2018 KTM 250 2 STROKE: Race gas for gains????

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12/17/2018 5:40 PM
Edited Date/Time: 12/17/2018 5:43 PM

picking up a new 250sx tomorrow and its going to need more top end, im happy to lose bottom end coming from my yz250, I hate midrange motors, no im not racing I dont care bout benefits, I like a 125-150 all top end power band and want the 250 to have the same feel of "wham its on all the way to the top" and have a gnarly hit. Wham it's on.
What kind of pipe to change? not lookin to put tons of money into it just the basics, pipe, silencer, jetting airbox mods and race gas? MR12 is big in my Superbike racing scene but thats for 4 strokes... Im fine paying 15$/gallon to pour in 10% hp....

Only play riding as a vet and want a "fun exciting" bike instead of a "fast" bike

cheers

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12/17/2018 6:13 PM

KTM power valve has several spring choices and preload adjustment to harden or soften "hit"

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12/17/2018 6:18 PM

yeah but that doesnt make its peak power move around... I want it to peak at like 9k instead of 7

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12/17/2018 6:28 PM

GCBC wrote:

yeah but that doesnt make its peak power move around... I want it to peak at like 9k instead of 7

Not gonna happen.

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12/17/2018 6:51 PM

Pc pipe, long silencer, red spring, jd jetting keihin carb, and if u need more hit up derek harris for porting and fuel choice

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12/17/2018 7:19 PM
Edited Date/Time: 12/17/2018 7:20 PM

GCBC wrote:

picking up a new 250sx tomorrow and its going to need more top end, im happy to lose bottom end coming from my yz250, I hate midrange motors, no im not racing I dont care bout benefits, I like a 125-150 all top end power band and want the 250 to have the same feel of "wham its on all the way to the top" and have a gnarly hit. Wham it's on.
What kind of pipe to change? not lookin to put tons of money into it just the basics, pipe, silencer, jetting airbox mods and race gas? MR12 is big in my Superbike racing scene but thats for 4 strokes... Im fine paying 15$/gallon to pour in 10% hp....

Only play riding as a vet and want a "fun exciting" bike instead of a "fast" bike

cheers

Well , for what it's worth , my 18' TC 250 is bone stock with 1.5 hours on it. That's all I've had time to ride it this time of year.

I'm going to build my 250 , a lot like I did my 125. The stock exhaust sucks , so that's getting replaced with another Scalvini pipe and FMF 2.1 power core ( non-shorty ). The reed's will either get the pedal's replaced or pick up a Gforce 4. A possible head mill from .065" stock , down to about .045"-.042". The Mikuni carb is going away as well , and I'm going with another PWK 38 , along with Derrick's STIC mod. I believe after these changes , the bike should be running pretty strong , and I should be able to swap down to a 40:1 , 927 mix with race gas , instead of this synthetic shit at 60:1.

If you build your's thew right way , you won't need to ride it like a 125 , where it's wide open every where.....unless you plan on lining up for a national. And if you can?......then good for you. But a well built 250 2 stroke , can go faster than what 99.9% of the rider's out there can handle wide open around a track.

Just my $0.02.

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And there goes Jeffro. One of God's own prototypes. A super high-powered mutant of some kind never even considered for mass production. Too weird to live, and too rare to die.

Pimpin' Ho's , Rollin' fatty's......drinkin' beers , beers , beers!! ~ Ja

12/17/2018 7:28 PM

I’m on my second one, for me pc works pipe, 304 silencer, v-force reeds, and Vp t2. I’d send the motor off if you’re really into a full blow top end bike.

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12/17/2018 7:44 PM

If you’re looking for a top end motor, you bought the wrong bike, IMO

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12/17/2018 7:56 PM

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-'09 KX500AF

- '19 KX450F

12/17/2018 8:00 PM

langhammx wrote:

If you’re looking for a top end motor, you bought the wrong bike, IMO

Seriously. The YZ makes nearly the same peak power, but closer to 9k RPMs in comparison to the KTM's ~8k.

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James

12/17/2018 8:04 PM

Add a tooth to the countershaft sprocket. Along with the other mods it should help give the feel. I usually prefer my 250 two strokes with a 14 tooth front , 48 or 49 rear. More low end the motor, more the taller gearing helps imo

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when in doubt, pin it out

12/17/2018 8:05 PM

I have a PC pipe and silencer. Rejetted, PV 1 3/4 turns in running u4.4 and on the dyno my bike is just under 51hp. I have a build thread on here with all my jetting info. You’ll for sure need a 49t rear on it.
Photo

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2018 KTM 250sx
Instagram CamaroAJ

12/17/2018 8:07 PM

I’m on my second one, for me pc works pipe, 304 silencer, v-force reeds, and Vp t2. This bike rips, but if you really want more up top, I’d send the motor off and have them focus the power for you.

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12/17/2018 11:56 PM

GCBC wrote:

picking up a new 250sx tomorrow and its going to need more top end, im happy to lose bottom end coming from my yz250, I hate midrange motors, no im not racing I dont care bout benefits, I like a 125-150 all top end power band and want the 250 to have the same feel of "wham its on all the way to the top" and have a gnarly hit. Wham it's on.
What kind of pipe to change? not lookin to put tons of money into it just the basics, pipe, silencer, jetting airbox mods and race gas? MR12 is big in my Superbike racing scene but thats for 4 strokes... Im fine paying 15$/gallon to pour in 10% hp....

