are all 400's the same??

I've been looking around on the internet for some specs for my maxim and was wondering if the xs400, xs400j, and xs400rj have the same engine specs? The reason why I ask is because I am thinking about getting a new cruiser (probably a Yamaha v-star 650) and want to compare weight-to-power for when I ride two up with my wife. So far I am finding conflicting numbers for the Maxim's horsepower and torque ratings, ranging from 27-45hp and 20-30 ftlbs of torque.

Thanks!

 

The XS400 is kind of confusing since for '82 and '83 there were two completely different "flavors" of them offered.

The original XS400 was a SOHC twin with rocker-adjusted valves and twin rear shocks.

For '82 we got the XS400J Maxim and XS400RJ Seca which had DOHC, shim-over bucket motors (like "half an XJ") and monoshock rear suspension. These bikes were almost entirely ignored by the aftermarket and folks who aren't aware of these differences usually assume that all of the 400 twins were the same.

 

That's what I thought, I knew that the xs400 were SOHC and the maxim's and seca's were DOHC but what does that mean for power ratings?

 

I'd bet the DOHC engine has close to 50% more power for these 400cc models. Experts will correct me if i'm wrong.

 

The earlier SOHC 400s were rated at 27HP @ 7000 rpm; the later, DOHC "half an XJ" bikes were rated at 45HP @ 9000 rpm.

 

66% more power, it's a huge difference!

 

Wow... I didn't think my bike had that much power but it makes sense. It scoots me along nicely but with my wife and I (about 280 pounds combined) it's a little doggy. The power-to-weight on a cruiser is less but the v-twin has more torque so I think it will be ok... Just not as peppy off the line as my maxim. Thanks for the help!

 

there were other 400's.

XS 400 Special - 2 cyl
XS 400 Maxim - 2 cyl
XS 400 Seca - 2 cyl
XJ 400 Maxim - 4 cyl

 

and the valve train allows 2,000 more rpm too!

CN