TOPIC:

Hi
I know this topic has been covered before but I have a couple of questions you guys maybe able to help with, at present I am running my bike on NGK BP6ES but it seems to foul plugs really easy so I am contemplating changing to bp5es, i know the recommendation is BPR
does this make any difference also if you simply put ngk bp6es into ebay it lists plugs for cars that are noticeably cheaper than the same reference for bikes is there any difference
many thanks
Paul

Car or bike a BP6ES is the same plug.

The other part was recently explained to me by a member (KawBoy) so I will quote him.

I wish that TrikeBldr would chime in on this. He is the "Subject Matter Expert " on this topic.

The stock wires on this bike was a solid steel core wire. The standard spark plug caps (ends) were resistor caps with a 4K ohm resistor in the cap. Then the sparkplug standard was a BPR6ES which is a resistor plug. The resistor cap helped reduce the radio frequency interference. Carbon core wires also have the same effect and typically carbon core wires come with a solid wire end (no resistance). We need a certain amount of resistance to restrain the radio frequency interference but too much will suck up the available energy going to the plugs.

There are lots of members out there who have
changed the coils
changed the wires
changed the caps and
changed the plugs and
any combination thereof.

I feel we've "lost "the standard. Without a standard to measure to we're all talking nonsense here.

The BPR6ES plug has a 5K ohm resistor built in to the plug. The service manual calls for a BP6ES non resistor plug EXCEPT for European and Canadian models and that standard is the BPR6ES resistor plug.

The original spark plug cap has a 4K ohm resistor built in to it.

So why did Kawasaki call for 2 different standards? Is it an availability issue with plugs or a licensing requirement to meet radio frequency issues? Don't know.

To answer the original question, I think if you maintain a total resistance of 4K ohm resistance in the wire and cap you'll be fine and your choice of either the BP6ES or the BPR6ES plug will be fine BUT consider going to a double platinum tipped plug to compensate for the unusual wear of the sparkplugs in a waste spark system. The NGK "Laser Platinum "plugs would be the ultimate but I haven't done the research here to get the spark plug number.

Personally I run bosch plugs.
I found that ngk plugs fail when run rich and don't recover.
Once you have sorted out the tuning ngk plugs should be fine.