Ktm 250 sx top end power

Tuck812
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Tuck812
Edited Date/Time 10/7/2014 8:33am
Guys I have broke in my new 250 now and noticed I want more top end pull. I have got a lot of great info on here from everyone that has a 250 sx and was wondering if I had missed anything that would help?. I have the jetting specs 40 pilot 175 main third clip necj needle, pro circuit pipe and shorty silencer, gearing 14x50 is there anything else that will help with top end pull? Or is this gonna take care of it when I'm finished installing it.
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Digger29
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Digger29 8/27/2014 11:07am
8/27/2014 11:07am
You can have some head work done and while that's being done you should check and make sure the cylinder & powervalve height are set correctly because if it's off and all the 250SX's that I've worked on have been off one way or the other and that could be costing you some top end power. When I installed the 300SXS kit on my new 15 I had my engine guy cut the head and tighten the squish and clean up the ports on the cylinder and match the cylinder to the cases. I had him raise the exhaust port a bit and all of these things really gave to bike a nice smooth but very torquey power with a way more top end than my 13 300 kit had. I'm super happy with the power on the new bike. All of these mods were very inexpensive and it was money well spent.
Digger29
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Digger29 8/27/2014 11:46am
8/27/2014 11:46am
I forgot. Put a VForce on it too.
Tuck812
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Tuck812 8/27/2014 11:55am
8/27/2014 11:55am
Thanks Digger29 you have been a huge help I appreciate it
JBernard_401
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JBernard_401 8/27/2014 11:57am
8/27/2014 11:57am
125/150sx carb. i notice mine pull better up top and not fall off as much.

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Digger29
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Digger29 8/27/2014 12:35pm
8/27/2014 12:35pm
JBernard_401 wrote:
125/150sx carb. i notice mine pull better up top and not fall off as much.
Ya that too :-) I let a pretty fast expert ride my bike on Monday at MX207 in Maine and he dropped off his 14 300SX at my house this morning because he said that my bike had way more power than his bike everywhere but he was especially impressed with my bikes top end power. We're doing the cylinder & head like mine, putting a 38 carb from a 13 125SX, V-Force & a Bill's Pipe and silencer on it and he's racing it this weekend at the NERC at Winchester Speed Park in NH. I just got it apart and the cylinder height was set incorrectly and it still had the stock needle and 158 main jet in his 36 carb. He is going to be very pleased when he picks it up on Friday and races it this weekend.
Tuck812
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Tuck812 8/28/2014 12:06pm
8/28/2014 12:06pm
Are you guys running race gas or pump gas ?
racer369
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racer369 8/28/2014 12:28pm
8/28/2014 12:28pm
Get their longer silencer. Short one gives bottem end. Long one gives top end. Change back and forth for different tracks.
Digger29
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Digger29 8/28/2014 5:56pm
8/28/2014 5:56pm
I'm running straight race gas but I've built a few 250SX's that are running pump gas and they run great.
Sandy
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Sandy 8/28/2014 6:19pm
8/28/2014 6:19pm
I have a VHM head and a few other parts if I can help you with anything let me know.
Crush
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Crush 8/28/2014 9:17pm
8/28/2014 9:17pm
Digger29 wrote:
I forgot. Put a VForce on it too.
Yarp. That made a big difference to my 300.
JBernard_401
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JBernard_401 8/28/2014 9:22pm
8/28/2014 9:22pm
you guys getting your vforce straight from moto tassanari or getting one off an older model KTM (that didnt have boyesen).?
any diff in design? im sure the ktm version is priced more if its the same anyways.
Digger29
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Digger29 8/29/2014 6:26am
8/29/2014 6:26am
Sandy wrote:
I have a VHM head and a few other parts if I can help you with anything let me know.
What do you have? and I get my V-Forces right from Steve Tassinari. He's awesome and the VForce 4 works so much better than the stock KTM/Boyesen reed system. Worth every penny.
Sandy
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Sandy 8/29/2014 4:45pm
8/29/2014 4:45pm
Sandy wrote:
I have a VHM head and a few other parts if I can help you with anything let me know.
Digger29 wrote:
What do you have? and I get my V-Forces right from Steve Tassinari. He's awesome and the VForce 4 works so much better than the stock...
What do you have? and I get my V-Forces right from Steve Tassinari. He's awesome and the VForce 4 works so much better than the stock KTM/Boyesen reed system. Worth every penny.
I have the head, 1 insert, FMF pipe & silencer. sprockets and some misc stuff I am sure I am forgetting. If I can help you with anything just give me a call. Thanks, 517-376-1438
Tuck812
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Tuck812 8/29/2014 10:22pm
8/29/2014 10:22pm Edited Date/Time 8/29/2014 10:23pm
What fuel mixture are you guys running with 40 pilot 175 main NECJ needle 3rd clip ?
Digger29
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Digger29 8/30/2014 4:53am
8/30/2014 4:53am
I'm running 32:1 with Maxima 927.
Digger29
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Digger29 8/30/2014 4:54am
8/30/2014 4:54am Edited Date/Time 8/30/2014 4:55am
Sandy wrote:
I have a VHM head and a few other parts if I can help you with anything let me know.
Digger29 wrote:
What do you have? and I get my V-Forces right from Steve Tassinari. He's awesome and the VForce 4 works so much better than the stock...
What do you have? and I get my V-Forces right from Steve Tassinari. He's awesome and the VForce 4 works so much better than the stock KTM/Boyesen reed system. Worth every penny.
Sandy wrote:
I have the head, 1 insert, FMF pipe & silencer. sprockets and some misc stuff I am sure I am forgetting. If I can help you...
I have the head, 1 insert, FMF pipe & silencer. sprockets and some misc stuff I am sure I am forgetting. If I can help you with anything just give me a call. Thanks, 517-376-1438
Could you email me a list of everything that you have? mx29@charter.net. Thanks, Mike
Tuck812
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Tuck812 9/3/2014 4:06pm
9/3/2014 4:06pm
We'll guys I ordered the pwk 38 carb but I'm still on the fence about losing a little bottom end power but really want some more top end. I guess my question is will the trade off be worth it ?
Digger29
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Digger29 9/3/2014 5:44pm
9/3/2014 5:44pm
Yes the trade off is well worth it.

