Ignition pick-up coil problem when engine warm

[Akatora]

Sirs, First of all, as a new guy here in the forum, I have to say that the place is great! There are really valuable pieces of information available here, as I've found out so far. :biglaugh: I've got -85 Max type 1FK full power model. There are 46000 miles on the clock. The set-up is as follows: stock engine, t-boost, needles shimmed with 2 washers each, crimp soldering done, new fuel filter, new 18 Ah battery, new spark plugs, regulator/rectifier recently renewed with -96 on type and then double D clutch. Will be soon receiving parts for solid engine mounts and furbur fix. Well, let's get into the business. The other day I was cruising in the city. Already some 20 km done and the weather was perfect. I had maybe 4th gear on and some 2...3 krpm on the clock when it happened. The bike started to make awful noise and engine died down shortly after. Noticed that the tach stopped working also. I was pretty sure that one or two cylinders fouled a plug, because the tach gets it's signal from one of the front cylinders in this model - and the signal obviously ended. There were also some reasons to expect that because that time the v-boost was all the time open and the low end mixture set up richer. I used pretty much low end with big gears in the city, as with this set-up the torque is tremendous and the engine just goes with any gear, any rpm and any throttle position. Now, I managed to get about 1 km forward couple of times and every time it happened again. Then it stopped completely. I got a lift from a friend to home to get some tools and spare plugs. Checked the spark from plug - and the result was normal! (There was about 1 hour break and the engine was cooled down.) It started and run normally again, when heading back home. However after about 5 km it did it again. Then, after cooling down it would start but once the temp gauge came close to mid part of the range, the problem occurred again. First I thought it would have been the carb problem (see "shooting the shotgun" at http://vmax.lvlhead.com/tips/shotgun.htm) and cleaned all the carbs according to the procedure. No difference. :bang head: Next I suspected the possibly too rich mixture combined with open v-boost. I restored the original setting and even tried with different spark plugs. No difference. Had to believe it to be electrical... Then I measured all ignition (HT) coils, both primary side and secondary side. Everything according to specs. Proceeded into measuring the resistances from the connector of the ignition pick-up coils. The resistance was ok between the black wire and all the others one by one - except the grey, which did not show any continuity. I checked the wiring between the coils (in this model there are two of them - 1 for cylinders 1 and 3 with orange and white-red wires, and the other for cylinders 2 and 4 with grey and white-green wires) and it looked suspicious. So I cut off the bad part of the wiring and made new with soldering the joints. Now the resistances were according to the specs. Then put it back again and started great - until getting warm! Same problem - and the resistance between black and grey was infinite. When the bike cooled down, the resistance became again normal. :bang head: Once more the same procedure - and this time I changed both grey and white-green wires from as close to the pick-up coil as possible all the way to the connector. Again ok. Started fine, but after getting warm the problem exist. And - guess what? - no resistance anymore between black and grey... until the bike cools down. Then it's again back inside the specs. So I guess there is no other choice than to renew the coils set (new one costs 375 eur). By the way, Mark Milne pointed out a thing that is very important to recognize when messing with these coils: The common wire from the pick-up coils IS black and NOT orange, as the Haynes manual and Yamaha manuals say. :clapping: In order to avoid that cost is still I'm thinking whether would be possible to open and fix the coil itself from inside... Does anyone have experience of this?:ummm:

 

[Akatora]

As it was clear that one of the ignition pick-up coils was bad, I decided to open it...
Bye bye 375 euro...

First tried to open it gently and smoothly in order to possibly put it back. Well, quite impossible! So I just wanted to see in and applied more force...by hammer - and got it in pieces finally. As predicted, there are two coils of very thin copper wire inside one pick-up coil. This means that one copper coil gives pulse for each cylinder that is behind this pick-up coil. Where the problem actually was could not be seen, but when copper coil starts to fail, it can do so that as the temperature changes (when the length of the copper wire gets longer or shorter), the contact can exist and disappear accordingly.

The Yamaha part number for a pick-up coil assembly (for older model 1985-89 with 2 pick-up coils and 5 pin connector) is 26H-81670-10-00. The pick-ups can not be purchased one by one.

 

[one2dmax]

Are wanting a replacement? I should have a good one or two around that would be less then the new one.

Sean

 

[Akatora]

Thanks man, but I already placed an order for new set of coils. When one coil makes problem, it is likely that the other one will do the same soon.

New set should guarantee plenty of problem free miles /kms - and that's what I want as this bike is a long term one.


Thanks anyway and regards,

AT

 

[gleno]

Good investigation and write-up.

Temperature related failure is a classic symptom of coil failure.

