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RM250 Bog issues

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I'm new on here and wondered if you guys can help me out.

Here's the deal:

I have a 98 250 and it idles well and the jetting is good but once I rev it up past half throttle it bogs out and fouls the plug. I took it to a shop and the guy couldn't figure out what was wrong with it. You guys got any ideas on what it could be?

It has a 160 main, 42 pilot, needle on the 3rd clip.

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i would clean the carb first off and chase the circuits on the just for good measure but if your fouling plugs i would think your too rich iether jetting or mixture or it could also be a bad crank seal i hope its just the carb good luck

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The first thing I did before taking it in was taking the carb apart and cleaned it like crazy. then I figured it was the piston took that and put new rings on it. then I got a new plug. It's running really weird it's snappy in the lower RPM's and bogs mid and is okay high RPM's.

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have you messed with the carb at all...done anything with the float?

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have you messed with the carb at all...done anything with the float?

No I haven't the dude at the shop I took it to, messed with the carb and tuned it.

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Powervalve, bad reeds, bad ignition timing, weak spark.

If the guy at the shop couldn't figure it out then find another shop that can. A well trained tech should atleast be able to narrow it down for you

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The first thing I did before taking it in was taking the carb apart and cleaned it like crazy. then I figured it was the piston took that and put new rings on it. then I got a new plug. It's running really weird it's snappy in the lower RPM's and bogs mid and is okay high RPM's.

Your needle jet is too lean. Move the clip down one position and report back!

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Your needle jet is too lean. Move the clip down one position and report back!

You thinkin it might be a dry foul?

post a pic of your plug if you get the chance alex86

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You thinkin it might be a dry foul?

post a pic of your plug if you get the chance alex86

According to the Pro Circuit website his needle and main jets are too lean. Try and use the needle they note too.

This should work well at sea level and 70*. Adjust accordingly elsewhere.

Pro Circuit 165 42 NOZG 4TH 1 1/2 NEEDLE# 16009-1759

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actually what all do you have done to the bike? is it stock? modified (how modified) that might help out a bit as far as jetting goes

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You thinkin it might be a dry foul?

post a pic of your plug if you get the chance alex86

I'll post the pic as soon as I get home today.

actually what all do you have done to the bike? is it stock? modified (how modified) that might help out a bit as far as jetting goes

The bike is stock except for a Pro Circuit platinum pipe and Turbine Core II silencer.

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The bike is stock except for a Pro Circuit platinum pipe and Turbine Core II silencer.

Since you have a Pro Circuit pipe on there now - see if you can re-install the stock silencer too - just to get the jetting right. The TC2 will almost always make it run rich. You're already leaner than stock and the Pro Circuit settings. Make sure your packing is tight and fresh enough, air filter clean, top end recent enough with good compression, power valve somewhat clean, reeds recently checked, and your chain overly tightened with a super armour-alled seat :)

Jetting the bike with the above and a stock silencer will make it easier to fix bogs or stuttering. Then throw back on the TC2 and lean it a bit. Sometimes all you need for that is an air screw adjustment followed by a clip change on the needle (upwards). :banghead:

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Here are a couple of shots of the spark plug it looks good.

I did a compression test and it read 180 psi.

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It doesn't look too bad, a little rich but the weather is warming so probably right on for summer.

Hit that Suzuki FAQ's sticky and click on jetting. Read it and follow that to the letter. That will help you better understand the jetting process. After a couple of times you'll be a pro at it.

Just for fun, drop the needle 1 clip and see what happens.

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Just for fun, drop the needle 1 clip and see what happens.

As a practical matter, do this ^^^

Will do.:)

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