Riddle me this....

[Demorgan]

upon inspection of my valve clearances, I became aware that the inspection covers for left and right exhaust valves are completely different! the right hand cover being identical to the intake valve covers, ie, triangular with 10mm dome nuts, but the left hand exhaust valve cover is SQUARE(ish) with 12mm dome nuts! I suspected a PO bodge but the head is a one piece casting and the flash from the square side still visible so definitely built like that. What possible reason could there be for this?? Mine is a 1977 XSD but even the one on the front of the Haynes has this square cover... mysterious!! any ideas??

 

[Growl]

The squarish cover is a hold over from the very early XS-650s that had a valve lifting mechanism in there (compression release) to make starting easier. The device was abandoned after a couple of years but the cover remained for all the remaining years of manufactor.

 

[Demorgan]

Vestigial squareness! Well, there ye go! Cheers!

 

[CDNTX650]

Now I'll mind fuck ya again. The first couple years had no e start so with no need for decompressor so all valve covers are the same. 4 roundies.

 

[gggGary]

More mess'n with you the o-ring for that "big" cover is the same size as the "little" 3 bolt covers.