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Hal_396
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Hal_396 9/4/2014 5:05am
9/4/2014 5:05am
I put the 38 on my Husky and it was well worth it. My buddy has the same bike I do and when we switch we both can notice the difference.
Fearo
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Fearo 9/4/2014 6:26am
9/4/2014 6:26am
This might be an unpopular opinion, but I say ditch the shorty silencer and go for the longer PC version or an FMF powercore. Makes a huge difference in my eyes.
Digger29
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Digger29 9/4/2014 10:28am
9/4/2014 10:28am
Fearo wrote:
This might be an unpopular opinion, but I say ditch the shorty silencer and go for the longer PC version or an FMF powercore. Makes a...
This might be an unpopular opinion, but I say ditch the shorty silencer and go for the longer PC version or an FMF powercore. Makes a huge difference in my eyes.
You're definitely correct on this because I tried them both at the track on the same day and the longer silencer definitely does a better job of spreading everything out. I personally like the snappiness and the sound of the shorter silencers. My Bill's MX2 silencer is 3" longer than the PC 304 shorty. I called Bill's and asked about it and why it was so long and told them I was going to cut it and they said not to because they did a lot of dyno work on their silencer and the version that they settled on works the best on the 250/300SX. I didn't cut it and really love it.
Tuck812
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Tuck812 9/4/2014 2:31pm
9/4/2014 2:31pm Edited Date/Time 9/4/2014 2:38pm
Fearo wrote:
This might be an unpopular opinion, but I say ditch the shorty silencer and go for the longer PC version or an FMF powercore. Makes a...
This might be an unpopular opinion, but I say ditch the shorty silencer and go for the longer PC version or an FMF powercore. Makes a huge difference in my eyes.
Digger29 wrote:
You're definitely correct on this because I tried them both at the track on the same day and the longer silencer definitely does a better job...
You're definitely correct on this because I tried them both at the track on the same day and the longer silencer definitely does a better job of spreading everything out. I personally like the snappiness and the sound of the shorter silencers. My Bill's MX2 silencer is 3" longer than the PC 304 shorty. I called Bill's and asked about it and why it was so long and told them I was going to cut it and they said not to because they did a lot of dyno work on their silencer and the version that they settled on works the best on the 250/300SX. I didn't cut it and really love it.
I might try that I'am having this done next week Checking to see if the cylinder & powervalve height are set correctly and cutting the head and tighten the squish and cleaning up the ports on the cylinder and match the cylinder to the cases along with installing the new carb and vforce4. I was wondering what spring you guys are running yellow or red?. I was talking to my local dealer about the 300 kit they were telling that adding that kit would just bring more bottom to mid power not top end
JBernard_401
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JBernard_401 9/4/2014 2:38pm
9/4/2014 2:38pm Edited Date/Time 9/4/2014 2:38pm
i think the carb swap will surprise you. try that and the reeds first before you start cutting the head.
i ride my 300 more in the higher rpm range and i felt like the stock carb really fell on its face noticeably. not so with the larger carb. doesnt sign off.
and i run the red spring. about a turn in from flush (backed all the way out)
Tuck812
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Tuck812 9/4/2014 2:46pm
9/4/2014 2:46pm
JBernard_401 wrote:
i think the carb swap will surprise you. try that and the reeds first before you start cutting the head. i ride my 300 more in...
i think the carb swap will surprise you. try that and the reeds first before you start cutting the head.
i ride my 300 more in the higher rpm range and i felt like the stock carb really fell on its face noticeably. not so with the larger carb. doesnt sign off.
and i run the red spring. about a turn in from flush (backed all the way out)
K thank you I will try that first with the red spring
Pilon_fx
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Pilon_fx 9/16/2014 10:18pm
9/16/2014 10:18pm
Tuck812 wrote:
Look what got here today [img]https://p.vitalmx.com/photos/forums/2014/09/12/65011/s1200_image.jpg[/img]
Look what got here today

