Valve Gap Question

[Texasmark]

My "Gator-ette....converted JD L110 to a get around vehicle with the deck removed and a big basket attached to the hood. Its getting old and I was thinking about, looking around for a replacement of some sort.

A 2 wd, 4 stroke Kawasaki 360 Prarie popped up on Craigs list with 580 hours used by a rancher to work his fences. He bough it new and didn't have any other people drive it and he didn't do Motor Cross or any racing....hours were 580. I jumped on it. Currently going through the getting used to it and fixing this and that. Owner's and repair manuals should be in next week. Rumor has it that these single engines have to have the valves adjusted frequently. I really doubt these have ever been adjusted.

The other thing is that even though the single cylinder is highly ribbed for heat dissipation, just letting it idle for a few minutes puts the combustion area in the 200+ range and the exhaust pipe half a dozen inches from the head pegs my 600F Non-Contact Infrared meter...which is accurate. In reading notes online an exhaust valve being too tight would be cause for hotter running......that makes sense.

Tomorrow I am going to dig into that area and verify the clearances. The reason for my question, and it would pertain to a tractor just as well, crrently the engine runs but backfires off and on. In N, no problem answering the throttle......it is right there. I am assuming that if an exhaust valve doesn't close properly, due to no gap or sticking, part of the combustion comes out before its time allowing for a backfire. An intake too tight would be belching fire out the carburetor I would think......am I on track? The fact that its hit and miss....sometimes it does and sometimes it doesn't makes me wonder about just a valve adjustment.....i.e. what would make it intermittent rather than continuous if that is what it was.

I have fresh gas in it and have been feeding it Sea Foam in the fuel, fresh oil and filter change, spark plug checks out. It has responded to the fuel and additives but still idles erratically and there is the backfire. I have a new carb ordered for it incase sitting up gummed up the jets which I never had any success cleaning out over the years. New carb was only $35....not worth the hassle on cleaning mine.
Thoughts appreciated,
Thanks Mark

 

[stdsch40]

You might want to be a bit more specific in your description of the problem, alot of useless emotion in your post...
What exactly did you check and verify regarding valves, timing, etc. Many people complain about engines that don't 'run right' Get yourself a manual.
Check out https://www.kawasakimotorcycle.org/whats-new/posts/857153/

 

[Texasmark]

You might want to be a bit more specific in your description of the problem, alot of useless emotion in your post...
What exactly did you check and verify regarding valves, timing, etc. Many people complain about engines that don't 'run right' Get yourself a manual.
Check out https://www.kawasakimotorcycle.org/whats-new/posts/857153/

"Owner's and repair manuals should be in next week." Going to dig into it today....just looking for some encouragement. Lots of stuff to get out of the way to get at what you want and then, especially on the exhaust valve, you can hardly get to or see what you are trying to measure. Waiting on the manuals would be the prudent thing to do but I can make some headway while waiting for them without worrying about tearing up something.

 

[Fritz Maurer]

While it's never a bad idea to adjust the valves, I don't think 200 degrees at the cylinder head is out of the ordinary for an air cooled engine with no bower. It needs to be moving, that is what keeps it cool. If you need to have it running stationary while adjusting it, you should have a fan of some sort to blow the hot air away from the motor.

If it is backfiring from the exhaust, that is a lean condition caused by dirt or water in the carburetor.

As a matter of opinion, I suppose a tight exhaust valve could cause elevated temperature, but in my experience the effort to crank the engine is greatly reduced, even more so when hot, so that the remedy was obvious. If the exhaust valve really is the problem you should be able to hear it, while holding your ear near the exhaust pipe while a helper cranks the motor with the ignition off.

 

[TerryfromSWIowa]

You don't say what year but 580 hours I think would mean a lot of setting not being ran.

 

[riverbend]

The temperatures don't sound out of line. On air cooled bikes, stainless exhaust pipes always turn blue (~5-600F). Give it a good tune up and see what you get. If it starts, idles and revs out cleanly, the carb is probably fine. Maybe drain the float bowl and see what you get.

If you really think the carb is the problem, I would not bother putting a $35 carb on it. Better to take it a bike shop and have them clean the one you have.

 

[Texasmark]

Thanks for these opinions. The carburetor is right in front of me now, with the fuel tank cover, tank, and shield removed, and the new one will be here shortly. After my first run and in checking the temps, I did put a shop fan in front of it. I hear you on keep it moving. Unlike my BS lawn mower V2 air cooled which has a built in fan, I guess when I get to where I am going I should just shut it off and restart it when moving on. Considering the effort required to get to that exhaust valve, I think I will wait for the carb, install it and go from there.

 

[Ozlander]

I don't think an engine with 600 hours on it needs to have the valves adjusted.
Especially a Kawasaki.

 

[Texasmark]

I don't think an engine with 600 hours on it needs to have the valves adjusted.
Especially a Kawasaki.

