KX100 Spark Plugs

[tightwoods]

Hello! The standard plug for a 2002 KX100 is a NGK R6252K-105. This plug is designed with the center electrode and insulator tucked up inside the plug body and the side electrode attached to the rim almost flat. As a result, there is very little electrode projection down into the combustion chamber. I am finding that these plugs don't last very long and that engine performance falls off rapidly as a result. In fact, the engine won't even rev high enough to open the power valve. At $7 a pop, I think this is a lousy deal. I tried a BP7ES ( $1.50) that I use in my CR500 (after making sure the piston wouldn't hit the electrode). The bike runs great and pulls hard! Is it OK to run a BR6(7)ES or BPR6(7)ES without causing any damage? Thanks.

Tightwoods

 

[Durt Cycler]

The 6 or 7 heat range is way to hot for a high revving 100 motor. I would run nothing but a BR9 in it.

 

[NO HAND]

As DC said, I too tend to believe the BR9ES would be your best bet. A 7 heat range is too hot for your bike.

 

[tightwoods]

Thanks for the advice. I couldn't tell what the heat range is for that plug since it's an oddball number. I couldn't find any specs for it on NGK's site.

tightwoods

 

[mr.remote]

The heat range for the stock plug is a 10. If you look in the manual it list the next hotter plug over stock is a 9. I personally run a 8 and have had no problems.

 

[nikki]

That's the same stock plug from my last KX 80. I fouled the stock R6252K-105 right away and switched to a BR8ES. Never fouled another plug. I rode at mostly lower RPM's. My racing buddies run BR10ES and BR9ES plugs in their KX 80's/100's. If you're trail riding - I would think the 8 should be fine - but I would be careful with the 7 and I wouldn't even try the 6.

 

[Durt Cycler]

Nikki brings a good point, I forgot to mention if the bike is bein ridin slow and at low RPMs then I would run a BR8. Just make sure to keep a eye on the insulator for signs of overheatings (plug heat range too hot). Once the bike is being ridden real hard then I would just a BR9 back in it.