Do you know of someone that can do the up grade?- this is a tic of mine - i love rephased motors...yes this is changing the crank set up so the pistons dont travel together...the advantage is that you dont lose energy when both pistons are at TDC as 1 piston is always mid stroke when the other is TDC..ie rephase-when one piston is not moving (TDC) the other is at max velocity (mid stroke)...removes the search for energy to overcome inertia when both pistons are stopped together (non-rephased TDC)
- so there is a power saving
- this leads also to less vibration as the motor runs smoother
- better responsiveness
- slightly torquier
- if you do this weld the pins to the flywheels...balancing helps too
- there are 2 ways of doing this
- split the crank in the middle-rotate the right hand side 3 splines and press back together...277 rephase
- split the crank, replace the 2nd flywheel from the right with a slightly modified 3rd flywheel (remove 21mm from the pin boss where the cam sprocket seats), use a 270° pin and press together 90° out of phase...270 rephase
- both of these processes require a suitably modified camshaft and a cam-driven ignition system...a good time to consider installing a permanant magnet alternator and dual lobe points cam
- in my opinion yamaha missed a golden opportunity to produce a truly extraordinary motor by turning this idea down...i have done this and highly recommend this to anyone interested in spending the effort...virtually all modern-day parallel twins are built this way
have the heidens cam on my 277 rephased bike , very happy with it , very good over the range of revs but better on top end , was told very simmiler to the xs1 and2 cam but dont know personly
I rephased an xs 15 years ago, to 277°. Big 750cc block on it, reworked head and cam. Ran great for years, and many miles, and happy smiles. Wanted more, so i sold it to an xs enthousiast, who loves it. I bought myself a Triumph Thruxton 1200 R, which i absolutely love, and it has the 270° crank, and much more than any xs ever will. Suffice to say, i'm not bothered with rephasing xs's anymore. Looking into rephasing an inline four cylinder now.(cause i believe yam's got it wrong with the R1
)
If I understand you correctly, crossplane is wrong for the four cylinder bike and correct for the two cylinder bike.cause i believe yam's got it wrong with the R1
Indeed, crossplane is good for a V8, not an inline four.(a 270° twin imo isn't a crossplane crank, because it is L-shaped from the side) An inline four should be rephased to two pairs(L+R) of 180° twins, that in turn are 90° out of phase to each other. Like Helmut Fath did with his URS engine.If I understand you correctly, crossplane is wrong for the four cylinder bike and correct for the two cylinder bike.
I think you're just one of those who can't leave well enough alone. You're in good company here.
Sorry, mate, don't know the definition.
You're right!
Yes indeed! New ignition required. I highly recommend only the VAPE system: $700.
Hmm. My problem - in giving a decent answer - is that each is on a very different chassis that get ridden differently. The rephase maybe doesn't rev as quickly (it's geared taller too), but seems like it likes higher rpm better than stock. I actually get a little more vibration on the bobber, but the floorboards and bars are solid mount and the tracker retains stock rubber isolators there.
What's your turn around time on a crank rebuild?
