XJ HP figures?

[jacuff1]

I've looked at some of the old ads for the XJ that are on this site and others, and I have noticed that you can find numbers for every imaginable spec for the XJ. Except for one item.....horespower! I consider that one of the most important figures of all, but for some reason (insurance companies?), Yamaha didn't seem to want to disclose this bit of info.
Does anybody know what that figure was, or could tell me how to find out? Would be nice to know for bragging purposes, if nothing else.
Thanks!

John A

[John]

Hosses

John, I've read that the early XS11's were 95 H.P. I know the carb jetting for an XJ is much smaller that the older XS, 112.5 mains vs. 137.5 for the 78 model, and 120-125's for an 80 model, and the EPA got involved in bike emissions by then, so it would be safe to say that the XJ H.P. would be less. What the exact number is, I don't know...maybe 80-85?

[John]

Jetting info

You may want to increase the main jets. I recently installed the carbs from a 78E model in my 80 SG, which is running an engine from an 82 XJ, and it runs fine. I am using the stock pipes and airbox with a UNI filter. You probably could change the jetting up to that of an SG, which is #120 for cyl's 1 & 4, and 125 for # 3 & 4. That is the factory jetting.

[John]

oops

That should be 120's in cyls 1 & 4 and 125's in cyls 2 & 3. The middle cyls had larger jets for cooling purposes.

[chevy45412001]

h.p.

ive heard 112 h.p. for the xj. Could be way wrong with that. As for jets mine stock did have 112.5s in it. Now with kerker header and aftermarket filters im running 137.5s in all the carbs. Runs real good.

[mitch]

HP

I cant give you an exact number but from talking to a lot of people and some of those yamaha mechs with 30 + yrs experiance the XJ put out around 88 to 90 hp stock , with pod filters jetting,and exhaust you might get 92 to 94...........MITCH