Blown Head Gasket?

[alph]

All right, here’s my dilemma.

Went on a ride with a buddy today and he informed me that I would have some white smoke whenever I accelerated.  I had always thought that I was loosing oil but not 100% sure if it was being burnt, or just blowing out past a cylinder ring.  A friend suggested that I pressurize my radiator, pull my spark plugs, and see if I’ve got a head gasket coolant leak.  He said that if I do, antifreeze will flood that cylinder with the bad gasket, and that’s the easiest way to tell.  I’ve noticed that I do loose power when it gets hot.  Seems to need a little more throttle to move along.

Has anyone else had white smoke problems? 

I have had to add oil last month, but I had just done an oil change and I don’t think I topped it off.  Have ridden over 500 miles since then with no loss of oil.  My radiator is completely full, so is the reservoir so it doesn’t seem to be losing antifreeze.  Not really sure until I do the pressure test.

I’ll be doing a compression test tomorrow.  Does anyone know what’s a good cylinder pressure value?

Thanks guys, I know there’s a gear head out there somewhere with the answers!!

Al.

[Madmike]

Not knowing the mileage on your bike:

Compression test - 170psi - results for all cylinders should be within 10% - if one cylinder is low you can put a small quantity of oil in that cylinder, crank it over one time and then recheck the compression and see if it comes up, if it does it indicates that there is a ring problem, if the compression doesn't improve it indicates a valve problem.

White smoke can be either from low compression or coolant as white smoke is basically "steam" either from the water or the fuel turns to "steam or vapor" instead of burning, if you aren't losing coolant then most likely you have a weak hole.  Blue smoke is oil.  It is sometimes difficult to tell the actual color depending on quantities of smoke produced.  There is a device called an "Ingelmann Smoke Chart" that we used to use on big stacks to judge colour of emissions but I haven't seen one in years.

You may want to check for a "cold hole"; when you first start the engine feel the pipes right at the head and see if one cylinder is noticeably colder than the others - they will warm up fast so watch you don't burn yourself.  

Often when you have a head gasket problem you will get compression pressure into the cooling system (air) when the engine is running as the compression pressure should be significantly higher than the coolant pressure, then when you shut it down the coolant will fill the cylinder.  You can't always trust the level in the header tank if there is a head gasket problem as the rad may empty out and the header tank stay full as there may not be a vacuum created as the coolant cools when it is shut off because the leak at the head gasket.  If you are not losing coolant or overflowing the rad (because of air in the cooling system) you may not want to spend a lot of time pressure testing the cooling system if you aren't already equipped for it until you have ruled out a few other things first.

I would check and make sure that all the plugs are not fouled and firing and then with all the plugs out I would do a compression test (with the throttle wide open).  

Your problem may be as simple as a bad plug, a plug wire or even a coil that is breaking down when it heats up.  If there is one hole that is fouling you could try to go to a hotter plug just in that one hole as this may help keep the plug cleaner.  If you suspect the coil then you will likely see problems on a set of running mates and if this is the case you could swap the coil to another set of holes and see if the problem  stays with the coil  as you move it.  

Please keep us posted on your progress, regards, Mike

[Robert]

Mad Mike was pretty through in what he said but I would like to add that if the carbs are flooding then there will also be white smoke. A compression test is not good for coolant leak testing the first test with a radiator pressure tester left on is about as good as it gets. If you have a bad enough coolant leak that is bypassing the head gasket and going into the cylinder the first thing that will happen is you will keep pressurizing the cooing system.

[alph]

Mike, my cycle has 58k miles.  Today I'm going to take the thermostat out and see if it's working, and also check my compresion.  Two of the easiest things first.

Al.

[Momz]

White smoke/steam is not necessarily an indication of a blown head gasket. It may be that there has been a minor breach athe gasket/head/block interface. That type of condition doesn't warrant an immediate replacement of the head gasket. It was a common problem with older Goldwings and could usually be corrected by using a very small amount of "Bars Leak". There are several types made under this brand, however only use the brown liquid form. Do not use the pellets, or the metallic flakes in a liquid suspension.

About 3 capfuls poured into the radiator while cold should be sufficiant. Sart the bike with the radiator cap off and left the bike warm up untill the thermostat opens and allow to run no more than another minute, then shut off your motor. At this point you may need to rinse off any antifreeze that may have spilled from the open radiator.

In about an hour you should put the radiator cap back on (fully tight!). Take your bike out and ride it untill fully up to temp (about 20 min.), and it should be ridden at a constant highway speed for at least ten minutes.

You may still want to replace a breached gasket or better yet both, but you will be able to continue riding untill the end of your "riding season". Trust me on this one.

[Patrick]

Did your white smoke go away after awhile?? Or has it continued?? Condensation in the exhaust can cause this to happen for quite some period of time.. Some of these Honda flat engines will also leak some oil thru the valve guides will cause some smoking for a period of time after start-up,, that smoke color should be a blueish color but many times could be mistaken for white..Neither of these conditions is a problem.. I'm not sure why you want to remove the thermostat, but, checking the compression is OK.. Checking compression doesn't tell you anything regarding the condition of the oil rings though.. If the oil rings were defective though, you would know it.. It would be using oil and these engines rarely have an oil consumption issue.. Pressurizing the cooling system and looking for the leaks doesn't take a lot of time if you find someone with that particular neat little gadget.. looking into the top tank of the radiator with the engine running at a fast idle will sometimes let you know if there is cylinder pressure entering the cooling system.. If its not loosing coolant or using oil why not drive it for awhile to get the exhaust good and dry and see what happens..