Replacement/aftermarket coils

[Sean]

So my coils are testing out of spec. Especially once the bike is warm. I have been looking at the accel coils (140404k I think) they're pretty pricy though. I want to avoid buying someone's used junk ones. Has any one found any less fancy not high performance ones that are still new? Will any .7 ohm set work? Electrical is new to me. I know some poeple use coil for non cdi bikes as well (nology). Help me out and share what you know. Stormy? TJS? Gsxr400racer? Anybody.

[TJS]

I'm tied for the next few days and can't get anytime in the garage.
There is a guy on here selling some Accel coils and the following pic is from a build on here using stick coils from a gsxr.

[Chris H]

You can easily covert to stick coils (cop's) but you want the shortest ones you can find.
If you look at the picture they can stick up quite a way.

You simpliy wire the 1.5ohm cop's in series (paired) and run these from your old LT wires.
Works well, i ran them for over a year and only removed them due to the no.2 cop being very tight against the oil pump of the VVC motor, not a problem on non VC.

[Sean]

I've seen that people have switched to coil sticks is it worth the effort? With the additional need for used parts. Seems like new accel at $190 is looking to be the best option. Unless used coil sticks would be better? Does it make a difference?

[Sean]

The more research I do the more confused i get (I hate electrical) what are the oem specs? TJS said 1.5 ohm per stick, the Dyna coils are 3 ohms but serve 2 plugs. Logical to me. If there's a good resource on how to find a good replacement coil or explanation of what the different resistances mean that might help me quite a bit. Or if there's a generous electrical guru that could explain everything to me :)

[tomacGTi]

I have the Dyna coils. I got them from Stormy oh-so-long ago for a great deal. I didn't need them but couldn't pass them up either. I would hazard a guess that any aftermarket coil is in the same realm.

Here is what I can tell you about them:

*Some of the bits I'm talking about may come with new, boxed coils. Remember, I bought mine second hand.*

-You will need to get different ends for the coil side of your wires. They use a "traditional" coil type of end found on normal coil vehicles. If you go to a speed shop, they'll sell you what you need.

-They are a PIA to mount because they're huge. I got creative and was able to use the factory mounting points using a couple of aluminum brackets and spacers. They're easily twice the size of the OEM (and twice the weight too).

-Oh, and due to the size, you'll have to shorten the wires on your factory leads so buy some wire and just start anew.

-You will need bolt-on spades for the exciter leads if you don't want to cut your existing ones to use ring terminals.

-I noticed NO DIFFERENCE from a healthy OEM coil to these. Same wires and everything: nothing. Fires the same, revs the same etc. etc. Regardless of being on track or on the street: no change. Somewhere, I'm sure I gained 1.1 gigawatts. Maybe I took a healthy dump that morning.

-What I can tell you versus the bakelite OEM coils is that they are much more robust. So if your OEM coils are toast and you want something to survive the apocalypse, then these are for you.

As far as COP go:

I'm sure they're fine. I don't think it's necessary and the OEM system is more than adequate for most people's needs. I applaud the ingenuity but if I can't seen the gain then I don't see the point. If you were tuning each cylinder with custom management, FI maybe but the reality is that you're not.

IIRC Bandit 1200s used the same coils as did a bunch of other Suzukis (Katanas, etc.) . Mind you, these bikes are 20 years old now and even a newer, used version of the part would be an improvement.

Obviously the easy, no BS choice is an OEM replacement but if you're one to tinker, you've got options.

Hope this helps.

-Randy

[Sean]

Ok I just got my new dyna coils in the mail. They were new but open box so I didn't get any paperwork or diagrams. Randy, how did you wire yours to maintain the correct firing order? Also I've been wondering why no one uses the dyna arc-2 cdi as a replacement for ours. Seems like it might work well.

[tomacGTi]

Sean, IIRC the coils will have a positive and a negative lead on them. Let me know if you need spades as I have the bolt on spades extra so you don't need to cut. These are the trigger wires to the CDI to fire them off.

The common on our bikes is obviously the negative so that eliminates that, IIRC it's orange. Don't quote me though, I have to look at my bike to make sure.

After that, if you have a hot rod shop or even a poop boys near you, they should be able to match the coil ends from the Dynas to something there. You can then unscrew the existing wire from the spark plug leads and connect them to your new wires.

I basically used some straight aluminum flat stock, a couple of bolts/nuts and the existing coil mounting bolts and spacers to hang them in the factory spot. They'll obviously hang lower than before so do this first before cutting your wires.

[Sean]

Thanks! Yeah I have a whole box of electrical connectors from when I did ky wiring harness swap. I was also wondering which port on the coil fires first, so which one would go in which cylinder.

Also, I might as well replace the sparkplug wire too. Is solid core a must or can I use shielded graphite wires like from a modern vehicle?

[tomacGTi]

The new shielded stuff is fine, the resistance is low enough and it's pretty difficult to find copper core stuff for a reasonable price.

The coils batch fire so obviously one does 1-LH and the other 2-3 RH. Just put them where the stock coils came from, wire them up the same and hit the starter. It's all I did.

If you do everything right, it should just start like before. It's that simple.

Little tip: hang them low enough to hug the frame rail by where the old coils were. There's just enough clearance and wire for the coil triggers.

[Sean]

Has anyone ever heard of the spark plug boots going bad? 2 of mine wouldn't spark (well) no matter how well I screwd them into the new (managed to find) solid cored wire.  Using the boots that came with the wire set tomorrow cause I got rained on.

[tomacGTi]

Probably the resistor inside has gone bad. I know you can get replacement NGK ends though, resistor or no resistor. You can apparently remove them as well though I never tried.

I went with pre-fabbed ends on the wires I had. I did have to use the screw-on terminal ends on the plugs though. I had some left over from my VW days.

I'd recommend sticking with the NGK ends. Removing the leads is a bit of a PIA now but as a whole is more compact with the huge flux-capacitor coils.

[Sean]

+1to TJS for the stick coils. These Dyna are really a pain to mount. Randy, could you put up a pic of your mount job? I'm afraid to put the coil right up on the radiator hose and would like to see how you did it.

[tomacGTi]

I don't have a pic and am away from my bike for the next week Sean, or else I would.

Basically:

I mounted them as close to the frame as possible (to the bottom) and literally directly under the old mounts using the existing mounting holes. One bracket will go straight down (front mount) and the other will angle from the stock mount to the Dyna (rear mount). This gives enough space for everything and you can literally make the tabs from some 1/2" wide aluminum stock. Obviously the rear tab is slightly longer than the front.

You will have to use some spacers (IIRC I used 10mm or so, stock was 5 I think) on the Dyna coils but the brackets (really, hanging tabs) will bolt directly to the frame. You need the spacers to move the coils inboard on the hanging tabs.

So your shopping list should be:

-Additional hardware for the coils/bracket/spacer (longer bolt, spacers, washers and nuts)

-Aluminum flat stock

-I assume you have a drill

This was the simplest way I could put it without images. In Speedking's now deleted pic (yes, I'm a dick...) You can find it on his bikepics page: you can see that the coil just barely peeks out from the frame tube from the bottom. That's how mine looks. It does clear everything as well.

[Sean]

No, his yosh spam was annoying. Lol gsxr400racer sold big bore kits and didn't bump the topic every other day like speedking.

So the coils kinda hang parallel with the ground whereas the stockers hugged the frame. Right?