'78 xs450

i have to replace the engine, with a used running engine. are there
any reasonable alternates to the original to consider? will the xs650
engine fit with little enuf adaptation?

 

Yamaha didn't make an XS450. In fact, nobody did in 1978, and I'm not
sure I've ever heard that model designation anywhere.

Get a clue, use some intelligence, and come back when you've worked out
what bike you have.

And it's an XS400, the answer is no. In fact, the answer will be 'no' to
pretty much any Yamaha from 1978.

Byeee!

 

Probably not. The XS650 engine is probably too tall. There are other
problems involved in installing an engine that wasn't designed for a
particular chassis.

To start with, the countershaft sprocket has to line up with the rear
wheel
sprocket, and that might mean that the XS650 engine would have to sit
to
the right in the chassis (assuming you could get it in there at all).

Then there is the problem with the location of the countershaft
sprocket
with relation to the swing arm pivot. The engineers at Yamaha designed
the
chassis so that the chain would have the correct amount of tension/
slack
as the rear wheel moved up and down in reponse to bumps.

There are probably lots of neglected low-mileage Suzuki GS400's and
GS450's around and you can buy the whole motorcycle cheaper than
messing around trying to swap a different Yamaha engine into the frame
you already have.

 

thankyou for imparting your clue upon me!
of course, your correct. xs400. absolutely.
may i please have anouther clue?

 

figured as much,
thankyou

 

Major clue: The Old Gasbag is *no* "gentleman, he's an *asshole* who
will **** with you as long as you keep responding to him.

 

Wrong again, alkie.

 

You've got it. The XS650 engine won't fit.

Yamaha made 250cc and 360cc versions of the 400 engine (the 360
metamorphosed into the 400). The engines are identical except for the
bores (and the balance factor on the crank) so either one of these will
work. The 250 is a bit gutless, though.

Don't make the mistake of thinking the engine from the rare monoshock
XS400 will fit, either. It's totally different.