br36 Posted November 29, 2014 Report Share Posted November 29, 2014 Hi, I've had a long running issue with my sons 2006 Sherco whereby it bogs down when you open the throttle sharply. Internet research suggests this is a pilot jet issue which can be solved using a combination of jet sizing and mixture screw adjustment. Unfortunately on this bike that doesn't work. Today I've progressively swapped the entire fuel system from my own Sherco 290 to the 125 with no positive effect. I started by fitting my 290 carb using the 125 throttle slide, still bogging: 290 carb + 290 throttle slide, still bogging: 290 carb/slide + 290 inlet, still bogging: 290 carb/slide + 290 inlet + 290 reed block, still bogging. I guess that confirms its not a mixture problem relating to the carb or inlet but internet searches don't throw up any suggestions that the bogging could be an electrical issue so I'm lost now:-( One thing I did notice when I removed the stator to do the main bearings and crank seals a few weeks ago, the factory marks weren't aligned so someone at some point has obviously altered the ignition timing. I'm going to borrow a DTI and a strobe to reset it all and see if it makes any difference but I'm not optimistic:-/ If anyone has any other suggestions they would be appreciated. My next plan (after setting the timing) is to progressively swap ignition system parts from the 290 to the 125 to see if that identifies the root cause. I don't like to admit defeat but this thing is trying my patience:-( Quote Link to comment Share on other sites More sharing options...
lineaway Posted November 30, 2014 Report Share Posted November 30, 2014 Sharply with the clutch pulled in or just trying to give this beast too much too fast. Quote Link to comment Share on other sites More sharing options...
zerorev3rev4 Posted November 30, 2014 Report Share Posted November 30, 2014 i would also try adjusting the timing it can make a big difference , i take it the air intake is all standard Quote Link to comment Share on other sites More sharing options...
copemech Posted November 30, 2014 Report Share Posted November 30, 2014 The bog is normal from low revs on 125. It is a bit over carbed(same carb and jets as 2.5 and 2. 9 for that). It is a rev and go machine Put the stator plate mark back to the right edge of the top casting web and it will be fine. Quote Link to comment Share on other sites More sharing options...
br36 Posted November 30, 2014 Author Report Share Posted November 30, 2014 Thanks for the replies guys. It does it in neutral from tickover and usually needs a blip when riding if you need to lift the front wheel. The intake is standard and with the exchanges I did yesterday with my 290 fuel system I'm sure now that it's not a fuelling issue. I'll set the timing correctly and see how it goes from there. Acknowledge the comment about this being normal on the 125 but my sons friend had the same bike and it didn't do it, it was very crisp. Quote Link to comment Share on other sites More sharing options...
zerorev3rev4 Posted November 30, 2014 Report Share Posted November 30, 2014 boysens maybe ? Quote Link to comment Share on other sites More sharing options...
br36 Posted November 30, 2014 Author Report Share Posted November 30, 2014 boysens maybe ? No mate, like I posted originally, I've tried the reed block from my 290 with no effect:-/ Quote Link to comment Share on other sites More sharing options...
2stroke4stroke Posted November 30, 2014 Report Share Posted November 30, 2014 Blocked exhaust perhaps? Quote Link to comment Share on other sites More sharing options...
zerorev3rev4 Posted November 30, 2014 Report Share Posted November 30, 2014 No mate, like I posted originally, I've tried the reed block from my 290 with no effect:-/ BOYSENS WORK BETTER THAN ORIGINAL ,OR MAYBE TRY RESTRICTING AIR INTO AIR BOX AS COPE SUGGESTED PROBABLY OVER CARBED Quote Link to comment Share on other sites More sharing options...
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