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Doug E.
Doug E., Kawasaki Master Technician
Category: Motorcycle
Satisfied Customers: 2886
Experience:  Professional motorcycle mechanic since 1978. Vintage motorcycle restorer.
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I have a Kawasaki 440 two cylinder air cooled engine. The exhaust

Customer Question

I have a Kawasaki 440 two cylinder air cooled engine. The exhaust gas tempature on the rear cylinder reads around 1200 degrees -normal. The front cylinder reads only around 600 to 700, yet the cylindar head tempature for the front cylindar reads normal-375.It is not running up to full power. What is wrong and where in South Jersey can I take it for service?
Submitted: 7 years ago.
Category: Motorcycle
Expert:  Doug E. replied 7 years ago.
Chat Conversation Started
Kawasaki Doug :

Hello,

Kawasaki Doug :

What type of motor is this? Is this in an aircraft?

Customer:

Hey Doug,

Kawasaki Doug :

Just wondering if this is a 2-stroke fan cooled motor like in an ultralight or is it a 4-cycle motor like the 440 motorcycle motor.

Customer:

Yes, it's in an ultra-light. I've heard this type of engine might have come off of a snow mobile. It's mounted upside down, the sparkplugs are on the bottem. There is a fan in front of the front cylindar.It is a 2-stroke

Kawasaki Doug :

You are correct. That engine was based on the snowmobile engine, but some changes were made.

Kawasaki Doug :

I have worked on both the snowmobile version and the ultralight version. Let me say up front that I am not an aircraft tech, but I have been around long enough that I did go to Kawasaki snowmobile service school. I understand that engine very well and I should be able to help you out.

Kawasaki Doug :

One thing to know up front is that your engine problem may suddenly develop into an engine seizure. Do not fly until you have the problem solved.

Kawasaki Doug :

I think you have an air leak in the motor. I suspect it's the crankshaft seal. This will cause a loss of power in one cylinder and cause the other one to work harder and overheat.

Kawasaki Doug :

I would do the following. Check your carb for dirt, water, etc. Verify that the manifold is not leaking. Also check to see if the exhaust gasket is leaking. If these checks find nothing, you should air test the motor. This is done by blocking the exhaust and intake. Air is pumped into the motor (use a fitting on the spark plug hole, or a fitting in the block off plate on the intake) and it is checked for leaks. You will want to use 8-10psi with a small hand pump. Have a gauge on it so you can shut off the air and read the gauge which will show any pressure loss. You should have none. Use soapy water to find any leaks. Repeat the test using a vacuum pump. This will test the seals in both directions.

Kawasaki Doug :

If you have a leak in the crankshaft seal, the engine will not build proper pressure in the lower end and not send the charge to the top end. You can have a loss of power, a lean condition or other things along that line. Rapid engine seizure can happen with this condition.

Kawasaki Doug :

Let me know what you have checked and if you will be able to check the engine for leaks. I would also do a compression test so you have a bench mark of the condition of your top end.

Customer:

I replaced the exhaust manifold I realy don't think it's an exhaust problem. I had the compresion checked about 6 months ago when the temperatures were only about 300 degrees differance.The compression test was around 155 and 160, only 5 lbs differance.

Customer:

Sorry Doug, I type very slow.

Kawasaki Doug :

Excellent, you have base compression numbers to compare against new numbers. Recheck the motor now to see if there is any change. An exhaust leak at the cylinder will raise the exhaust temp while the head temp will stay near normal. You can have some scoring on the piston if the leak is bad enough. It's just something to check and rule out. I don't want you to go digging into the motor if it's just a simple problem like a bad gasket.

Customer:

There is some oil leaking from a gasket. I forgot to say I checket the intake manafold with soapy water, no leaks.

Kawasaki Doug :

It's very common to see some oil seepage on that engine. It's only a problem if the gasket has failed and the engine is leaking air. On a two stroke engine it's critical that the engine hold air pressure. Unlike a 4-stroke engine, the 2-stroke uses the intake, exhaust and lower end in place of valves. It must be air tight or it won't work properly. One key is to use grease on the paper gaskets to seal them. If you use gasket sealer, they will leak. The paper gaskets will bond to the metal if you use grease instead of gasket sealer. It took me years to find this as the cure for gasket seepage on these motors. You do need gasket sealer on the exhaust gaskets. I use high temp Arctic Cat gasket sealer, but there are other brands that will work.

Kawasaki Doug :

The only way to verify that a gasket leak is a problem, or if the seals leak, is to air test the motor. It takes some time, but it is the proper way to tell the condition of gaskets and seals when you are faced with an odd problem. You can use rubber corks to block off the exhaust, or make block off plates out of aluminum and put a rubber gasket on these. Be sure to check the impulse line to your fuel pump if you are running a vacuum operated fuel pump with an impulse line to the crankcase.

Customer:

I'm hopeing to find someone to test and repair this problem for me. Where do I look?

Kawasaki Doug :

Are you in a local ultralight club? They might have a list of people you can use. Due to liability issues, most mechanics won't touch these. Any shop who works with snowmobile engines can do the test. I'm going to check with one of my buddies to see if he knows anyone in your area who can do this for you. He worked for Kawasaki for many years and knows everyone.

Kawasaki Doug :

I'm going to switch this from chat to regular question. That will give me time to ask him and get back to you. You can still reply and ask additional question as needed.

Doug E. and other Motorcycle Specialists are ready to help you
Expert:  Doug E. replied 7 years ago.
Chat Conversation Ended

If you are still working with your Expert on this question, you can post additional replies and receive additional information on this page.  If you received a satisfactory answer in Chat, you can accept the chat conversation above.
Customer: replied 7 years ago.
There are no snowmobiles in New Jersey. I could pull the engine off and ship it for $100 each way and hopefully remount it, I know of someone to send it to. I would rather take it to someone local
Expert:  Doug E. replied 7 years ago.
Sure there are. I've met a few. There are more snowmobile dealers there than you would expect. I've contacted Kenny to see if he can personally recommend a Kawasaki mechanic to you. A shop that restores Kawasaki snowmobiles would be ideal.

Doug
Customer: replied 7 years ago.

Sorry, I had to go to bed. Now I'm off to work.Please Email me at [email protected] if you have any more info.I am accepting your answer now so that you can get paid. Thanks so much for your help.

 

Bob

Expert:  Doug E. replied 7 years ago.
I heard back from Kenny but he doesn't know anyone in your area for this work. Any motorcycle shop should in theory be able to do an air test on that motor. It's a common service done on any 2-stroke motor.

All phone numbers and e-mails are blocked by JA so I can only reply from here. Sorry.

Doug

Edited by Kawasaki Doug on 8/19/2010 at 12:40 AM EST