I disagree. The needle ramp and needle jet alone can utterly kill you and be the correct lengths, which has little to do with the ramp on such. Getting pure dead idle on along with absolute main jet are both easy too, it is the transitions off the dead idle and through the middle of throttle that most have fits with. Thinking any needle and jet 'matched' together will work is a recipe for disaster and carbs calibrated like the claim here of for small race 2 stroke will be among the worst if true.
4 strokes are different animals. They can take a little more abuse and also if you read the plugs from varrious chops you can diagnose where the problem is at. If you tune the main your needle is the least of your worries. Still important though. Don't get me wrong a lean low end and a rich top end are a bad day in general but manuals and service techs always say tune the pilot then the main then move the needle. That will get you 90% the last 10% is taper and length for the most part.
"What does one do if the needle is fine at half throttle yet slightly more is too rich and slightly less is too lean? Since needle controls 1/4-3/4 of the throttle? "
This would mean your pilot circuit is lean. The 2 systems overlap for a bit 1/2 being not used and lets say 3/8 is where they overlap witch would mean your off idle is bad or it hangs when reved.
"I say that having tuned so many carbs I cannot count. 2 strokes have a 'gulp factor' for lack of a better word that has them suddenly want up to twice as much fuel instantly within say 50 rpm when any race tuning (porting) begins to line up, a 4 stroke gets nowhere near that demand change and the needle has to cover that and the ramp will be much more radical to cover it.
The gulp factor is high rev. That's a 2 stroke. They do that. The xs is a 4. The needle is important. But its not as drastic. Plus you will know when you stumble or it seems lacking in certain areas.
"Why there are a hundred needles covering each basic length, if it were that easy you wouldn't need more than 2 or 3 for every carb made. Take the extra needles that come in a late model Dynojet big Honda four DOHC kit, they are worthless, unless you have like pro stock cams in the engine. Put them in every possible clip location, they do NOT work and never will. But then Dynojet kits suck anyway, they on purpose stamp bigger numbers on smaller jet hole jets to make you think you are 'doing something' when you go bigger and you may have even jetted DOWN."
Do you have a thing against a company that has been doing blanket kits for decades? The reason they come with so much is that every bike is different "even same model and everything". Thats why you run get the numbers and change settings/parts and run again. And if then numbers are not correct identifiers then how do people tune with them?
"I could tell a story of early Honda DOHC 4 and how Dynojet personally promised somebody a kit that would work with all stock Honda DOHC with simply changing from airbox to pods, it did not happen and despite much dyno tuning and eventually the owner of Dynojet admitted it 'could not be done' using various needle sets cut specifically to cure the problem. They wasted thousands chasing the issue to never solve it."
Your telling me the company that sends a tech out when a dealership that gets stumped could not tune 1 bike?
"Yeah, it's not as hard as some say it is. Go on believing that."
So everything that I'm reading or hearing is complete crap? Everywhere is saying get your pilot circuit in order, then your main then your needle. Your needle is just metering for the main really. Come on man it's not rocket science. Jut air fuel ratios at different multiple ratios. If backyard bob could do it in the 70's I'm pretty sure someone with the sum of all knowledge in a device that we keep in our pockets can get you pretty close.
But what the hell do I know?
