'18 250sx build (update BNG!)

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4/6/2018 2:28 PM
Edited Date/Time: 4/17/2018 12:09 PM

This is going to be a slow build because I'm also saving money for a house, building a car, and a gf that hates that I waste money like it grows on trees lol.

This is where I started with a stock '18 KTM 250sx in October of '17. So far I've rejetted it and worked on getting used to riding again after a 10 year break. I installed the ride engineering CRF steering damper bracket and damper they had and it helped a great deal in turns and dropped one tooth on the rear sprocket.
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With this round of changed I installed the Neken air/spring clamps so I had to build a bung and weld it to the steering neck. (I'll get a picture later) for the steering damper. I also swapped in the TLD McQueen kit. I changed some suspension settings and Hopefully tomorrow I'll get to ride it and see how it feels.
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Next up on the list is depending on how it handles this weekend. The bike has been handling well, but some pictures the gf took for me confirmed that the rear suspension is packing in braking bumps and the front rides to high in the stroke in turns. If my adjustments help then I'm aiming for exhaust. If it still isn't better then I'll be headed for a revalve front and rear. Still undecided on who to go with though, local race tech guy, FC, MXT, or a different local guy with national proven results.

Currant build:
jetting
MJ 490
PJ 37.5
Needle 42-75
Clip 4th position or 3rd depending on temp.
Needle jet s-4
AS 1.5
U4.4 mixed 60:1 with amsoil donionator

Suspension settings:
Front Rear
rebound 19 rebound 14
compression 23 low speed 8
air pressure 144psi high speed 1.25
sag 110mm

CRF 20mm Showa steering damper
Neken air/spring triple clamps
49t rear sprocket
Power valve turned in 1.75 turns from all the way out. Stock yellow spring.

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2018 KTM 250sx
Instagram CamaroAJ

4/9/2018 12:04 AM

Like!.

Will be following this my friend, have been looking out for a '18 myself but found a '14 with the 300 SXS kit so have bought that for the time being!.

How do you find the vibration?.

Enjoy coming back to mx.

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2020.5 KTM Cairoli Factory Edition 5.7hrs
2019 Alta Redshift MXR - 0.9hrs!.
2020 KTM 250 SX 5hrs.

imoto34 wrote:
Look at all that torque. The kid on the lawnmower may have laughed so hard he shat his pants.

4/9/2018 6:14 AM

#76 wrote:

Like!.

Will be following this my friend, have been looking out for a '18 myself but found a '14 with the 300 SXS kit so have bought that for the time being!.

How do you find the vibration?.

Enjoy coming back to mx.

There is zero vibration with this bike. That balance shaft they worked into the engine is amazing. I'd say it vibrates less than any 125 I've owned and with as light as it is I feel like I'm riding a 125, just a fast one.

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2018 KTM 250sx
Instagram CamaroAJ

4/10/2018 8:35 AM
Edited Date/Time: 4/10/2018 8:36 AM

blue looks so right on these orange bikes!

I see youre in Texas, hopefully youre building a turbo car lol

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4/11/2018 6:17 AM

gunters96lt1 wrote:

blue looks so right on these orange bikes!

I see youre in Texas, hopefully youre building a turbo car lol

I have a '69 Camaro I've grafted on to a C5 Vette frame with a LSA that I'm building. Its in a holding pattern currently as I lost my work space for it.
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2018 KTM 250sx
Instagram CamaroAJ

4/13/2018 12:03 PM

How did you get on at the weekend mate?.

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2020.5 KTM Cairoli Factory Edition 5.7hrs
2019 Alta Redshift MXR - 0.9hrs!.
2020 KTM 250 SX 5hrs.

imoto34 wrote:
Look at all that torque. The kid on the lawnmower may have laughed so hard he shat his pants.

4/13/2018 1:16 PM

I would reccomend PowerBandRacing for your susp, he is the KTM guru! Ask for Billy, he knows more about the WP stuff than many other tuners- great looking bike!

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4/13/2018 3:06 PM

JBoneMotorworks wrote:

I would reccomend PowerBandRacing for your susp, he is the KTM guru! Ask for Billy, he knows more about the WP stuff than many other tuners- great looking bike!

I would also like to recommend JBoneMotorworks engine porting, and head work. Made the bike run like it should for less than an exhaust system.

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4/13/2018 4:20 PM

I did? lol, who is this?

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4/13/2018 5:50 PM

JBoneMotorworks wrote:

I did? lol, who is this?

