750 vs rephased... bigger bang for the buck?

[scabber]

With a light weight bike the stock 650 cc is all you really need. Don't get all wrapped up with the hype of the rephrase. The motor will still vibrate. Leo left out the price of the new cam also needed. I never noticed much difference in vibration when going to 750CC.

 

[Jack]

Pretty much what the title says...

I'm rebuilding my motor. It was seized when I bought it. Unfortunately, I broke a piston skirt during the tear down, so I at least need to buy pistons and rings.

After owning a hardtailed and non-rephased XS this past year, I told myself that a rephase should be a pretty high priority on this build. However, the budget is pretty tight.

So which makes more sense? A rephase and just buying a set of standard bore pistons, or get the 750cc kit and live with the vibes? I'm leaning toward the rephase, and I realize that all answers will be very subjective, but humor me...

Rephasing is an expensive route no doubt,reducing vibes on a standard firing XS is all in the tuning,mounting,frame weight,chain,lower bottom end tolerances and reciprocating masses on the small end,etc,etc,the lighter the piston and piston pin the less the vibes. H-11 tool steel thin wall wrist pins for a GSXR 1100 cut to XS dimensions would do nicely in dieting the small end masses. Rephased engines prefer heavy reciprocating masses while it's the opposite for a standard firing XS. Both engine figuration's would run smoother with re-balancing or live with the outcome.

 

[vsop-dk]

I cant say much about the 750, but can chip in on the rephased 277. Its my experience that the sound is way more stable and sounds great. The engine allso goes much steadier, the sensation and feel is that its a completely different engine. 22 years ago I got my first xs650 stock engine and it ran great, but the 277 rephased I got now is much more enjoyable.

The cam is a EN40B billet steel adjustable 277 rephase billet cam as seen in this Picture and is cnc made 100% by specs.

 

[chizler62]

That cam is slotted? How far can you open the intake?

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[Dman4222]

I'm rephasing my second and it will be a 706 and I am not planning to spend any $ except for the pistons. I will remake the shaft for the single point.

 

[arcticXS]

I cant say much about the 750, but can chip in on the rephased 277. Its my experience that the sound is way more stable and sounds great. The engine allso goes much steadier, the sensation and feel is that its a completely different engine. 22 years ago I got my first xs650 stock engine and it ran great, but the 277 rephased I got now is much more enjoyable.

The cam is a EN40B billet steel adjustable 277 rephase billet cam as seen in this Picture and is cnc made 100% by specs.

Vsop,
where did you buy this cam? And what kind of lift/duration are we talking about? Or maybe just state if it is equivalent of any other cam, like Shell#1, Megacycle/Webcam XXXyyy or any other reference.

 

[vsop-dk]

arcticXS it equivalent to megacycles and is cnc made in one piece and is specifically made for a 277 rephased cam. Credit goes to smedspeed Wich is WW the only supplier of such. If you need refs pm me.