Only play riding as a vet and want a "fun exciting" bike instead of a "fast" bike

cheers

Either you're pulling the piss or hitting the bucket bong??? What vet play rider wants a 250 2t that's all top end and hates midrange motors? You're happy to pay for expensive race gas and say it's going to need more top end and you haven't even ridden it yet.C'mon you can't be serious, I didn't even talk that much shit when I was 12.....it's not April 1 is it?

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12/18/2018 6:06 AM

Does the OP like to wash boots and gear too?

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vomiting equals disqualification.

12/18/2018 6:26 PM
Edited Date/Time: 12/18/2018 6:33 PM

GCBC wrote:

picking up a new 250sx tomorrow and its going to need more top end, im happy to lose bottom end coming from my yz250, I hate midrange motors, no im not racing I dont care bout benefits, I like a 125-150 all top end power band and want the 250 to have the same feel of "wham its on all the way to the top" and have a gnarly hit. Wham it's on.
What kind of pipe to change? not lookin to put tons of money into it just the basics, pipe, silencer, jetting airbox mods and race gas? MR12 is big in my Superbike racing scene but thats for 4 strokes... Im fine paying 15$/gallon to pour in 10% hp....

Only play riding as a vet and want a "fun exciting" bike instead of a "fast" bike

cheers

CPR wrote:

Either you're pulling the piss or hitting the bucket bong??? What vet play rider wants a 250 2t that's all top end and hates midrange motors? You're happy to pay for expensive race gas and say it's going to need more top end and you haven't even ridden it yet.C'mon you can't be serious, I didn't even talk that much shit when I was 12.....it's not April 1 is it?

new bike is beautiful, ergonomic, brakes are great and I love it. Would like to try some 5gal cans of race gas tho as a starting point from here to at least have that as a starting point that is more consistent than what shit we have out here at the pumps. Id think for top end you want a shorty silencer vs a long can. Does anyone make a "rev" pipe for it? looked at some other ones here briefly and not finding many dyne charts or comparisons.

Im just looking to make the thing NOT want to short shift as it does now and every other (250 ive rode) but rewarding to rev all the way to the top.

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12/18/2018 6:38 PM

GCBC wrote:

new bike is beautiful, ergonomic, brakes are great and I love it. Would like to try some 5gal cans of race gas tho as a starting point from here to at least have that as a starting point that is more consistent than what shit we have out here at the pumps. Id think for top end you want a shorty silencer vs a long can. Does anyone make a "rev" pipe for it? looked at some other ones here briefly and not finding many dyne charts or comparisons.

Im just looking to make the thing NOT want to short shift as it does now and every other (250 ive rode) but rewarding to rev all the way to the top.

I think you should try the shorty and report back.

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2019 KTM 250 SX
2016 Husqvarna FC-450
2015 KTM 150 SX
2015 KTM 200 XC-W

12/18/2018 6:44 PM

CPR wrote:

Either you're pulling the piss or hitting the bucket bong??? What vet play rider wants a 250 2t that's all top end and hates midrange motors? You're happy to pay for expensive race gas and say it's going to need more top end and you haven't even ridden it yet.C'mon you can't be serious, I didn't even talk that much shit when I was 12.....it's not April 1 is it?

GCBC wrote:

new bike is beautiful, ergonomic, brakes are great and I love it. Would like to try some 5gal cans of race gas tho as a starting point from here to at least have that as a starting point that is more consistent than what shit we have out here at the pumps. Id think for top end you want a shorty silencer vs a long can. Does anyone make a "rev" pipe for it? looked at some other ones here briefly and not finding many dyne charts or comparisons.

Im just looking to make the thing NOT want to short shift as it does now and every other (250 ive rode) but rewarding to rev all the way to the top.

Tomok wrote:

I think you should try the shorty and report back.

Longer than stock silencer for the win lol

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when in doubt, pin it out

12/18/2018 6:52 PM

gsxr6 wrote:

Add a tooth to the countershaft sprocket. Along with the other mods it should help give the feel. I usually prefer my 250 two strokes with a 14 tooth front , 48 or 49 rear. More low end the motor, more the taller gearing helps imo

It comes stock with a 14 tooth front sprocket.

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2019 KTM 250 SX
2016 Husqvarna FC-450
2015 KTM 150 SX
2015 KTM 200 XC-W

12/19/2018 7:26 AM

I've been using the Bud Racing Pipe on my 250sx and 150sx. It revs on to the pipe very quickly. It has been a while since I've tried the PC pipe so I can't compare the two. The kreft power valve adjuster is nice for on the spot adjustments. JD Jet Kit w/proper jets is just perfect on the 2018. You can run it like a 150.

