17' TC250 Jetting Help

opyguy
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opyguy 12/1/2017 7:03pm
12/1/2017 7:03pm
sdhuskyrider wrote:
Mini-update! I bumped the pilot to 37.5 and warmed the bike up at my storage so I could get an idea of where air screw is...
Mini-update! I bumped the pilot to 37.5 and warmed the bike up at my storage so I could get an idea of where air screw is going to end up. What a difference in the throttle response and off idle power this thing has! Granted I only cruised it around my storage, I can feel a major difference in power and the air screw is actually responding now. Sounds much cleaner too. No more off idle bog when you crack the throttle from a stand still to WoT. I'm going out to Pala tomorrow and it's going to be about 10 degrees warmer and about 30% less humid so I expect to mess it some more but this has me quite excited! Here's my base settings for tomorrow.

5.0 Slide
37.5 pilot
1.5 AS
450 main
43-73 in position #3
thats where I'm at now with stock slide, think its about perfect. 55 degrees wednesday, as 1.5 out..no issues
sdhuskyrider
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sdhuskyrider 12/1/2017 7:08pm
12/1/2017 7:08pm
sdhuskyrider wrote:
Mini-update! I bumped the pilot to 37.5 and warmed the bike up at my storage so I could get an idea of where air screw is...
Mini-update! I bumped the pilot to 37.5 and warmed the bike up at my storage so I could get an idea of where air screw is going to end up. What a difference in the throttle response and off idle power this thing has! Granted I only cruised it around my storage, I can feel a major difference in power and the air screw is actually responding now. Sounds much cleaner too. No more off idle bog when you crack the throttle from a stand still to WoT. I'm going out to Pala tomorrow and it's going to be about 10 degrees warmer and about 30% less humid so I expect to mess it some more but this has me quite excited! Here's my base settings for tomorrow.

5.0 Slide
37.5 pilot
1.5 AS
450 main
43-73 in position #3
opyguy wrote:
thats where I'm at now with stock slide, think its about perfect. 55 degrees wednesday, as 1.5 out..no issues
I think for slower riders like myself it's really noticeable. It seems like the slow guys and the trail riders who want to lug the bike around have the most issues. The faster guys don't notice it as much. The colder temp helps too I'm sure. Are you in a humid environment or dry?
jeffro503
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jeffro503 12/2/2017 12:35pm
12/2/2017 12:35pm Edited Date/Time 12/2/2017 12:36pm
I couldn't book mark this page fast enough. Lots of good info in here. This does bum me out to even hear we have to do this kind of mods and jetting work to get these bikes to run well. I know it'll be worth it in the long run. When I pick mine up , before I even ride it I'm junking the stock reeds. Either I'll lap the stock cage and get some carbon pro reeds or just order the Vforce 4 like I did with my 125. Hell , I might just say screw it and get a lectron carb and be done with it!
sdhuskyrider
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sdhuskyrider 12/2/2017 2:15pm
12/2/2017 2:15pm Edited Date/Time 12/2/2017 8:00pm
Looks like I'm going to end the day with these settings. Spent a few hours swapping brass and this what I came up with for Pala Raceway.

Temp = 80F
Barometer = 29.96inHg
Elevation ~ 500ft
Humidity = 58%

Slide = 5.0
Pilot = 30
AS = 3.0
Needle = 44-73
POS = 3
Main = 450

Observations: The 5.0 slide is probably good for the coastal San Diego weather where I live BUT it's not the best for the Pala desert where I ride. I'm going to have to test more slides until I nail it. I guess I'll go the 5.50 next and on to the 6.0 if need be. I needed to drop pilot to 27.5 for these conditions however, I did not have one on hand. The next size I had was a 25. Overall much better but there is still a bit of a bog off idle that can be cleaned up. If wasn't terribly picky, I probably wouldn't really notice it at this point or think it was just normal. The power is definitely smoother and more controllable than it was from the factory. Plug reading is also much improved as you can see in the pic...just a hair too dark.



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AJ565
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AJ565 12/2/2017 3:00pm
12/2/2017 3:00pm
"digger wrote:
The !7' and 18" KTM's, 250-300's, really need a leaner slide, 5.5 or #6. With the leaner slide it will clean up that area that you are describing, and you will be able to use OEM needles. I'm pretty sure, but check to see if your 18' uses the s-4 needle jet. With the s-4 and #6 slide along with a 42-75 needle in the #3 clip, start out with a 30 pilot and 450/460 main jet. Those setting should get you in the ballpark."

