TZR 1KT stator practically identical to KR-1...!

Dodgy Kips motor? CDI? battery? diode? reg/rect? its all gobbledygook to me but some people understand it ask tham a question here
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James P
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TZR 1KT stator practically identical to KR-1...!

Post by James P » Fri Jun 19, 2015 1:18 pm

This may be old news to some, but was quite a surprise to me.

As far as I can tell, the stator from any Yamaha which uses the 1KT-based engine (i.e. 1KT, 2AW, 2MA, 2ME, 2MY, 2XT, 2XU, 2XV, 2XW, 2YK, 3CK, 3CL, 3NR, 3XC) can be used on a KR-1/1S simply by changing the plug on the wires and swapping over the rubber grommet (or modifying the Yamaha one). The 6-way plastic connector for the KR-1 stator wires is a fairly standard item which can be bought from a variety of sources.

This could be very handy if you can't locate a good Kawasaki stator. Popular opinion suggests that less than 10,000 of the KR250B/C/D models were made, whereas my research (based on frame number ranges) suggests that more than 200,000 Yamahas using the 1KT-based engine were made.
ElectrexWorld does make a replacement stator for the KR-1S, but it doesn't look as neat as the OEM item and hasn't got the plastic coil formers which assist in retaining the windings in position. I'm not suggesting that the ElectrexWorld stator is no good - just that the OEM Yamaha stator could be a more cost effective option.

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The Yamaha stator in the photos came from a 1991-92 R1-Z (3XC). The plugs on an early stator (pre-1988, using separate CDI and YPVS controller) are different, but the stator itself is the same.

The Yamaha stator loom comes with integral wiring (white with green stripe and white with black stripe on the later-model stator in the photos) for the pick-up/timing coil (as well as that coil itself), but this can be removed if converting for KR-1 use. The Yamaha pick-up/timing coil doesn't fit the KR-1 magneto housing and the specified coil resistance is different.
The Yamaha stator loom also has two extra single wires; black (stator core earth) and blue (neutral switch). These are not required if converting for KR-1 use, although it may be a good idea to make up an extension for the black earth wire and connect it to the frame at a suitable point.

The important wiring details are as follows:

For 3-phase AC supply, the Kawasaki stator uses 3 yellow wires. These wires are white on the Yamaha stator.
The wires for the LT ignition coils on the Kawasaki stator are black, red and white. The same wires on the Yamaha stator (in corresponding positions) are green, brown and red. The specified resistances are very similar, the Yamaha coil resistances having tighter tolerances, but wholly within the wider Kawasaki tolerances:

Kawasaki white to red - 2 to 7 ohms
Yamaha red to brown - 3.6 to 5.4 ohms

Kawasaki black to red - 100 to 200 ohms
Yamaha green to brown - 128 to 193 ohms

I have tried the Yamaha stator on a KR-1 magneto housing and it fits perfectly. The general dimensions of the core and coils are practically identical. I also test-fitted a KR-1 flywheel rotor with the Yamaha stator and there seemed to be no fouling anywhere.
Unfortunately, the Yamaha flywheel rotor is NOT the same (crankshaft taper and woodruff key are different), so it can't be used on a KR-1.

Regards,
James

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JanBros
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Re: TZR 1KT stator practically identical to KR-1...!

Post by JanBros » Sat Jun 20, 2015 10:33 am

now that's a nice find 8)
You know it's cold outside when you trip over dog shit instead of standing in it.

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