First of all the plug comes out black and dry after running, might I need to jet it the only differences I made to it was planed the head, cleaned the air filter (it was fairly clogged) Sharpened transfer ports, new piston and cleaned everything. So what you recon.

Secondly could it be possible my head gasket is blowing after about an hour of runnin. Its a cometic, I torqued it, and the head has bigger bolts than stock. My reason for thinking this is because I seen a few drops of lquid around the head.

Also the bike is hard enough to start and If it doesn't start you have to take out the plug and clean it. Any help would be great.

 

Im not sure about your starting question but I know that I have tried cleaning plugs after they get fouled and that never seems to work I usually just put in a new plug and im ready to run.

 

I tried a mew plug but the same seems to happen and there not cheap plugs 13Euro a piece for me. I was talkin to a local bike guy today and he said to move my main jet down a notch( I.E move the circlip up one)

 

if you head gasket is seeping coolant out after an hour,i would suspect either the head is warped or the cylinder deck is warped somehow. if the head gasket was totaly blown youd be burning up all your coolant prety quick and smoking like a freight train. if it is hard starting or the plug is black, your probably a little rich,i would personally buy the manual and go through the check list of things

 

what main jet are you running? drop it down a size. for the hard starting up the size on the pilot jet. and it sounds like the cylinder might not be flat letting the coolant leak out.

 

I took the head and cylinder and head to be planed but the machineist did not want to plane the cylinder as he said there was a groove for the gasket in it, is that true? And which is the main jet and which is the pilot jet? when it comes to carbs I haven't got a clue.

 

Oh Yeah I don't know what main jet I have and I won't be able to work on my zilla til the weekend (homework, study and exams suck but I suppose it will help me get a job to buy more quads!! lol)

 

i have never heard of special grooves on the cylinder unless your cylinder is mofified in some way,do you have a normal head gasket or does it have those rubber ring things? be very careful how much is hacked off your cylinder if you ever do do it,i had 20 thousandths taken off of my old 250 and then it was to short so the piston hit the head,so i had to use a fat basegasket. i dont even think if you have the o-ring style head gaskets that there would be grooves in the cylinder for it. but i would definitely take off the least you can if you do. you should do a plug chop to check jetting,if its black its probably to rich,light light brown is to lean

 

as for the grooce in the cylinder- thats not true, take it somewhee else

your jetting is to rich, drop the main down about 3 sizes. 1 size wont do much but get a couple to make shure your covered. starteing hard is proly because its running to rich, thats why your plug keeps on fowling. what do you mix the gas at?

 

theres your problem right there. stock 500 cylinders don't have a grove in them. they should be flat. thats right if you do take to much off the cylinder it will cause the piston to hit the head and you will need a thicker base gasket to take up the space.
when you take off the carb. pull the bowl, and the hex jet in the middle is the main, and the one in front of it is the pilot. little small thing.