It looks like digger was spot on if you want to try a 5.5 slide. I'm still waiting on my #6 slide, I already have the s-4 needle jet and the 42-75 needle. Thanks for doing the hard work for me so I know what to go straight to when my parts show.

sdhuskyrider
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sdhuskyrider 12/2/2017 7:57pm
12/2/2017 7:57pm
AJ565 wrote:
"digger wrote: The !7' and 18" KTM's, 250-300's, really need a leaner slide, 5.5 or #6. With the leaner slide it will clean up that area...
"digger wrote:
The !7' and 18" KTM's, 250-300's, really need a leaner slide, 5.5 or #6. With the leaner slide it will clean up that area that you are describing, and you will be able to use OEM needles. I'm pretty sure, but check to see if your 18' uses the s-4 needle jet. With the s-4 and #6 slide along with a 42-75 needle in the #3 clip, start out with a 30 pilot and 450/460 main jet. Those setting should get you in the ballpark."

It looks like digger was spot on if you want to try a 5.5 slide. I'm still waiting on my #6 slide, I already have the s-4 needle jet and the 42-75 needle. Thanks for doing the hard work for me so I know what to go straight to when my parts show.

Yea digger was right.

Why are you going to the S-4 and 42-75 needle again? The 17's have the S-1 which seems to be fine unless the larger cutaway becomes an issue with the S-1 and 43-73. Where did you get a #6 slide?

No problem on the leg work lol. I'm a mechanical engineer and a chronic tinkerer...this stuff is fun to me Smile

Pic from one of the freelance photographers at Pala...

endurox
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endurox 12/3/2017 8:55am
12/3/2017 8:55am
Latest set up - cut my stock slide to a 5.0 with a dremmel sand paper wheel. My 150 with the float level set, running a 42 pilot and jd blue needle at 2.5 and 480 main. Going to cut slide just a bit more to clean up the bottom just a bit. Also which added to jetting was Vee Force reed block and VHM with sx insert( always ride about 3000 ft.) This tightened up the squish band about .010".
sdhuskyrider
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sdhuskyrider 12/3/2017 10:23am
12/3/2017 10:23am
endurox wrote:
Latest set up - cut my stock slide to a 5.0 with a dremmel sand paper wheel. My 150 with the float level set, running a...
Latest set up - cut my stock slide to a 5.0 with a dremmel sand paper wheel. My 150 with the float level set, running a 42 pilot and jd blue needle at 2.5 and 480 main. Going to cut slide just a bit more to clean up the bottom just a bit. Also which added to jetting was Vee Force reed block and VHM with sx insert( always ride about 3000 ft.) This tightened up the squish band about .010".
I ordered a spare OE head to have the squish tightened up. How do you feel it effected jetting? What's your float height? I'm at about 8mm.
endurox
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endurox 12/3/2017 11:18am
12/3/2017 11:18am
endurox wrote:
Latest set up - cut my stock slide to a 5.0 with a dremmel sand paper wheel. My 150 with the float level set, running a...
Latest set up - cut my stock slide to a 5.0 with a dremmel sand paper wheel. My 150 with the float level set, running a 42 pilot and jd blue needle at 2.5 and 480 main. Going to cut slide just a bit more to clean up the bottom just a bit. Also which added to jetting was Vee Force reed block and VHM with sx insert( always ride about 3000 ft.) This tightened up the squish band about .010".
sdhuskyrider wrote:
I ordered a spare OE head to have the squish tightened up. How do you feel it effected jetting? What's your float height? I'm at about...
I ordered a spare OE head to have the squish tightened up. How do you feel it effected jetting? What's your float height? I'm at about 8mm.
Will lean out jetting a bit. Float level also about 8mm. The lower volume head helped the bike pull technical stuff better for a seat of the pants dyno.
digger
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digger 12/3/2017 1:37pm
12/3/2017 1:37pm
sdhuskyrider wrote:
Yea digger was right. Why are you going to the S-4 and 42-75 needle again? The 17's have the S-1 which seems to be fine unless...
Yea digger was right.

Why are you going to the S-4 and 42-75 needle again? The 17's have the S-1 which seems to be fine unless the larger cutaway becomes an issue with the S-1 and 43-73. Where did you get a #6 slide?

No problem on the leg work lol. I'm a mechanical engineer and a chronic tinkerer...this stuff is fun to me Smile

Pic from one of the freelance photographers at Pala...

The S-4 needle jet flows more fuel down low, and when combined with the leaner 6 slide and leaner diameter needle, it just seem to work better overall than the S-1, IMO. Have you tried an S-4 yet ?
sdhuskyrider
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sdhuskyrider 12/3/2017 1:39pm
12/3/2017 1:39pm
sdhuskyrider wrote:
Yea digger was right. Why are you going to the S-4 and 42-75 needle again? The 17's have the S-1 which seems to be fine unless...
Yea digger was right.

Why are you going to the S-4 and 42-75 needle again? The 17's have the S-1 which seems to be fine unless the larger cutaway becomes an issue with the S-1 and 43-73. Where did you get a #6 slide?

