dyno a big bore

[elf]

Bclapham I am running a r1468d on the 2nd clip. stock is a 1469 and I also have a 1470 Eric told me to use the 1470 but it ran too rich in the middle. I spent the whole summer trying different main jets with the 3 needles I have. I also tried different grooves on each needle with different sizes of mains.The main jet seems good I have 158-188 mains but the bike pulls the hardest with the 162at wide open.

 

[bclapham]

the xy- 68, 69, 70 is the needle diameter, with 70 the largest diameter which is the leanest- however, the needle diameter only dictates the 1/8-1/4 throttle position.

i would strongly suggest trying the stock reeds again and seeing what happens, make sure the rest of the motor eg fuel, seals, rings, sielncer packing plug and ignition contact points are up to par also.

 

[fishhead]

Originally posted by elf
Bclapham I am running a r1468d on the 2nd clip. stock is a 1469 and I also have a 1470 Eric told me to use the 1470 but it ran too rich in the middle. I spent the whole summer trying different main jets with the 3 needles I have. I also tried different grooves on each needle with different sizes of mains.The main jet seems good I have 158-188 mains but the bike pulls the hardest with the 162at wide open.

The 14xx are single taper needles and the stock slide is a 5.5. The 1470 should not be richer in the middle since it has a larger straight section diameter than the 1468 and 1469. I suspect you might be loading up a bit on the bottom and it is taking time to clear out. Another possibility is the richer straight section is masking the lean main.

It is not necessary to guess. It's easy enough to find out if you need to change tapers or what ever. If you check out my post on the maintenance forum on "Throttle position jetting to the wet oil line dimension" you should info enough info to check it out.

A diciplined approach is better than jetting on heresay or chasing your tail. The tuners recomendations are just that. It is a very good place to start. Ultimately the proof is in twisting the throttle.

Props to James Dean and Dumonde Tech for making the info available and making sharp tools to get after it.

Happy Jetting

;)

 

[marcusgunby]

angus those dyno runs are from steve:) 40 hp is a dream IMO, steves 144s are setup to have not much more bottom than std but alot more mid and top, to get another 2 hp will really compromise the engine.Like is said you should ride a 38 hp 144 before worrying about a 40 hp engine.

 

[elf]

fish head ,Perhaps I didnt explain it the right way. when I used the 1470 on the middle groove it was to rich. I moved the clip up and it got to lean. the 1470 on the middle and the 1468 on the 2nd are pretty close with the 1468 just a bit leaner. But you are right the 1470 is the leaner needle. I just dynoed my bike and its making 41.5 hp....... Just kidding

 

[fishhead]

OK, gotcha!

KTM makes 1/2 clip adjustments in another series of needles so you can split clip positions as I recall but I don't have the numbers at hand. 1470j or g sounds right though. A dcl-4 will be 1/2 clip richer than 1470d-3. The dcl needles are available through Sudco or Carbparts Warehouse for about 6 bucks plus shipping.

 

[elf]

Thanks to every one for all the help.

 

[CamDayKX125(4)]

any more dynos are appreciated(mainly on 125s)

 

[ragingbull]

Kx144

Just to chime in I have a 2001 KX144 and run the Rad valve with a Pro-Circuit pipe (wish I had a Fatty). This thing was very easy to get jetted and made a big difference in the bottom and mid power.