yz stator into rt motor

[Andrew L]

This has probably been answered already but will a 1980-84 YZ490 stator plate and flywheel go into an rt360 motor does it require any modification to fit if so what needs to be done cheers mav.

[crossedup2]

Not a 100% sure but I think tapers may be different size.

The simplist change over is a DT250 / 400 (I run a DT250F flywheel and stator) and YZ400D CDI.

You'll find more of these anyway. IT, DT and YZ from 1977 to 1978 and DT's up to about 1982'ish fit and run great.

Rgds
Peter B

[vandy010]

This has probably been answered already but will a 1980-84 YZ490 stator plate and flywheel go into an rt360 motor does it require any modification to fit if so what needs to be done cheers mav.

this is exactly what my RT1 motor runs.
i didn't take any pics so here's the story in words.
No,
it won't bolt straight in.
the stator plate diameter is smaller so i welded some tabs on it to increase the diameter , then spun it up in the lathe so it fit.
the taper on the flywheel is way too small, so it went into the lathe and a larger taper machined to suit the RT1 crank. this is where it can go wrong as just the right amount needs to be machined otherwise the flywheel can sit either too close or too far away from the stator.
don't worry too much about the keyway being machined off as the next step is to lap the flywheel onto the crank with valve lapping paste. this'll make it all nice 'n' snug so when you tighten up the flywheel nut it'll hold good and proper.
for the amount of effort there are easier options.
i just happened to lay my hands on the YZ490 set~up on the cheap and was able to badger my mate with the lathe enough so he'd do the job for me.

[firko]

Vandy and Crossed Up have got it. I too tried and found the taper too small. I considered doing what Vandy did but figured that there are much easier alternatives such as the DT400 set up that seems to have become the standard conversion. You could use the YZ ignition box with the DT ignition if that particular torque curve is what you're looking for but I don't think you'd notice much difference.

[Freakshow]

are all the yamaha cranks the same size and angle ?  like for YZ, TT ,IT, RT and so on

[vandy010]

are all the yamaha cranks the same size and angle ?  like for YZ, TT ,IT, RT and so on

No
angle of taper seems consistent
diameters do change over the years/capacities/models etc
as do some stator plate diameters
from what i've found

[Freakshow]

so your saying if you follow the same taper through, you can keep that the same but you just need to widen the bore ?

[Andrew L]

Thanks for the info Vandy might have to go with the modified yz unit (have a lathe) not to many dt400 etc ones around on ebay (only need stator plate & flywheel have the rest) or anywhere for that matter unless someone can point me in the right direction.cheers mav

[vandy010]

so your saying if you follow the same taper through, you can keep that the same but you just need to widen the bore ?

Yes