A bit more fuel on needle.

[adriano.ro]

Hi,I use pj42 N3CG@3 mj 180 as 1 out. Bike ec 300 2008 carb as1.
Bike runs well,and clean,I used needle in 4th position,bike was more powerful and linear but in 3th gear and constant throttle was rich . In 3th position if I accelerate from 1/4 to wot I feel a little hesitation,after 1/2 runs superb. So my question is, N3CH@4 will put the tapers between n3cg@3-@4?

 

[Jakobi]

N3EG#3 will put you precisely half a clip between N3CG#4 and N3CG#3

..or you could use N3CH#4 to try and clean up the very small throttle burble and keep everything above 1/8th throttle same as it is with N3CG#4, but may need to adjust the pilot too.

 

[adriano.ro]

Tnx,so the right pilot for n3ch can be 40,I really like EG but I hate the lean side after 1/2.

 

[Jakobi]

N3Cx and N3Ex are exactly the same taper profile. They are just half clip adjustments of each other.

 

[5valve]

Adriano do you have any riding videos.
Do you like snappy response for fast riding or user friendly bike for steep slippery rocky...romaniacs type riding

 

[adriano.ro]

I like Romaniacs style ( not because I'm from romania ) but i like snappy response to 3/4. I consider to take off the reed spacer,if I don't lose to much torque.
https://youtu.be/nzyIkhRd1ds

 

[adriano.ro]

Yesterday I make some trail,only to see here I need to make the changes. So if I run at 1/4-1/2 throttle position and I torn very quickly to wot ,bike will have an hesitation,lean hesitation, and if I release the throttle 1-2sec. and I accelerate again,bike will go well.

 

[adriano.ro]

No body knows what I need to change to reduce hesitation on midrange band? If I accelerate progressive is ok,but if I accelerate very quickly to wot,will hesitate for few seconds.

 

[Jakobi]

What do you mean hesitate?

Think about in the car. In many instances if you put the foot to the floor the engine still needs to build rpm before it rips. The bike can be somewhat the same depending on gear selection and load.

Mid range is clip position, however it could be that you need just a bit more fuel off the bottom to act as an accelerator pump - close the air screw a bit. It'll make the bottom end less smooth but give some punch back when whacking the throttle off the bottom end. Always compromise somewhere.

 

[adriano.ro]

Exactly! That's the point! When I close air screw I feel some improvements but I need to close more then 1 torns out. And I'm on the edge with pilot, pj 42(45??!) N3CG#3 mj180 7 slide notched. I wander if that can happen with bypassing pilot circuit,I just played with idle screw and air mixture screw and somehow I ended up bypassing the pilot circuit.

 

[Jakobi]

Try the 45 pilot if you like.

I doubt you've bypassed the circuit, but you can always back the idle down to where the slide is all but shut and start tuning from there if you're unsure.

 

[adriano.ro]

Hmm, maybe I was screw in too much idle screw and I was forced to rich up mixture by closing air screw.

 

[5valve]

My small expirience; needle clip position really changes the behaviour of the midrange.
needle raised makes it more useful for controllable torque buildup from lower rews, but it has problem overreving, especially on fatter main jet.

needle lowered makes it perfect for track use, as it hits in mid and pulls through top.

I too have problem in idle circuit, which is overly rich, no matter the jet, tested 42 to 35 currently.
Still have to compensate with idle screw almost fully in to idle, and air screw doesn't really affect the idle, except when fully closed, engine stalls.

I've completely rebuilt the bike and checked every similar issues, that riders had, like float level, possible leakages, float lever wear, reeds, but problem persists.

Only thing I havent tested yet, is leaner carb slide and bigger straight portion needle.

What is N3xx series diameter 2.695, 2.705 or more?

 

[adriano.ro]

If you already have #7 slide,I don't think that is the problem,80% of the same bike like yours have the same slide. So not all the bikes suffer from rich behavior. Anyway leaner slide seams to help a lot,cleaning the pilot part and giving more responsive throttle action.

