Spoke with my wallet 250sx

opyguy
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567
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8/22/2016
Location
Boston, MA US
5/5/2017 6:51am Edited Date/Time 5/5/2017 10:33am




All help appreciated, coming from a 350 that was dialed in perfect .
Bike seemed blubbery down low turned the air screw out to 2 1/2 seem to clean it up. Also has a "knock" while idling at low RPM I'm assuming shitty gas?
Again any tips appreciated .
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imoto34
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3781
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1/28/2010
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TN US
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3151st
5/5/2017 7:14am
Congrats, sweet ride. Those bikes are kinda harsh sounding at idle, better fuel could help. Totally different sounds then the 4 stroke if you haven't been on a smoker in a while. I suggest running many many tanks of fuel thru it as fast as possible.
5/5/2017 7:15am
Nice bike! Harry want!

I have no tips as I've never had one, but did want to say your wallet is speaking loud and clear.
ThatOneKid
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Royal Oak, MI US
5/5/2017 7:24am
Had the same problem down low with my 150, it's because of the Mikuni carbs they switched to for 2017, they come jetted extremely rich. Lean out the jetting and it should help (the biggest issue is the pilot jet). From the dealer mine ran rough down low and had a ton of splooge coming out of the exhaust. I'm running similar to the MXA recommended jetting for a 150 and its running much better. 460 main, 42.5 pilot, richest needle (i think its the 43-74) clip at the top, air screw 1.5 turns out. That's as close as i Could get to the MXA settings with the jets that come stock. I have since purchased some extra pilots and will be experimenting a bit more.

fyi I am at about 700ft elevation and when ive ridden its been low to mid 70s.
wide open wally
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Beverly Hills, CA US
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3762nd
5/5/2017 7:27am
I put a fmf pipe and silencer on. Helped it a ton, stock felt sluggish but that was coming off a fe 450. Still fighting the jetting, seen where people do carb swaps but I haven't ventured that far into it.

Also have footpeg spring ready, broke mine right at 10 hours mid ride. They were cheap so no biggie to have a extra set in the tool box

The Shop

JWACK
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NM US
5/5/2017 7:46am
Just don't let off the gas!
Problem solved.Tongue

seth505
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SD, CA US
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1048th
5/5/2017 8:11am
Congrats!

I'm runnin a 35 pilot, 460 main vforce 4r and Bud/HGS exhaust. I won't beat around the bush, I'm in love with the bike.
opyguy
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567
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8/22/2016
Location
Boston, MA US
5/5/2017 9:37am
seth505 wrote:
Congrats!

I'm runnin a 35 pilot, 460 main vforce 4r and Bud/HGS exhaust. I won't beat around the bush, I'm in love with the bike.
stock pilot is 42 1/2....35 seems really lean, you at high elevation?
I'm at sea level, 42.5 PJ, airscrew @ 1.5 out bad blubber...2.25 out made it crisper.
What did the HGS exhaust do? looking @ scalvini, dyno looks great.
endurox
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3/22/2014
Location
Garden City, ID US
5/5/2017 10:12am
ThatOneKid wrote:
Had the same problem down low with my 150, it's because of the Mikuni carbs they switched to for 2017, they come jetted extremely rich. Lean...
Had the same problem down low with my 150, it's because of the Mikuni carbs they switched to for 2017, they come jetted extremely rich. Lean out the jetting and it should help (the biggest issue is the pilot jet). From the dealer mine ran rough down low and had a ton of splooge coming out of the exhaust. I'm running similar to the MXA recommended jetting for a 150 and its running much better. 460 main, 42.5 pilot, richest needle (i think its the 43-74) clip at the top, air screw 1.5 turns out. That's as close as i Could get to the MXA settings with the jets that come stock. I have since purchased some extra pilots and will be experimenting a bit more.

fyi I am at about 700ft elevation and when ive ridden its been low to mid 70s.
Also the float level is way to high. That needs adjusted quite a bit lower.
hellion
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12/19/2009
Location
Westfield, MA US
5/5/2017 10:25am
There's a lot of info on the new 250/300 over at ktmtalk. It's not the Mikuni, although it is more finicky than the Keihin. It's warped reeds/reed block, bad jetting, and poor cylinder head design. Most seem to be happy once sorted though, but some bikes seem to need more attention than others. I think it's just some guys are pickier than others.
slotsquid
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Lowell, AR US
Fantasy
3028th
5/5/2017 10:30am
Check your owners manual, But I think the ratio for the premix is 60-1.
ThatOneKid
Posts
195
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2/18/2016
Location
Royal Oak, MI US
5/5/2017 10:32am
seth505 wrote:
Congrats!

I'm runnin a 35 pilot, 460 main vforce 4r and Bud/HGS exhaust. I won't beat around the bush, I'm in love with the bike.
Did the Vforce 4R help alot? Thinking of grabbing one for my 150 once they're in stock.
erik_94COBRA
Posts
948
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7/21/2016
Location
Houston-ish, TX US
5/5/2017 10:32am
Good to see other wallets speaking truth.

My recipe for satisfaction:
Inspect (and correct) reeds.
Adjust float (now at 8.5mm.
Change jets (430, 30, JD blue 4th).
Fix squish (0.020" taken off head).

I'm extremely happy with mine. The stock needle and stock head are just fine, but the JD and squish fix made it even more crisp.


seth505
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SD, CA US
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1048th
5/5/2017 10:33am
seth505 wrote:
Congrats!

I'm runnin a 35 pilot, 460 main vforce 4r and Bud/HGS exhaust. I won't beat around the bush, I'm in love with the bike.
opyguy wrote:
stock pilot is 42 1/2....35 seems really lean, you at high elevation? I'm at sea level, 42.5 PJ, airscrew @ 1.5 out bad blubber...2.25 out made...
stock pilot is 42 1/2....35 seems really lean, you at high elevation?
I'm at sea level, 42.5 PJ, airscrew @ 1.5 out bad blubber...2.25 out made it crisper.
What did the HGS exhaust do? looking @ scalvini, dyno looks great.
I'm near sea level out in CA. I was close to going with the Scalvini, the dyno definitely looked awesome and I had one on a old YZ and it ripped. The Bud Racing/HGS is awesome though. It is very snappy off the bottom but also pulls a little longer than stock. I ended up turning my powervalve spring out a few turns to take some bang out of the hit because I would wheelie out of every corner with good traction. I swear I can almost ride this thing like a 4stroke and hit stuff pretty easily out of the inside of corners.

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