Fitted an Oberon Slave Cylinder and bled up satisfactorily. Fitted the original 10mm spacer and no joy. Fabricated a 19mm spacer and works a bit better, as in when in gear with clutch pulled in there is no drive, clutch out there is drive (but still slips). The biting point however is close to the bar (lever is roughly about 10-12mm from grip) so making me think that I don't want to take more off the spacer piece? Is it travel that is the issue or indeed this spacer length? Has anyone ever come up with a definitive spacer length when fitting these units?

Thanks
Will

For future note it is 17mm, not 18.25, and set up the adjustment screw in the lever.

Funny how this has come up now. I fitted one a couple of years ago and can't remember having issues at the time but when I was having issues with the starter last year the original spacer dropped out and got lost. I tried fabricating one but always had problems with it being too long or too short resulting in clutch drag so difficulty engaging gear and selecting neutral or clutch slip and no drive. I had ended up with one at 6.3mm long but wasn't happy with it.

I had no idea how long the original was so just this week I contacted Oberon via the link on my website and they sent me 2 spacers free of charge which arrived yesterday.
I was surprised to see that they were 10mm long as I can't remember the original being that long. However I went and fitted one anyway. Result - no drive! It was far too long and was holding the pressure plate off the stack.
I resorted to making another spacer and have ended up with 7.0mm which seems to work just fine.

I'm not sure why the supplied spacer is too long as, as far as I'm aware, the clutch, crankcase dimensions and alternator cover dimensions should be the same as the single phase Supersport, Monster, 916/748 engines. The stack height would have some effect but surely not 3.0mm of a difference.

Correction. Road testing shows that the clutch still slips with the 7.0mm spacer so I have reverted to the 6.3mm which seems perfectly ok. No clutch slip and easy neutral selection.

Be interesting to compare pushrod length, next time I'm anywhere near there I'll fetch mine out and have a measure. What does seem odd though for what should be identical clutch units the identified spacer length is radically different.
Took the bike out for a 45mile test though and everything was successful, no clutch slipping and clean shifts between gears. Only thing of note was a slight grabbyness on initial pickup.