Stick coils: are 750 and 1000 items the same?

[Dezza]

I think i am going to try stick coils on my oil cooled project bike. (Green dyna coils are shite as they crack and a set of the mini jobs and leads costs a fortune.) I know a few on here have used the items from the GSXR 1000 but I was wondering if those fitted to the later 600s or 750s would also work. The 1000 is based on a 750 srad engine (at least the early ones were) so this is why I am asking.

[370steve]

i have used GSXR600  K4 ones before on my B12 and B6 motors

Edited January 22, 2019 by 370steve

[Dezza]

Ok, that enables me to widen my search so many thanks. Did you use the loom that came with the bike or make your own with new connectors? Also, was there any particualr reason for going back to conventioanl coils and HT leads?

[370steve]

I made the loom with new fittings, went back to stock coils as my stick coils were worn and wouldnt grip the top of the plug very well, didnt

want to buy some more, when i still had the OEM coils, will fit some more sticks when i find some better ones.

[Dezza]

1 hour ago, 370steve said:

I made the loom with new fittings, went back to stock coils as my stick coils were worn and wouldnt grip the top of the plug very well, didnt

want to buy some more, when i still had the OEM coils, will fit some more sticks when i find some better ones.

Ok, it sounds like I need to source the newest set possible. From where did you get the connector blocks that fit the top of each coil?

[370steve]

12 minutes ago, Dezza said:

Ok, it sounds like I need to source the newest set possible. From where did you get the connector blocks that fit the top of each coil?

yep, mine seemed to be a bit "used" when i got them!

i got the connectors from E-bay i think, i will look for the link

[Dezza]

Ok thanks. I would appreciate that

[Oilyspanner]

One thing to be careful of Dezza -

Although it's a few years back when I converted my bike, from what I remember the earlier K series engine 600/750/1000 all had very similar stick coils (1000 had that base engine unit to K8, 600/750 to K5) - the newer engines I believe had lower resistance coils, which wouldn't be suitable. The GSR600 used the same rated coils as the earlier K's too - as did the 1st gen Hayabusa (don't know about the gen 2). I certainly remember that the 1000K9 - onwards coils were differently rated.

[Dezza]

Ok, thank you OS for your useful advice I now know I need to go for 1000 up to and including K8; 600/750 up to and including K5

[Damienga15de]

I have a mix of early k series coils on my 750M,  the resistances are the same but the lenghts are different. 

[Mark]

Interesting stuff, tagging along. Any information on wireing them in? Or loom pictures?

[Dezza]

It looks like there is variation at 2 levels: 1) the resistance rating of individual coils and 2) the overall length of the coil. From what I gather, early coils are 1.5 ohm but some of the slightly later ones are 1.3ohm. Presumably, both of these would be OK to run on a stock OSS engine's ignition. The very latest coils have a lower resistance (<1ohm) so are not suitable for an OSS motor. The coils vary in length but I do not know if any are too short to use on an OSS motor, or so long they look naff and/or cause clearance issues so hopefully someone who has done this and can remember precisely from which machine their coils came from can fill us in.

[Buzuki]

 To use those modern low primary DC resistance stick coils with standard ingition box there`s two possible solution ,

one solution is not to tweak inside of ingition box but just to add one more power wire-wound resistor in series with those two stick coils to get that optimum nominal DCR value which is suitable and will not overload ignition box two power switching transistors , for example two stick coils in series 0,7R+0,7R=1,4R  plus 2,2R resistor = 3,6R  or 3,6 ohm , but must say that this solution will probably significantly reduce secondary side sparks power delivered on the spark plugs,

second IMO better solution is to use those modern low RDC stick coils but connected in parallel , in that case ignition box need to be tweaked ,at least that two bipolar junction transistors ( N-type high voltage power darlingtons ) need to be replaced with modern N-type high voltage switching power Mos-Fets , those Mos-Fets is wide available and very cheap now.

 

 

[Arttu]

43 minutes ago, Buzuki said:

 second IMO better solution is to use those modern low RDC stick coils but connected in parallel , in that case ignition box need to be tweaked ,at least that two bipolar junction transistors ( N-type high voltage power darlingtons ) need to be replaced with modern N-type high voltage switching power Mos-Fets , those Mos-Fets is wide available and very cheap now.

A couple of issues with that solution:

-If you connect the coils parallel their primary voltages are tied together. And when spark hits voltage on both will be limited by the coil that can break a spark first. And most likely that's the coil on exhaust stroke so then there will be less voltage available on the cylinder that actually needs it. Although I have to admit this is based on pure theory, I haven't tried how it would work in real life. This issue can be fixed by adding own transistor / MosFET for each coil.

-Second issue is that these low resistance coils are designed to be driven by controlled dwell time. Like charging for 1.5ms before the spark and then resting rest of the enngine cycle. Controlled dwell limits the current to safe level and since the coils spend most of their time un-energized they don't get too hot. But wasted spark ignitors on older bikes charge the coils some fixed part of the engine revolution so the dwell time gets pretty long, especially at low revs. So there is quite high risk to fry the coils quickly even if you can modify the transistors to handle the current.

