Questions about FJs / Xs

[79XS11F]

The FJ1100s and 1200s are chain drive bikes ... right? If so are they closely based on the XS engine? If so is there a different and separate part, transfer case where our middle gear is? If so is the bolt pattern the same ... or in other words .. would it bolt right onto our engine where our middle gear is?
Rob

[Wildkat]

Nope...

XJs are shaft drive... the engine is basically the same (I believe) as the XS... otherwise... there might have been a huge mistake made when Tod did the 750 final drive modification to his XJ...

[Wildkat]

Wait a minute.... did I read that right?

or did I speak out of turn (again)?

Don't listen to me... I'm just here for comic relief...

[Wildkat]

Oh hey now!

You're changing this up on me now!


The FJs ARE chain driven... this I know for certain...
(WooHoo! Yea for me!)

Not so certain about the rest as I believe the FJ works in stranger and more mysterious ways than the XS... but I will defer that to those in the know...

[79XS11F]

Hey Wildcat .. Yes I edited my post when I saw my own mistake so your OK .. no worried :-) Anyway I was over at Bike bandit looking at the cases for the FJ and there dose not appear to be a big difference at the back end where our middle gear goes. I bet you can see where I'm going with this ... I have never seen a FJ up close and always wondered if parts from the final drive could go into XS cases or bolt on to have a FACTORY XS chain drive modification.
Rob

[trbig]

Kat dear.... put the bottle down now and go on to bed.

I think this is something we need to find out. Maybe that could be our weekend project... totally strip Kat's FJ (I said the bike Kat!) and stare blankly at all the little pieces... then go home? She has a running XS now anyway... she doesn't need that thing any more.


Tod

[audijunky]

I was just looking at a photo of an 86 FJ1200 and it looks like the starter is different, however the engine looks to be built the same and the area where the front sprocket would go looks to have the same dimensions as our middle gear housing. Have a look

[audijunky]

While were on the subject .... why not put the entire engine in an 11??????

[79XS11F]

Well the early XS1100 engines are more powerful overall ar they not? I also don't have a FJ 1100 or 1200 engine laying around.
Rob

[webbcraft2150]

Originally posted by trbig
Kat dear.... put the bottle down now and go on to bed.

I think this is something we need to find out. Maybe that could be our weekend project... totally strip Kat's FJ

Tod

Rooooaaaad trip!!!!!!!!!

[79XS11F]

Originally posted by audijunky
I was just looking at a photo of an 86 FJ1200 and it looks like the starter is different, however the engine looks to be built the same and the area where the front sprocket would go looks to have the same dimensions as our middle gear housing. Have a look

Yes it is very similar in appearance and size and the fich of the FJ cases also look very similar. It would be far less costly for Yamaha to make the change there as compared to redesigning the cases. I am just curious if the XS could receive an FJ final drive that ether bolts right on or can be installed easily if /when cases are split. It would sure be a lot easier then messing around with making your own output parts.

Rob

[pggg]

Pretty sure there's too many differences between the two engines for an easy bolt-on swap, you'd still be looking at a major project.. and actually the shaftdrive is one of the elevens best features anyway... smooth, clean,quiet, clean, no maintenance, clean... what person in their right mind would WANT a dirty greasy chaindrive?

[79XS11F]

I was thinking for my next project bike. If it was an easy switch out I would do it to get the extra horses to the ground. After all .. Yamaha did the same thing when they made the FJs.
Rob

[pggg]

Hi 79, yeah for normal road riding those extra ponies don't really come in to play unless you're hard-out full throttle everywhere! Shaft versus chain, getting power from the crank to the rear tyre, the difference in efficiency between chain and shaft ain't as much as some would have you believe... there IS a difference, but not huge...

[John]

I have been elbow deep into both the XS and FJ engines, and I can tell you the only thing they have in common is the crankshaft main bearings. The FJ engine is a 4 valve per cyl engine, and it rotates backwards compared to the XS. I'm sure somebody somewhere could find some way to graft some kind of middle drive to an FJ engine.