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KTM 380 exc - jetting specs that work

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Hey all.  Worked on a 2002 KTM 380 exc this winter, getting it set up for Michigan trail rides.  These specs are on a brand new carb because the stocker had too many worn out parts, notably the float pins for float tower.  Not a lot of jetting specs on the internet for this bike so I'll tell you what's working for me.  When I got it, it was horribly rich from the stock needle and slide and would  have made it tough to ride on tight single track.  If any of you tackle a similar project here's what's working for me.  Jetting specs that work on the stock carb:

 

PJ: 45

Needle: JD jet kit blue needle, 2nd notch from top

Slide:  #7  Slide cut to a #8 by RB Designs in Oregon

MJ: 168 (a 162 was in it when I bought it and it ran fine mid/top end)

Cooler weather today (55 F) but air screw is at 3/4

 

Engine mods:  New boyesen pro series 2 stage reeds, wiseco piston kit, cylinder head mod (head reshaped for efficiency), Pro Circuit pipe (platinum series) and silencer (USFS spark arrestor), very clean and oiled twin air filter

The bike runs great, no bogging, and is nice and crisp.  Keep in mind the most important issue to fix is the cylinder head.  Getting it reshaped is the key to it running right.  I know the 168 mj is leaner than what most guys are running but maybe it's the pro circuit pipe on there, I'm not sure.  It was surging a little down low but a half turn in on the air screw fixed that.  Now that it's jetted right the power is much smoother in early throttle openings.  The "hit" is actually pretty mild now and very managable on the trail.  The point is, this is what works for this bike to give you a good baseline.  

 

 

 

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I ended up raising the needle (lowering the clip) 2 positions.  I was getting some detonation from lean condition, I think due to the head mod.  It wasn't a minor knock either, between 1/2 and 2/3 throttle it was pretty bad.  It went away.  So clip is 4th position from top with Blue needle.  MJ and PJ are the same.  

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Final specs are:

45 PJ (I tried a 48 and it ran HORRIBLE.  With the A/S only 3/4 turn out I thought Id need to go up on PJ, but it didn't work)

170 MJ  (pre owner had a 162 in there and it ran ok, I think because stock needle was super rich)

JD blue needle, 4th position from top

#7 slide (8 seemed too lean, 7 is definitely better.  Stock is 6 or 6.5)

A/S at 3/4 turn out

Float height adjusted: floats sit just a little lower than std.  Bend the tang up about 1 mm and it should be good.  This is necessary because these carbs are angled down when in the rubber boots (thanks KTM).  Stops the overflow problem also.  

I put the green power valve spring in also.  Takes the hit out mostly, which is smart at this point riding tight woods.  Feels like a trials motor in low rpm.  

 

I hope these settings help somebody.  No surging on decel or closed throttle.  You can grab a handful riding just off idle and no bog, just pulls.  Idles as good as any 2 stroke I've ever had.  No hesitation anywhere, at any throttle setting.  Where I ride is 600-700 ft above sea level.  

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GAWD! I bet that bike screams! I would think the specs are a little richer than the 300.. I wanted to get a 380 when i was in NM but, never could.

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You're wishing this helps someone has come true lol. I just bought a 2002 this year, I've had a 2001 for about 5 years but that has a lectron on it.  Could you go into detail about the head needing "reshaped" please? 

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1 hour ago, yamaha-hillclimbs 15 said:

You're wishing this helps someone has come true lol. I just bought a 2002 this year, I've had a 2001 for about 5 years but that has a lectron on it.  Could you go into detail about the head needing "reshaped" please? 

Stock the squish is big. I found mine impossible to jet well until cut. The bowl was opened up to keep compression stock. 

 

 

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Stock the squish is big. I found mine impossible to jet well until cut. The bowl was opened up to keep compression stock. 
 
 
It runs well, I haven't tried to jet it yet at all, I've only fouled 2 plugs . My 2001 would foul 1 or 2 per ride, put the lectron on it haven't fouled since. I guess I'll have to get the squish on both adjusted this winter.

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2 minutes ago, yamaha-hillclimbs 15 said:
24 minutes ago, seer said:
Stock the squish is big. I found mine impossible to jet well until cut. The bowl was opened up to keep compression stock. 
 
 

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It runs well, I haven't tried to jet it yet at all, I've only fouled 2 plugs . My 2001 would foul 1 or 2 per ride, put the lectron on it haven't fouled since. I guess I'll have to get the squish on both adjusted this winter.

I consider it a mandatory mod on that bike. 

 I didnt foul plugs before but had small rpm ranges that would act up. I was using it as a 90/10 dual sport. Once set up it was very safe to cruise on the road with for miles at any rpm. 

 The power was the smoothest ive ever ridden on a 2t. I had people label it "electric".

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I consider it a mandatory mod on that bike. 
 I didnt foul plugs before but had small rpm ranges that would act up. I was using it as a 90/10 dual sport. Once set up it was very safe to cruise on the road with for miles at any rpm. 
 The power was the smoothest ive ever ridden on a 2t. I had people label it "electric".
That's how I feel about my 2001 lol, it rides the way you describe, but probably cant cruise on the road. I'll be looking into doing this on both, but the 2002 is going to eventually be a supermoto, it's already got a plate I just need the wheels and tires. But I would like to be able to cruise as you described

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