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Help Me fix up the YZ 250

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Bike runs super strong and is great. I love it. Has a fresh top end. Everything else is stock with the exception of the FMF header pipe and slip on. What can I do to make it have better throttle response and just make the performance better? Should I go with some reeds? Different carberator? I mostly ride single track but there are some water bars/jumps out on our trails that I like to hit going pretty fast. So I guess suspension would be good to adjust. The front forks are good I think but the rear shock is a little soft and the seat sits lower than I would like but to be honest the way it is set up now I can fly through single track just would like the rear a little stiffer. Should I adjust the spring taller then adjust the clickers? I am about 200lbs with gear.

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Good quality reeds will liven things up a little, especially if the reeds are old and worn.  Replacing the carb will be pointless without major engine mods.  Proper jetting for your area would be more beneficial than just replacing the carb.  If you want to spend money to get more performance, I'd recommend going with a big bore cylinder and high compression piston setup.

 

As far as suspension, have you tried stiffening up the preload on the spring?

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Before any engine work, go with suspenders.. Springs, valving, oil and level, can make you faster. To pep up the engine make sure you have your timing where you want it, brass is correct, and look to the pipe for what range you ride in mostly. Low end peppy pipes, mid range pipes, top end pipes, and the stock all range pipes are there. If you wan't more out of the bike, thats my 2 cent.

17 minutes ago, Kinger317 said:

 

 

( . Y . )

 

 

 

 

 

That can go a long way.

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Im not sure what fmf pipe it has but I will look into it. I would want a low to mid range pipe. Also when setting the rear shock spring, if I make the spring taller with a spanner wrech will that make it so I can make the suspension more jump friendly or would I want to compress the spring more then adjust the compresion and rebound? I would think me being 6ft 200 lb I would want to make the rear shock spring taller then adjust the clikers?

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3 minutes ago, YZF1825 said:

Im not sure what fmf pipe it has but I will look into it. I would want a low to mid range pipe. Also when setting the rear shock spring, if I make the spring taller with a spanner wrech will that make it so I can make the suspension more jump friendly or would I want to compress the spring more then adjust the compresion and rebound? I would think me being 6ft 200 lb I would want to make the rear shock spring taller then adjust the clikers?

Look up in the technical section on how to set rear sag.  It will make a big difference if you've never adjusted the rear suspension.

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You would benefit from a stiffer rear shock spring. There is two sag measurements that are important. 103 mm (with you on the bike) and 30 mm with no one on the bike (static). If you crank up the preload on your spring you will have less than 30 mm static. It won't handle well like that. Stiffer spring would be my starting point.

 

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3 minutes ago, YZF1825 said:

Im not sure what fmf pipe it has but I will look into it. I would want a low to mid range pipe. Also when setting the rear shock spring, if I make the spring taller with a spanner wrech will that make it so I can make the suspension more jump friendly or would I want to compress the spring more then adjust the compresion and rebound? I would think me being 6ft 200 lb I would want to make the rear shock spring taller then adjust the clikers?

No, no, no...

Set up the bikes sag proper. If the springs are stock (and forgive me, I do not know the year) the springs are best for a 165-185 lb rider. You would need a little stiffer springs for the 200lb rider. So I am guessing you are 185-190 street cloths. Depending on bike, you can change oil, re-valve, and set up the clickers for you riding the same line over and over until it feels sweet. 

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If the performance is less than u desire for single track you sir are one bada$$ rider.u may need a 5.4 or so spring on the rear,I would match the front springs to whatever u decide,racetech has an online spring rate calculator u can mess around on.but I would set the sag first with the stock 4.9 spring.a flywheel weight will give it keep it from stalling on real technical terrain,I myself run a 13oz on my yzx.again my hat is off to you if u can wring that bike out down the trails.cheers.

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2 hours ago, YZF1825 said:

Bike runs super strong and is great. I love it. Has a fresh top end. Everything else is stock with the exception of the FMF header pipe and slip on. What can I do to make it have better throttle response and just make the performance better?

carb jetting , best mod you can do

( if you want a torquey manageable feel you can't go wrong with a suzuki needle )

i would replace reeds petals  with boyesen 

hopefully you got a fmf gnarly pipe 

Edited by kxrob

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No problem stalling ever not like I did on my arms E450 the performance is good I love the way the backgrounds I would just like to get maybe a little more out of it maybe I'll try some V Force reeds and definitely stiffer rear shocks.

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Here's best advice I got as a young racer. Get on the gas and shift! Better than any mod and works:thumbsup:

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