Cams

[Johann]

Hi Team..I need help please. I bought a XS1100SH bike( to be rebuild) with 3 sets of cams. I looks like the 3H5 is the set to use but the other ones has the code 4A(in)/3A(ex)and the other set 35(in)/36(out). What is the history of these 2 sets? Thanks

[MaximPhil]

Hi Johan,
Welcome to the joys of owning an XS11.
I suggest a PM (private Message) to member Crazy Steve with your question.
There are some subtle differences between early (78) and later (81) cams and valves & pistons. Some will work together others will not.
Phil

[crazy steve]

Well, I wish I could give some history... To my knowledge, Yamaha only used two camshaft sets in these; the 'early' 78-79 2H7 set, and the 'late' 3H5 ('80-up) set. At one time there were some aftermarket camshaft companies that produced hi-performance cams from new blanks, but those have been unavailable for years; these days all you can get is re-grinds on welded 'exchange' shafts. So it's possible you may have sets of early performance cams by some aftermarket manufacturer, although I can offer little help in identifying them. Best bet is to physically measure them, and compare the numbers to the stock specs. That still may not give the whole story, as there's little difference in the factory manual specs between the early and late cams (same intake lift on both, and .02" more exhaust lift on the 'late' cam), although there's about 20 degrees difference in duration between 'types' (a spec not given). The duration difference makes a big difference in how the bike runs and how it's tuned.

Just to muddy the waters a bit more, keep in mind that Yamaha occasionally used 'assembly line' parts that aren't totally identical to the 'service' parts, which are the part numbers usually referred to. Add in some of the differences between the various 'market' models (i.e., North America, Europe, Oceania), and it's all-but-impossible to give a definitive answer in some cases. It's also possible these are for another make/model bike, so I'd be extremely cautious before attempting to use them.