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michael2211

Help with Mikuni flatslide

8 posts in this topic

I am trying to get some help. I posted a week or 2 ago with a problem and now I am following up. Basically I have an XR650L (97) that I just got and I am trying to sort it out. It idles and runs like crap and I am guessing it has to do with the jetting. Basically it has a Mikuni TM38 flatslide in it along with a WB E2 and a K&N pod filter. I am guessing that since it has the pod it is getting to much air, I don't know. The main jet is a 250 w/ a 22.5 pilot. I have done a search but it didn't really help me out. Basically it won't idle and when it does idle it will just all of a sudden make a loud sound and then die on me. I checked the plug FWIW and it was a light grey. Any adivce on jetting would be greatly appreciated. Also for the air/fuel screw how many turns out should it be, i have it at 2.5 right now. Thanks in advance for any help.

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I am trying to get some help. I posted a week or 2 ago with a problem and now I am following up. Basically I have an XR650L (97) that I just got and I am trying to sort it out. It idles and runs like crap and I am guessing it has to do with the jetting. Basically it has a Mikuni TM38 flatslide in it along with a WB E2 and a K&N pod filter. I am guessing that since it has the pod it is getting to much air, I don't know. The main jet is a 250 w/ a 22.5 pilot. I have done a search but it didn't really help me out. Basically it won't idle and when it does idle it will just all of a sudden make a loud sound and then die on me. I checked the plug FWIW and it was a light grey. Any adivce on jetting would be greatly appreciated. Also for the air/fuel screw how many turns out should it be, i have it at 2.5 right now. Thanks in advance for any help.

My air fuel screw on my 41 is 1.5 out,sounds like it's not really ritch from your plug reading.

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Have you checked the fuel flow? Open up the carb bowl screw to see if its flowing well. I think a 22.5 is a big pilot for that carb on your bike but my only reference is a 650R. Have you bumped up your idle for starting/warm-up? That might help for starting.

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I just put one on my bike, works great now. 17.5 pilot, needle in 3rd posision from top, 240 main, idel screw 1.5 turns out. Make sure your air box snorkel is removed. no more on idel screw. good luck

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The carb just has a pod filter on it although I am going to put an air box back on it. The previous owner cut it pretty much out so I am going to go back to that. I will give it a try with a 17.5 pilot, i thought the 22.5 might be a bit big on it. Also I will have to check the needle position.

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How sensitive are these carbs? I just got a 94 xr600 with the full 628 HRC kit barrel,HC piston,cam,valves,new rod,main bearings,2nd and 3rd gears,clutch baskets just about everything,including a XRS only 41 flatside. PITA to start,Kick,kick nothing. Put on the Kehien from my 89. Starts 1 to 3 kicks hard to keep the front end down up to 4th gear. Is there some kind of magic jetting? What do you people who like them get that's better than stock? Is it worth trying to get it to work?

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