In my case,the problem was accelerating quickly from ~1/2-wot, in that area I have a hesitation. Now I put bigger pilot 45(was 42) witch make some difference,idle more stabile. In this weekend I will see if the bigger pilot helps to resolve the middle range. I also removed the reed spacer,to rev quicker.

 

[5valve]

I usually ride 1 to 2 gears higer than other guys, as motor is quite turquey and have more elasticity to rev up.
I f I go to lower gears, it is too explosive.

i like idea of fixing main jet first, then correcting needle, and then pilot jet.
This is copy/paste from yamaha xjr1300 forums


Follow steps in order....First, dial in:

1. Top end (full throttle / 7.5k to redline - Best Main Jet be selected before starting step 2!
Select Best Main Jet
To get the best, most even top end power (full throttle/after 7500 rpm), select the main jet that produces the highest top speed / pulls hardest at high rpm.
If the bike pulls harder at high rpm when cold and less hard when fully warmed up, the main jet is too large. Install a smaller main jet and retest until you find the main jet that pulls the hardest at high rpm when fully warmed up. This must be done first - before moving on to the other tuning ranges.
If the bike doesn't pull well at high rpm when cold and gets only slightly better when fully warmed up, the main jet is too small.
In order to properly tune the midrange and low rpm carburetion, THE MAIN JET MUST FIRST BE PROPERLY SELECTED after 10 to 15 minutes of hard use!
Do not pay too much attention to the low-end richness when you are changing main jets - you still need to be using the main jets that produce the best power at high rpm. You will deal with the low-end / cruise later - after step 2.

2. Midrange (full throttle /5k-7k)
Select best needle clip position
To get the best power at full throttle / 5k-7k rpm, after you have already selected the best main jet,
If the engine pulls better on a full throttle roll-on starting at <3k, when cool but soft when at full operating temperature, it is too rich in the midrange and the needle should be lowered.
If the engine pulls better when fully warmed up but still not great between 5k-7k, try raising the needle to richen 5k-7k.
If the engine pulls equally well between 5k-7k when cooler as compared to fully warmed up, the needle height is probably properly set.
Do not pay too much attention to the low-end richness when you are changing needle clip positions - you still need to be using the clip position that produces the best full throttle / 5k-7k power in conjunction with the main jets that produce the best power at high rpm. You will deal with the low-end / cruise next.

3. Low end (full throttle / 2k-3k)
Float height (AKA fuel level & how to..)
To get best low-end power, set float height (fuel level) so that the engine will accept full throttle, without missing or stumbling, in 2nd gear from 2.5k to 3k rpm at minimum.
Float heights, unless otherwise specified in the installation guide, are measured from the "gasket surface" of the carb body to the highest part of the top of the float - with the float tang touching but not compressing the float valve spring.
If the engine has a "wet" rhythmic, soggy area at full throttle / 3k-4k rpm, that gets worse as the engine heats up, lower the fuel level by resetting the float height 1mm greater (if the original was 13mm - go to 14mm). This will lower the fuel level, making full throttle / 2k-3k rpm leaner.
If the engine is "dry" and flat between 2k to 3k rpm, raise the fuel level.
Example: change float height from 15mm to 14mm to richen up that area.
REMEMBER, since the main jet WILL affect low speed operation, the MAIN JET has to be within 1 or 2 sizes of correct before

 

[adriano.ro]

Update 45 pilot: so first thing,bike will idle in all situations,cold super hot,after a wot. Very nice idle,very linear and consistent. But is too rich,if I use 1,2 gear at low rpm will load up,and is a bit more lazy.

 

[Jim Cook]

Update 45 pilot: so first thing,bike will idle in all situations,cold super hot,after a wot. Very nice idle,very linear and consistent. But is too rich,if I use 1,2 gear at low rpm will load up,and is a bit more lazy.

You can use the 45 pilot jet if you adjust or change the jet needle to a bit leaner to accommodate the change. I use a 42, but when I am going slow, working trail, etc, when it is really hot weather (95F+), the idle will eventually start to slow as the engine gets hotter.