Sick! I've debated on swapping carbs. I ride a ton of desert, and really feel the sign-off, even after significant carb tuning. Where'd you buy that?
JBernard_401
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JBernard_401 9/16/2014 11:30pm
9/16/2014 11:30pm
Tuck812 wrote:
Look what got here today [img]https://p.vitalmx.com/photos/forums/2014/09/12/65011/s1200_image.jpg[/img]
Look what got here today

yeah buddy! make sure to take the slide out of your 250sx stock carb and put it in that one. and put that slide back in your 250sx carb and sell it.
but wait till i sell my carb on ebay first so we both come out on top ; )
Tuck812
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Tuck812 9/17/2014 6:54am
9/17/2014 6:54am
Pilon_fx wrote:
Sick! I've debated on swapping carbs. I ride a ton of desert, and really feel the sign-off, even after significant carb tuning. Where'd you buy that?
I ordered it from Ktm parts wharehouse.com it was 272 shipped
Tuck812
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Tuck812 9/17/2014 7:01am
9/17/2014 7:01am
JBernard_401 wrote:
yeah buddy! make sure to take the slide out of your 250sx stock carb and put it in that one. and put that slide back in...
yeah buddy! make sure to take the slide out of your 250sx stock carb and put it in that one. and put that slide back in your 250sx carb and sell it.
but wait till i sell my carb on ebay first so we both come out on top ; )
I will wait a little while first want to make sure I like the new carbSmile . I was looking at both slides and the are exactly the same size what is the difference ?
JBernard_401
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JBernard_401 9/17/2014 7:16am
9/17/2014 7:16am
i think you'll like it a lot better.
one should be a 6.0 and the other a 6.5 slide. which model/year did you get.

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