Other high speed and low speed screw adjustments

[ATS_Aaron]

Is there a rule of thumb for X amount of turns out on the high (or low) speed screw = 1 jet size?

And (possibly dumb question here) but how much is one jet size? 120-125, or 120-130, or 120-122.5?

Aaron

 

[DirtyJ]

120-122.5 half sizes

 

[chriselmore_1]

I was told over 1.5 turns to go up a size. But it depends if the screws have the fine threads or not

 

[Mark44]

I was told over 1.5 turns to go up a size. But it depends if the screws have the fine threads or not

Correct and you will notice your RPM's have stopped increasing on the tachometer/ or you are now in tune.

 

[ATS_Aaron]

Correct and you will notice your RPM's have stopped increasing on the tachometer/ or you are now in tune.

That's part of the issue. With this low pitched freestyle prop I'm pretty sure I can hit the rev limiter. Plus hanging on to a 967cc Rickter at top speed isn't exactly easy.

 

[swapmeet]

When reading the Mikuni tuning guide, I was lead to believe that the screws perform somewhat independant of the jets.
I'd have to go back and read it again (and will have to soon) to be sure.

 

[Big Kahuna]

alot of tuning is "by the seat of your pants"................. How does it feel. You should be able to feel if it is way out of tune.

 

[THRUST]

2 turns out and then rejet
If your scared or lazy then do 2 1/2 no more than that though .
You should try it on a Xfs

 

[Tyler Zane]

man im in the same boat. im slowly learning how to tune carbs. im on the easy track because my carbs, porting, timing curve, and prop where all done by jetworks but, one problem is i came off a stock 550 to a arm jerking sj so i dont know what it feels like to have a fine tuned monster. im dieing to get someone to ride my sj that has experience so i can get an honest opinion about it. to me its a mother ing monster and i cant wait for the sun to get up and warm the air a little!

 

[AtomicPunk]

man im in the same boat. im slowly learning how to tune carbs. im on the easy track because my carbs, porting, timing curve, and prop where all done by jetworks but, one problem is i came off a stock 550 to a arm jerking sj so i dont know what it feels like to have a fine tuned monster. im dieing to get someone to ride my sj that has experience so i can get an honest opinion about it. to me its a mother ing monster and i cant wait for the sun to get up and warm the air a little!

I would be surprised if you need much additional tuning if you bought a complete package..... maybe the idle.

 

[DirtyJ]

I would be surprised if you need much additional tuning if you bought a complete package..... maybe the idle.

X2 My Bro has the same set-up.
Tzane, Art would be able to tell you exactly where you need to be or damm close. Is your intake crossover filled?
If it is your jets would be in the area of 125m/82.5p

 

[Tyler Zane]

I would be surprised if you need much additional tuning if you bought a complete package..... maybe the idle.

ya i know but i really want a second opinion. Art made every decision about the boat, i just told him how i like to ride.

 

[Tyler Zane]

X2 My Bro has the same set-up.
Tzane, Art would be able to tell you exactly where you need to be or damm close. Is your intake crossover filled?
If it is your jets would be in the area of 125m/82.5p

ya man i know, Art is tons of help. he filled the crossovers and all kinds of other stuff to my carbs. all i know is the throttle response is instant lol.

 

[Mark44]

Remember the low speed adjuster is ONLY for adjusting the idle mixture. Do not use it to alleviate a low speed hesitation, most people do not knowing.

Carb tuning is more than a seat of the pants thing. IMO There is a science to this.

Read your Mikuni manual and purchase a tachometer is the best advice I can possibly give.

Mark44

 

[Matt_E]

Remember the low speed adjuster is ONLY for adjusting the idle mixture. Do not use it to alleviate a low speed hesitation, most people do not knowing.

Carb tuning is more than a seat of the pants thing. IMO There is a science to this.

Read your Mikuni manual and purchase a tachometer is the best advice I can possibly give.

Mark44

x100
Read the manual.

TZane, I wouldn't worry about trying to tune those carbs much. In my experience, Art's settings have always been spot on.

 

[Tyler Zane]

x100
Read the manual.

TZane, I wouldn't worry about trying to tune those carbs much. In my experience, Art's settings have always been spot on.

roger that!

 

[Crab]

read it 10 times

 

[Tyler Zane]

http://www.mediafire.com/?wtwgnmjgxtm -mikuni super BN manual (i love the tech FAQ section)

im about to read it, ill be posting a test tomorrow!

 

[swapmeet]

Remember the low speed adjuster is ONLY for adjusting the idle mixture. Do not use it to alleviate a low speed hesitation, most people do not knowing.

Carb tuning is more than a seat of the pants thing. IMO There is a science to this.

Read your Mikuni manual and purchase a tachometer is the best advice I can possibly give.

Mark44

Kinda what I was getting at.

 

[ATS_Aaron]

The low speed screw hole is "open" even when the throttle isn't. I like to run my ski 1.5 or 2 turns out on the low speed screw for easier starting especially when cold.

Aaron