Differences between xs250 & xs360 motors?

[Greasey Fingers]

Hi chaps! I just tore down a xs360 motor and was comparing the differences between it and the 250 motor. I have a 250 head and rocker cover here and a 250 gearbox. And was comparing the differences between them and the 360 motor.

After a quick eyeballing, apart from the barrels I saw very little difference between the two.

Rocker cover: Looks identical
Head: looks identical although I didn't measure the diameter of the valve inlets/outlets
cam: Looks identical
crank: Looks very very similar, only slightly different and feels like the same weight.
Gearbox: looks identical

Am I missing something here, I was under the understanding the head at least would be a bit different (bigger valves?), and maybe the gearbox would be geared differently, and the crank would be different?

The only real difference was obviously the barrels which have 358cc stamped on them and bigger bore/pistons.

I guess what I want to work out is, can I just use the 250 head and rocker cover if I rebuild this because they are in better condition than the 360 head and rocker cover?

Keep in mind I only had a real quick look & comparison so I may be missing small details that are significant.

 

[xschris]

Best thing would to start measuring and see what the numbers say. Then you will know for sure.

 

[Greasey Fingers]

Yeah will do, what are the key things to measure? Just dont wanna miss something important!

 

[xschris]

I would look at valve and combustion area, cam lobes that sort of stuff.

 

[Greasey Fingers]

ok, just had a better look at the heads. Valves are much bigger on the 360. Maybe the gearbox is geared differently but I just couldn't notice from a quick look...

 

[Scorpio1963]

The bore and stroke could possibly be larger on the 360 also.

 

[drewpy]

bores and valves are the main differences, then there's the ancillaries like carbs and sprockets to consider

 

[xschris]

They all have a 52.4mm stroke engine.