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94 DR350 running poor in top of gears

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I've got a 1994 DR350, idles beautifully. However when I'm in the top end of my gears it starts sputtering and I have to keep on the throttle to keep it running. Cleaned and rebuilt the entire carb, also replaced the spark plug. Wondering if it could be the fuel air screw or maybe a timing/other electrical issue. Anyone have any ideas? Any ideas would be appreciated.

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I've got a 1994 DR350, idles beautifully. However when I'm in the top end of my gears it starts sputtering and I have to keep on the throttle to keep it running. Cleaned and rebuilt the entire carb, also replaced the spark plug. Wondering if it could be the fuel air screw or maybe a timing/other electrical issue. Anyone have any ideas? Any ideas would be appreciated.


Is it CDI or points ignition? Any specific time it does it, or speed? My XR100 did that when I first got it. I think the spark was blowing out. New plug, still did it, had good spark at low rpm but changed a bunch of stuff and eventually realized it had been converted to points (it was a 1994, should have been CDI) and I put a new condenser in it and it ran great after that.

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Is it CDI or points ignition? Any specific time it does it, or speed? My XR100 did that when I first got it. I think the spark was blowing out. New plug, still did it, had good spark at low rpm but changed a bunch of stuff and eventually realized it had been converted to points (it was a 1994, should have been CDI) and I put a new condenser in it and it ran great after that.


All DR350's are CDI.

Is this a street or dirt version?

Have you checked any inline fuel filters? Checked your petcock has good flow? Could be running out of fuel at the higher speeds so check float height and the things I mentioned before.

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No inline fuel filters, and it is a street version. New petcock, and seems to flow fine.

Is this a new problem that surfaced or is the bike new to you?

I'm unfortunately not the greatest for jetting questions but if you post back with your jet sizes and any airbox or exhaust modifications that would be helpful.

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The bike is new to me. The gentlemen I got it from had the problem since the day he bought it from his buddy. He just gave the bike to me. It has no airbox mods, but It does have an fmf aftermarket exhaust on it. Supposedly one of the previous owners said it ran fine when he sold it to the gentleman I got it from (but you know how that goes).

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Sounds like it isn't getting enough fuel on the top end.  That probably means the main jet is a size or two too small.  That would be consistent with the upgraded exhaust.

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Sounds like it isn't getting enough fuel on the top end.  That probably means the main jet is a size or two too small.  That would be consistent with the upgraded exhaust.


Ill check it out

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I rode it yesterday for 10 miles or so, and it appears to run smooth up to 1/4 throttle. Any higher and it starts chugging and I have to give it more throttle. Once it gets to the top end of it, it stars chugging again and I have to either shift up or let it get back to below the 1/4 throttle range.

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Well, it could still be the main jet that is the culprit as the needle jet/needle draw fuel through the main, but more than likely you need to raise the needle to richen up the mid-range and go up at least a size on the main jet to take care of the top end.

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The general rule of thumb is that the pilot jet and throttle slide cut away take care of the first 1/4 of the throttle travel.  The needle jet and needle take care of the 1/4 to 3/4 part of the throttle travel and the main jet takes care of the 3/4 to WOT part of the throttle travel.  Given the way that a carb is put together these are not absolute cut over regions, but since your bike seems to run good off the bottom up until about 1/4 throttle I would think that your pilot jet and slide cut away are in the ball park.  You might try raising the needle up a notch or two to see if that helps the mid-range out before you change the main jet.

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By the way, I don't know if the needle is adjustable in this carb, I just assumed it was.  If there is not a circlip on the needle then you will need to get some thin washers to place under it to raise it up in the needle jets bore.

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So your choices to enrich your mid-range are either increase the needle jet size or find some small thin washers that will fit around the needle and settle down into the slide pocket.

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@GlennRay thanks for all the help. I put in an 1/8" or so worth of spacers on the carb. needle and the bike is running like a top. 

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