Thanks I agree especially when it was owned for 20 years by a rancher that just checked fence with it and was 50 years of age at the time. He sold out and moved to town, keeping the machine thinking he'd use it putting around town which he said he didn't. His house was in a new subdivision so it hasn't been sitting all that long......forgot to ask him. Phew. I hope we are spot on with our assumptions. Would surely save me a whole lot of work in an area unknown to me.......not being a tractor. Grin.

Edit: Thinking about what you said, running lean could explain why the backfiring is random, not repetitive like one (I would) would expect with a mechanical malfunction that would manifest itself with every stroke of the piston.

 

[Eric in IL]

My "Gator-ette....converted JD L110 to a get around vehicle with the deck removed and a big basket attached to the hood. Its getting old and I was thinking about, looking around for a replacement of some sort.

A 2 wd, 4 stroke Kawasaki 360 Prarie popped up on Craigs list with 580 hours used by a rancher to work his fences. He bough it new and didn't have any other people drive it and he didn't do Motor Cross or any racing....hours were 580. I jumped on it. Currently going through the getting used to it and fixing this and that. Owner's and repair manuals should be in next week. Rumor has it that these single engines have to have the valves adjusted frequently. I really doubt these have ever been adjusted.

The other thing is that even though the single cylinder is highly ribbed for heat dissipation, just letting it idle for a few minutes puts the combustion area in the 200+ range and the exhaust pipe half a dozen inches from the head pegs my 600F Non-Contact Infrared meter...which is accurate. In reading notes online an exhaust valve being too tight would be cause for hotter running......that makes sense.

Tomorrow I am going to dig into that area and verify the clearances. The reason for my question, and it would pertain to a tractor just as well, crrently the engine runs but backfires off and on. In N, no problem answering the throttle......it is right there. I am assuming that if an exhaust valve doesn't close properly, due to no gap or sticking, part of the combustion comes out before its time allowing for a backfire. An intake too tight would be belching fire out the carburetor I would think......am I on track? The fact that its hit and miss....sometimes it does and sometimes it doesn't makes me wonder about just a valve adjustment.....i.e. what would make it intermittent rather than continuous if that is what it was.

I have fresh gas in it and have been feeding it Sea Foam in the fuel, fresh oil and filter change, spark plug checks out. It has responded to the fuel and additives but still idles erratically and there is the backfire. I have a new carb ordered for it incase sitting up gummed up the jets which I never had any success cleaning out over the years. New carb was only $35....not worth the hassle on cleaning mine.
Thoughts appreciated,
Thanks Mark

A lean mixture can cause excess heat.

I was breaking in a fresh overhaul on a Massey 65. Every setting was per the service manual. Plowing with a 3 bottom plow. Tractor was running warmer than it had in the previous 30 years. Opened the main jet about 1/8th of a turn. Temperature got better. Opened it another 1/8th turn. Temperature gauge then ran in the same spot it had for 30 years.

I would save the original carb until you know if the $35 carb works.

40 years ago I added a small 12 volt fan to a Polaris trail boss (air cooled). Put a switch on the handlebars. Turned it on when I was putzing around spraying fence rows. Seemed to help.

 

[Mule Meat]

So you bought a used Kawasaki 360 Prairie with only 580 hours.

What prompted you to tear into the engine in the first place? Was it actually missing or was it more of a just "something I heard about" that got you digging into it? Sitting letting the engine idle will have the exhaust pipe turning cherry red in a short period of time. Especially on an air cooled atv.

Daughter has a 2008 Honda Rubicon 500 that has over 18,000 miles and nearly 2000 hours on it. It's never had the plug out of it nor the valves adjusted. Only thing that has been replaced with OEM parts are the front wheel bearings, swing arm bearings (got busted towing a kids170 RZR about 20 miles to get him home) and a starter.

 

[Factotum]

Tight exhaust valves can cause popping out the exhaust. No harm in checking the clearances. If it is close to the small end of clearance it can become no clearance once warm and begin popping. Set them to the high end of the specification, valve clearance goes away, never gains clearance. Good luck and have fun, sounds like an interesting project.

 

[Ray,IN]

Every engine I know about has a specific hot and cold valve lash setting clearance. Either one works fine. I do however agree with Ozlander, valve lash should not require adjusting.
An example; Cummins diesel engines recommend resetting valve lash every 150,000 miles.
This online hrs to mileage calculator says 580 hrs = 5,800 miles @ 10 MPH, That's a lot of miles on a UTV.

 

[Mule Meat]

Every engine I know about has a specific hot and cold valve lash setting clearance. Either one works fine. I do however agree with Ozlander, valve lash should not require adjusting.
An example; Cummins diesel engines recommend resetting valve lash every 150,000 miles.
This online hrs to mileage calculator says 580 hrs = 5,800 miles @ 10 MPH, That's a lot of miles on a UTV.

You can't compare a Cummings or a car engine to one used on an ATV. Diesel engines normally operate between 800-2100 rpm and a car/ truck 900-2500 during normal driving while an ATV engine spends most of its time in the 3000-5000 rpm range.


Just getting broke in..

