Spark Plugs for M400/SS

[koko64]

Anyone know what plugs to run in M400/SS motors?

Discussing this with Brad today and there seem to be a range of plugs used. Not sure what the correct plugs should be. Some plugs that seem to have been found in these bikes include Champion L82YC, NGK BP6HS, BP7HS, and even BP5HS. These are 14mm plugs and my guess would be that a 14mm version of the RA4HC plugs in 600s might work well.
What concerns me is that a resistor plug should best be used with the Kokusan ignition. I have noticed the coils on the 400SS I am working on get very hot with non resistor plugs at idle and lower revs.

[koko64]

Have found NGK BPR7HS and Bosch WR6BC. Thst sound correct?

[samuraibiker]

i have a 400M ... i will pop up to my garage in the morning and check out what the plugs are.

[koko64]

Thanks.

[Speeddog]

I think the NGK 7's should be fine.

Coils getting hot?
Does this 400 have an Ignitech on it?

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EDIT f*3king phone predictive text.

[koko64]

I found non resistor plugs in it of different heat ranges (5 & 6). It has Kokusan Ignitors one of which is blown. Someone has fitted coils similar to but slightly different to the stockers. Ive seen this miss match of ignition parts before, once resulting in a bike catching fire. Im going through it all. I can tell the bike has been messed with (chain clip on the wrong way, misaligned sprockets, dodgy brake line). It has been jump started off a running car motor regularly, so probably voltage spike damage to the ignitor.

[koko64]

7s it is.
Cheers.

[DarkMonster620]

Sorry, jsut saw this, here is my help:

carb engine BP7HS
efi engine DCPR8E

[Speeddog]

Loose battery cable connections can whack the ignitors also.

Maybe 5's or 6's in LAMS, where the throttle is so restricted, to keep the plugs from fouling.
A regular 400 should be able to keep 7's hot enough.

[koko64]

Yep, thats also happened. Resistance seems high in the pick ups. I'll give the ol girl an ignition freshen up.
Thanks fellas.

[samuraibiker]

i am using ngk BPR6HS...doesnt get so cold here in winter but summer gets up to 40+ centigrade and I find these work really well

[koko64]

Cheers.