Guest Posted June 17, 2015 Posted June 17, 2015 hi peoples..de-baffled my bike this morning, which was a pain in the ass job...of course, i then proceeded to jump the next size up jet..from stock 97.5, to the next one up, which is 100...gave my bike a ride around to warm it up properly.. then took it for a high speed ride down the A10... see a lay-by up ahead, so pulled clutch in, and killed the engine, to roll to a stop...Spark plug showed engine lean..(black soot around the edge with grey, dry electrode)so went home, jumped to the next size jet.. 102..same warm up, ride and killswitch job... plug still grey and dry...jumped up to next size. 105... tada, plug remains the same..110 jet... same112 jet, same115 jet, same...stopped right there...seams a pretty drastic jump up in jet sizes, just for a de-baffle, and still running lean.....this doesnt seam normal to me..normally id expect next size jet, maybe two..but now a few.. from 97.5, 100, 102, 105, 110, 112, 115 and still lean!the engine was running with perfect mix before hand...(browny moisty electrode)...so WHAT THE HELL.... Quote
Stu Posted June 17, 2015 Posted June 17, 2015 try raising the needle slightly with the 100 jet a small washer or two over the needle will be enough there is no point in a larger jet if the needle is restricting flow Quote
Guest Posted June 17, 2015 Posted June 17, 2015 try raising the needle slightly with the 100 jet a small washer or two over the needle will be enough there is no point in a larger jet if the needle is restricting flow there is no needle adjustment mate..my carb is one of those ones with the needle and barrel attached to the throttle cable...had a look earlier for a way to try and adjust that.. Quote
Stu Posted June 17, 2015 Posted June 17, 2015 I have never seen a needle where you cant adjust it! usually those set ups still allow the needle to be removed other than that you will need to replace the needle with a more tapered one Quote
Guest Posted June 17, 2015 Posted June 17, 2015 I have never seen a needle where you cant adjust it! usually those set ups still allow the needle to be removed other than that you will need to replace the needle with a more tapered one yeah thats what i thought too mate..ive seen many of those carbs with the cylinder ends, much like clutch cable fitment, which can be removed..but not mine Quote
Guest Posted June 17, 2015 Posted June 17, 2015 sounds like your bit stuck then yepp. looks it dont really fancy my chances riding it as it is..its clearly rather on the lean side Quote
eastanglianbiker Posted June 17, 2015 Posted June 17, 2015 seeing as its under warranty should of left it alone untill it runs out if you cant raise the needle is there not a mixture screw on side of carb? Quote
Guest Posted June 17, 2015 Posted June 17, 2015 seeing as its under warranty should of left it alone untill it runs out if you cant raise the needle is there not a mixture screw on side of carb? yes mate, there is a mixture screw, but thats only for idle / low end mixture.. which does not need to be adjusted...otherwise i would just change the pilot jet...its the main jet for WOT, that is lean.. Quote
Joeman Posted June 18, 2015 Posted June 18, 2015 Sure there is no clip on the top of the neeedle?How is the needle secured into the slide?An old trick is to put the needle in a drill and spin it up whilst holding sand paper over it to basically file it down and make it sharper. Careful if you try that though! Quote
Guest Posted June 18, 2015 Posted June 18, 2015 Sure there is no clip on the top of the neeedle?How is the needle secured into the slide?An old trick is to put the needle in a drill and spin it up whilst holding sand paper over it to basically file it down and make it sharper. Careful if you try that though! it looks like its moulded into the barrel bit itself mate..Okay, i gave it one last jet earlier, just to see.. went to 117 jet, and well, it ran like shite..constantly misfiring in 5th gear... all the other gears were perfectly fine, at all revs, but 5th... it did not like it...ive just put the 100 jet in for now... its bigger than stock, but not too big...once i find a way, i can go from there Quote
Grumpy Old Git Posted June 25, 2015 Posted June 25, 2015 try raising the float level by 1 or 2 mm ???I think I know what you are trying to do but that won't have the desired effect. If the issue was fuel shortage, then the engine would be mis-firing or cutting out.The needle needs raising ('normal' carbs allow for this by having stepped notches on the top of the needle which can be removed from the slide). It this case, it would appear that the OPs carb has a single slide/needle unit (no removal / adjustment of the needle). Only way out of this is to (carefully) increase the taper of the needle by grinding/sanding down - Not an easy task if the needle cannot be removed.i would therefore advise ether replacing the carb completely (with a 'race' varient) or, ensure fuel contains UCL (RedEx) on every fill.Good luck. Quote
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