It can be differentiated from carb and fuel problems because they usually become worse over time whereas this is like someone flipped the kill switch on or you just blew a fuse.

Thermal expansion shorts the windings and the magnetic inductance field of the coils collapses instantly. This can happen in any of the bike's coil windings i.e. alternator windings, pick-up coil winding and ignition coil windings can all fail this way.

I got caught with this on a brand new XS1100E with only 400kms on the clock so it's not necessarily a problem that's restricted to older bikes.

Symptoms were identical to yours.

 

[Akatora]

Received and installed the new set of pick-up coils two days ago. The problem is solved, as expected. It's nice to see clearly the colours of the wires coming from the coils. From the old ones, it was extremely hard to see, as they were all looking the same brown oiled mess.

Anyway, for the confirmation, the colour codes from the pick-up coils mean following:
white/red - pulse for cylinder 3 (rear right)
orange - pulse for cylinder 1 (rear left)
white/green - pulse for cylinder 4 (front right)
grey - pulse for cylinder 2 (front left)

and the black is the common ground wire for all the coils.

 

[MONTREALMAX]

I called my local dealer and was told that this part for a 96 was $216 cnd

has this part come down in price???

It lists on the usa sites for over 400 retail

 

[Clyde Porter IV]

Are wanting a replacement? I should have a good one or two around that would be less then the new one.

Sean

You got any coils for 07 Vmax? And Sean could that Cause the Vibration you and I was discussing? May be it’s still firing just loosing a little *** behind it.

 

[Fire-medic]

Remember this is about the pick-up coil(s), 2 on the '85-'89 and one on the '90-'07. In 29 years of VMaxes, I've replaced two pick-up coils. Sometimes the bike won't run at all, sometimes it goes to an open circuit (non-conducting/non-sensing) when it gets hot, and returns to normal function once cold.

I haven't ever heard of anyone repairing a pick-up coil, "replace with one of good operational quality," as the manuals say.

High tension ignition coils, of which the VMax has 4 can be replaced with proper resistance COP's. The early ignition has proven to be sensitive to failure when presented with the incorrect resistance COP's. Some lucky souls haven't experienced TCI box failures when using COP's on early ignition systems, with other than OEM resistance for their COP's.

Another possibility is the circuit board for the TCI may have cold-soldered joints, re-sweating the wires seems to have effected a repair in some cases.

 

[Clyde Porter IV]

Yea I just know that 1 was wrapped tight and neat with electrical tape, I seen it before I ever test rode it I didn’t pay it a bit if mind out side of telling him I bet it needed one to knock off 250.00

 

[Clyde Porter IV]

I’m about to pull into the Garage and shut off the lightso

 

[DreamV4]

I’m about to pull into the Garage and shut off the lightso

Did you diagnose problem or just guessing?
My bike had bad ignition module.

 

[Clyde Porter IV]

Naw Hell Naw I didn’t diagnose nothing except for Mother F—-ker it was oil in the reservoir that gave it that Nice **** Color at the Full mark.

 

[Clyde Porter IV]

Did you diagnose problem or just guessing?
My bike had bad ignition module.

What in the Heck are these 2 bolts holding? Do you have any idea?
And I’m not busting on anybody I’m just stating the obvious but at the time who ever dressed this motor up with the machined looking buttons on the head of every single Allen Head and you guessed it gotta hold those on with something why not black silicone that’s what I would of used…. No serious at one time I might of bought that kit to dress it up so I’m not busting on people being individual just that when times comes to work on it you fighting that stuff trying not to strip one out.

 

[Clyde Porter IV]

Did you diagnose problem or just guessing?
My bike had bad ignition module.

Where is the ignition module how easy is it to change and how do you test for it

 

[DreamV4]

Where is the ignition module how easy is it to change and how do you test for it

read service manual, location and electrical diagram. I would explain everything, but I am not smarter than service manual.

 

[Clyde Porter IV]

read service manual, location and electrical diagram. I would explain everything, but I am not smarter than service manual.

Not sure if this

 

[Fire-medic]

Where is the ignition module how easy is it to change and how do you test for it

It's behind the steering head. #1 below: transistorized controlled ignition unit.

VMX12- Service-Manual.pdf (vmoa.net) Chapter 7 is Electrical.

Ask Sean for his electrical kit of used components to be sent to you. You pay for whatever you find out fixes the issues you have. As the manuals say, "replace with one of good known operational characteristics." The Ignitech replacement unit is a good substitute as it allows many functions besides controlling the engine ignition, like a rev limiter and the VBoost operation. Sean should have those too.