PDA

View Full Version : Yamaha XS650 motor question



Nunnu
02-03-2010, 2:12 PM
I'm going to be starting a xs650 bobber project and I have a question...

Is there any difference between, let's say a 72 and a 82 xs650 motor?


Thanks

MikeMigs
02-03-2010, 2:31 PM
Some of the differences I can think of off the top of my head are the Carbs and the Ignition..

Punkskalar
02-03-2010, 2:38 PM
Some of the differences I can think of off the top of my head are the Carbs and the Ignition..

Carbs, Ignition, yes.


Also slightly different cam specs. 72 is hotter

Transmissions are cut differently, but geared the same.

72 MIGHT be a 22mm wristpin engine, if it is a 256 Engine, 447 Engine (82 model) will be a 20MM wrist pin and has alot more options for engine mods.

72 MAY not have an electric starter

256 Engines (early stuff) also have different Cam chain tensioners, and less teeth on the cam/crank gears.

Late Model Engines have an oil sight on the sidecover

Late model engines are CDI ignition, early are points/condenser stuff.

Externals mostly swap over throughout the years, but if you had a 256 Engine, I'd sell it to someone who needs it, and run a 447 engine just for parts availability.

Nunnu
02-03-2010, 3:05 PM
Thanks for the info.

The reason why I ask is because I have an oppurtunity to start my hard tail bobber project with a 81 yamaha xs 650. I wasn't quite sure which route to go (earlier or later years). I'm assuming the 70's through the early 80's motors looked the same?

Thanks again!



.

Punkskalar
02-03-2010, 3:15 PM
Thanks for the info.

The reason why I ask is because I have an oppurtunity to start my hard tail bobber project with a 81 yamaha xs 650. I wasn't quite sure which route to go (earlier or later years). I'm assuming the 70's through the early 80's motors looked the same?

Thanks again!



.

Yep, damn near identical on the outside. Early motors have a 4 bolt cam chain tensioner, later have 6. You want 6... BUT, some 256 engines DID have 6 bolt tensioners. Look at the number on the engine, it will say 256, 447, or something else. 447 or something else is 447.

Nunnu
02-03-2010, 4:21 PM
OK, Thanks!


BTW,
Mint ride, Punkskalar!



.

philbey
02-03-2010, 5:33 PM
So basically, if it doesn't say 256, then it's a 447?

Because mine is an aussie 3W6 number, I've always wondered what actual motor it is (1980 model, I just assumed it's a 447)

jamesgs4
02-03-2010, 9:08 PM
The 256 motors had higher compression too, so they are a bit more powerful than the lower compression 447's

jamesgs4
02-03-2010, 9:14 PM
Thanks for the info.

The reason why I ask is because I have an oppurtunity to start my hard tail bobber project with a 81 yamaha xs 650. I wasn't quite sure which route to go (earlier or later years). I'm assuming the 70's through the early 80's motors looked the same?

Thanks again!



.
Yeah they look the same, and mines an 81 also, and though the electronic ignition adds a lot of wires to the rats nest, not fucking with points is worth it.

Punkskalar
02-03-2010, 10:02 PM
Yeah they look the same, and mines an 81 also, and though the electronic ignition adds a lot of wires to the rats nest, not fucking with points is worth it.

Go for Pamcopete's ignition. 3 Wires, no magic black boxes, and it all fits under the cam covers. No more Rats nest, and new electrics....

scotttowne
02-05-2010, 9:15 AM
so carbs from a 75 won't fit an 81?

Punkskalar
02-05-2010, 12:05 PM
so carbs from a 75 won't fit an 81?

Use the intakes from the 75, should be a direct fit. 81 Intakes might fit as well, just see what happens...

scotttowne
02-05-2010, 10:33 PM
that's where I'm at. thanks Punk!

jamesgs4
02-06-2010, 2:22 AM
Go for Pamcopete's ignition. 3 Wires, no magic black boxes, and it all fits under the cam covers. No more Rats nest, and new electrics....

yeah if my cdi ever craps out that is definately what i will do.