Didja know?

[John]

That the FJ11 take the same main bearings as the XS/XJ? I didn't until yesterday when SWMBO saw a partial set of main bearings on ebay and they were listed for both bikes. I went to Yamahas' web site and checked the P/N's... they are the same . The P/N for the FJ11 bearings is a 2H7 part number. I checked the xs part number...the same number. The set that I saw was incomplete, all of the brown, and green bearings were gone, and the guy had the balls to ask $225 for it! I just bought a complete set for my bike for $70, shipping included.

[Dennyz]

John,

I heard a rummor that the top end of a FJ1200 would bolt on to the case of an XS. I was told that this is how to bump an XS up to a 1300 and a better valve system.

Can you verify this? Or at least debunk it?

Thanks

[randy]

I know nothing about FJ's. But I do know this, if that were true, the combustion chambers of the FJ would have to be 50cc's larger than the XS.

Doubtful.

[Dennyz]

There is a big-bore kit for the FJ1200 that takes it to 1300cc.

Taking an XS to 1300cc would be a 50cc increase in displacement per cylinder.

FYI: combustion chambers don't determind the CC of an engine, the bore and stroke do.

[randy]

Duh-Uh!

Thanks, Denny for the shot to the head. What was I thinking?

[Dennyz]

I checked the part numbers on the cylinder gasket for the XS11 (2H7-11351-00) and FJ1200 (4CR-11351-00-00). The FJ1100 uses the same gasket as the FJ1200.

If anybody has a used (unservicable) case to cylinder gasket for a FJ1100 or FJ1200, I would like to have it (please!).

This rumor has been haunting me for years, I would like to resolve it one way or another.

[John]

One difference between the XS and FJ engines is the direction of rotation. From the looks of the cam chain tensioner, that would be my guess. It is on the back of the engine, like that of an engine with CCW rotation.. I don't know if the chain guides from the FJ will adapt to the case of an XS. I don't have the top end off SWMBO's FJ, or I would try the swap. I've got a partially disassembled XJ engine out in the garage. The FJ is also four valve per cylinder technology, and I don't recall seeing an oil tube up to the top of the head.

[Dennyz]

John,

Engine rotation direction differences would squash the rumor. Next time you have the side cover off the FJ, verify the rotation direction for me.

Thanks

[John]

Side cover?

Dennyz, I have the case split, and the trans is out. Next time I look at it, I'll check, but with the tensioner on the back side, that tells me that CCW is the direction of rotation. I just read in the factoy manual, and there is no mention specifically of the direction of rotation, but it does tell you to turn the engine in a CCW direction after reassembly to make sure everything moves smoothly. Also the XS top end is lubed by a tube that runs up the back of the cylinder, and ffeds the cams. The FJ has a pressurized oil galley cast into the cylinder, and head for lubing the cams.

[Dennyz]

Thanks John, sound like this myth is "Busted" (watch too much Discovery)!

[John]

Naw...can't watch enough.

[Geezer]

Originally posted by Dennyz
John,

Engine rotation direction differences would squash the rumor. Next time you have the side cover off the FJ, verify the rotation direction for me.

Thanks

Maybe not, there is a chance that the cylinders can be turned around.

I've never tried but I've worked on a few bikes over the years that could have the cylinder installed backwards.

I never had an XS11 and a FJ1100 torn down at the same time so like you, I'm only speculating.

I know the pipes on a FJ are spaced differently but that could only be from the angle of the exhust ports.

BTW, I'm pretty sure the FJ had a geared primary instead of the chain like the XS uses.

Geezer