Meh.. did a long post and lost it....


Basically been doing more measuring....

see new pics at http://exeter-computer-repair.co.uk/tr1/index.php?folder=VENJLXBpY2t1cHM=

5.9 + (8.73/2) = 10.26

39.83 - 10.26 = 29.57 mm

29.57 is distance from face to centre of pickup iron in rotor.... pics show rotor to face distance as 42 but this is incorrect, one hand for camera, one for vernier, not able to measure in correct method or place, 39.83 is a closer to correct number

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25.0 - 2.88 = 22.12 this is measurement from face on outer case to where pickup carrier plate sits... 2.88 is thickness of vernier used for straight edge.

In previous post I say centre of pickup is 11 mm from mounting plate.

22.12 + 11.0 = 31.12

Centre of pickup iron on rotor is out ----> from face of inner casing by 29.57 mm

Centre of pickup sensor on stator is out ------> from face of outer casing by 31.12 mm

31.12 - 29.57 = 1.55 mm

Note the two underlined bits above, between these two casings there must be a gasket.. this will INCREASE this number... 0.5 mm gasket + 1.55 mm = 2 mm out....

And also this is the "wrong" direction if I am going to be replacing original pickup sensors, with "B" height of 11 mm with ignitech ones with a "B" height of 14 mm.

At this time, I'm not convinced of the accuracy of my measurements either, sure, they are close, but I am giving numbers with 2 digit precision, 0.01 mm, no way my measurements were that good, too quick and dirty.

My thinking is Mr Yamaha got the centre of the iron slug on the rotor, and the centre of the pickup sensor, to within plus or minus 0.1 mm.

I need to clean up and measure properly, eg get REPEATABLE measurements for these things, I think the current 1.55 mm "error" will disappear, but I *need* these accurate numbers, because as we see, there is no point doing this unless we do it to a professional standard, and these motors are unusual in that the pickups positioning is not adjustable.

Two vital points.

1/ I need to do this in a workmanlike way and measure and document everything, because *if* it works but is not quite right, I am no longer able to go back to the starting point... once you modify something you cannot measure what size it b*used* to be...

2/ I, or someone else, may (will) want to repeat this, and get it right first time, and have faith in the other guy's measurements...  

OK, so we start to make some progress, no work this morning so was able to go out to workshop and put outer cover on the mill and fire up DRO and take some measurements.

DRO is a glass scale 3 axis job accurate to 5 microns 0.005 mm, of course only using X and Y scale for these measurements.

Visual positioning from a red dot laser centre finder, as always a camera flares the laser and makes it look a lot less precise than it is, particularly with edge finding, 25 microns (0.001 inch) movement creates a very visible difference in the beam.

If you know the co-ordinates of three points, you can accurately plot the exact circle that they lie on, for this and the rest of the simple CAD work I will be using the excellent Rhino package.

I first found three points on the inner radius of the stator, and used these to calculate the centre. X=0, Y=0

A random selection of the 25 other points measured was re-verified after going back to 0,0, they were all within 25 microns.

I say all this here because it is important to understand the methodology before you can have any faith in the numbers generated.

Meaningful accuracy in the real world of 0.1 mm is good enough, certainly when it comes to machining or fabrication for stuff like this you do not need to work to the same accuracy as grinding a crankshaft journal, but these base measurements are all "good enough" at 25 micron or 0.025 mm or 0.001 inch accuracy, certainly the alloy casing will expand and contract this much going from ambient temp on my mill of 16 degrees to operating temperature in a hot running engine...

Accurate measurements as a starting point are GOOD, but we do not need to be anal in carrying the same level of accuracy forwards through the process.

Off to Rhino....

You list the following..

All wiring connections - there are none, I threw away the old wiring loom in entirety... this was brand new cable made up for a "hotwire" temporary loom.

No breaks in system, no bad connections in system, no handlebars in system, no emergency switch in system....


NEW spark plugs
NEW HT leads
NEW coils
NEW TCI
NEW wiring and connections, just the basics, no handlebar kill switch, no sidestand kill switch, no nothing
NEW battery

Literally ONLY old thing in system is ignition pickups and attached wiring.

IF ignition pickups were pristine, then this would have been apparent in the following tests, which were done, and which were listed in this thread.

Crank engine and easure ends of ignition pickup connecton wires with Oscilloscope.

Do the same again with digital multimeter, for impedance and ac voltage when cranking

Put pickups in lathe and spin a lump of metal past, and get exact same readings all over again.

All this said in the thread.

You tell me, what else is in this system to make you think pickups by Mr Yamaha do not age or deteriorate over 33 years?... and I am only person on the planet to won a TR1 in which the pickups died?

Not trying to be funny, genuinely interested in your answer... I am always open to the possibility I have been a complete asshole and overlooked something trivially stupid..

Hi John,

Please don't get me wrong, it's not my intention to critizise you. I wouldn't say the pickups do not age, but I don't believe they are failing at same time. Reading your listing, I agree that you have thought about everything. The only things coming to my mind now, are the new wiring loom, where I assume you have checked already several times so it could be excluded, - and the pickups, I must agree. Attached wiring would fit to my assumtions, as this could cause both pickups to fail at once. Assume you checked this in depth already, so I'm lost now. If it would be my issue, I would try to get another pickup assy from someone else in the Forum, just for tryout. If you are convinced, it MUST be the pickups, I found some here: http://www.ebay.de/itm/Yamaha-XV1000-TR1-XV920-1981-Pick-Ups-/310869805001?pt=UK_Motorcycle_Parts_13&hash=item486148c7c9, and another one in the German side.

Jürgen