No problem on the leg work lol. I'm a mechanical engineer and a chronic tinkerer...this stuff is fun to me Smile

Pic from one of the freelance photographers at Pala...

digger wrote:
The S-4 needle jet flows more fuel down low, and when combined with the leaner 6 slide and leaner diameter needle, it just seem to work...
The S-4 needle jet flows more fuel down low, and when combined with the leaner 6 slide and leaner diameter needle, it just seem to work better overall than the S-1, IMO. Have you tried an S-4 yet ?
No I haven't...where can I order one and get it quick?
sdhuskyrider
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sdhuskyrider 12/3/2017 2:24pm
12/3/2017 2:24pm Edited Date/Time 12/3/2017 2:43pm
sdhuskyrider wrote:
My KTM dealer is quick. The KTM warehouse is close. Does KTM offer 42-75 needle as well?
digger wrote:
Yes, they do. Here's the part #-- https://www.babbittsktmparts.com/oemparts/p/ktm/55431034400/jet-needle-…
Awesome thank you. It was still rich off idle when I went to the 30 pilot with the 43-73 in position #3. 43-73 in position #2 was too lean which is why I went with the 44-73 in position #3.
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digger 12/3/2017 2:50pm
12/3/2017 2:50pm
sdhuskyrider wrote:
My KTM dealer is quick. The KTM warehouse is close. Does KTM offer 42-75 needle as well?
digger wrote:
Yes, they do. Here's the part #-- https://www.babbittsktmparts.com/oemparts/p/ktm/55431034400/jet-needle-…
sdhuskyrider wrote:
Awesome thank you. It was still rich off idle when I went to the 30 pilot with the 43-73 in position #3. 43-73 in position #2...
Awesome thank you. It was still rich off idle when I went to the 30 pilot with the 43-73 in position #3. 43-73 in position #2 was too lean which is why I went with the 44-73 in position #3.
That 1/2 a clip position can have a drastic effect, but The stock oem needles have a short straight section, meaning, the straight section of the needle doesn't stick much past the bottom of the slide, thus it makes the richer clip positions not nearly as effective as you would expect especially when you get into the leaner diameters.
seth505
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seth505 12/4/2017 8:15am
12/4/2017 8:15am
So mine is going good on the track but I just changed over to JD jet kit and I have the same issue I had before. When I rev the bike everything is crisp except when it comes back down to idle, it is always stumbling. I think I am ready to try a different slide.
AJ565
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AJ565 12/4/2017 8:38am
12/4/2017 8:38am
AJ565 wrote:
"digger wrote: The !7' and 18" KTM's, 250-300's, really need a leaner slide, 5.5 or #6. With the leaner slide it will clean up that area...
"digger wrote:
The !7' and 18" KTM's, 250-300's, really need a leaner slide, 5.5 or #6. With the leaner slide it will clean up that area that you are describing, and you will be able to use OEM needles. I'm pretty sure, but check to see if your 18' uses the s-4 needle jet. With the s-4 and #6 slide along with a 42-75 needle in the #3 clip, start out with a 30 pilot and 450/460 main jet. Those setting should get you in the ballpark."

It looks like digger was spot on if you want to try a 5.5 slide. I'm still waiting on my #6 slide, I already have the s-4 needle jet and the 42-75 needle. Thanks for doing the hard work for me so I know what to go straight to when my parts show.

sdhuskyrider wrote:
Yea digger was right. Why are you going to the S-4 and 42-75 needle again? The 17's have the S-1 which seems to be fine unless...
Yea digger was right.

Why are you going to the S-4 and 42-75 needle again? The 17's have the S-1 which seems to be fine unless the larger cutaway becomes an issue with the S-1 and 43-73. Where did you get a #6 slide?

No problem on the leg work lol. I'm a mechanical engineer and a chronic tinkerer...this stuff is fun to me Smile

Pic from one of the freelance photographers at Pala...

I don't remember. JD shows them in stock on their website though so thats where I should have gotten mine from.

