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watches you sleep.
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Discussion Starter · #1 ·
I need spark plug wires and coils for my 1992 GSX-R750 project and it got me thinking about converting it to a modern "coil on plug" setup. I've been searching the internet for people that have already done the swap but all I've found so far is a few pointers and a few people that say they did it, but didn't say how or what they used. Has anybody here done this conversion before? Here's all the info I gathered and please correct me if I'm wrong on any of this:

-The coil on plug coils or "sticks" have to be the correct length as well as the correct ohms resistance(obviously)

-The stock ohms resistance for the oil cooled GSX-R 750 is 3 ohms

-Most "sticks" operate at around 1.5 ohms

-To make this work I will have to wire the new coils in series so that they get 3 ohms to each plug

-I also need to worry about the CDI box, but I'm not sure in what respect

-The stick coils off a K6 GSX-R will fit in the valve cover



Thats all the info I gathered. A lot of you are probably wondering what the benefit of this conversion is. The main reasons I would do this conversion is because A. It will clean up the engine area a lot by getting rid of separate coils and spark plug wires and B. There's less parts to fail me. If a coil goes bad on the stock setup than I lose 2 cylinders for example. A coil on plug conversion will simplify the setup and just look cleaner and therefor much more badass lol.

So again has anybody here done this conversion? Do any of yall know anyone who has or do you have a writeup on exactly how to do this and what I'll need? Here's the only good links I found on the subject and they didnt have any good links within them to get me any further:

http://www.gixxer.com/forums/showthread.php?t=338921&page=2

http://www.gixxer.com/forums/showthread.php?t=348374

Thanks in advance.
 

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I have come to the same conclusion as you and have read both of those threads but haven't found any actual write ups. I hope to have this conversion done by mid march though and can post back with my experience if you haven't already completed it. The only issue i have noticed so far is the coil sticks out about the top of the head about 2 inches. but my motor is out of the bike so i dont know if it will cause a real issue. I will post a picture here soon.
 

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perfectly imperfect
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This is actually a common mod on RC51. People use cbr600 stick coils. There are several write ups on speedzilla. The only tricky thing is finding the right plugs or modifying (slighty grinding the tip) to fit the cbr coils.

The rumored benefits aren't hugely significant but they're enough for me. (on the rc) you're not going to get a hp boost. But you get a more "reliable" spark that starts better in the morning and supposedly is easier on the reg/rect which on Hondas are prone to failure. the biggest benefit for me (and for others on CF) is that you can get rid of the big ignition coils taking up valuable space in the tail section.

Try searching on speedzilla or rc51forums. Otherwise, when I get some time I'll track down the threads and post up links. good luck JJ
 

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watches you sleep.
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Discussion Starter · #5 ·
So you're using could off a 2001?model? I've got a few questions. Did you happen to s7emthe wiring from another bike than what the coils came off of? What I mean is are the plugs for the coils and the coils themselves scecific tp eavh bike? Can you show me and tell me how to wire them in series, I need 3 ohms from each coil, and not the sick coils stock 1.5 or whatever. What bike is this going on? Also don't worry about them sticking up a bit I read an article where that happened and they just zip tied them down and had no other issues. Thanks for the pics.

Sent from Motorcycle.com Free App
 
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Ive also looked at this for my oil boiler gsxr's etc & really cant find a benefit to doing it....

FYI gsxr stock coils are not 3 ohm they are like every other coil & have a range, in this case 3 to 5 ohm so working off 3 ohms as your base number is incorrect
Hope it helps
 

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The coils I am using are from a 03 gsxr 600 I am also using the wiring harness from a r6. I don't remember the year. I can post up the part number for the coils later since I know that those do come out to 1.5 ohms
 

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Jonny, I picked up 929 coils for my gs750 last year which needs the same range as your gsxr. I can't use them as my motor is taller and they hit the frame. If you are interested, let me know. I also have the wiring harness for the coils too.
I posted some info about the setup I found from the zrx forum:http://www.customfighters.com/forums/showthread.php?t=62019
 

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watches you sleep.
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Discussion Starter · #9 ·

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watches you sleep.
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9,116 Posts
Discussion Starter · #11 ·
Ive also looked at this for my oil boiler gsxr's etc & really cant find a benefit to doing it....

FYI gsxr stock coils are not 3 ohm they are like every other coil & have a range, in this case 3 to 5 ohm so working off 3 ohms as your base number is incorrect
Hope it helps

Actually no it's not incorrect, it's just the lower end of the range from what you're saying. Considering COP setups I've been looking at run at around 1.5 ohms and I would need the resistance to come up to at least 3 ohms by running them in series than I would say technically NO my data is NOT incorrect. Its just the minimum target I need to reach to be within spec.