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12/19/2018 7:33 AM

GCBC wrote:

picking up a new 250sx tomorrow and its going to need more top end, im happy to lose bottom end coming from my yz250, I hate midrange motors, no im not racing I dont care bout benefits, I like a 125-150 all top end power band and want the 250 to have the same feel of "wham its on all the way to the top" and have a gnarly hit. Wham it's on.
What kind of pipe to change? not lookin to put tons of money into it just the basics, pipe, silencer, jetting airbox mods and race gas? MR12 is big in my Superbike racing scene but thats for 4 strokes... Im fine paying 15$/gallon to pour in 10% hp....

Only play riding as a vet and want a "fun exciting" bike instead of a "fast" bike

cheers

CPR wrote:

Either you're pulling the piss or hitting the bucket bong??? What vet play rider wants a 250 2t that's all top end and hates midrange motors? You're happy to pay for expensive race gas and say it's going to need more top end and you haven't even ridden it yet.C'mon you can't be serious, I didn't even talk that much shit when I was 12.....it's not April 1 is it?

I like my powerbands like this too ..... well not 100% this focus but very simiar

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12/19/2018 11:35 AM

Throw another base gasket under the cylinder and retard the timing. That will make it shriek, although you might loose some of the punch.

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KTM250SX YZ125 YZ85 PW80 ZX6 FZX700

12/19/2018 11:42 AM

GCBC wrote:

picking up a new 250sx tomorrow and its going to need more top end, im happy to lose bottom end coming from my yz250, I hate midrange motors, no im not racing I dont care bout benefits, I like a 125-150 all top end power band and want the 250 to have the same feel of "wham its on all the way to the top" and have a gnarly hit. Wham it's on.
What kind of pipe to change? not lookin to put tons of money into it just the basics, pipe, silencer, jetting airbox mods and race gas? MR12 is big in my Superbike racing scene but thats for 4 strokes... Im fine paying 15$/gallon to pour in 10% hp....

Only play riding as a vet and want a "fun exciting" bike instead of a "fast" bike

cheers

CPR wrote:

Either you're pulling the piss or hitting the bucket bong??? What vet play rider wants a 250 2t that's all top end and hates midrange motors? You're happy to pay for expensive race gas and say it's going to need more top end and you haven't even ridden it yet.C'mon you can't be serious, I didn't even talk that much shit when I was 12.....it's not April 1 is it?

GCBC wrote:

new bike is beautiful, ergonomic, brakes are great and I love it. Would like to try some 5gal cans of race gas tho as a starting point from here to at least have that as a starting point that is more consistent than what shit we have out here at the pumps. Id think for top end you want a shorty silencer vs a long can. Does anyone make a "rev" pipe for it? looked at some other ones here briefly and not finding many dyne charts or comparisons.

Im just looking to make the thing NOT want to short shift as it does now and every other (250 ive rode) but rewarding to rev all the way to the top.

Top end you'll want the longer silencer. Shorty is for low to mid. Longer length for more mid to top.

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2017 RMZ450
2005 YZ250-sold :,(
1998 YZ250
2005 KX250F

80% of the time it works every time
IG @hamdaddyof2 & @2HRacing
Thanks to : Factory Effex, N2Dirt, Acerbis, DT1, Fasthouse, Matix, FMF, ASV, 100% & Mika Metals

12/19/2018 3:19 PM
Edited Date/Time: 12/19/2018 3:21 PM

YZed250 wrote:

Throw another base gasket under the cylinder and retard the timing. That will make it shriek, although you might loose some of the punch.


If this is what you gents are recommending..... then consider it on order.
https://motocrossactionmag.com/mxa-team-tested-pro-circuit-works-ktm-250sx-pipesilencer/
Also looking at the RK head.



Also I desperately need a quick turn throttle for this, I have wrist issues and need quicker rotation, dont need a cam system just something much faster. Please advise.


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12/19/2018 3:24 PM

Short and fat is where it’s at
Long and skinny no winnie
Ask Mitch

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12/19/2018 4:37 PM

ob wrote:

Short and fat is where it’s at
Long and skinny no winnie
Ask Mitch

For supercross style power maybe. Long silencers add over Rev. It's all about the timing of the return wave. Shorty=less top end over Rev. Period

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when in doubt, pin it out

12/19/2018 4:42 PM

ob wrote:

Short and fat is where it’s at
Long and skinny no winnie
Ask Mitch

gsxr6 wrote:

For supercross style power maybe. Long silencers add over Rev. It's all about the timing of the return wave. Shorty=less top end over Rev. Period

Yep

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12/19/2018 4:59 PM

ob wrote:

Short and fat is where it’s at
Long and skinny no winnie
Ask Mitch

gsxr6 wrote:

For supercross style power maybe. Long silencers add over Rev. It's all about the timing of the return wave. Shorty=less top end over Rev. Period

zehn wrote:

Yep

I'll times that by 3. I ride bigger outdoor tracks , and it's why I don't use shorty's. Use the longer silencer's for your bigger out door tracks , and keep the shorty's inside.

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And there goes Jeffro. One of God's own prototypes. A super high-powered mutant of some kind never even considered for mass production. Too weird to live, and too rare to die.

Pimpin' Ho's , Rollin' fatty's......drinkin' beers , beers , beers!! ~ Ja