XJR rear wheel swap?

[Pat Conlon]

Randy and Tim FYI,

Many years ago, Steve Conklin installed the XJR output shaft and sprocket cover on his HSR1349 motor.
What he found out (the hard way) after putting the motor back in the frame, is that he could not get the XJR cover off with the motor installed in the FJ frame.
Steve ended up having to take his new motor back out, taking off the XJR sprocket cover, and performing major surgery on the cover, so he could get it on and off with the motor installed...

Just so you know...

How many days until the WCR....?

[axiom-r]

Thanks Pat-  I am really hopeful that only some minor "adjustment" will be needed on the stock cover to allow more comfortable clearance.  it clears now but it is tight....

WCR coming fast...  there is a still a slim chance that i am going to show up on the FJR1...  but I refuse to hurry as that leads to mistakes!

tim

[RichBaker]

The sheet metal piece inside is likely only for noise suppression, I would take it out and remove the bosses it mounts to if it was mine....

[Pat Conlon]

The sheet metal piece inside is likely only for noise suppression, I would take it out and remove the bosses it mounts to if it was mine....

Rich, I've always wondered what that in there for.. noise suppression you say?
Hmmmm, I wonder if that's why the oem counter sprocket had that hard rubber collar? Noise?

It makes sense, but really, how much noise can or does that area of the motor produce anyway?

[simi_ed]

Pat, Rich; I think you're a right, but it's not engine noise they're trying to cover, but the chain going around the countershaft.  Every little bit helps when you're trying to make the noise meter happy.  Less chain/engine noise SHOULD equal MORE intake/exhaust noise (which hopefully means more power).

My $0.02

[rktmanfj]

The sheet metal piece inside is likely only for noise suppression, I would take it out and remove the bosses it mounts to if it was mine....

Rich, I've always wondered what that in there for.. noise suppression you say?
Hmmmm, I wonder if that's why the oem counter sprocket had that hard rubber collar? Noise?

It makes sense, but really, how much noise can or does that area of the motor produce anyway?

IIRC, I read back in the day that it was a real challenge to meet noise standards in the ride by tests, so they were doing anything they could to cut mechanical noises in order to keep from further strangling the intake and exhaust.  Bikes with air cooled mills needed some tricks.

Randy T
Indy

[axiom-r]

The sheet metal piece inside is likely only for noise suppression, I would take it out and remove the bosses it mounts to if it was mine....

Thanks Rich! I was thinking that Yamaha added it to give more strength to the cover for a thrown chain but noise suppression makes perfect sense.  It also jibes with the odd rubber collars on the stock CS sprocket.....  its all making sense and it adds up to removing that plate.  Just taking the bolts off should give me the clearance I need.

[RichBaker]

Pat, Rich; I think you're a right, but it's not engine noise they're trying to cover, but the chain going around the countershaft.  Every little bit helps when you're trying to make the noise meter happy.  Less chain/engine noise SHOULD equal MORE intake/exhaust noise (which hopefully means more power).

My $0.02

Ed got it.....

[Seanextra]

OK SO who has done this Any link to the Counter Shaft Off set sprocket i need any other mods  needed and What about the XJR1300 Front Wheel will it fit as well ??

[WestOzXJR]

There are several generations of XJR wheels...
From about late 2003 XJR 13's had electronic speedo drive sensor off the tranny output shaft nut so no speedo drive adapter on the front wheel...
Same generation and up also ran 19mm front axle so would require some adaptation to the smaller FJ front axle...

XJR 1200 and early 1300 non SP ran the smaller diameter axle and took the same brake disc mounting PCD as 90-ish FJ so that's probably the easiest rim to go for...

The good news is, I've just measured my own FJ and XJR along side each other and they have the same fork tube center to center at 210.0 mm and the same disc to disc mount spacing so an early rim would slot right in to the FJ lowers with little or no spacer modification and the brake calipers would line up to the discs too (and it also opens the door to the possibility of easily fitting the late XJR 43mm cartridge forks with minimal modification if anyone else reading ever wanted to try that).

[fb747]

Hmmm...

So are you saying that a whole front end from a XJR1200 will slot straight in to the FJ triple tree with no modifications, or would you have to bore out the clamps? (cant remember/find FJ fork diameter)

If so you would get the benefit of a 3.5" front rim and thicker cartridge forks without compromising your ignition/steering lock setup?

[WestOzXJR]

So are you saying that a whole front end from a XJR1200 will slot straight in to the FJ triple tree with no modifications, or would you have to bore out the clamps? (cant remember/find FJ fork diameter)

fJ Is 41mm, you'd need to bore the triples out...

If so you would get the benefit of a 3.5" front rim and thicker cartridge forks without compromising your ignition/steering lock setup?

In terms of performance - I don't know much about early XJR12 forks except what I can tell you is they are noetheless by then 43 mm. So I'm not recommending nor vouching for earlier XJR 12 forks as being even cartridge... I've never really thought about using them...

The only forks I consider to be worthwhile are later ones from XJR 1300 SP (suspension package) which take the 19mm hollow axles and therefore gen 2 wheels which in turn take the 150mm PCD discs (same PCD as mid era R1 discs). This setup would give you a speedo drive and after boring out the triples would bolt right in...

Best yet would be current 07 and up forks that Yamaha finally got the spring rates correct (only took 'em 40 years). THESE forks are what I'd recommend and would also take either the gen 2 (curved spoke) or gen 3 (straight spoke) rims...

If I decide to do this conversion on my own FJ I'd make the compromise to have no on-board cable drive speedo and use the current rim which between the front and rear rims saves over 3kg (6.6lbs) of rotating un-sprung mass - a worthwhile compromise IMHO to have no speedo... You can always use GPS speedo (I don't run a speedo on my XJR anyway, air/fuel ratio data-logger display is more important)...

[Seanextra]

Well i have just recieved XJR 1200 Rim no idea of the model unless its stamped in the rim (ill check it later) going to get a friend with a lathe to help me mount it up, looks to be about 8mm difference in the sprocket alignment thinking about doing the Out Put Shaft swap  to the XJR 1200 Shaft to save using a off set sprocket ? Does anyone know the price of the XJR 1200 OutPut Shaft and where to get one ? I have the motor for this FJ 1200 pulled down at the moment and think id be crazy not to swap the shaft while its apart, Off set sprockets would be good enough for me but if i swap the shaft now i can use standard sprockets in future. Also have a set of FZR 1000 Rims now for my stock FJ 1200 but now realising the 18" Rear has a limited range of tires(tyre) but its got to be easier than the FJ standard wheel for sure?

[andyb]

Not really.  Not much worth a crap in 18" sizes, perhaps a slightly different poor selection than the 16" is all.

[WestOzXJR]

Well i have just recieved XJR 1200 Rim no idea of the model unless its stamped in the rim.

If it's actually from a 1200 (not a 13) then there's only one type rear rim and it takes the solid small diameter axle and has three curved/swept spokes?