You did my 250SX motor about a year ago. Name is James.

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4/17/2018 12:10 PM

JBoneMotorworks wrote:

I would reccomend PowerBandRacing for your susp, he is the KTM guru! Ask for Billy, he knows more about the WP stuff than many other tuners- great looking bike!

LumpDog841 wrote:

I would also like to recommend JBoneMotorworks engine porting, and head work. Made the bike run like it should for less than an exhaust system.

I'll keep both in mind when I start calling around and looking for stuff.

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2018 KTM 250sx
Instagram CamaroAJ

4/17/2018 12:17 PM

#76 wrote:

How did you get on at the weekend mate?.

Weekend was good, I went out to Cycle Ranch. I was having some front end trying to tuck in corners on me so I ended up backing off two clicks on front compression and taking the fork pressure up to 150 for the sand and it made a huge improvement in the handling of the bike.

Here is a few laps, don't mind the big table, I wimped out after I came up short earlier in the day and tweaked my ankle.

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2018 KTM 250sx
Instagram CamaroAJ

4/17/2018 4:22 PM

Man I miss that place. Looks fun, that finish line table is a big one I remember that. Do they still have the night track?

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4/17/2018 7:04 PM

Pirate421 wrote:

Man I miss that place. Looks fun, that finish line table is a big one I remember that. Do they still have the night track?

It’s closed right now, they are rebuilding it to start some night races soon.

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2018 KTM 250sx
Instagram CamaroAJ

5/1/2018 10:41 AM

Hi, just seen this post up, been so busy!.

Awesome footage, tell me more about the Garmin please!.

Anymore time in the seat?.

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2020.5 KTM Cairoli Factory Edition 5.7hrs
2019 Alta Redshift MXR - 0.9hrs!.
2020 KTM 250 SX 5hrs.

imoto34 wrote:
Look at all that torque. The kid on the lawnmower may have laughed so hard he shat his pants.

5/2/2018 2:12 PM

#76 wrote:

Hi, just seen this post up, been so busy!.

Awesome footage, tell me more about the Garmin please!.

Anymore time in the seat?.

I was out this past Sunday. I went out for my last moto of the day and clipped a tree branch with my camera after two laps, so not much video. Camera is ok though.

I compared the Garmin Virb ultra 30 to the GoPro Hero 5 Black as the 6 wasn't out yet. If you're just walking around the GoPro is the way to go. The Garmin is a better choice for moto as it shoots in a higher quality with stabilization than the GoPro does. I shoot 2.7k@30FPS. I need to play with it some more as its not as stable of video as it was with the original settings I had and I always forget to change it before I go out and ride. You're also able to link a ton of data loggers to it. I only use my heart rate strap with it, but it will also link to my Garmin VivoActive HR to turn the camera on/off, take pictures or start video. I has better sound than the GoPro and uses all of the GoPro mounts. The case it comes in is good to 40m water depth.

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2018 KTM 250sx
Instagram CamaroAJ

6/1/2018 6:33 AM

Picked up a Pro Circuit Works pipe and silencer and threw them on yesterday. No ride time yet, but it sounds amazing. I can see where they are picking up the over rev if you look at the pipes side by side. The factory pipe is pretty restrictive in terms of smooth flow.

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The expansion chamber is much larger on the bike and runs a bit closer to the radiator shroud. Overall it fits pretty nice and I'm looking forward to riding it in a few weeks to see how it does.

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2018 KTM 250sx
Instagram CamaroAJ

6/1/2018 7:10 AM

Nice work on the build!!!
Would you mind showing pictures of how you are running the Showa 20mm stabilizer and the neken sfs triple clamps? I am guessing you welded on a bung like I did but would love to see what you did. I am running the 24mm, racetech gold valve and Motovate Racing off road re-valve with the spring/air Neken SFS triple clamps.

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6/1/2018 7:24 AM

smv ryder wrote:

Nice work on the build!!!
Would you mind showing pictures of how you are running the Showa 20mm stabilizer and the neken sfs triple clamps? I am guessing you welded on a bung like I did but would love to see what you did. I am running the 24mm, racetech gold valve and Motovate Racing off road re-valve with the spring/air Neken SFS triple clamps.

Thank you.

I'll have to get pictures of it later when I get home. I used a 3/4" bolt I had laying around and cut it down to 28mm. Checked it up in a brake lathe and ground it down to fit the stabilizer, welded it on, then drilled and tapped a hole. I revalved mine by moving the shim stack around based off a link I found on thumper talk and filled it with 15w fork oil.