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AJ565
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AJ565 12/6/2017 9:32am
12/6/2017 9:32am
I got an email from motosport.com last night and the slide is on an extended back order. I ordered it through JDjetting.com this morning and it shows they had 10 in stock. It also says they If its going in a KTM to let them know because they have to modify it to fit.
sandman768
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sandman768 12/6/2017 10:56am
12/6/2017 10:56am
AJ565 wrote:
I got an email from motosport.com last night and the slide is on an extended back order. I ordered it through JDjetting.com this morning and it...
I got an email from motosport.com last night and the slide is on an extended back order. I ordered it through JDjetting.com this morning and it shows they had 10 in stock. It also says they If its going in a KTM to let them know because they have to modify it to fit.
They just told me they are out of them? Let us know how you make out....I may just have mine cut...
sdhuskyrider
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sdhuskyrider 12/6/2017 11:32am
12/6/2017 11:32am
My dealer spoke directly to the Mikuni America folks. None of the 5.5 or 6.0 slides showed up and they just got a HUGE order delivered. Looks like cutting by RB Designs is the best option.
AJ565
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AJ565 12/6/2017 11:39am
12/6/2017 11:39am
AJ565 wrote:
I got an email from motosport.com last night and the slide is on an extended back order. I ordered it through JDjetting.com this morning and it...
I got an email from motosport.com last night and the slide is on an extended back order. I ordered it through JDjetting.com this morning and it shows they had 10 in stock. It also says they If its going in a KTM to let them know because they have to modify it to fit.
sandman768 wrote:
They just told me they are out of them? Let us know how you make out....I may just have mine cut...
Crap, you're right. Rockey mountain shows they have a 5.75 in stock, but not a 6.0. I think I'm going to order the 5.75 and see where that gets me. If it needs to go to a 6.0 I'll just send the stock slide in to get cut.
sdhuskyrider
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sdhuskyrider 12/6/2017 11:56am
12/6/2017 11:56am
AJ565 wrote:
I got an email from motosport.com last night and the slide is on an extended back order. I ordered it through JDjetting.com this morning and it...
I got an email from motosport.com last night and the slide is on an extended back order. I ordered it through JDjetting.com this morning and it shows they had 10 in stock. It also says they If its going in a KTM to let them know because they have to modify it to fit.
sandman768 wrote:
They just told me they are out of them? Let us know how you make out....I may just have mine cut...
AJ565 wrote:
Crap, you're right. Rockey mountain shows they have a 5.75 in stock, but not a 6.0. I think I'm going to order the 5.75 and see...
Crap, you're right. Rockey mountain shows they have a 5.75 in stock, but not a 6.0. I think I'm going to order the 5.75 and see where that gets me. If it needs to go to a 6.0 I'll just send the stock slide in to get cut.
JD has no slides FYI.
sdhuskyrider
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sdhuskyrider 12/6/2017 12:07pm
12/6/2017 12:07pm
I just ordered a 5.75 from Kawasaki. They have them in stock.
sdhuskyrider
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sdhuskyrider 12/7/2017 3:34pm
12/7/2017 3:34pm
Just got a call from GP motorcycles. Sounds like the 6.0 slides are in. Mine will be in possibly tomorrow but, if not then by Tuesday next week.
seth505
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seth505 12/7/2017 5:52pm
12/7/2017 5:52pm
sdhuskyrider wrote:
Just got a call from GP motorcycles. Sounds like the 6.0 slides are in. Mine will be in possibly tomorrow but, if not then by Tuesday...
Just got a call from GP motorcycles. Sounds like the 6.0 slides are in. Mine will be in possibly tomorrow but, if not then by Tuesday next week.
Damn I should go get one from them as well.
endurox
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endurox 12/8/2017 4:26pm
12/8/2017 4:26pm
Got out today on my 17 150 xc-w for some more jetting and suspension testing. After the last ride went down to a 40 pilot and shaved a bit more off the slide. Dropped the main jet down to a 450, JD blue needle at 2.5 and slide about 5.25mm. Revised jetting cleaned up the bottom end but still have a slight rich spot when rolling on throttle from 5000 ish rpm. So either slide needs cut a bit more and install a 42.5 or different taper needle? Any thoughts
thanks
sdhuskyrider
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sdhuskyrider 12/8/2017 6:38pm
12/8/2017 6:38pm Edited Date/Time 12/8/2017 7:59pm
endurox wrote:
Got out today on my 17 150 xc-w for some more jetting and suspension testing. After the last ride went down to a 40 pilot and...
Got out today on my 17 150 xc-w for some more jetting and suspension testing. After the last ride went down to a 40 pilot and shaved a bit more off the slide. Dropped the main jet down to a 450, JD blue needle at 2.5 and slide about 5.25mm. Revised jetting cleaned up the bottom end but still have a slight rich spot when rolling on throttle from 5000 ish rpm. So either slide needs cut a bit more and install a 42.5 or different taper needle? Any thoughts
thanks
Go with the leaner slide. I have been going off of this chart and it's done me good.

sdhuskyrider
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sdhuskyrider 12/9/2017 4:40pm
12/9/2017 4:40pm
Installed some sweet ZLT backgrounds today. No riding this weekend though...the Lilac fire is a few miles from Pala and along the way to Perris, Smellsinore and Cauhilla. Going to steer clear of I-15 until that clears up.

My spare head showed up today. Anyone have recommendation on where to send for squish tightening and rechambering to maintain stock compression? I was thinking about sending it to XPR Motorsports in Murrieta, CA. I spoke to Chad about the Huskatoom 250 for about an hour and he seemed to know it well. Sounds like he has a really good porting package too but, I'm not ready for that.

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