Oh crap, doo tell about your settings on the jetting, timing there that you have found comfort with. May be helpful to others!

Did you try the Boyesens?

Didn't do much really ..dropped the needle 1 & 1/2.. set float height correct cleaned the carb out it had the white gunge others have mentioned. Timing just trial and error ..it's quick to do with the right tools (had to replace oem washers on the 3 m5 socket cap stator bolts;think they're made of toffee or something ;.. I don't want it flat just smooth and of course you run the risk of running too hot if too retarded, it still hints at big bang (only on tickover) but I think I would have to mess about with compression ratio which I'm loath to do. Boyensens ..what spend money! ..I have plenty of time now retired so I made a 3mm spacer twixt reed block and crank .as I said above probably better to put some thick base gaskets in but like you say I'm only massaging/tinkering with it. not into needless surgery. I think the biggest change for better (for me) was the yoke and shims to a) reduce the trail a bit (32 mm @ wheel spindle) and put bar mounts foreward and up (up by 10mm now) It just feels better. I think the net effect I stumbled upon is quicker turning in which can sometimes make steering heavy(flop effect) compensated for by more leverage as the bar mounts are further from the headstock spindle this is all relative to where one puts the bars but for me bars foreward means too much weight on my old arms, I went through several years of tendonitus at elbows untill I found the cure was to pull the bars back a bit (slow learner) all best CW

Didn't do much really ..dropped the needle 1 & 1/2.. set float height correct cleaned the carb out it had the white gunge others have mentioned. Timing just trial and error ..it's quick to do with the right tools (had to replace oem washers on the 3 m5 socket cap stator bolts;think they're made of toffee or something ;.. I don't want it flat just smooth and of course you run the risk of running too hot if too retarded, it still hints at big bang (only on tickover) but I think I would have to mess about with compression ratio which I'm loath to do. Boyensens ..what spend money! ..I have plenty of time now retired so I made a 3mm spacer twixt reed block and crank .as I said above probably better to put some thick base gaskets in but like you say I'm only massaging/tinkering with it. not into needless surgery. I think the biggest change for better (for me) was the yoke and shims to a) reduce the trail a bit (32 mm @ wheel spindle) and put bar mounts foreward and up (up by 10mm now) It just feels better. I think the net effect I stumbled upon is quicker turning in which can sometimes make steering heavy(flop effect) compensated for by more leverage as the bar mounts are further from the headstock spindle this is all relative to where one puts the bars but for me bars foreward means too much weight on my old arms, I went through several years of tendonitus at elbows untill I found the cure was to pull the bars back a bit (slow learner) all best CW

Well, I never thought the newer 2.5 bad to begin with as compared to my 2.9, yet having contend with them for a while, coming off 20 quid for Boyesens may have more smoothing effect than you even want if you are happy now.

Thing about reducing timing just a bit from its initial setting is it reduces kickback on starts and stalling at low revs, bike chugs better if needed. Mine is set at about -3 mm on the plate, and one can roughly equate that to degrees of timing.

Once again, as these bikes come fairly optimized, I think the same principal reflects in the flyweight. I would like to try one with just a bit more, yet it has not been practicle to this point.

It seems S3 has released a flyweight for the Beta that requires no housing cover extension. I am wondering if these might be someway adaptable, although I know the Sherco is not drilled and tapped for it.

I think this might should be investigated a bit, yet no specs as yet.

Cope The only time $4,5000 of new bike arriving new out of the box with a carb full of white gunge , an engine awash with petrol, bike wanting to run backwards and a dodgy rim could be considered optimised would be if you wanted to spend more hours in the garage than riding it. I would accept that Sherco isn't a bad bike compared to what else is available but it's not a bike anybody can buy and just ride to the best of thier abilities....IMHO. (born from first hand experience). all best CW