Mid range needle question

[rody]

Hey guys. I got a question regarding tuning the midrange needle. My buddy bought a band new K4.6 HO with the midrange needle, and the engine runs like crap. He broke it in (not sure how), and we tried to tune it today. We set it to factory, and it's very slow, and his little torque off the line. We tried setting the needles to flush like the manual said, and it ran crappy, but the temps were getting really high into the 300 range. I know you've all said to leave the midrange alone, but we leaned it a tad and it seemed to run a little better, although it still had no real power, and the temps seemed to go down a little, but still high.

My question is IF you were going to tune this, what is the order? I know with a normal nitro engine you tune the HSN first then the LSN. With my Baja, you do the reverse and do the LSN first, then the HSN, but what do you tune first, second and third with this engine? I know a lot of you just put the midrange on flush, and then seal it, but if you were to tune it, what's the order, and what would you look for when tuning the midrange? Thanks for your help with this.

 

[Purenitro]

The MSN only determines the placement of the spray bar in the carb, any adjustments to the MSN will will have a direct effect on the LSN. The manufacturer determines the best placement of the MSN and you just have to set the LSN to work best with the setting.

 

[Meatwad]

During break in of my k4.6 it got to about 280. Tuned it and got reasonable power but still somewhat high temps. And yes there are too many factors regarding engine temps

After noticing the msn back out a couple times, I sealed the entire engine including the msn almost flush with holes thru the needle facing horizontally and it really woke up. "Regular" temps and alot more reliable tuning, power

IMO seal engine but leave msn and set it how it feels/sounds best and seal msn last

 

[MikeK1981]

My k5.9 MSN had 3 holes in it, I believe, I lined on of these holes directly up with where the HSN goes in. Is this right, or does it make a difference? It seems to run good now and I don't plan on changing anything but I was just curious how these holes interact with/affect the fuel flow to the motor.

 

[rody]

Mike, where are the holes in the MSN? I don't have the engine, so I can't take it apart and look at it. Did you take the needle out to look at the holes? If so, how did you line up the holes? Funny, we seem to be having the same issues on our Savvy's across the board.

 

[Meatwad]

There were 4 on my msn. As if drilled straight thru the needle twice. Not sure if lining it up or sealing made the diff but somehing worked for me

 

[MikeK1981]

Yeah if you take the MSN out you'll see the holes. When mine was about flush I could shine a light into the hole where the HSN goes and I could see the holes line up as I turned the MSN. I just got it flush and then lined one of the holes up with the HSN hole. I don't even know if it makes a difference but I figured they were close to the same size and lined up when flush so I thought maybe the HSN's tip was supposed to go through both holes when tightened down so I just gave it a shot. I figured if it wasn't right I could always readjust it but it seems to work fine that way.

 

[Purenitro]

There is a channel 360 deg that matches up with those holes, that way fuel can flow regardless of the position. To get them lined up is a tiny reduction in resistance, every bit helps.

 

[MikeK1981]

Thanks for the info.

 

[noogie]

Rody,

I am experiencing the same issues with a xl I received 4 free. I sealed the engine and have not found a solution yet so any progress u make would b appreciated.

 

[rody]

Noogie, it's not actually my truck, I was just helping my brother in law with his. He said he was going to have someone at the LHS tune it for him, but if he tells me anything, I'll be sure to post it up.

 

[noogie]

Rody,

tx, I would appreciate it

 

[MikeK1981]

If it helps this is what I did on the k5.9. I took out the MSN and HSN, then I put the MSN back in and got it close to flush and then shined a flashlight into the hole where the HSN goes. I turned the MSN slowly until one of the holes in the body of the MSN lined up with where the tip of the HSN goes in. Then I just put the HSN back in and put it 1.5 turns past the line to start with since my motor was already broken in. If yours isn't broken in then you'll want to start the HSN flush with the groove on the HSN body. According to Purenitro's info it probably does not make a difference on where the holes line up but this worked for me pretty well and I experience very little half tank lean with stock length fuel lines. Good luck.

 

[noogie]

Mike,

tx giving that a try right now