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125 in deep sand question.

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Hi, I ride a  completely stock 125 (2stroke) at a very deep sand track and it tends to struggle, especially against newer 250f's, I don't have the money to buy a 250f, so I was wondering what mods I could do to add power or torque. One marshal at the track said it looks as if the back was just spinning so would a FWW slow the revs enough to get more traction? Thanks, and I cant bore it as I am in the Lites class.

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A weight might help, playing with the gearing of the sprockets might help, or if tire spin is the main problem as the marshall suggests, the solution could be as simple as a better rear tire.

If the tire is spinning, more power won't make it spin less, you need to start by using what you've already got to the full.

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Yes but I'm also getting pulled on the straights and uphill sections at full throttle. I have a proper sand tyre and even rode my friends 250f with a normal nobby and it gets so much more traction. So would adding more power or torque via the use of pipes ,silencers, reeds etc in combination with a FWW make a more tractable power delivery type?

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Yes but I'm also getting pulled on the straights and uphill sections at full throttle. I have a proper sand tyre and even rode my friends 250f with a normal nobby and it gets so much more traction. So would adding more power or torque via the use of pipes ,silencers, reeds etc in combination with a FWW make a more tractable power delivery type?

and gearing it down a little

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Yes but I'm also getting pulled on the straights and uphill sections at full throttle. I have a proper sand tyre and even rode my friends 250f with a normal nobby and it gets so much more traction. So would adding more power or torque via the use of pipes ,silencers, reeds etc in combination with a FWW make a more tractable power delivery type?

Get the suspension set up properly, this will help get the rear to hook up, allow you to enter the corners faster, thus carry more speed out of them.

Sound to me that suspension to get the bike to hook up is what you should be chasing, not power, or taming the power delivery

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In reply to Pasa: I'm no 125 2t tuning expert by any means, in fact I hate 125s, but I did grow up riding in sand. That's why I suggested tires as a starting point. If you already have as good a tire as you think you can get, the next step is to tame the hit so it will resist breaking traction. I would try dropping a couple teeth on the rear sprocket. If that isn't enough, then ad FWW. Make sure your power valve is working right, and find out if it's tunable on your engine. Maybe opening the PV earlier will tame the hit too, but will need the advice of a real tuner to guide you with that.

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Thanks for the replies guys, I forgot to mention I have actually had my suspension revalved and they said the springs were good for my weight 149pounds or about 66kg(any adjustments I should make to improve traction?). How can I check my PV is working properly, also would retarding the timing help at all for more bottom end. Also the bike is a 2003 yz125 and sorry for so many questions ,but thanks for the help

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Thanks for the replies guys, I forgot to mention I have actually had my suspension revalved and they said the springs were good for my weight 149pounds or about 66kg(any adjustments I should make to improve traction?). How can I check my PV is working properly, also would retarding the timing help at all for more bottom end. Also the bike is a 2003 yz125 and sorry for so many questions ,but thanks for the help

Ask the guy who did your revolve for suggestions on what to try to get better traction.

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Flywheel weights are the last thing you want in sand.  The tire is going to spin.  There's no point in fighting that.  Suspension tuning can help put the power down but the most important thing is carrying speed and keeping it pinned.  Four strokes can take inside lines and lose speed because they have enough power to lug their way out and accelerate leaving the corner.  125's require outside lines and commitment.  Come in fast, keep it pinned and figure it out.  That's why 125's are hard to go fast on and force you to be a better rider.  Four strokes make people lazy.

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Flywheel weights are the last thing you want in sand. The tire is going to spin. There's no point in fighting that. Suspension tuning can help put the power down but the most important thing is carrying speed and keeping it pinned. Four strokes can take inside lines and lose speed because they have enough power to lug their way out and accelerate leaving the corner. 125's require outside lines and commitment. Come in fast, keep it pinned and figure it out. That's why 125's are hard to go fast on and force you to be a better rider. Four strokes make people lazy.

thanks, I suppose ill just have to get better

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Outside lines and keep it pinned. Or sell it and buy a 250 2t. 250 4 strokes most of the time will have an advantage over the 125.

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Get the suspension set up properly, this will help get the rear to hook up, allow you to enter the corners faster, thus carry more speed out of them.

Sound to me that suspension to get the bike to hook up is what you should be chasing, not power, or taming the power delivery

 

Definitely true.  Not only will it get the power to the ground, it will increase your braking power tremedously. 

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Thanks for the replies guys, I forgot to mention I have actually had my suspension revalved and they said the springs were good for my weight 149pounds or about 66kg(any adjustments I should make to improve traction?). How can I check my PV is working properly, also would retarding the timing help at all for more bottom end. Also the bike is a 2003 yz125 and sorry for so many questions ,but thanks for the help

Retarding the timing will lose bottom end and increase top end and vice versa.

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If you try to ride it like a 250f you're gonna get smoked by a 250f. 125s require a completely different style of riding than almost any other size bike. Imo, go down two teeth in the rear sprocket then avoid using tighter inside lines.

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You will never get a 125 2t to hook up and challenge the 250 4t's. The 4t's just get better traction. And like others have said...putting a 250 4t up against a 125 2t is kinda like cheating for the 4t guys.

If you become a better rider and learn how to keep up with (or almost) the 4t guys, if/when you get onto a 4t you will blow them away. Guys that learn on a 125 are way better riders than the guys that learn on a 4t.

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Get on youtube and look at how Stewart and Carmichael rode 125's.  Try to do it like that.

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Thanks for the replys, I know that a 250f will pretty much be better than a 125 in all aspects but for this season I'm stuck on the 125, also thanks for the help.

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