The only service bulletins I can remember about the Gen I bikes was regarding
a general recall of cams and rockers on '81 and '82 750s and 920s -- due to improper hardening.
Interestingly, I still come across parts that were missed. Most bikes were fixed before they
went on the showroom floor. The ones that had been sold: Yamaha sent registered letters to the owners-of-record.
Apparently, some people ignored these and rode the bikes as-is as they seemed to work okay.
Just lately, I've learned that -- in some markets at least -- the XV920RH was prone to blowing head gaskets.
I don't know what the problem was, and I hear that there was a fix that worked. I don't know the details on
either end. I don't recall that being the case here in Southern California, but who can say?
I can't find my factory manual, so I don't know what Yamaha has to say about the following. Both Haynes manuals
and contemporary issues of Motorcyclist Magazine state that the XV920RH had 43mm intake valves and 37mm exhausts -- just like
the 750 Virago. Haynes allows that the RJ had 47mm and 39mm respectively, as did the Virago And all the bigger engines.
However, I have found two sites (so far) that have parts break-downs of Yamaha motorcycles and both show the same part
numbers for the RH as for all the later and larger bikes. Except for the painted parts, RHs and RJs show the same numbers
throughout the bikes. Nor did I hear of any performance differences between the years. Grain of salt.
I've been informed that Canada got the XV920RH, but not the RJ. I have gotten universal reports from my Canadian connections
that their RH engines have 47mm intake valves and 39mm exhausts. I cannot imagine Yamaha making the bikes to different
specifications for different markets without a different model designation.
More to come . . .
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