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Flywheel Weight?

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I have an RM250 that I bought a few months ago.  This is my first bike ever, I've been riding quads for a few years.  Learning the ropes and gradually getting better but I've been reading up on flywheel weights.  I only ride in the woods and will occasionally go to the MX track but I don't do anything crazy there.  Would a flywheel weight help me out at all, what size should I get, and how much will it help?  Most of the trails that I ride are tight, technical trails and I like to hit the hill climbs when we find some.  Let me know what you guys think!  Thanks in advance!

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The only thing I can tell you about the FWW is that I decided not to get one for my RM250 after I had ridden it for a while. The weight will help in the low RPM to keep the engine from dying, but it will take some of the hit out too when you get into the engine's sweet spot. I do the same kinds of riding you are talking about. The RM was also my first dirtbike, having ridden quads in the past. Once I got used to the clutch and the 2-stroke hit I ended up really liking the way the RM handles in the woods without the FWW. Again, I don't have one to tell you but from my understanding the engine will lose some of it's 'snappiness', which to me equates to throttle response and faster revs at higher rpm. Maybe I am incorrect, and maybe someone will have other advice for you. This is just my experience on my RM.

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The only thing I can tell you about the FWW is that I decided not to get one for my RM250 after I had ridden it for a while. The weight will help in the low RPM to keep the engine from dying, but it will take some of the hit out too when you get into the engine's sweet spot. I do the same kinds of riding you are talking about. The RM was also my first dirtbike, having ridden quads in the past. Once I got used to the clutch and the 2-stroke hit I ended up really liking the way the RM handles in the woods without the FWW. Again, I don't have one to tell you but from my understanding the engine will lose some of it's 'snappiness', which to me equates to throttle response and faster revs at higher rpm. Maybe I am incorrect, and maybe someone will have other advice for you. This is just my experience on my RM.

Thanks.  I'm not entirely set on the FWW, it's got plenty of power to make it up hills even if I'm at low RPMs when I start.  I adjusted the AFR and got it to idle perfectly in the woods also, so that's not a problem.  Just figured I'd get some feedback on what they do and how effective they are.  Thanks for the input!

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I have one on my yz250 and its a bigger FWW and its awesome in tight stuff never fouled a plug or barely stall I'd go with a medium size FWW like a 6 or 8

Thanks man. I foul a plug every time I go out. I raised the needle one clip position to lean it out because it had no power down low when I first got it. That helped out a lot but didn't make it perfect so I ordered a 42 pilot jet (45 is in there right now). I'm gonna see how much,if at all, that helps and go from there. If it's still not where I want it to be I think I'll do as you suggested and get a 8oz FWW.

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You shouldn't be fouling plugs. Once your jetting is fixed it shouldn't happen any more.

Here are threads on flywheel weights;

http://www.thumpertalk.com/topic/1098620-04-rm250-flywheel-weight/

http://www.thumpertalk.com/topic/898251-flywheel-weights-for-rm250/

Yeah, I know my jetting is off. I have so much spooge coming out the exhaust that it stains my rear fender and a decent amount even gets on the swingarm.

I'm just not sure if it's only the pilot or if it's the main also.

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Yeah, I know my jetting is off. I have so much spooge coming out the exhaust that it stains my rear fender and a decent amount even gets on the swingarm.

I'm just not sure if it's only the pilot or if it's the main also.

 

What year is your bike? Post your temps, elevation, current jetting and pipe/silencer. 

Edited by Kenpo1

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What year is your bike? Post your temps, elevation, current jetting and pipe/silencer.

1998 RM 250 with the PJ carb. 162 main, 45 pilot. Fmf fatty with a pro circuit 304 silencer. Temps are 70-90 Fahrenheit, and elevation is 500-1500.

Edited by DeJay126

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1998 RM 250 with the PJ carb. 162 main, 45 pilot. Fmf fatty with a pro circuit 304 silencer. Temps are 70-90 Fahrenheit, and elevation is 500-1500.

 

From the FMF website, , 0-1500 elevation and 70 degrees temp;

 

  • Main Jet
  • 162-165
  • Pilot Jet
  • 42-45
  • Needle
  • STOCK
  • Needle Position
  • 3RD
  • Power Jet
  • N/A
  • Air Screw
  • 1.5

 

  • Fuel Screw
  • N/A

 

 

You're pretty close. Some variables that could be making your bike run richer; dirty air filter and/or heavier air filter oil. High humidity (the jetting numbers above come from CA, so while temps and elevation is close, I'm guessing PA is much more humid). 

 

Also, as temp increases, air gets thinner and your bike runs richer. If you're out on a 90-100 degree day with higher humidity, that may well richen your bike enough for the spooge. I'm no jetting expert, but that may be the case. 

 

So keep in mind a dirtier air filter and heavier oil will richen the bike a little, as will high humidity and increased temps. 

 

Also, have you repacked your silencer? 

Edited by Kenpo1
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From the FMF website, , 0-1500 elevation and 70 degrees temp;

  • Main Jet
  • 162-165
  • Pilot Jet
  • 42-45
  • Needle
  • STOCK
  • Needle Position
  • 3RD
  • Power Jet
  • N/A
  • Air Screw
  • 1.5
  • Fuel Screw
  • N/A

You're pretty close. Some variables that could be making your bike run richer; dirt air filter and/or heavier air filter oil. High humidity (the jetting numbers above come from CA, so while temps and elevation is close, I'm guessing PA is much more humid).

So keep in mind a dirtier air filter and heavier oil will richen the bike a little, as will high humidity.

Also, have you repacked your silencer?

I repacked it the day I bought it because I assumed that was why it was spooging. That didn't help at all. I'm not sure that moving to a 42 pilot is going to help the excessive spooge but I guess it's worth a try.

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I repacked it the day I bought it because I assumed that was why it was spooging. That didn't help at all. I'm not sure that moving to a 42 pilot is going to help the excessive spooge but I guess it's worth a try.

 

I wouldn't think the pilot would do it either.... I was surprised to see you were as close as you are. Maybe you mentioned it, but what premix are you using and what ratio? 

 

Hopefully a jetting expert will chime in....

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I wouldn't think the pilot would do it either.... I was surprised to see you were as close as you are. Maybe you mentioned it, but what premix are you using and what ratio?

Hopefully a jetting expert will chime in....

I was running 34:1 but with the spooge I decided to go for 40:1. So I've been running at 40:1 for a while now.

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