 

[Ray,IN]

Assuming your engine is a Kawasaki 4-stroke, 2-cyl; this is the service manual. ".004"-.006" cold every 300hrs." So, you are right about valve clearance adjustment.
I was completely wrong earlier, sorry.
Were it my engine I'd add a bottle of Gumout to the gas before performing valve adjustment to clean away any carbon deposits first. Run that tank out first.
When I use Gumout in an auto engine, I remove air pipe from top of intake and using my thumb trickle about ½ the bottle in slowly enough not to stall engine. The rest of the bottle I pour in quickly and the engine stalls. Turn off ignition, next day start engine, it normally smokes and runs rough, but when it smooths out the difference in the engine is obviously much better.
I once had a Dodge V-8 that backfired out the exhaust so bad it blew exhaust gaskets. That Gumout trick stopped the backfiring completely.
An old mechanic taught me that method in the late 1950's.

 

[Mcrafty1]

Just thinking out load....I bought a new Chrysler Concord in 92, thing had a lifter that hammered when started cold from day one, it obviously had been run by the dealer before I got to it the day I bought it. I listened to that about a week and decide to try some snake oil....first thing I came to was a can of Gumout, grabbed that and poured it in the oil and ran the vehicle home (about 40 miles) and never heard it again, I traded the car of in 99 with 91,000 on the clock. Great stuff.

 

[Texasmark]

A lean mixture can cause excess heat.

I was breaking in a fresh overhaul on a Massey 65. Every setting was per the service manual. Plowing with a 3 bottom plow. Tractor was running warmer than it had in the previous 30 years. Opened the main jet about 1/8th of a turn. Temperature got better. Opened it another 1/8th turn. Temperature gauge then ran in the same spot it had for 30 years.

I would save the original carb until you know if the $35 carb works.

40 years ago I added a small 12 volt fan to a Polaris trail boss (air cooled). Put a switch on the handlebars. Turned it on when I was putzing around spraying fence rows. Seemed to help.

Adding a fan has already been a thought. I do a lot of putting around and stopping to check out this and that. To restart every time would not be to my liking.

 

[Texasmark]

So you bought a used Kawasaki 360 Prairie with only 580 hours.

What prompted you to tear into the engine in the first place? Was it actually missing or was it more of a just "something I heard about" that got you digging into it? Sitting letting the engine idle will have the exhaust pipe turning cherry red in a short period of time. Especially on an air cooled atv.

Daughter has a 2008 Honda Rubicon 500 that has over 18,000 miles and nearly 2000 hours on it. It's never had the plug out of it nor the valves adjusted. Only thing that has been replaced with OEM parts are the front wheel bearings, swing arm bearings (got busted towing a kids170 RZR about 20 miles to get him home) and a starter.

The engine wouldn't start without a dose of starting fluid. The PO had drained the tank when he put it up but didn't run the engine out of gas. I started chemical gas treatment (Sea Foam which has worked wonders for me over the years) and improved it significantly but there were still issues. I may get a can of Gumout the next time I go to town and give it a try while I still have access (Ha) to things.

I had forgotten when I drove a motorcycle to work that air cooled bikes needed air over the fins to keep them cool.....so I put a shop fan in front of it while I was running it to let the chemicals work and hopefully clean out the carb's passages. I would have been happy having to do nothing but change the dirty oil and filter.

I thought about converting another one of my lawn mowers (tractors ha) to the task and decided to visit Craigs list and see if anything caught my attention. The ATV popped up, great price, great history and a much softer ride on my hard clay soil than a lawn mower so I checked it out and made the purchase......not sorry. At my age I am more of a user than fixer. It it works I leave it alone but with 7 Diesel tractors, 30 to 84 HP, seems something is always needing attention.

 

[TerryfromSWIowa]

You can't compare a Cummings or a car engine to one used on an ATV. Diesel engines normally operate between 800-2100 rpm and a car/ truck 900-2500 during normal driving while an ATV engine spends most of its time in the 3000-5000 rpm range.


Just getting broke in..


View attachment 97313

I don't know what a Cummings is only heard of a Cummins.

 

[Mule Meat]

Assuming your engine is a Kawasaki 4-stroke, 2-cyl; this is the service manual. ".004"-.006" cold every 300hrs." So, you are right about valve clearance adjustment.
I was completely wrong earlier, sorry.
Were it my engine I'd add a bottle of Gumout to the gas before performing valve adjustment to clean away any carbon deposits first. Run that tank out first.
When I use Gumout in an auto engine, I remove air pipe from top of intake and using my thumb trickle about ½ the bottle in slowly enough not to stall engine. The rest of the bottle I pour in quickly and the engine stalls. Turn off ignition, next day start engine, it normally smokes and runs rough, but when it smooths out the difference in the engine is obviously much better.
I once had a Dodge V-8 that backfired out the exhaust so bad it blew exhaust gaskets. That Gumout trick stopped the backfiring completely.
An old mechanic taught me that method in the late 1950's.

I don't know what a Cummings is only heard of a Cummins.

And I do not see "autocorrect" as an option. But there it is doing its thang.