Fouling spark plugs on std service Honda 2012

[King500]

Hello there, I'm still fouling my ngk br8ecm plugs after 6 yrs of Bush riding. Std main jet is 175 ive got a 160. Slow jet std is 55 I'm at 38 and are about to put a 35 jet in. What needle do u think would work for some tight single but mainly 4wd/open tracks. Fuel was bp98 mixed at 50:1 with mogul 800 oil but will be trying caltex 98. Clean air filter with mogul oil, repacked muffler and always fresh fuel. Bike starts easy hot or cold runs great inc idle docent blow smoke then fouls plug.. done my head in.. carb is pwk39 Kevin.

[Okotokian]

What happens when you put in regular 91 octane at 50:1?
Also never heard of that plug in this engine before. BR8ECM has a 2.5mm tip vs CR5 standard 1.5mm tip BR8EG plug.

[King500]

Hi thanks for ur reply.. i havent tried 91 or 95 pump gas yet but are changing to a different brand 98 but was thinking to try 95 next if it keeps fouling plugs..the plug is just shorter cause i have a bigger tank and the standard size plug wouldnt fit.

[john stu]

Let me guess you have a #6 slide? Servicehonda shiped the bikes with a number 6 slide which is actually richer than the stock 6.5 slide that Honda put in stock CR500s, the first thing you should do is get a number 6.5 slide! the number 6 is Rich the number 7 is Lean and the 6.5 is perfect for the CR500 trust me I've tried them all and if your riding singletrack Bush riding it is 100% worth it to get to 6.5 slide they're a little hard to find not every place carries them for the pwk I think I got mine at carparts.com and once you put in the 6.5 slide you're going to have to go back to a more normal sized pilot jet around a 50-52 Then start with a CGK needle and then a CGL needle if its still rich. If you're near sea level I would start in the 3rd clip with a 168-170 main jet.