smallboy Posted February 12, 2012 Report Share Posted February 12, 2012 Hi all Since fitting boyesen reeds to my EVO 250 2010 model,it is running rich,i have a NGK BR6ES plug which is very black,when cold running rough better when warm,idea's? Cheers Quote Link to comment Share on other sites More sharing options...
peterh Posted February 13, 2012 Report Share Posted February 13, 2012 Hi, I fitted Boyesen Reeds to my 2009 Evo 125 and as indicated by Boyesen it was running rich. I initially started re-jetting using plug chops but that was difficult to do in a suburbia streets. Ended up using the process as indicated at this website: Rejetting carb This process worked very well for me and it was very clear with each of the changes I needed to make. I ended up decreasing the pilot/slow jet by one size, lowering the needle to the 2nd clip from top to make it leaner (rather than changing needle diameter) and decreasing the main jet by 3 sizes. But expect that the 250 to be different, so best to get a couple of sizes smaller of the pilot/slow jet, and say 3 different smaller sizes for the main jet. Only change one size at a time. The result on the 125 was a crisp responsive and consistent response throughout the rev range and was a joy to ride. Hope that helps. Quote Link to comment Share on other sites More sharing options...
peterh Posted February 25, 2012 Report Share Posted February 25, 2012 Have now fitted Boyesen Reeds to my 2012 Beta Evo 200. Followed the procedure I used previously (see the link in previous post) and ended up lowering the needle to the 2nd clip position from top (thus leaning the 1/4 to 3/4 throttle response) and decreased the main jet from 125 to 118 - I should have tried a 115 size to convince myself that 115 was too lean, but 118 ran nicely through to full wide open throttle (WOT) so hopefully is all good. Did not decrease the pilot jet from the std 48 size but found that best 1/8th throttle position was with air screw out 2 1/4 turns out from fullly seated. The real test will be practicing at our Trials Park tomorrow. Quote Link to comment Share on other sites More sharing options...
0007 Posted February 26, 2012 Report Share Posted February 26, 2012 They change jetting because they increase "signal strength" so it's possible they would improve lower mid range by increasing velocity The problem I have with boyesen reeds is that over time they gradually lose tension so they go back to what you had originally but now you have lean jetting Just keep an eye on your plug Quote Link to comment Share on other sites More sharing options...
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