Vintage Dirt Bike Q & A

Hi,
I'm looking to fit a new plug cap and HT lead to my MT/CR hybrid.
I use NGK B9EV plugs and wondered what NGK plug cap to use as there are so many different ones out there either suppressed or non suppressed. Do I need a suppressed cap and if so, what ohm, or do I need non suppressed?
Whatever cap I go for wants to be waterproof.
Anyone got any ideas of what I actually need?

Many thanks in advance,
Grae

Grae,

I use only non-suppressed (no resistor) plug caps with vintage ignitions, on the theory that there's not a lot of excess spark energy to throw away. I've also seen cap resistors burn out, which can be difficult to diagnose unless you're looking for it. I use non-resistor plugs for the same reason, but many of the precious-metal-electrode ones (BxEV, BxEVX, BPxEV, etc.) have been discontinued and are getting harder to find. I use BP7EVX's or BP8EV's in my Hondas, my buddy uses a BP7ES in his MT250.

Here are the NGK caps:

http://www.sudco.com/spark.html#cover

I've used the LZFH (non-resistor) and LB01EP (1K resistor) caps, which both worked fine. Even though my bikes use the aluminum terminal 'nuts', I believe that removing the nuts and using the LZFH-type caps that grip the threads directly is the way to go - they hold really tight, and all the looseness/oxidation/etc. issues go away. Both are waterproof, and the seals fit real tight on the plug.

I make a hole in the middle of the plug wire strands and spread them apart in a cone shape with a small pick before putting the plug on the cable. I've had the cap screw tunnel in between the cable and the rubber sheath a bunch of times, and the cap never feels tight and sometimes starts cutting out.

Ray

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'74 CR125M (175cc), '75 MR175, '82 RM250Z, '08 YZ250F, '14 Zero FX electric, '14 Zero MX electric, '18 Alta MXR electric

Thanks Ray, that was the information I was looking for!
I'll get a LZFH plug cap on order.

Grae.

What a great site this is!