compatible heads

[dnseal]

does anybody know for sure if the heads of a 79 will work with a 1981 motor? If so which parts from which bike engine must I retain?

thanks
be well
gil

 

[Pork Chop]

G'day Gil,

I know that '78 xs400 jugs and pistons fit on an '81 xs250.

 

[Robsteeler66]

I believe the only difference is the 81 has a rubber mounted engine. I'm not sure if there is a difference in the heads exterior mount or not. I do know pork chop is correct. The head itself is the same.

 

[dnseal]

So if the cylinder head is the same, my 81's valve cover should fit and therefore meet any upper motor mount concerns.

This brings up a question. Are the heads and valve cover (rocker arm assembly) machined as one unit. Can I mix (without machining) or plug and play a cylinder head and valve cover from differen engines and not create tollerance issues?

thanks
gil

 

[xschris]

All sohc xs400 head will work on any xs400 jug. Most people like to keep the square heads with square jugs. Heads are match with the rocker boxes from the factory so yes you need a matched set. There is a letter/number code stamped in every set just above the intake ports where the carbs go on. This has been covered before just have to look

 

[dnseal]

Where would the stamp code be on the valve cover component?
I'm guessing these numbers are for boring of cam lobes. That said, I would think the odds of finding a cylinder head to match a valve cover would be difficult. Bottom line I need a matched set to replace the one the machine shop screwed up.

Thanks
gil

 

[xschris]

This is where they are.

 

[dnseal]

I see said the blind man..... Are you selling that set?... smile


thanks
gil