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2018 KTM 250sx
Instagram CamaroAJ

6/1/2018 8:10 AM

PC silencer was by far the best mod to my bike, could not believe the difference in over -rev.

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6/1/2018 11:46 AM

opyguy wrote:

PC silencer was by far the best mod to my bike, could not believe the difference in over -rev.

I'm looking forward to riding it with it on there. After reading this even more so.
MXA Review

"(3) Performance. Every MXA test rider loved the 2017 KTM 250SX powerband; but, if given the opportunity to tune it to our tastes, we would want more top-end power and some added over-rev. The stock pipe delivers incredible midrange but falls off quickly after its peak at 8200 rpm where it was making 47.30 horsepower. With the Pro Circuit Works pipe installed, peak is moved to 49.60 horsepower at 8300 rpm. That is a 2.2-horsepower gain at peak, but most important, the pipe didn’t fall off as quickly after peak as the stocker. The Pro Circuit pipe made the same power as the stock pipe from 5000 rpm all the way to 7200, then the Pro Circuit pipe made 1 horse more at 7500 rpm, 1.6 more at 8000 rpm and 4 horses more at 9000 rpm. Best of all, it kept all the good traits of the KTM 250SX and just added more power after 7200 rpm."

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2018 KTM 250sx
Instagram CamaroAJ

6/1/2018 8:20 PM

opyguy wrote:

PC silencer was by far the best mod to my bike, could not believe the difference in over -rev.

Are you running the "R" shorty? Or the longer 304?

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6/2/2018 4:59 AM

Longer 304
I cannot reiterate how much more noticeable the overrev was
I would not consider myself a very good rider 51-year-old vet but as I said made a noticeable improvement

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6/6/2018 4:34 PM

Nice bike EZ Designs Graphics saw them there i have 18 SX150 With EZ Designs Graphics they Call Me Moto D Racing see you at Track you have nice build!!

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[Moto D Racing

6/7/2018 6:49 AM

honda70 wrote:

Nice bike EZ Designs Graphics saw them there i have 18 SX150 With EZ Designs Graphics they Call Me Moto D Racing see you at Track you have nice build!!

Danny? Hopefully see you at Murphy's this Saturday. I'm going to try and make it out there.

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2018 KTM 250sx
Instagram CamaroAJ

6/7/2018 2:43 PM
Edited Date/Time: 6/7/2018 2:45 PM

Just got a "deal" on 304 silencer for my 17 TC250 -$101 shipped from http://www.pdi-racing.com/pro-circuit-304-2-stroke-silencer-1051725/

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6/8/2018 7:01 AM

riv187 wrote:

Just got a "deal" on 304 silencer for my 17 TC250 -$101 shipped from http://www.pdi-racing.com/pro-circuit-304-2-stroke-silencer-1051725/

I found my pipe on amazon for $197 shipped and my silencer on here brand new for $85 shipped. If you're not in a rush to get them you can stumble across good deals places. Hoping to go ride tomorrow and see how it runs. If I get to I'll post up a ride report.

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2018 KTM 250sx
Instagram CamaroAJ

6/10/2018 10:56 AM

riv187 wrote:

Just got a "deal" on 304 silencer for my 17 TC250 -$101 shipped from http://www.pdi-racing.com/pro-circuit-304-2-stroke-silencer-1051725/

AJ565 wrote:

I found my pipe on amazon for $197 shipped and my silencer on here brand new for $85 shipped. If you're not in a rush to get them you can stumble across good deals places. Hoping to go ride tomorrow and see how it runs. If I get to I'll post up a ride report.

Dang...I was happy to save 24 on silencer...you really found the deal !

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7/2/2018 7:36 AM

I never got around to posting how the bike runs with the PC combo on it. Amazing is all I can say. First off it now sounds like a 250 should. All that bark with all the bite. What I noticed right off was no loss in the low-mid, but an actual gain in both. The over rev that the bike now has is amazing. I really helped with that few extra feet where you would waste time up shifting just to down shift right away. Since it pulls harder everywhere it was much easier to click up an extra gear earlier for the long straights after a jump.

Also, I remembered to grab a picture of my steering stabilizer that I was asked about.
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2018 KTM 250sx
Instagram CamaroAJ

7/6/2018 8:27 AM

Dude im really digging this build thread and the bike looks amazing!! Cant get no better than 250 2 stroke and a 69 camaro build ?

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