vmax 86 pickup´s

[gavicool]

Hello;
All the problems started suddenlly...engine start to "run in 3 cylinders" specially at idle...
I took the bike to the YAMAHA workshop and their comment is that they are not sure, the problem is in the pickups or in the CDI...ignition coils are ok
Looks like the pickups are damage(according with the Resistance Test - omhs meassurements- pointed in the SERVICE MANUAL,..),the CDI I will send it to CARMO ELECTRONICS for testing....
I couldn´t find the pickups for my bike in the market...and I do not know if it is possible to replace the pickups for the one´s of other year(90 to 95)...
I think that I have to replace the CDI and the flywheel....

Well,wait for your comments and thank you very much in advance..

 

[maleko89]

With early model, not so sure on p/u coil since there are only two. One for front cylinders and one for rear. On my '89, it either ran on 4 or two with bad p/u coils. Another option is plug wire, boot, plug, ignitor or compression. Have you tried switching components to see if the bad fire switches sides?

Mark

 

[one2dmax]

The most likely problem is a bad CDI. The pickups can go bad but it's not as common on the early bikes.

 

[gavicool]

With early model, not so sure on p/u coil since there are only two. One for front cylinders and one for rear. On my '89, it either ran on 4 or two with bad p/u coils. Another option is plug wire, boot, plug, ignitor or compression. Have you tried switching components to see if the bad fire switches sides?

Mark

Hello Mark;
Thank´s for the info.
I checked the coils with the plug wires conected(I think that part is ok,..at least the values are according to the manual)..
What do you mean by " other option is boot, ignitor.." ?sorry but I do not understand which parts are you refered to...and about switching components...well,the think is that everytime that I start the bike something diferent about the bad fire happen..some times are rear cilinders other times front...very extrange...that´s why I think that the problem could be in the pick ups or CDI....
About the compression,good point,I was thinking about it but I´m still preparing the "special tool" for meassument..

Thank you very much for your comments Mark..really...

 

[gavicool]

The most likely problem is a bad CDI. The pickups can go bad but it's not as common on the early bikes.

Thank´s I sent the CDI and Pickups for testing..I will let you know the results...

 

[maleko89]

Hello Mark;
Thank´s for the info.
I checked the coils with the plug wires conected(I think that part is ok,..at least the values are according to the manual)..
What do you mean by " other option is boot, ignitor.." ?sorry but I do not understand which parts are you refered to...and about switching components...well,the think is that everytime that I start the bike something diferent about the bad fire happen..some times are rear cilinders other times front...very extrange...that´s why I think that the problem could be in the pick ups or CDI....
About the compression,good point,I was thinking about it but I´m still preparing the "special tool" for meassument..

Thank you very much for your comments Mark..really...

The other things I mentioned and to check were spark plugs themselves, plug cap, plug wires. You can measure those and switch around to different cylinders to see if the problematic cylinder(s) move.

Mark

 

[Fire-medic]

Hello Mark;
Thank´s for the info.
I checked the coils with the plug wires conected(I think that part is ok,..at least the values are according to the manual)..
What do you mean by " other option is boot, ignitor, compression.." ?sorry but I do not understand which parts are you refered to...and about switching components...well,the think is that everytime that I start the bike something diferent about the bad fire happen..some times are rear cilinders other times front...very extrange...that´s why I think that the problem could be in the pick ups or CDI....
About the compression,good point,I was thinking about it but I´m still preparing the "special tool" for meassument..
Thank you very much for your comments Mark..really...

'Boot' is spark plug boot, it could be letting the coil short-through it to ground, or the brass contacts inside are corroded. Watching the boots at night, for signs of arcing to-ground is one way to check, another is to spritz a bit of water onto the plug caps, and see if the presence of a water film creates a short to ground from the boots.

'Ignitor' is the ignition box, it's usually either it works, or it doesn't, though sometimes it works intermittently. This is where the factory service manual, says, 'replace with one of good, known operational qualities, and compare.' If it runs OK after this parts-swap, you've found the problem.

'Compression' is loose valve clearances, resulting in low compression on a compression check. If all cylinders are within say, 5% of each-other, and compression is > 100 PSI, that's probably not going to be your problem. Sticky rings from sitting idle, say, for years, especially close-to a body of water, or outside, & uncovered, can cause a loss of compression due-to this. Sometimes, a few heat/cool cycles can free-up sticky piston rings, especially if you use some-sort of penetrating oil squirted into the spark plug holes. Not a lot, you don't want to have a hydraulic lock, resulting in bent connecting rods or other damage.

