check the clip and or replace. the needle is Al Alloy the clip is spring steel. something has to give, if indeed the clip was in that slot and eating the softer alloy. needles are oem Mik or Kei yes not clones or other material aftermarket type ex.JD? those OEM ones are rare to break and they are all hard surface treated. 2 fails does not constitute a trend necessarily, but 2 breaks in the same bike may. Makes me think outside the needle itself. It most probably will be an outside cause (not the actual needle, but still the needle does remain a possible of course)- worn slide causing slide and excessive needle vibe, worn needle jet causing excessive needle play, motor with excessive vibes. I would rebuild the carb with new components. new needle and clip, new needle jet, all new jets, perhaps even a new slide.... and don't forget (alloy) carb bodies wear as well.....slides are also hard coated (chrome over brass usually) lots of hours on that carb? You always need to be objective and try hard not to focus on that exact part- ask what cause, we already know the effect. I think if needles were breaking in some sort of trend the intertube would be full of whining.....about it. I would be fairly sure a thorough rebuild and wear inspection of this carb with replacement of wear parts will cure any further needle breaks. (possible new carb, sudco is the best source) as long as all the parts are OEM (Keihin or Mikuni or other)
It didnt happen with the stock needle... I didnt buy these needles and I'm sure they are an aftermarket needle knowing the dealer he bought it from.... BTW the clip was not in that clip it was in 2nd from the top
Please excuse the "stream of thought" style: What does the tip of the needle look like: bent? scored from rubbing on the needle jet? And could you give us a pic pls? (is the needle jet worn from contact also?) is the clip flat? is the needle out of round now? Is there something in the slide end (or clip itself) causing a slight misalignment of the needle... so that at full throttle the needle jumps out of alignment with the needle jet- thus when the throttle closes, it impacts (and scores something or leaves an impact mark) eventually fatiguing at the first and weakest place. Which would be the bottom groove or highest needle position). did you find the broken needle in the needle jet? what about the other one? I'm guessing something is wrong at the slide end. I'm kinda with Robert on this one- I think the needle(s) are a symptom of the problem, not the problem itself. I'm just throwing ideas out there. (and I'm still on the stupid probation thing AGAIN. grrrr. So you'll probably get a few responses under this one before this post shows up. I "was" shovelhead85 before my account got hosed- also the guy you introduced to SSR last year). good luck.
Twice on a 1988 KTM 250, both times it waited until I was miles from truck, down in a canyon. (uphill both ways). Replaced main jet, and slide as I recall- all ok after that.
Either something is off center not inline. Or the bottom of the grooves have square corners that's causing fractures.
