BannedCR500Riders.com

Hi there, still fouling plugs on my bike. South eastern bush riding manily.. some tight single tracks but mainly 4wd/open tracks. 160 main, 38 slow jet, bp98 with motual 800 mixed fresh, clean air filter, repaked muffler. Starts easy hot or cold, idles great and runs crisp no flat spots etc then fouls plug.. going to 35 slow jet and what needle do u think? Carb is keihn pwk39. Thanks.

I think I'd be focusing on the needle rather than the pilot or main. 160 main seems way too lean.
I don't recall ever seeing anyone go that lean on the main on their 500 regardless of which carb they had.

Have you run out of adjustment on the needle?
My instinct says you've gone too lean on the main and are compensating with too much needle.

There's 33 pages of discussion using search.php?keywords=pwk+needle

What about the float? If it's out of adjustment / trashed you can end up pouring excess gas in via gravity. Though this will usually make starting a bitch unless you're diligent about turning off the petcock.

What are you doing when if fouls?

And don't forget, change only one thing at a time.

Standard needle on a pwk39 is a cej ive been told. Circlip is top position leanest on this needle im using. I want to go one needle leaner in the low to mid section. Not sure what numbers/letters etc that is but i have read that a dgk needle with a smilar slow jet size works well in Austraila. I can feel when the plug starts to load up and depending on what sort of riding im doing i will either rev it out threw the gears or if not possible pull the clutch in and rev it till it clears. It last a bit longer either way then fouls.. What needle do u think will suit?

Float is 16mm and checked heaps.. thanks for ur help to mate....