 

[gavicool]

CDI and PICKUPS update.
According with the workshop,that it is none of them are defect.
The ignition unit responds to all signals and all four sparks are good and strong.
The pickups have the resistance they should have and stay within specifications when they are heated. Also when metal is passed close to them the generate strong signals.
But I´m concern with the resistece that I got before dissasembly and sent it for inspection.
According to the Service manual Pickup coil resistance,meassure between colors(Orange-Black, Orange-Gray, Orange-White/Green, Orange-White/Red),must be within110 Ω +-15% at 20 C (68 F),and I got the next values(cold condition);
0range-Black-116 Oms
Orange-grey- 229 Oms
Orange-White/red-232 Oms
Orange-White/grey-230 Oms
This confused me,that´s why I sent it for test, the workshop test show that the pickups are ok,but I do not know why the resistence show diferent values in between pins...
I already send to the workshop an email with the same coments...lets see what they are coming with.
By the other way,I will check the compression once I recive back the CDI and pick ups...but I´m really pissed off about this results...I will wait for ther comments about it.

 

[maleko89]

The service manual for the testing of the early p/u coils is incorrect. Use the black instead of orange as your common when testing the four p/u coils.

 

[gavicool]

The service manual for the testing of the early p/u coils is incorrect. Use the black instead of orange as your common when testing the four p/u coils.

Hi Mark;
Now make sence,thank you very much for you help..
Best regards.

 

[Hipnip]

Thank you so much for this important info. I have been trying to troubleshoot ignition problems on my 1988 using factory manual. Using this corrected info, pickups are testing OK. Will now search elsewhere for the problem. Makes me wonder how many other screw ups are in manual.

 

[gavicool]

Thank you so much for this important info. I have been trying to troubleshoot ignition problems on my 1988 using factory manual. Using this corrected info, pickups are testing OK. Will now search elsewhere for the problem. Makes me wonder how many other screw ups are in manual.

..that´s a good one...maybe we should open a forum in the future with those errors that we find...

 

[maleko89]

That's the biggie. Another is the shim chart that's a bit off.

Mark

 

[Norwichscott]

The most likely problem is a bad CDI. The pickups can go bad but it's not as common on the early bikes.

Hi, I've had a problem lately where my bike holds back at a certain revs. The rev counter also cuts out. Do you know what it is? I think it's an ignition problem. Could it be the ignition advance unit?

 

[one2dmax]

Hard to know for sure what you have going on. There is no factory rev limiters on thee bikes.

 

[Norwichscott]

Hard to know for sure what you have going on. There is no factory rev limiters on thee bikes.

Thanks anyway. It's an 85. I lose the signal to the rev counter and the bike stumbles at certain revs. I think it's the grey wire. The one on the rev counter/ fuel pump relay / cdi circuit.

 

[gavicool]

Sorry to no update my conclussions.The problem in my bike was the carburator(pilot jets blocked and mixture in very bad conditions ).
Once everything was cleaned,(all rubber parts replaced),mixture screws loose and replaced,and after a carb syncro,the bike runs perfect.
Well not perfect,when its rev further than 6000 rpms,a "noise" from the left side,near to the scoop (I removed it and try to feel the noise,but without sucess). It does not afect the ride of the bike (that I can feel it...),maybe is the fuel pump,well I will keep investigaiting....

 

[gavicool]

..sorry the noise is like " when a relay gets stucks.."(sounds like -"neeeeeeeeeeeee") and stops when I slow down,but never under 5000 rpm´s....

 

[Fire-medic]

My '71 Kawasaki 500 Mach III would 'sing' to me like that, when you turned on the CDI ignition. It was one of the first bikes to use such an ignition. Of course once the triple ran, you couldn't hear anything like that. As Dean Martin or Sammy Davis Jr. would have said, 'ring-a-ding-ding!'

When people have issues with cylinders cutting-out, especially at idle/off-idle, and to 3K rpm, I always suspect plugged pilot jets, especially if the bike has been idle for weeks. Along with that, draining the float bowls individually to study any sediment, and checking the gas tank for corrosion/sediment, are necessary.

 

[Norwichscott]

Thanks anyway. It's an 85. I lose the signal to the rev counter and the bike stumbles at certain revs. I think it's the grey wire. The one on the rev counter/ fuel pump relay / cdi circuit.

Hard to know for sure what you have going on. There is no factory rev limiters on thee bikes.

I found out what it was... it was the CDI