Maintenance & Technical > KX500 Original

Help smashed or melted spark plugs

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BMH:
I have just recently got a new to me KX 500 1990 fresh rebuild top and bottom by a shop. I put a new oem head gasket on. The problem is... I was out for my first long ride and thought i fouled a plug so i took it out BR8EG (new)and the gap was smashed into the electrode the color is fine. I put in my spare and 10 miles later the same thing happened. I wont claim to be a genius mechanic but I took the the extra crush washer off the first plug and doubled up washers put it back in and made it home from BFE it ran a little weird not quite as responsive it was jetted perfect before. I pulled the 2nd BR8eg after getting back alot of high speed sandwash and it looks kind of melted? The original plug was a NGK B8ES.
 I am running the jetting on the great chart from this site with the moose reed spacer. I was doing alot of really tight single track first gear both times it happened. I dont think there smashed just melted. I am running 91 octane at 32 to one with red line pre-mix. any help would be appreciated. (jetting 162 main 58 pilot 2nd notch needle.)

GDubb:
I've never seen anything like that and it doesnt make any sense... if you are hot enough to melt plugs it seems you would be overheating like crazy or burning a hole in the piston.

BMH:
I am at a loss but not for power (so no hole in piston) I didnt overheat no loss of coolant it was a cool morning 60's, the first plug i pulled i didnt look at too close I was trying to hurrry and catch my buddy. I was riding a gear high trying to get some hook up, lugging it a bit thats why I thought I fouled the plug. The rest of the ride I stayed on the pipe thats when plug 2 melted down. The stranger part was after i replaced plug 2 with the 2 washers I ran flat out in sand washes for 20 plus minutes and got home I pulled that plug and it was fried.

BDI:
I would start by making sure your carb is clean with no pluged jets. Then I would follow that up with a leak down test. Doing a leak down test is easy and you can make your own leak down tester for cheap If you are interested I will explain how to do It. I wonder if it could be caused by a ignition timing problem :?.

    P.S. Don't take the engine apart before you do a leak down or you may never know what the problem is.

medicman:
I would be intrested in the leak down tester :-D

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