Just picked up a "new to me" 1992 Kenny Boyce pro street- has 96" build with dual plug heads, less than 5k miles on it. I will be running a Dyna 2000i ignition, single fire operation, it presently has a Dyna S installed in dual fire mode. It has plugs in it now, bike fires up, but frankly I am not sure if the correct plugs are in it and there are virtually no references as to what should be used. Anyone familiar with this dual plug evo mod and know what plugs to use on carby side / primary side? should these be different plugs or same in all four holes?

 

autolite 4164

 

Thanks- all four holes? I was wondering if there are differing length requirements one side vs other. the carby side obviously needs a narrow plug

 

screwed up,didnt see evo,the plugs i recommended are TC plugs,you want 4265 autolites

 

You might need both. A lot of guys put a 12mm on the carb side. I've seen some use 10mm.

 

Thanks bud, appreciated. What do you like as far as heat range of plug, static timing and advance curve? bike is going to be mainly town riding and romping around So. Cal. Given your reputation and experience, I hope you don't mind my asking :0)

I have not taken motor apart so not sure what cam is in it. heads / jugs are SS, case is Delkron. internals are SS. there was about $30k put into this bike when built and the original owner told me it got 'everything but the kitchen sink". lol - The bike was built for Daytona bike week 50th Anniversary.

has a super G on it with thunderjet- normally I would not use a G on anything smaller than a built 103 but will see how it goes with tuning before I change it out. right now it's a bit flabby on the twist.

interesting- never seen PMFR wheels like this- they are pretty damn cool. I was told the trees are Kosmon - At least those items will never break heh.

 

thanks - yeh- problem I am seeing is matching up heat ranges of plug. i don't see anyone making a 5 heat range in a 12mm plug. 14mm no problem. the Autolite 4265 looks like heat range 23.

 

pulled plugs in bike - this is what I got. no bueno. (96" Evo motor circa 1992)

primary side 14mm - NGK BPR5EY (Resistor Type) Heat Range : 5 Size: 14.0mm x 19.0mm x Hex 13/16
carby side 12mm - NGK D7EA (Non-Resistor Type) Heat Range : 7 Size: 12.0mm x 19.0mm x Hex 18.0mm

D7EA's were gapped at .030 / BPR5EY were gapped at .035 - not good. this is all trash.

plug wires are solid core cheapos, no suppression- those go in trash / making new set of MSD cables.

condition of plugs were normal but very black, gassy - running rich -and- this was not set up right with these plugs, gaps, wires, Dyna S dual-fire ignition and dual 3.0 ohm Dyna coils.

should I go with heat range 7 plugs on both sides? or a 5 on primary and 7 on carby? seems odd to mismatch heat ranges.
the BPR5EY were dirtier with carbon buildup, the D7EAs were not - probably due to diff in heat range of plug.

This is what I am thinking of going with as both heat ranges are 6:
NGK 7133 BPR6ES-11 - primary side - heat range 6 (14mm x 1.25 plug, 3/4" reach, 5k ohm res, 13/16 hex)
Autolite 4164, 4163, or 4162 - carb side - heat range 6 (12mm x 1.25 plug, 3/4" reach, 5k ohm res, 11/16 hex)



Front Cylinder

Rear Cylinder

 

I would go with 7's on both sides & get your tune in order [jetting, timing etc.]. Once that's done you'll be able to pull the plugs & get a read on the ground strap. You'll know which way to go then.

 

You a gambler?! I can't see the point of mixing brands and heat ranges, especially as you have a suggestion a few posts ago. KISS!