650 head, 600 cams and valves

A seller in the uk has a set of valves, springs and cams from a 600 for sale. Does anyone know if the valve seats in the head are wide enough to take 600 valves, and if the cams slot in? (A pic of an empty head would be good). I guess the cams depend whether the engine is a yics or not - my 650 is non yics, not sure about the 600 (were they xf 600 in the states?).
Now before everyone chimes in with "just fit a 750, 900 etc", let me just say the 650 is here, probably would benefit from a valve job, and these bits are cheap. Add to that that My hobby is making car engines go faster, and I would love to my xj, once its up and running of couse....
I should also add, the seats and head will be set up on my flowbench, studied, and the ports and seats modded to produce any extra swirl, and importantly as much gas flow as possible without enlarging the port excessively.

 

Only way to know is if measurements are the close . The 600 shares a similar engine as the 550. IMHO nothing but shims are interchangeable.

 

The 600 is almost a clean-slate engine, but based in part on the 550 architecture.
I don't think anything from it will bolt up to the 650/750/900 family, since nothing from the 550 will.
The YICS system was dropped when the 600 engine was developed.

 

I'm tempted to buy the cams, cheap at £20... so, assuming I do, anyone got a decent pic of the 650 head upside down, preferably showing the seats?

 

This thread has pics of a 750 head.
https://xjbikes.com/forums/threads/my-82-750-seca-project-with-short-valve-springs-look.27584/page-2
The Valves and seats are the same part numbers, and the combustion chamber base diameter is only 2mm larger on the 750 than the 650.

 

It's really only a bored and stroked 550, all the bits interchange between them

 

I though there was more done to the internals than that. Thanks for the correction.
Externally the cylinder tilt is different, and the downdraft carbs.

Not much swaps between them and the shafties though.

 

I think you have the early 600 and the diversion 600 mixed up kmoe (apologies if I have this wrong).
Ive just spent an hour and a bit looking at ebay pics of these, and am truly confused as to which early heads are yics, which ones are rubber bush clamped/vs all bolted. I do know how to recognise the diversion heads (different shaped covers, all bush clamped, with hyvo type cam sprockets).
Given the 550 is visually very similar to the 600 I suspect it has a chance that bits will swap, but my engine is non yics, with hard clamped cover, nothing like the 550 or 600.
Ah well, it was a thought..

 

I very well could have things mixed up. Yamaha called everything by a different name here, and we didn't get everything that the rest of the world got.
If I look at the FZ600 it has the same engine as the early XJ600 (which we didn't get).

All of the YICS cylinders will have a bolt at the ends of the YICS manifold, which is just below the intake ports.

The head has brass (sometimes aluminum) plugs in the YICS port drillings.

This view is from the rear (and is of an XJ1100 so you'll see some obvious differences) , and does not show the manifold end bolts, but it gives you an idea of where to look should a seller not give a rear view of the engine. It also shows the extra bolts (stude really) at the rear that provide clamping force to seal the o-rings between the manifold and the head passages.


The long tubular casting (middle arrow from 'passages') is the YICS manifold, and the bolts that close it up are at each end.

You can bolt a YICS head up to a non-YICS engine, but you'll have to make plugs to block off the passages (and maybe remove the short studs at the rear).

 

Thanks, what also confuses things is sellers listing heads as turbo (yics) which aren't. But that might just be because POs have swapped things around in all the time these have existed.
That thread you posted has some good pics of the chamber (and a completely knacked valve btw), it looks from that like there might be enough seat insert metal to go bigger valves.
So will 550 cams go into a 650 head? If so there might be a glimmer..
PS, the pic of the yics inlet looks like the ports are angles inwards - surely this is a quirk of the camera?
A light has just come on in West Wales, that transverse yics port is in the cylinder block (jugs or whatever you call them) ooer sorry...
Now that makes some sense.

 

The YICS ports do angle inwards on the XJ1100 to promote swirl in the chamber.
How they were drilled and spaced was changed at least once (Yamaha liked to do that sort of thing in the 80's; same idea/different execution on different machines).

 

Agree on offset ports producing swirl, have used it myself on modified production engines. I did wonder if that was an xj 1100 engine, i bet it was to get the carbs and filters in the frame though?

 

Yes, here we had an XJ600 from 84 on which was the bored and stroked 550 and the same as the FZ600 engine, the Seca II or Diversion is different again but some parts still interchange

I'm not aware of any interchange of motor parts with the shafties

 

The 650 and 600/550 have different bore centres. I can't see how the cams could interchange.

North American 1984 FJ600 is essentially the early XJ600 the rest of the world got.