylinder B&S on my 27 year old Deere Sabre costs all of $250.

 

[WinterDeere]

...I would not be tearing off the heads for any reason every 300 hours. That’s ridiculous.

Agreed. I didn't even consider it at 300 hours, or at 600 hours. Now I'm at 1000 hours, and wondering if I should eventually do it.

All I've done so far is fluid changes every year, carb and idle adjust around 600 hours, and check the valve adjustment every 300 hours.

 

[Runner]

It's not just John Deere requiring it. I have a Cub Cadet with the Kawi FS730V engine and the engine manual from Kawi specifies cleaning the combustion chamber, check/adjust valves and clean and lap the valve surfaces at 300 hrs.

The manual for my Kawi Mule says to check/adjust valves at 50 hours.

On the other hand, the manual for my 1989 JD 185 with Kawi engine doesn't mention any of those items, they've never been done and it still runs fine.

I'm seriously considering just blowing it off.

 

[RandyT]

Some of the maintenance intervals for small engines are leftovers from the L or flat head days where carbon buildup was common and valve clearances needing adjustment along with cleaning and adjusting the points.

 

[WinterDeere]

Some of the maintenance intervals for small engines are leftovers from the L or flat head days where carbon buildup was common and valve clearances needing adjustment along with cleaning and adjusting the points.

Maybe, but I’d honestly be surprised if that’s the case for these Kawi 25 hp V-twins, as their most common application is commercial mowers that run 40-60 hours per week in-season.

 

[dfkrug]

It's not just John Deere requiring it. I have a Cub Cadet with the Kawi FS730V engine and the engine manual from Kawi specifies cleaning the combustion chamber, check/adjust valves and clean and lap the valve surfaces at 300 hrs.

Yes, that is absurd and you should ignore it.

These Kawasakis do have some weaknesses, which are infamous. The company struggled to make cam gears that would last. Plastic is not the best material for cam gears, but Honda and Kohler use them in some engines and their records seem to be better.

That said, the cam gears are so bad in Kawa twins that there have been cheap aftermarket kits available for years. Problem is, you have to pull the engine and take it completely apart.

I got a 4x6 Gator here a couple of years ago, where someone attempted the cam gear update, and did it incorrectly. He lost the oil pump spring, for one.

All of these OHVs need periodic attention to their valve clearances, but it is usually very easy. Hard to start is the clue.

Also, it you have a diaphragm fuel pump, E10 fuel makes the rubber stiff, and they often need replacement every few years.

 

[KennyG]

Valve adjustment, oil and filter changes on schedule. Everything else should be what we used to call RTF (Run To Failure).

 

[WinterDeere]

Valve adjustment, oil and filter changes on schedule. Everything else should be what we used to call RTF (Run To Failure).

Thanks, guys. That's the plan I'm presently on, just wanted to make sure I was in good company.