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

GCBC
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12/17/2018 5:40pm Edited Date/Time 12/19/2018 5:00pm
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
4
|
12/17/2018 6:13pm
KTM power valve has several spring choices and preload adjustment to harden or soften "hit"
GCBC
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12/17/2018 6:18pm
yeah but that doesnt make its peak power move around... I want it to peak at like 9k instead of 7
12/17/2018 6:28pm
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.
yz133rider
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Avondale, PA US
12/17/2018 6:51pm
Pc pipe, long silencer, red spring, jd jetting keihin carb, and if u need more hit up derek harris for porting and fuel choice

The Shop

jeffro503
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St Helens, OR US
12/17/2018 7:19pm Edited Date/Time 12/17/2018 7:20pm
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...
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.
urbanlift707
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Humboldt, CA US
12/17/2018 7:28pm
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.
langhammx
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12/17/2018 7:44pm
If you’re looking for a top end motor, you bought the wrong bike, IMO
2
SoCalMX70
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Thousand Oaks, CA US
12/17/2018 8:00pm
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.
gsxr6
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Anderson, CA US
12/17/2018 8:04pm
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
AJ565
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San Antonio, TX US
12/17/2018 8:05pm
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.

urbanlift707
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Humboldt, CA US
12/17/2018 8:07pm
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.
CPR
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AU
12/17/2018 11:56pm
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...
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?
9
BR8ES
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12/18/2018 6:06am
Does the OP like to wash boots and gear too?
5
GCBC
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Pittsburgh, PA US
12/18/2018 6:26pm Edited Date/Time 12/18/2018 6:33pm
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...
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...
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.
1
Tomok
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Epping, NH US
12/18/2018 6:38pm
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...
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.
1
gsxr6
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Anderson, CA US
12/18/2018 6:44pm
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...
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
Tomok
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Epping, NH US
12/18/2018 6:52pm
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...
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.
brian9
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Panama City Beach, FL US
12/19/2018 7:26am
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.
Lightning78
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Huntington Beach, CA US
12/19/2018 7:33am
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...
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...
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
1
YZed250
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Costa Mesa, CA US
12/19/2018 11:35am
Throw another base gasket under the cylinder and retard the timing. That will make it shriek, although you might loose some of the punch.
1
mattyhamz2
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12/19/2018 11:42am
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...
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...
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...
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.
2
GCBC
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Pittsburgh, PA US
12/19/2018 3:19pm Edited Date/Time 12/19/2018 3:21pm
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-25…
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.


ob
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Carlsbad, CA US
12/19/2018 3:24pm
Short and fat is where it’s at
Long and skinny no winnie
Ask Mitch
gsxr6
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1956
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Anderson, CA US
12/19/2018 4:37pm
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
2
zehn
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Anchorage, AK US
12/19/2018 4:42pm
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
jeffro503
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Location
St Helens, OR US
12/19/2018 4:59pm
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.
1

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