RD400G plug and Dave f help

[jamuba29]

Hi all

I'm from New Zealand and have a 1980 RD400G, its currey dressed up as a Daytona Special, I want to change it back to look like a G.
I've just rebuilt the engine and I'm looking for some help.
It's a stock engine no porting.
The stock pipes are badly damaged so I have some stainless chambers,  the air box has seen some fire and had plenty of fatuge cracks at mounting bosses, so I've gone with unfilters and doing the Dave f carb mod.

The bike was running NGK BR8S but my Haynes manual supplement for the RD400G stated BP9S, would the hotter 8's be better?

Also with the Dave F mod, once the air jets are drilled out do I replace the brass balls?

Regards Chris

[SoCal250]

Welcome

The OE spark plug for a 3M4 model is a NGK B9ES. You can run the hotter 8 range plug if it's not causing any issues like detonation, but there's no need for it if the 9s are working fine and not fouling. (Note: The "BR" is the resistor version of the plug, which is the only thing available since NGK discontinued the standard "B" plugs a few years back. Or you can run the B9ES-10 and adjust the pre-set gap.)

No need to replace the brass balls after completing the Dave F mod, you can leave the AJ unshrouded.

[jamuba29]

Thanks SoCal250, I appreciate your help.
I'll fire her up for a test ride!

Cheers Chris