benbeta23

https://www.ebay.co.uk/itm/B20-157-Alternator-Bearing-Compatible-with-Mitsubishi-PFI-20x42x9mm/272382151055?epid=645265262&hash=item3f6b3dc98f:g:JbEAAOSwSYpZz41K:rk:1:pf:0 There what you need if you've done a conversion from Marzocchi to tech unless you change or machine the hub to take a 12mm wide bearing then you could use 6004

Yes it's the map switch for dry and wet conditions, It does make a considerable difference I've found but if you really want more power swap it for the later Dual spark CDI and it really livens it up, Make sure to use Part no 6416 if you change it, not from the 18 onwards models.

Cracking bike, absolutely the best machine I've ever owned and won't be changing anytime soon, On my second Factory model now, You won't be disappointed. Carburate absolute perfect out the box, No such issues like you mentioned, If any doubts give Birks a ring and he'll talk you through them.

Probably because the CV carb is fine for 90% of riders, it's only the other 10 at a very high level that need the instant power that a CV carb can't deliver as the engine vacuum isn't great enough to do so, There not designed as a performance carburettor but there great for low end smoothness which is probably what Beta have aimed for a good clubman bike, There's nothing to stop them trying a Mikuni pumper and changing compression with titanium valves, CDI for higher rpm to work with the ti valves, different cam profile etc.. and get a top rider running one, It'd get the job done as there a great reliable engine, In my opinion Beta should be working on a special 4t to run in the Trial2 class. It's about time it was promoted more.

Get a flatslide pumper Mikuni carb on it and it'll be right up there with the Monts

TOM's are one of the top companies in Japan for parts for the 125F, Not used one of there silencers myself but I'd be saying go for it, Or the Mitani is another good option, Best jetting I can recall is 102.5 main, 17.5 pilot, Forgot the rest of the settings.

Does the 98204Y have rubber shields? I'd make sure beforehand, I had same problem on mine with a tech conversion, Used same 20x42x9, either that or change the hub! SKF produce them with rubber shields but there not cheap!

If the bearings for the Marzocchi now are the 6905 you won't be able to simply swap them for 6004 as the 6905 are 9mm in width opposed to the 12mm for 6004, So you'll need a 20mm ID bearing with a 9mm width also

The VHST 28 with the pump jet hasn't been available from Eurocarb (Dellorto UK) for a long time, You'll have a hell of a job finding one, I have two of them on my bikes, I know somebody with a brand new one if required.

I used to run one on my Evo factory, Was very good, It would only fit with the bump stop at the bottom but it is very tight on the exhaust side, Like you say the reservoir wouldn't clear the swingarm if it was the other way up like the Monts are, They are adapted for the Beta as the Montesa is a different length, Beta is 280mm and Montesa is 265mm, Mine had different internals and the nitrogen pressure was lower than what Monts use.

As above I'd go for the Flywheel weight first and also the slow action throttle, I had a ride the other day on a 16 Sherco 250 & 300 & a 16 Scorpa 300, Both 300's felt far to powerful for me even compared to my 300 Evo, and I agree the revs do build up very quickly which is probably why you are struggling with grip, The flywheel weight should help this a lot, Also make sure the rear suspension is set up for your weight, This will also help with grip, Hope you get it sorted.

Is the fuel tap in the correct position? It should be facing upwards, If it's downwards it won't shut the fuel supply off when the bike is on it's side, It's an electronic tap, If the bike won't run right with it in the upwards position the tap has failed.

He's after a 250F 4t, Not a 2 stroke.

Try a BPR5ES plug rather than standard 7, Engine runs cleaner, It may help improve it.