Beta evo factory throttle

[splashcroft]

Hi, everyone. I have just bought a 2022 250 factory to replace my 2017 standard 250.  I have found the throttle to be a bit slow when revving up. Is there any easy telĺ to see if the previous owner put a slow action throttle on it? Instead of standard? As grips have been changed at some point too. Given the condition of the bike and only a year old it seems strange to change the grips to me.

[lowside]

If its a domino throttle then a white tube is fast action, black is slow.

[splashcroft]

Hi lowside, it's a black domino one. Is that standard from beta themselves? May need to look a bit closer as to why it seems to rev up slower. Cheers for the reply

[splashcroft]

Tell a lie, turns out its a white one. Strange, seems previous owner maybe had problems with power.

[wheelieman14]

White Domino throttle tube is definitely "Fast action" throttle with less movement required than black tube throttle ~120 degrees total turn.

What are you using for final gearing? My '22 Evo Factory 250 came stock with 10/42 gearing and had no problems revving right up. I switched to 9/43 gearing and prefer to use 2nd gear, instead of 1st; when riding sections - which allows closer steps to 3rd or 4th gear. Typically if bike is geared with taller gearing (i.e 11 or 12 tooth front sprocket) then 1st gear is still pretty usable, but then there is pretty big gap; shifting from 1st to 2nd gear. A 250 is generally a little more mellow than a 300, but something doesn't seem right, if "slow-revving" is interpreted as "sluggish".

[splashcroft]

My old standard 250 had the black throttle body and just seemed zippier when opening the throttle. Same gearing as standard 10-42. Does rev up but you used the perfect word, sluggish and runs pretty well at idle but just slow to pick up and take off. Clutch doesnt drag. I will check to see if previous owner put an extra flywheel weight on.  But seems like they may have had whatever problem I'm having hence the quick throttle tube

[wheelieman14]

8 hours ago, splashcroft said:

My old standard 250 had the black throttle body and just seemed zippier when opening the throttle. Same gearing as standard 10-42. Does rev up but you used the perfect word, sluggish and runs pretty well at idle but just slow to pick up and take off. Clutch doesnt drag. I will check to see if previous owner put an extra flywheel weight on.  But seems like they may have had whatever problem I'm having hence the quick throttle tube

Where are you located? From my limited knowledge outside of USA-spec models; I believe in UK, that Beta UK prefers to have their 250/300cc Evo Models built with "heavier weighted flywheel" as standard build. With proper flywheel puller tool; it "might be possible" to remove flywheel to check if there is a weight "added onto the Standard flywheel (used in other countries). My experience is that in USA, the Beta Super Smooth heavier flywheel is built as a solid piece and not just an added on weight to increase Mass.

[splashcroft]

Hi, I'm in the south uk. Just want to get the bike back to standard. I was just going to take the case off and see if thf previous owner bolted any extra weight on.although from quick inspection there ix no extra thick gasket between casings. I will get round to checking carb needle sizes and reed valves when i have the chance. It only had one owner before me and seems odd in the space of a year it seems sluggish but has a quick throttle on unless it was sluggish from new and someones trued to rectify it with the quick throttle.  I will need to dig a bit deeper tonight and check some basics

[splashcroft]

Checked the flywheel. No obvious weights bolted on apart from one on the back i assume is factory standard for the 250 as seems a good fit and can't see and markings. But going to check over the carb and reeds before pulling it off to check. Sparkplug after a ride too.

[wheelieman14]

@splashcroft you actually need to use flywheel puller to see if there is removable weight added that can be removed... The newer generation Evo 250/300 models, since around 2013-15) have "inverted Flywheel/Stator" meaning the stator is attached to the flywheel cover (instead of internally). If flywheel is removed and you can view the backside (hidden in pic), that's where any possible screws would be located. That spark plug indicating a very rich (black) condition. Try raising the needle clip from 4th position down (stock, with 125 MJ) to 3rd clip position from the top (dropping needle into needle jet housing) to lean out low to midrange jetting. Might even be able to run 122 MJ and try increasing 48 Pilot (slow) jet to 50 or 52 to see if you can get maximum idle and crispness, once warmed up with air screw between 1.5 and 2.25 turns out?

Last question... what Pre-mix oil and ratio are you running? I wouldn't go with any more oil than 80:1 ratio and prefer Motul 710 synthetic (over Motul 800, which has too high flashpoint), typically letting "spooge" drip out of exhaust silencer...

Edited May 31, 2023 by wheelieman14
Need to know what pre-mix oil and ratio

[splashcroft]

Sorry for slow reply, 

Stripped and cleaned carb, all jets standard, air screw was only one turn out so set that 2.5 turns out from closed as per manual to get a base line.  

Reeds seem to be carbon fiber ones in good condition.

After riding the bike tonight over the same sections it seems a bit sharper but not too noticable.

I mix 60:1 fuel, not much in the way of spooge and never had a problem before. But maybe i should tweak? 

I'm running out of ideas, making me think it's just me. At the next trial my mate uses a 2020 factory 250 so will give that a ride and compare. 

 

[splashcroft]

At a trial at the weekend it seemed to improve. Maybe just clearing something through. I rode my mates factory after and feels very similar. Seems to have solved itself possibly. Will give it some more bike time and fingers crossed whatever it was seems to have gone.

Thank you for all your help guys