84 RM250 Fouling plugs - Page 2 - Motorcycle-Journal Forums

digipoi · 06-23-2005, 04:14 AM

Quote:

Originally Posted by Dave2122

Even though you have a spark.....Change to a brand new plug of the same #......

One of the first things you learn owning a 2 stroke is.......

Just because the bike is showing a spark doesnt mean the plug is good.

Aint that the truth. Picked up an aftermarket pipe a couple weeks ago and rejetted to what FMF recommended just for the heck of it. Went riding and of course the jetting was off a bit so I was planning on rejetting once I cleaned the bike. Pressure washed the darn thing, let it dry a bit, and fired it up to move it up into my toolshed. The bugger quit on me and after kicking it a bunch of times to no avail and almost believing I got water in the wrong places, I took out the plug and cleaned it (was brand new, ridden for about 4 hours worth). Popped that sucker back in and the bike started and ran for about 15 seconds then it killed again. Changed plugs and its been running fine ever since. My kickstart leg was worked over but I learned something new which is worth more than a few days of muscle aches.

stingray_69 · 08-06-2005, 04:45 PM

I'm still having problems with the bike. I have a 290 main in it now and it still fouls the plugs though the plug is lasting longer now. I was wondering about changing the pilot. I have a 47.5 but I would like a little advice on this before doing it. The whole look alot smaller than the 50 that is it.

As far as the plugs, any time I cant get it fire I run out to get a new plug. I really appreciate that advice else I would be really giving my leg a work out like digipoi.

stingray_69 · 08-06-2005, 07:42 PM

The holes on the 47.5 look way smaller. Could it be possible that the one that is not a 50 but maybe a 60. It says 50. Also I would like to add that I had leaned the gas out 50:1.

Dave2122 · 08-07-2005, 08:40 PM

You need to do a plug chop. Put a new plug into the bike then run the bike thru the gears and kill it with the throttle wide open in 5th. Now look at your plug. If it is a light tan or brown your main jet is spot on. If it pulls clean thru each gear you know the needle height is good. The pilot is from zero to 1/4 throttle. Go one size smaller on the pilot and adjust your idle after the new pilot is in. Let me know what you find with the plug chop.

stingray_69 · 08-08-2005, 08:41 PM

I have heard of doing this test but I have no place to do at. Best I can get around here is half way through third before I have to shut it down. Most of my riding is down all out it first and second gear. As far as the needle jet, the best I can tell pulls great throught the gears I can hit. It usually runs good. Just before the plug fouls I can tell that it just not hitting the power ban as hard as it should. Usually, it runs good until you stop or stall the bike and then you cant get it started again until you change the plug.

The bike has never idled and the if im reading between the lines correctly in the clymer manual it shouldnt idle. The only idle adjustments the book talks about is for 125's and recommend that it should not idle if you are racing. With that in mind, I have tried to get it. I have adjust the cable so that the slide is up as far as I can get it with the throttle shut. It wont idle but only requires slight pressure on the throttle to keep it running.

Doesnt the pilot feed fuel at all times so that a smaller pilot when mean less fuel what ever the position of the throttle?

Dave2122 · 08-08-2005, 09:15 PM

One other thing to consider and I mentioned it in an earlier post. Does your needle valve look in good shape. If it is not in good shape it will allow fuel into the float bowl even if the float is adjusted correctly. Just one more detail to look at Stingray.

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08-06-2005, 04:45 PM	#22 (permalink)
stingray_69 Newbie Joined: May 2005 Posts: 22	I'm still having problems with the bike. I have a 290 main in it now and it still fouls the plugs though the plug is lasting longer now. I was wondering about changing the pilot. I have a 47.5 but I would like a little advice on this before doing it. The whole look alot smaller than the 50 that is it. As far as the plugs, any time I cant get it fire I run out to get a new plug. I really appreciate that advice else I would be really giving my leg a work out like digipoi.

08-06-2005, 07:42 PM	#23 (permalink)
stingray_69 Newbie Joined: May 2005 Posts: 22	The holes on the 47.5 look way smaller. Could it be possible that the one that is not a 50 but maybe a 60. It says 50. Also I would like to add that I had leaned the gas out 50:1.

08-07-2005, 08:40 PM	#24 (permalink)
Dave2122 Sprocket Pilot Joined: Sep 2004 Bike: Which one of the 9? Location: USA Posts: 887	You need to do a plug chop. Put a new plug into the bike then run the bike thru the gears and kill it with the throttle wide open in 5th. Now look at your plug. If it is a light tan or brown your main jet is spot on. If it pulls clean thru each gear you know the needle height is good. The pilot is from zero to 1/4 throttle. Go one size smaller on the pilot and adjust your idle after the new pilot is in. Let me know what you find with the plug chop.

08-08-2005, 08:41 PM	#25 (permalink)
stingray_69 Newbie Joined: May 2005 Posts: 22	I have heard of doing this test but I have no place to do at. Best I can get around here is half way through third before I have to shut it down. Most of my riding is down all out it first and second gear. As far as the needle jet, the best I can tell pulls great throught the gears I can hit. It usually runs good. Just before the plug fouls I can tell that it just not hitting the power ban as hard as it should. Usually, it runs good until you stop or stall the bike and then you cant get it started again until you change the plug. The bike has never idled and the if im reading between the lines correctly in the clymer manual it shouldnt idle. The only idle adjustments the book talks about is for 125's and recommend that it should not idle if you are racing. With that in mind, I have tried to get it. I have adjust the cable so that the slide is up as far as I can get it with the throttle shut. It wont idle but only requires slight pressure on the throttle to keep it running. Doesnt the pilot feed fuel at all times so that a smaller pilot when mean less fuel what ever the position of the throttle?

08-08-2005, 09:15 PM	#26 (permalink)
Dave2122 Sprocket Pilot Joined: Sep 2004 Bike: Which one of the 9? Location: USA Posts: 887	One other thing to consider and I mentioned it in an earlier post. Does your needle valve look in good shape. If it is not in good shape it will allow fuel into the float bowl even if the float is adjusted correctly. Just one more detail to look at Stingray.

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