Topic: Where to buy/How to install plug wires on a CB650?

[DammitDan]

I was reading on the Tips & Tricks forum that it may be worthwhile to change out your spark plug wires to get a boost in performance... My wires/caps are pretty dirty and are 100% original.  I'm thinking putting new wires on certainly can't hurt the bike, but I've never done it before.

It doesn't look complicated, but does anyone have experience or tips/tricks to installing new wires & caps? I'm pretty sure the 1982 CB650's coils have non-moulded screw-on type plug wires.  And where would be the best place to buy them, and what size should I be looking for?

- Dan0

[cb650]

Usually just trimming 1/4 - 1/2 inch off the ends ans reassemble with a little silicon works.




                         Terry

[paulages]

don't know, but i tried fitting the 650 coils to both the 550 and the 750 (to no avail), due to the replaceable wires. wish they had done that on the earlier bikes.

[DrMark]

Bulk 7mm copper core wire can be purchased thru several sources. I purchased mine thru the local Honda dealer for 50 cents/foot.  Kingsborne has RED 7mm wire for $1.25 foot (10 foot minimum).  Z1Enterprises.com has a set of Dyna wires for about $16.

I did the CB900 coil upgrade for my CB550K last year. Worked out great, no mods needed other than flipping the mounting brackets around on one end. Now I can change wires anytime I want. Purchased a set thru EBAY for $14 plus S/H.

[dusterdude]

if im not mistaken,you need to run resistor wire on the 650 because of the cdi ignition unit.

[Pinhead]

I haven't looked... Is the '79 the same as the '82?

Resistor wires or resistor plugs?

[dusterdude]

i think all the 650`s had the electronic ignition,dont worry,you can buy the wire at any napa store.

[Pinhead]

Yeah, they're all electronic ignition but I wasn't sure if all of the coils were the same (thus needing different resistive wires/plugs).

[dusterdude]

the resistance factor is built in to the wire,any wire of that type should work just fine.

[kettlesd]

I believe HondaMan stated once that SOMEWHERE along the line there needs to be a resistor to increase spark intensity - not just for RF interference. If you use resistor wire, you use a non-resistor plug - and vice versa.

[Ibsen]

The US models of the CB650 didn't have resistor spark plugs as standard, but the European and Canadian models did. But they had  resistor plug caps. The plug wires on my 650 are not the resistor type, they have got a metal core.
The resistance are not there to create a larger, or reduce, the spark. It is there to prevent electrical interference with the radio and TV reception.

Dan, if you have any doubt about the type of wires you have on the bike just do what Terry suggested and cut off a few mm's and you will see if there is metal or fibre inside the wire. And his advise about cutting off a little on all of them is a very good advise. If you have got wires with a metal core, it is often sufficient to restore the spark. And with age the resistors in the plug caps will increase their resistance, so replacing the plug caps along with cutting the plug wires might be all you need to do.

Btw, the CB650 have got an electronic ignition and the coils are not the same as used on the models with a points ignition. The resistance in the primary windings are different, 2.5 ohm for the 650 coil, and I think 3.5~4.0 for the 500/550/750 coils if I remember correct. The 650 coils have got a resistance of 12 Kohm in the secondary windings, but I'm not sure what the other coils have got. Anyways, what normally happens if you use the 650 coils, or any coils with a 2.5ohm resistance in the primary windings, on a bike with a points ignition is that there will be more current running in the coil to points circuit and you run the risk of burning out the points pretty fast because of arcing, and the engine won't run good when that happens.  And the coils used for the points ignition will not work well on the electronic ignition system because of the higher resistance.

[paulages]

i'll look at mine when i'm at my shop---but if the coil end screws onto the plug wire, you could replace the wires with any new wires that match the resistance.

[Dennis]

I like to run them the way they come from the factory, metal core wire and resistor plug caps. (I don't know if that is true for the 650 coils also)

All of the NGK Caps (OK - any of the ones you would want to use) are most commonly available as 5K resistor caps. As DrMark mentioned above, get copper core wire for $.50 / foot.

I don't care for resistance wire on a bike. You don't need the RFI suppression and it tends to be a lot more delicate than copper wire unless it is specifically for motorcycle use. Then it's a lot more $$$$.

Have you ever priced some of those specialty wires? They are a lot more than half a dollar a foot.

[Pinhead]

So what if you go non-resistor everything and then open up the spark gap? That'd put all of the available voltage across the gap to make for a hotter spark... Right??

[Dennis]

So what if you go non-resistor everything and then open up the spark gap? That'd put all of the available voltage across the gap to make for a hotter spark... Right??

No, it's a little more complicated than that. And if the plug gets a little dirty or if the gap is slightly too large then the voltage will bleed off across the insulator and you will get no spark.

Search Hondaman's post on this subject, he explains it far better than i ever could.