XTZ/SRX?XT cases

[andy230]

Hello all.

I have just been told that the XTZ cases have a mount slightly offset when compared to the SRX cases.  This would explain why we thought the frame was "bent".  So maybe its not...

Anyone got any info on this...?  Would also explain why the spricket appears to be very close to the frame...

And has anyone got a contact for Pascal?? He put a watercooled engine into a standard SRX frame....

Cheers for now

a

[Steve H]

The SZR, XTZ, XT600E and SRX monoshock engine cases have the sprocket offset by 10mm.
I would guess this is to clear wider tyres (could be wrong though), I would have thought this would work in your favour as you are probabaly running wider rims than the stock SRX ones.
I beleive Pascal machines the heads off the seal retaining bolts to clear the chain and uses a slightly offset spocket to get the chain alignment back.

[andy230]

Hi Steve,

Am currently less concerned about sprocket offset, other than the fact that its a function of the offset of the mounts.

The SZR, XTZ, XT600E and SRX monoshock engine cases have the sprocket offset by 10mm.
I would guess this is to clear wider tyres (could be wrong though), I would have thought this would work in your favour as you are probabaly running wider rims than the stock SRX ones.
I beleive Pascal machines the heads off the seal retaining bolts to clear the chain and uses a slightly offset spocket to get the chain alignment back.

I had thought about that.  Or turning the gearbox sprocket round.

Do you know if its the sprocket itself, or the whole lump which is offset??  This may be difficult as the cylinder head mount (XT top end) may not want to line up with the chassis mounts when the XTZ cases are bolted in.

a

[Steve H]

Do you know if its the sprocket itself, or the whole lump which is offset??  This may be difficult as the cylinder head mount (XT top end) may not want to line up with the chassis mounts when the XTZ cases are bolted in.

I beleive the output shaft is longer. The rest of the mounts are in the same position.

[andy230]

Right.....

will hang it from the cyl head and front mounts, and see where the rear mount wants to sit...

So maybe the frames not bent after all.  Maybe we are just buffoons!!

a

[andy230]

Apparently XTZ and SRX cases are the same (re. mounts) and the XT is the odd-one-out...

a

[Steve H]

Apparently XTZ and SRX cases are the same (re. mounts) and the XT is the odd-one-out...

a

Must admit thats not been my experience.

[Steve Lake]

Andy.....the 'yellow' track bike I have, is an SRX mono chassis with a twinshock 640cc lump in it, and there is a 10mm offset between the rear sprocket and the engine sprocket.....the chain length is so long that the offset is of little consequence (on a track iron.....but on a proper race bike might need adressing).... but i don't seem to get accelerated chain or sprocket wear so far.

[OMEGAMAN]

Dunno if this is of any help, but when I tried to fit an XT lump into my std. srx frame, I got it in ok but then found the sprocket out by 10mm & also could not get the exhaust pipes back in as the front frame rails were in the way.

[andy230]

Cheers for that...

Anyway, disaster averted.  The frame's not bent.   

The SRX and XTZ motors have the lower rear mounts in the same place.  The XT is different (i think) and this frame was built for an XT lump.

If you line up the centreline of the motor (ie crankcase gasket mating surfaces), the line bisects the cylinder head mounting nut at the rear of the barrel, the two inlets, and comes slap bang in the middle of the head mount.  Which is central on the frame.

However, if you continue this line to the rear, it doesn't end up central at the swingarm pivot.  Its about 15mm off to the left.

So I think it will be a case of cutting off the two ally mounts, mounting the motor from the existing, usable mounts, getting it central and welding the mounts on to suit.

Hurrah.

First I want to get the motor finished, and these shim-things sorted out under the valve springs.  And yes Steve, I hear ya.  I will contact RD, tho I have not heard good things about the "comms".  No email address, but there is a fax number on the paperwork.  Will check their site, maybe they have a "contact us", I'll ask their opinion, and let you know what the say.

Cheers for now

a

[Steve H]

info@rdvalvespring.com

[andy230]

ta!  will do it today.  help, interest, points of view and conversation all appreciated!

will let you know

a

[Steve H]

However, if you continue this line to the rear, it doesn't end up central at the swingarm pivot.  Its about 15mm off to the left.

Andy, this still doesnt add up to me. Before you do any cutting is it worth putting up a picture so we can see what you mean.
"Measure twice cut once"

[andy230]

Will post on blog and let you know when its up.

Thanks as ever

xx   

[OMEGAMAN]

Cheers for that...

Anyway, disaster averted.  The frame's not bent.   

The SRX and XTZ motors have the lower rear mounts in the same place.  The XT is different (i think) and this frame was built for an XT lump.

If you line up the centreline of the motor (ie crankcase gasket mating surfaces), the line bisects the cylinder head mounting nut at the rear of the barrel, the two inlets, and comes slap bang in the middle of the head mount.  Which is central on the frame.

However, if you continue this line to the rear, it doesn't end up central at the swingarm pivot.  Its about 15mm off to the left.

So I think it will be a case of cutting off the two ally mounts, mounting the motor from the existing, usable mounts, getting it central and welding the mounts on to suit.

Hurrah.

First I want to get the motor finished, and these shim-things sorted out under the valve springs.  And yes Steve, I hear ya.  I will contact RD, tho I have not heard good things about the "comms".  No email address, but there is a fax number on the paperwork.  Will check their site, maybe they have a "contact us", I'll ask their opinion, and let you know what the say.

Cheers for now

a

    Andy,    if this is the frame you bought off me, then I GAURANTEE it had a SRX motor in it when it last ran!!!   

I have an XT motor (tuned 640) & was considering fitting it in but found that I would have had to cut away part of one of the rear engine mounts so did not continue???