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DocMaddie

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About DocMaddie

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    California
  1. Removed the FMF Powercore 4 that came with the bike when I bought it used, and put a stock muffler on today. It was then that I realized that that clamp was missing where the FMF slides into the header pipe, the muffler was only being held in place by the two mounting bolts. Fitted the stock muffler with proper gasket and clamp and went for a ride, sure enough runs great. So I think the diagnosis was an intermittent lean condition caused by an exhaust leak that varied depending on small changes in pipe joint seal based on vibration or movement, and got worse as the bike warmed up and the pipes expanded, worsening the leak at the joint.
  2. That would make sense why condition is worse with new K&N air filter as opposed to prior filthy one. I am going to wait for new muffler to arrive and then cross my fingers.
  3. Update - put it all back together without changing any carb parts and started right up. Still misfiring/backfire/hesitation at mid/high revs with perfect idle. Seems worse as bike warms up. Maybe it is running rich because it is using stock jetting with the FMF muffler? Also while always present seems to vary a bit in degree, sometimes worse and sometimes better, with no clear associations - which would argue more of an electrical problem like the ECU. Argh, will probably have to cave and bring it in to a shop. Ideas?
  4. Hi. 2011 XT250 with CA emissions stuff. New to me, 4800 miles. Missing alot at mid-high revs, some backfiring. Starts great with a little choke, sometimes none depending on the temp outside. Bike came with an F4F PowerCore 4 muffler, PO did not recall if any other work done when installed. Bike had a filthy air filter so I put a brand new K&N in. Bike ran worse. Took out the filter and ran open - bike stalled. Played with mixture screw no improvement. And anyway the problem is only at mid-high revs. To me this says "lean". So I pulled the carb expecting to see some weird jetting that was done when muffler put on. Pulled the carb (PITA) and none of the jets or the needle have any info on them, so I don't know if stock or not. Shop manual says there should be several positions for the needle clip but the needle in this carb has only one clip position possible. Check coil resistances etc... and all is good. Spark plug is good. Float looks good. I am hesitant to simply clean and put back together since it is such a PITA to take apart. Any way to tell if these are stock jet/needle etc...? I am thinking maybe just buy all new parts and clean and reassemble. I have a stock muffler coming via ebay but to my knowledge the F4F should be a bolt on with no carb changes needed. Any ideas? Maybe some of the emissions are clogged?
  5. DocMaddie

    YZ Clutch Lever Easy pull Mod

    I just did this for my '78 XL125. Slight improvement, I have lady hands so it still kinda sucks. But thanks and great idea! I found it was easiest to drill all the way through with a uni-bit up to 5/16", then flip it over and drill from the other side with the uni-bit to meet the hole. Then I cleaned it out with a dremmel. I did this after I tried to not drill through and exploded a lever when a bit got stuck, after starting with a uni-bit and then trying to continue from the same side with a straight 5/16" bit. Go slow and use lots of oil.
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