evo boy Posted July 3, 2022 Report Share Posted July 3, 2022 Afternoon all wonder if you can give me some advice. I have a 2019 2t 300 Factory running boyson carbon reeds and a bosi system but I'm finding to really soft off the bottom like it has a delay before the power comes in. Any ideas would be grateful. Quote Link to comment Share on other sites More sharing options...
htrdoug Posted July 3, 2022 Report Share Posted July 3, 2022 Is it running smoothly when you are waiting for it to come on or is it burbling until you open the throttle more? You can try turning the mixture screw out about 1/2 turn at a time to see if it helps the burble. I bought a 2017 Factory a couple of yeas ago that ran that way until I turned it out some. I eventually put the remote mixture adjuster on it so I could keep it tweaked in for the weather. Then the bike was smooth and linear all the way up. Quote Link to comment Share on other sites More sharing options...
mcman56 Posted July 4, 2022 Report Share Posted July 4, 2022 (edited) Does it have a flywheel weight? If so, removing it should make it much sharper on the bottom. I read somewhere that all UK models come with the weight and are what is sold as the Super Smooth in the US. I'm not sure if that is true. Although, I had a 2014 Evo Factory 300 2t with no weight and it was very soft on the bottom. It was quite powerful when wound up. The response was slower than the 250 or even 125. The 125s had a little tiny flywheel so even though it lacked displacement, the response was quick. Edited July 4, 2022 by mcman56 add detail Quote Link to comment Share on other sites More sharing options...
evo boy Posted July 4, 2022 Author Report Share Posted July 4, 2022 22 hours ago, htrdoug said: Is it running smoothly when you are waiting for it to come on or is it burbling until you open the throttle more? You can try turning the mixture screw out about 1/2 turn at a time to see if it helps the burble. I bought a 2017 Factory a couple of yeas ago that ran that way until I turned it out some. I eventually put the remote mixture adjuster on it so I could keep it tweaked in for the weather. Then the bike was smooth and linear all the way up. Hello Htrdoug I'll get it out and give it a try thanks for your advice. I was also told to try a number 3 slide. Quote Link to comment Share on other sites More sharing options...
dan williams Posted July 5, 2022 Report Share Posted July 5, 2022 Carb is probably due for a disassemble and cleaning. The Keihin can get water trapped in the bleed passages for the pilot system that can make it feel soft off the bottom. Is this a new behavior or something it's always done? Also as the weather changed you can expect the jetting to shift slightly with air density. Quote Link to comment Share on other sites More sharing options...
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