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4th gen Coil on Plug mod (split thread)


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Accel simply replied to say that they do not offer any products for this VFR.

I didn't put out any other inquiries.

No worries. After I get my bike running again, I already figured out how i'm going to wire them up, I just need to do a little more research on what coils I want to use, as it looks like length is an issue that I hadn't accounted for.

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900rr is tci. All coils share a positive switched feed and ignition module grounds the coils. As does almost all honda street bikes (with the exception of the vtr1000 and the rvt1000, as stated earlier, which are cdi).

If this is in fact the case, shouldn't this mean this mod is possible on the VFR, and should be fairly easy???

Thats what im hoping!

Soon as oil cooler pipes come back shortened and rewelded to help fit different shape oil cooler, can get these COPs tested.

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we discovered that the pulse generator was only sending .8v to the ECU. Since my ECU is dead, I wasn't able to find out what the output voltage was supposed to be.

0,8V is OK. If it is defective, nine out of ten don't produce any voltage at all.

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900rr is tci. All coils share a positive switched feed and ignition module grounds the coils. As does almost all honda street bikes (with the exception of the vtr1000 and the rvt1000, as stated earlier, which are cdi).

If this is in fact the case, shouldn't this mean this mod is possible on the VFR, and should be fairly easy???

Thats what im hoping!

Soon as oil cooler pipes come back shortened and rewelded to help fit different shape oil cooler, can get these COPs tested.

Let see some pics of your oil cooler setup, I'm nearly at that point with mine as well.

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Well, yes today a stage further. I have the cooler fittings ready for clean up and paint.

post-5025-0-00092700-1335906584.jpg

The original pipes were cut and shut. Altho now i think i made a big effort over nothing as the fittings into the original cooler might fit into the head and can be used once persuaded to bend in the correct position. Another day, another quick trial fit?

After pulling off the starter motor, i found access a lot better. Will clean some of that grime off before the next stage.

post-5025-0-35829800-1335906746.jpg

A quick test fit.

post-5025-0-90346300-1335907029.jpg

Just tarting things up now really. A little scotch bright and silver spray should clean things up.

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The slipper clutch was very easy to install.

Especially with the help of a hand held battery hammer drill for easy center nut removal/fit..(Disclamer- no sorry you have to do it the proper way with that silly clutch tool)

£579 + VAT if you want one. Get from me, delivery is next day.

I spoke with the guy who runs Sigma on Friday as a mate wanted one for his VTR.

He was in Spain at the moto GP and informed me he has stock ready to go when hes back this week.

Full factory back up so no worries if there is a hiccup!

post-5025-0-66084300-1335909448.jpg

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I may be interested in a slipper eventually, I remember my 5th gen having a lot of engine braking. Good to know that there's one that fits and that I can buy it from you!

I like the oil cooler setup as well, I'll probably be running the stock cooler for now until I get more of the bike sorted. Really jealous of your 2 bros. full system!

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Ok, after doing some thinking on the issue of the ECU/TCI/CDI boxes after mine decided to stop working...from what I was able to gather in troubleshooting my VFR, it looks like the ECU just makes sure the parameters are correct for firing the plugs, and sending the signal to the coil. It ensures that the bike is in neutral with the kickstand down, or kickstand up, and in first gear before it tells the coils to fire. I didn't take a voltage reading from the output side of the ECU, as I wanted to remove the donor ECU so it didn't get fried as well. To me, it looks like the ECU is more of a go-no go/input-output device, than a voltage regulator for the coils. I'm going to get an ECU or two, and some coils from eBay, and see what happens here shortly, now that I've confirmed that my ECU did die. Wit hall that being said, please correct me if I'm incorrect, as I really don't see how the ECU is a player in all of this, other than ensuring that the parameters are correct to send a signal to the coils to fire. The Pulse Generator tells the ECU what plug to fire, the ECU checks to make sure that it's ok to fire the plug and send the appropriate signal, but this is just my guess after doing alot of troubleshooting on my VFR...

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The Pulse Generator tells the ECU what plug to fire,

The pulse generator is attached to the crankshaft so the (TCI) ICM only knows the crankshaft position, not what stroke it is on (in the 4 stroke cycle), for that you also need a camshaft position sensor or something similar and I can't find one in the wiring diagram. That means the ICM with one coil per spark plug is not a wasted spark type of system, but it does fire the plugs twice per cycle, not a big deal.

As mentioned before, when decribing the differences between TCI & CDI (reply #73),a TCI coil takes some time to charge: dwell time. The ICM takes care of this and uses the TPS signal to calculate engine rpm so it knows exactly when to start charging the coil so it reaches maxmimum current at the time of ignition. with a TCI system, ignition occurs when the charging current of the primary coil is suddenly switched off.