[Buzuki]

Arttu 

I understand your concerns  , 

and I think you are right , the best solution will be when each ignition stick coil have his own IGBT transistor (driver) ,

but if that original drive signal which arrive on to IGBT gate have to long dwell time maybe again some series connected power resistor can limit current via primary side and to prevent coil overheating , well need to try all these options ...

 

Edited January 25, 2019 by Buzuki

[Dezza]

On 1/22/2019 at 5:03 PM, 370steve said:

i have used GSXR600  K4 ones before on my B12 and B6 motors

Did you find where you got the connectors?  I see that Kojak's or whatever they're called stock some but the bloke who runs the place doesn't know what fits what. My guess is all the Denso 129700 coils take the same plug though. I have some now from a 750 Y/K1

Edited February 7, 2019 by Dezza

[370steve]

I couldnt find a link to where i got them from, but E-bay is a good bet.

[Gixer1460]

Can get them on the Bay of EEEEEE's - £10 - 12.00 for a set?

[Dezza]

2 hours ago, Gixer1460 said:

Can get them on the Bay of EEEEEE's - £10 - 12.00 for a set?

Link doesn't work. The only similar ones I can find are in the US or Australia.

[Gixer1460]

Try this ....... https://shopbhp.com/products/denso-pencil-stick-coil-on-plug-cop-connectors-cbr-gsxr-hayabusa-motorcycle?variant=25483609793 This where I was planning to get some from but not urgent for me.

If you can't find actual plugs then possibly fit mini blade connectors to fly leads, fit on terminals and silicon into place and weatherproof - bit ghetto but would work, make up a whole sub loom for the COP's with one single plug 5 or 6 pin?

[markfoggy]

I was just going to ask the question today, has been going round my head.

https://www.Eblag.co.uk/itm/4x-Denso-Pencil-Coil-Connector-Plug-Clip-Gurls blouse-CBR-Suzuki-Hayabusa-GSXR-Yamaha/282945224023?epid=18024917201&amp;hash=item41e0d97d57:g:pnMAAOSw17payoP4:rk:17:pf:0

sorts them into a loom

There must be a slightly shorter set out there that would work, the water seal into the plug tunnel is also an issue...

Steve got it right.

[markfoggy]

Has anybody got a Blandit 12 motor running cops that they could run a ruler over, I have found these and would like to know if they fit well.

[Oilyspanner]

I expect B12 plug caps are the same as 1100K/L/M/N ones - my N ones were 82mm(ish) from tip of rubber plug surround, to upper rubber shroud that stops rubbish falling down the plug well. That top rubber shroud would probably need to be swapped for the oil cooled one anyway, this stops vibration pulling the coil off the plug, it needs to be snug.

My primary circuit of the stick coils in series measured within the Slingshots' tolerance - it was quite a long time ago, but 2.6/2.7 ohms if I remember correctly - the standard coils have quite a wide window 2.4 - 3.2 tolerance, so the ignitor has never played up - B12 coils are much the same as Slingshot ones I think.

Only two things have really caused a problem since my conversion, the clip that locates on the threaded spark plug tip on one coil was weak and vibrated loose - I replaced it. The other problem was that a digital dash I had needed a wire feed from the coil signal to work the displayed revs, the stick coils' spark was affected at lower revs - I bought a different dash that could use the normal feed from the ignitor and the motor was lovely and crisp again. I love the stick coils, it declutters the area above the engine (makes servicing easier) and it saved weight - I was putting my bike on a weight loss program at the time....but the best thing is that it just works so well.

[370steve]

2 hours ago, Oilyspanner said:

 

Only two things have really caused a problem since my conversion, the clip that locates on the threaded spark plug tip on one coil was weak and vibrated loose - I replaced it. 

yep, i had the same problem, seems that if the coils havent been fitted correctly, or been on and off a few times, the wire clip that holds the spark plug top can wear badly and not grip the plug well.

[Dezza]

On 2/9/2019 at 1:13 PM, markfoggy said:

I was just going to ask the question today, has been going round my head.

https://www.Eblag.co.uk/itm/4x-Denso-Pencil-Coil-Connector-Plug-Clip-Gurls blouse-CBR-Suzuki-Hayabusa-GSXR-Yamaha/282945224023?epid=18024917201&amp;hash=item41e0d97d57:g:pnMAAOSw17payoP4:rk:17:pf:0

sorts them into a loom

There must be a slightly shorter set out there that would work, the water seal into the plug tunnel is also an issue...

Steve got it right.

These are the same connectors as supplied by Kojaks for about £13 quid for four, although I don't yet know how much they charge for post.

https://kojaycat.co.uk/epages/950000457.sf/en_GB/?ObjectPath=/Shops/950000457/Products/RFW-2WFBx4

 

I was aiming to modify the stock rubber seals to fit around the coil to stop the things vibrating loose and the plug wells filling up with shite. Obviously these are needed whatever caps/coils are used so it's not any extra cost of doing a stick coil conversion.