Could someone translate? I don't speak...

[K31Fan]

...Sparkplug. I'm really hoping this is the last motorcycle question I'm going to be posting here. Long story short I have a really bad problem with overheating. To the point where the coolant is boiling over into the reservoir tank, and out onto the ground.

I've tested the entire cooling system for blockages/leaks. I've tested and replaced the thermostat. I've replaced the fan temp switch; the fan works great now. There are no air bubbles of any problematic apparency in the system, I'm using the correct coolant, the water pump is functioning exactly as it should, the radiator cap doesn't seem to be leaking, and it hisses when I depressurize the system when its hot.

In short, I believe the entire cooling system is functioning as it should.

But I'm still overheating and boiling coolant.

Blown head gasket is a no-no. No white smoke from the tail pipe, and the oil wasn't milky.

Onto the spark plugs! I've heard that running too lean can cause the engine to overheat. So naturally I yanked the spark plugs out of my bike. After I'd discarded the unimportant parts (i.e. the rest of the motorcycle) I examined the spark plugs. But I can't 'read' them definitively to assess weather I'm running lean or not. Here are some photos:


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These are still new spark plugs. Only about 100-150 miles on them total. Although I did get the bike up to some pretty high revs riding it. I'm just curious if that little layer of white at the tip is indicative of lean running.

Also it seems 'reading' spark plugs is kind of a redneck way of telling if its running lean. But if it is running lean, wouldn't it be as simple a fix as turning the air screws a little tighter?

Any ideas that you guys could throw my way I'd really appreciate! I suppose the air filter could be the next thing to check. I'm running under the assumption that the jet sizes are stock. Maybe I should check that too...

[Hannu]

Please tell, what kind of bike / engine ? I know what engine it is not from spark plugs

If it is traditional type of carburettor, air screw has more effect on mid to high end rpm mixture. Your photos seem little colored so it is hard to say what is the real color of the plugs...
If you push the bike and it runs lean, yes it will heat engine up somewhat and also cause local boiling points, specially inside the cylinder head. However, it is not so simple. If you run the bike easy on city streets, have to be super lean mixture and some other problems if it boils.

And regularly de-pressurizing cooling system when it is hot is one of the best ways to cause local coolant boiling...

Depending on engine and circumstances, blown head gasket does not always mean huge amount white smoke and "milk".

[clublights]

Had the EXACT problem with my 86 Honda VFR.............


Bad Radiator Cap......... and a bad seal do to a crash from before I owned the bike the neck was messed up a bit.. smoothed that out and a new cap.. problem gone.


check that cap again!....


also to be DOUBLE sure.... you can "rent" a radiator tester from advance auto ( and others I'm sure) make sure your holding pressure in the cooling system... it's cheap ( you "pay" 70 for the tester.. return it get all your cash back) and you have the full piece of mind that the cooling system is solid... it will also test the cap. ( when I tested my cap .. tho it didn't seem to be leaking was only holding 5-6 lbs of pressure.. shoulda been 16... new cap all fixed... and since I found a "car version" it was only 6 bucks instead of the apparently gold plated one that honda sells for 50. )

[clublights]

And I'll piggy back on this topic unless I get no responses .. then I'll make a new one...

does anyone have a 4 Carb Sync I can borrow?

Tho Tfogg's rates are VERY reasonable...

I think I might have more of a problem then just carbs outta sync so I don't wanna ride over there...do it .. then figger out I have more issues to fix then redo it ...

Beer, or Ammo of choice can be provided for this favor ...

[JohnTRourke]

head gasket.

[streetglideok]

Have you used a coolant tester to test the freezing point/boiling point of the coolant? If its not at least a 50/50 mix, your boiling point will be too low, and youll have your problems. If that checks fine, Id suspect the radiator cap not holding pressure in the system. Plugs are too new to tell anything. Its not running rich, I can say that. More info would be great as to the bike.

[K31Fan]

Please tell, what kind of bike / engine ?
However, it is not so simple. If you run the bike easy on city streets, have to be super lean mixture and some other problems if it boils.

Depending on engine and circumstances, blown head gasket does not always mean huge amount white smoke and "milk".

Its a 1995 zx7-L3. So far the motorcycle has only been overheating at idle, or slow speeds. It seems the air rushing around it at highway speeds cools it enough to keep it under correct temp...wait, wha-? How do I diagnose a head gasket leak then?

Bad Radiator Cap......... and a bad seal do to a crash from before I owned the bike the neck was messed up a bit.. smoothed that out and a new cap.. problem gone.

Sounds like a damn good idea. I'll bet my local Autozone would have one.

If its not at least a 50/50 mix, your boiling point will be too low, and youll have your problems.

The coolant came premixed 50/50. So I may be incorrectly assuming that the manufacturer mixed it correctly. But that seems a little out there to me. What else would you like to know about the bike? In terms of miles it has 13xxx on it, and it's a 1995 Kawasaki ZX7-L3 model.

What type of test did you do checking the water pump's function?

I saw the coolant get sucked back into the bike when I blipped the throttle (also makes me think it's not a head gasket problem). And I took the water pump cover off and saw the impeller turn while the engine was running. The impeller isn't loose, and it won't turn after the engine is off since it's gear-driven.

Timing. incorrect timing will cause over heating / lean running

Good idea! That's definitely a possibility. I haven't worked on the timing yet... Are you talking about ignition timing? Engine timing? Or are they both the same thing?

[Byte Stryke]

Are you talking about ignition timing? Engine timing? Or are they both the same thing?

yes,

correction... they are USUALLY the same thing, as long as your timing chain/Gear hasn't jumped

[Hannu]

If you want to be sure about head gasket and/or other internal mechanical problems, bring your bike to a place that has engine leakdown tester... and someone who knows how to use it
Side note; many Japanese motorcycle engines have adjustable cam wheels so you can actually adjust each cam separately.

If your bike ONLY boils while idling or driving slow and works nice when ur on I-25 going 80mph, do not worry about fuel mixture, ignition / cam timings etc. things that need pressure inside cylinder to heat up the engine.

You probably know you need lower temp thermostat at 5000 ft than at sea level ?

[K31Fan]

If your bike ONLY boils while idling or driving slow and works nice when ur on I-25 going 80mph, do not worry about fuel mixture, ignition / cam timings etc. things that need pressure inside cylinder to heat up the engine.

You probably know you need lower temp thermostat at 5000 ft than at sea level ?

...That really doesn't make sense to me - not contesting it, just saying I don't understand.

Anyway, there's only one type of thermostat available for the bike. And that's the 82 Centigrade (179 Fahrenheit) one.

Also, why would running lean not be a problem if the bike doesn't overheat at highway speeds? Doesn't that just mean the air is cooling it down faster?