What can happen when you replace the coil for one that has different specs like a lower primary coil resistance and/or lower impedance is that the ICM will put more current through the coil and may overheat.

Below is a sketch of what the charging current curve may look like. Top is with the regular coil, bottom is a COP with the specs as decsribed above: less resistance and lower impedance. Due to the lower impedance the current will rise quicker and due to the lower resistance the maximum current will reach a higher level and possibly will reach that higher level "long" before ignition. This can possibly overheat both the coil and the ICM. The hatched surface below the curve represents the amount of energy the ICM has to put out.

chrg.png

I am not saying that you will fry your ICM, but when it happens you now at least know of one possible cause of why it happened :biggrin:

Isn't there a shop on base where you can work on your bike with maybe the assistance of someone who can operate a scope? You could swap one coil for a COP and then compare the currents between the two. Electronics can withstand higher operating temperature for some time, use that when testing the COPS by only using one COP at a time and swapping it between the cilinders.

Btw, are 6th gen COPS not an option? It looks like they have a very low profile which can be useful behind the radiator, and maybe they fit the 3rd-4th gen head well.

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Thanks for being the guinea pig! My wiring harness is all stripped down to the basics for ignition/starter, just waiting to see if the cop's are going to work before I finish it up!

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Unfortunately, we don't really have any place on abse that has the necessary equipment to do this type of testing. Would it also be possible to install some type of in-line resistor or diode prior to the CoP? Plus my ECU already died once, don't know why though, perhaps the issues experienced on the way to and from Mugello contributed??? This is one reason why I'd like to change coils, to ensure that doesn't happen again...

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With putting a resistor in line with the cop you not only decrease the current but also the voltage and the total impedance also changes. I am not sure by what amount a voltage drop influences the spark. You would need high power resistors like these. Again, starting out with just one cop and resistor might be worth a try.

Hard to say if the overheating coils were the cause of the ICM getting fried. After the roadside repair it ran great, didn't it?

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It felt like it had a miss recently, don't remember if it felt that way last year, but that could be attributed to the ECU going bad I suppose. I did look at all the plugs, and they looked fine, not running rich or lean. I'll probably buy another ECU one of these days once I get the wiring for the CoPs, and give it a shot...I just need to get a second ECU first, as I don't want to fry the one that I just bought...

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  • 2 weeks later...

hey,

So i was thinking on the fan situation. Now its all dependent on how what the CFM is for the stock fan, but....couldn't you use 12v DC muffin fans (the kind found in your desktop) ? I know the fans are designed to work in 100 degrees C +...and they do make water proof and dust proof fans...not to mention the large selection of fan sizes and shapes, you could run two or more depending on total CFM needed. idk just an idea...

Matt

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  • 2 weeks later...
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Using a desktop fan is a no. They may be skinny enough, but unless you crank the volts up on them, they won't spin anywhere near as fast to make any impact on the temperatures.

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  • 2 weeks later...
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yes, the fans gone.... now approx another 2 kilo lighter!

Had a small water pump arrive this week so will hopefully run the engine a touch cooler when plumbed in..

Still need to tinker with my temp guage as its not reading anything yet...

Same as the reserve fuel lamp...

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Btw, are 6th gen COPS not an option? It looks like they have a very low profile which can be useful behind the radiator, and maybe they fit the 3rd-4th gen head well.

6th-gen COPs are three-wire plugs. They remain permanently fed by a common 12 volt source and the ECU sends a trigger command to the coil which causes it to charge up and then fire. The "ignition control module" is inside the coil, so there is no risk of the coil drawing too much current and damaging the ECU; it can only damage itself (the primary windings and transistor).

I suppose the real question is - how does the trigger circuit work and could it be connected to the 4th-gen ignition module? I don't know enough to say why it would be possible or impossible.

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Im gonna touch back on the fan thing, Im not sure how much air a motorcycle fan moves, but a car fan will move somewhere in the range of 500 cfm. here is a link to a 12v computer fan that looks like it might work if used two of them. that would total 444 cfm. That to me seems like sufficient air flow.

http://www.sofasco.c...ial/d12738.html

I would think that two of them would fit behind the rad (side by side, 5"x5"x1.5") providing the needed air movement (444 cfm). or at least one(222 cfm). I mean something has gatta be better then nothing right?

if someone knows how much air our stock fan moves, this would help find some real alternatives to making the COP work

matt

Edited by manapuaman1121
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