Alrighty, before anyone jumps to any conclusions, this post is not what you are thinking about. It all goes down like this.

While running the DS wide open down a long stretch, it appears that my coolant is overflowing out of the overflow bottle, and making a mess everywhere.....including my leg.....lol

At first thought, bam head gasket leak-compression escaping into the water jacket and overpressureing my rad cap, blowing all of my coolant out the overflow....but I'm not burning white smoke.....It only seems to happen when it's pretty warm, (fan not coming on yet though), and when it does happen, if I stop it continues to **** out for some time.

I did a leakdown test, at TDC of the compression stroke....well the secong attempt anyways, lol....Results were only slightly tight intake valves. Nothing out the exhaust, nothing out the oil tank, nothing out the crankcase vent, and nothing out of the rad. I then thought the thermostat might prevent the leak from being detected, so I took off the cover and removed that. With the water jacker exposed, still nothing....

This pretty much baffles me, except for the possibility of maybe the rad cap isn't properly holding back pressure??? Thats my only guess. Has anyone else run into this problem before?

And on a side note, I decided to try running a hotter plug for methanol, but could only get them in Autolite brand. The two plugs are almost identical, with the exception of the autolite being just a hair longer...Less than a millimeter longer. I'm running 13:1 compression, and after the quad started running wierd, stumbling kind of....I pulled the plugs to discover that the piston had made love to my plug. The one plus was tapped just everso slightly so that the ground strap was toughing the electrode, and moved slightly to the side. The other plug had just a very tiny mark where the piston almost hit it.....It's a JE piston. Perhaps I can align the plugs in such a manner that the ground strap is facing in a way that it won't be hit? I wouldn't think the clearances were that close.... Hate to see a 14:1. Just thought I'd throw that out there for some FYI.

Thanks for the advice anyone has.

 

Sounds like you need to lift your leg when whizzing... hehehe

I vote for either a headgasket that is just starting to go bad, or a crack (my guess) between the combustion chamber (head or cylinder wall) and the coolant system.

The leakage point may be small enough that the higher psi of the combustion chamber will allow exhaust into the coolant system, but not back the other way. This would account for your not burning white smoke, or atleast not enough to be visually detected. A crack would account for it only doing it when warm.

I don't remember what pressure is used in a leakdown test. Is it anywhere close to compression pressure? Was the enging totally warmed up when you did the leakdown test? A very small crack may only leak when it is warm.

There is a pressure tester that is made to test both the radiator cap and the cooling system of your atv. (Often used at reputable auto repair shops)

A thermostat wouldn't prevent a leak from being detected--they don't seal all that well (for this test).

At times, magnafluxing the head and cylinder is the only way to locate some very small cracks.

There are different thickness aluminum washers (spacers) made for sparkplugs to align the opening of the plug in the desired direction. (Available from auto parts stores)

These are just my thoughts. I hope that they help.

 

I know this may sound stupid but I had the same thing happen to me.
I also did just about every test out there and all was okay.
The problem I had was when I put a temp gauge on the bike I
replaced the coolant with a cheap one, that boiled , which then blew
out of the water tank.

After replacing coolant with a good quality one it was ok, hope this helps.

 

Try engine Ice... but you have to flush the system good before hand it dos'nt mix with any other coolant.

 

Thanks for the replies, and I understand the idea of the crappy coolant and all, but why did it only start doing this now? I also thought of the idea of a small crack somewhere, but I'd have to and hope to think the chances are slim that thats the problem given the circumstances. doing the leakdown test, i hit ip with up to 110 psi by the time I was done, and not a trace of a leak in the coolant system. I guess I will switch out caps and see what happens. Thanks guys.

 

Another thought--could your water pump not be working at full capacity?

 

choose my rm did it to make sure the cap and the flanges are go, my cap was twicked a little

 

The first thing I have to ask is this:
Is it boiling out or pressurizing out.
Big difference between the two.
Lots of things can cause it to boil over and puke.
Only a few can cause it to overload the can and puke.

From the sound of it, it sounds like the latter? You don't mention any burns from your **** so I think your over pressurizing it? [img]i/expressions/face-icon-small-happy.gif[/img]

 

When it starts and I stop and watch it if I can, it seems likt it's boiling over, mind you this is the same characteristics as pressureing out....IE bubbling, hissing, etc. However, it does continue to do it for a short while after the quad is turned off. So no pressure is being created anymore to cause it to continue....but there could still be enough heat to cause it to continue to boil over. I picked up a new rad cap this weekend...However to no avail, same thing happens.

And on that side note I mentioned earlier about the spark plugs getting tapped by the piston.... It is happening more and more frequently now...even with the original NGK's!! Might have to investigate some carbon buildup or something...Wierd though. These both are baffling me, especially the rad coolant. I'm gonna throw in a coolant temp guage and see what the story is there. Maybe I'm runnign really hot for some reason.....

 

yes check your coolant temp like you said, to make sure it isn't just boiling over. but if the temp is alright and its pressuring out it pretty much must be a head gasket, staying optomistic of course that there are no cracks. combustion pressure is much higher than your air compressor is capable of, it is possible for a head gasket failure to be causing it that is undetectable with leakdown testing.

about the plug tapping, oh no you don't want that - if the strap comes off the whole top end is destroyed by it.
I run 14:1 compression piston and my outside plug strap will get its gap closed by the piston if its screwed in too tight - plug manufacturer directions say take it down finger tight and then use wrench to go 1/2 to 3/4 turn more and that is all. going all the way down to the point of total cush washer compression will cause my piston to tap it, but it will not get touched going by manufacturer directions of plug installation. and of course, everytime you take a plug out and put it back in it will be cushed further and further each time, eventually reaching the point of hitting the piston, making the need for having extra new plugs around that much more important. plug manufacturers also say total cush washer compression will interfere with the plug's designed heat range, but to what degree I do not know.
FYI a millimeter is about the thickness of a totally crushed cush washer.