Also there are several benefits to running coil on plug setups. 1. It looks much cleaner 2. Each plug has their own coil rather than sharing one, so if one coil goes bad it only affects 2 cylinder rather than 2 and 3. Theyre much newer than a stock coil off a bike from 1992 in in turn will have "more life" left in them with a better chance their not shot. Im sure there are other benefits but I figured 3 were enough.
 

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watches you sleep.
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Discussion Starter · #12 ·
This is a k3 coil
If you have an oil boiler GSX-R than you should have just at 2" of room as long as the sump on the bottom of your gas tank doesnt get in the way. The watercooled tanks have a MASSIVE "sump" on the bottom that will almost surely get in the way. I think the oil cooled ones arent so bad. I THINK the stick coils I need will have to be around 3.5" overall length max but Im not sure. It all depends on how far in the spark plugs themselves go into the coil. I hope this info helps and please do keep in contact with me with your findings and Ill do the same. whoever finished first can just mimick the others setup and we can finally do a proper writeup. Im surprised with how popular the oil cooled GSX-R's are, someone hasnt done one already. I read one guy did a wirteup by the name of PP on the oldskoolsuzuki.com forum but I never checked it out.
 
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Actually no it's not incorrect, it's just the lower end of the range from what you're saying. Considering COP setups I've been looking at run at around 1.5 ohms and I would need the resistance to come up to at least 3 ohms by running them in series than I would say technically NO my data is NOT incorrect. Its just the minimum target I need to reach to be within spec.

Also there are several benefits to running coil on plug setups. 1. It looks much cleaner 2. Each plug has their own coil rather than sharing one, so if one coil goes bad it only affects 2 cylinder rather than 2 and 3. Theyre much newer than a stock coil off a bike from 1992 in in turn will have "more life" left in them with a better chance their not shot. Im sure there are other benefits but I figured 3 were enough.
Hey i'm not trying to put you off as its obvious you are going to do it anyway, your bike your choice fella :) you asked the question & i answered simple! :)

You want to run with stick coils just in spec carry on, my choice is not to bother, as for benefits i still cant see one
Like i said your bike your choice i was just giving you the info i have what you do with it is up to you
 

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Running c.o.p setups allows for a reduction of clutter under the gas tank. While they can go bad over time like traditional coils, there are no wires and plug boots to deal with going bad also. No more figuring out which cylinder isn't firing from the coil.
It isn't a magic cure and for most, the traditional coils are fine. For those who like to tinker, c.o.p allows for greater consistency in spark strength and duration.
As a singular mod, no, you won't see great returns. But in conjunction with other mods (efi, turbo, n2o) it will help in the long run. I'm doing it to help with my tuning when I convert my dinosaur to efi.
 

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Discussion Starter · #15 ·
Ok so heres the latest news. Taylorjr says He's got a set of 2001 Honda 929 stick coils. They are the right dimensions. The problem is the run at 1.0-1.2 ohms each. Now what I've been reading is that people are getting their sticks with a resistance of 1.5, and running them in series in pairs giving them 3.0 ohms. Well if I do that Ill only get 2.0-2.4 ohms. So what Im asking yall is can I run them in series with all FOUR of them wired together? Would that get me between 4.0-4.8 ohms? If what 4cups says is true and they spec is 3-5 ohms then aren't I still within spec or would I get a weak spark if they're running that much resistance? Thanks in advance.
 

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Find a set that's right got you
I got the stick coils and wiring harness for my Cbr1000f for $45
I cannot remember what the ohm rating on them was
But they came off a 05 Cbr1000rr
 

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I think im lost
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JJ the Cbr1000rr coils I got are 1.6 ohm each and if there a bit long then u could use the 600 coils
I can get you a measurement on the 1000's if u want
 

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watches you sleep.
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Discussion Starter · #19 ·
taylorjr is sending me a set of 92 coild and harness plugs. they read 1.2 ohms which IS fine because I checked the FSM today and the ohms spec for the 92-92 GSX-R 750 is 2.4-3.0 ohms, not 3-5 like 4cups mentioned earlier. So if I run them in series paired up they should just cut it.
 
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I checked the FSM today and the ohms spec for the 92-92 GSX-R 750 is 2.4-3.0 ohms, not 3-5 like 4cups mentioned earlier. So if I run them in series paired up they should just cut it.
Sorry if the info i gave is wrong but it did come from my genuine suzuki manual :confused: Good luck with it anyway :)
 
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