30 replies to this topic

[Chris B]

I read an article in Practical Sportsbike about upgrading to stick coils. Seeing as the TDM's ignition is a tad ropey, especially when wet and the fact that I happen to have 2 stick coils in the garage, I thought I would give it a go.In the article they used TT600 coils, which is handy as I have Speed Four ones which are the same. I stopped by a bike breakers today and picked up a coil loom off something that fits the coils for a fiver. Providing the coils fit in the plug hole this should be a relatively easy mod, that with any luck will stop the bike dropping to 1 cylinder in the wet, and negate the need for coil maintenance. should also save weight


I'll let you know how it goes!

PS if anyone has a TDM 900 plug cap handy that they could measure that would save me wasting my time, if it doesn't fit.

Edited by Chris B, 16 April 2012 - 01:44 pm.

[LewisBlackburn]

Are these the ones where the Coil is basically in the plug cap?

My brother has them on his bandit 1250.

Pretty neat little things and i can see where your coming from here.

Be very good to see if it helps or not.

[Studley Ramrod]

I seem to remember there being a potential problem if the stick coil resistance is high, I think some have a high and some have a low resistance and ya need the low resistance or it could fry the brain/ecu. I might be wrong, could be the other way round, but worth checking Chris.

Look forward to the weight saving experiment


EDIT: think there's some info in Anda2343's thread.

Yeah, post number 93...............

I consulted the workshop manual and found this:
For the 850 the primary winding resistance on the ignition coil (between the low voltage pins) should be between 3,1 to 4,6 ohm.
The secondary winding resistance on the ignition coil (between the HT cable connection and one of the low voltage pins) 10,4 to 15,6 Kohm.
The resistance in the spark plug cap should be 10 Kohm.
All measured at room temperature.
I assume the same specs for the 900 since the coils can be changed between the bikes.

Then for a combined plug cap/coil the primary winding resistance should be the same 3,1 to 4,6 ohm.
And for the secondary winding, the resistance should be higher, both winding and cap resistance. Aprox 20 to 25 Kohm.

On second thought the secondary winding resistance should not matter. Only the primary winding resistance.

Yamaha YZF R1 2007 -> the primary winding resistance is 0,85 to 1,15 ohm.
Yamaha YZF R1 2004 -> the primary winding resistance is 1,19 to 1,61 ohm.

I will read some in the ZZR website

From topic......... http://www.carpe-tdm...o...95&hl=stick

Edited by Studley Ramrod, 16 April 2012 - 02:04 pm.

[Stratman]

A few of the guys over on the VTR1000.org forum have done this, though some of the "solutions" looked a bit of a bodge to me, whereas others claimed an extra 2 bhp. I didn't think the faff was worth 2 bhp I didn't use anyway!

[ssray]

A few of the guys over on the VTR1000.org forum have done this, though some of the "solutions" looked a bit of a bodge to me, whereas others claimed an extra 2 bhp. I didn't think the faff was worth 2 bhp I didn't use anyway!

very popular on the gpz900r forum, not the extra power, better starting, smoother running-no ht lead to break down and modern tech

[Chris B]

Not really bothered about extra BHP, but to have bike not go onto 1 cylinder when it rains would be nice!

[Favs]

Please post pics, how to, effectiveness & so on cos I'm also considering this mod on the 4TX

[Chris B]

My bike is with MCT now, getting the suspension refreshed, I'll hopefully have it back sometime next week and I can start the mod.

Edited by Chris B, 16 April 2012 - 06:45 pm.

[JBX]

Be carefull with those coil as they are made to work with a CDI - low primary resistance coil, found on 4 cylinders engines mainly.
The TDM family has a TCI which requires higher resistance coils.

That means that fitting stick coil (low resistance) on a TDM may lead to a TCI failure.

Edited by JBX, 16 April 2012 - 10:06 pm.

[JollyGiant]

very popular on the gpz900r forum, not the extra power, better starting, smoother running-no ht lead to break down and modern tech

And also to stop No1 cylinder having a miss fire in the wet.. Because the rain lands on the right hand side of the rocker cover when it is on the stand and the lowest point is No1 plug hole on the left so it runs into there and fills it up.

[Studley Ramrod]

Be carefull with those coil as they are made to work with a CDI - low primary resistance coil, found on 4 cylinders engines mainly.
The TDM family has a TCI which requires higher resistance coils.

That means that fitting stick coil (low resistance) on a TDM may lead to a TCI failure.

Speaking as an electro-numpty, would it be possible to incorporate an inline resistor to offset the difference ?

[Chris B]

Be carefull with those coil as they are made to work with a CDI - low primary resistance coil, found on 4 cylinders engines mainly.
The TDM family has a TCI which requires higher resistance coils.

That means that fitting stick coil (low resistance) on a TDM may lead to a TCI failure.

Could you explain that a bit more please

Cheers,


Chris

[Studley Ramrod]

Too low resistance = to high current = frazzle time baby !

[Chris B]

Too low resistance = to high current = frazzle time baby !

But surely that would only fry the coils not the CDI (equivilent)

[JBX]

Many people think all ignition systems are CDI (capacitor discharge ignition) but this is only one of the electronic ignition technologies among other ones.

A CDI is a non-classical ignition system in the way the energy is stored inside a capacitor with a high voltage source, the coil is used as a transformer to give a very high tension when the capacitor is discharged by a thyristor. This is used in high-rpm engines as the capacitor can be charged very quickly, but it requires a low primary resistance coil to work.

The TCI (transistor controlled ignition) uses the coil to store the energy (low voltage) like in classical ignition systems. The coil is then discharged by a transistor using the Faraday's law which gives a high-voltage coil output but requires a higher resistance coil. This ignition technology is used for lower rpm engines as charging the coil requires a longer time.

Speaking as an electro-numpty, would it be possible to incorporate an inline resistor to offset the difference ?

A resistor is a passive component and it don't store energy like a coil do.
Adding a serial resistor will decrease the energy inside the coil and therefore it will lower the spark energy...

In a similar way using a low-resistance coil with a TCI will increase the current inside the switching transistor (up to five time) and will probably fry it.

I hope my poor english is ok to explain that...

Edited by JBX, 18 April 2012 - 12:24 am.

[MadAd]

A very accurate description JBX!!

I hope this is not the end of the project as I would like to see how this works!!
Praps some digging required for coils of the correct resistance!!

[Studley Ramrod]

Brilliant explanation there JBX !

It does appear though that the chances of finding a suitable high resistance stick coil are gonna be pretty slim if they are, as you say, required to have a low resistance.

Highest resistance stick coil I've read of was around 2-2.4ohms about half that of the standard coil in the TDM.

[MadAd]

It would be handy to know what IGBT is used on the out put of the TDM ignition module as it may be capable of 2-2.4 ohms?

Had anyone pulled the resin out of a duff brain?? Picks would be good!!

[Studley Ramrod]

I've seen a mk1 unit that had come apart, no resin in there and if you pulled the socket it came out of the housing attached to a printed circuit board. And, it still worked. No piccies tho. Bike belongs to BarnsleyTDMrider but I aint seen him on here for ages.

[JBX]

Don't forget that the TCI uses low voltage to feed the higher resistance coil (14V) versus the high-voltage (200-300V) / low resistance coil with a CDI. This is why TCI & CDI use different coils.

A low-resistance coil on a TCI would not only be risky for the switching transistor, it will also give a lower energy spark.

Unfortunately stick coils are usually made to go with CDI (same technology step) and finding high-resistance stick coils is likely to be a hard job.

That said there have been lot of problems with stick coils on cars : a coil remains a delicate electronic equipment, sensitive to heat and vibrations and fitting them on the hottest part of the engine is something strange on tourism vehicles imho...
Japan origin stick coils seems to have better built quality than other asian countries.

There are easier ways to protect the oem coils against moisture : relocation, insulation, etc.

Edited by JBX, 18 April 2012 - 06:48 pm.