Super Jet adjusting low and high speed needles

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i have some hesitation/bog in the low end and was wondering if i could just adjust the low speed to fix it or if i had to re jet my carbs
i have a 2002 superjet
factory b
ada head
but i not sure what jets or needle and seat are in the carbs right now, all i know is they were jetted by the previous owner for this setup

 

[jetpilot808]

Pull the carb, take a look. Better be sure than sorry. It's good to know what you are running anyways.

 

[Tyrant1919]

What he said. You should get comfortable removing and working on carbs if you ride any decent amount. You may have some crap in your filters, or you just need to turn your low needle a bit.

 

[Little Trumps Super Jet]

I need to do this to. My low end is super boggy and non responsive, But im unsure where to start

 

[Vumad]

I need to do this to. My low end is super boggy and non responsive, But im unsure where to start

Check the popoff.

Remove the carb and check the popoff BEFORE you clean or dismantle anything, so you know if it was the problem. Don't say "I don't have a pop-off gauge". Buy one. They are worth the money. They are necessary. Just buy one.

If pop-off is leaking from N&S, replace N&S. If pop-off is leaking and it's not bubbling at N&S, rebuild the fuel pump.

Remove everything from the carb (including fuel pump side), clean thoroughly. Take pictures as you go if you need help remembering how to reassemble. Do not use wire to clean the jets. Spray the jets with carb cleaner. Soak the jets in carb cleaner and clean with a nylon brush bristle if they are too dirty. A product named "Chem-dip" available at the auto-parts store works great, soak only metal, do not soak rubber or plastic, clean off the parts with carb cleaner. Do not let parts sit out of the bucket with chem dip on them, it will dry and become thick and gummy.

IF you have a carb with caps on the high/low adjuster screws, remove the caps, and replace the adjuster screws with extended length T-adjuster screws so you can dial in the carbs more accurately and easily. Be sure to screw the adjuster screws all the way in counting the number of turns before you remove them. That will be your baseline to reinstall.

I'm also sold on the jetmaniac allen head kit, so I would suggest upgrading to those. Makes it easier to get the carbs tightened down nicely without the concern of stripping the screw heads.

Don't use the SBT kits. The O-rings in them are the wrong size and they leak. Spend the extra few $$ on genuine mikuni. you will be glad you did.

be sure to write down you jet sizes (pilot is the small one and main is the big one), needle and seat size (on the brass seat), the color of the spring that works with the N&S rocker, the number of turns of both screws high and low, and what your correct popoff should be. If you tune the ski and change a screw position, add it to you tuning log.

 

[Vumad]

i have some hesitation/bog in the low end and was wondering if i could just adjust the low speed to fix it or if i had to re jet my carbs
i have a 2002 superjet
factory b
ada head
but i not sure what jets or needle and seat are in the carbs right now, all i know is they were jetted by the previous owner for this setup

Yes and no. I have bog because my ski is not yet tuned. Mine mostly just needs adjustments to the screws. I have gone through just about everything, and I know my bog is from fine tuning.

However, bog can be caused by... low pop-off from bad needle and seat or from bad fuel pumps, clogged internal fuel filter, clogged jets... It can also be less commonly caused by a leaking vacuum (that line from the crank case to the carb), clogged up pet-cock, clogged fuel filter, bad one-way valve on the tank causing too much pressure or vacuum.

You see, you simply can't post... "I have bog. I don't know anything about my ski other than these parts I see on the outside. How do I fix it." You need to take the time to diagnose the problem. You learn how to diagnose the problem by researching it. Mikuni's manual tells you where to start. There is a lot of information available. No one expects you to be a carb expert, you aren't expected to know everything, but it sounds like you've made very little effort on your own to find a problem and solution, otherwise you would have likely explained some of that.

Read the post I made above this one, and do everything in that post before you start messing with carb settings. Do not change your screw settings prior to counting the turns and writing that info down so you can put it back if you mess it up.

 

[blank]

I just cleaned and rebuilt my carbs and fuel pump but I forgot to check my pop off before I put them back in the ski , basically my question is can my bog be caused by the tuning of the my needles if so is turning them in or out leaning my carbs and if tuning my needles can't fix it then I will check pop off but hopfully tuning it fixes the bog

 

[Drewwho]

+1 on OEM rebuild kit. I bought the SBT and the oring leaked on non fuel pump carb. Luckily I kept my original o-rings and was able to stick that back in and it sealed fine. I didnt know jetmaniac sold an allen kit for carb, I ended up going to hardware store and buying those to torque down carb better than a phillips could, definitly worth it there too.

I'm shocked no one has asked you to go read mikuni manual
http://www.x-h2o.com/threads/39846-Tuning-tips-for-Rookies
http://mikuni.com/pdf/sbn_manual.pdf

Yes, your bog can (and very likely) be just the low adjuster, read above two documents. Turn in to lean. There's bog and hesitation, lean or rich.

 

[Vumad]

I just cleaned and rebuilt my carbs and fuel pump but I forgot to check my pop off before I put them back in the ski , basically my question is can my bog be caused by the tuning of the my needles if so is turning them in or out leaning my carbs and if tuning my needles can't fix it then I will check pop off but hopfully tuning it fixes the bog

Yes. It is possible. My main point was to make sure the carbs are working perfectly before you mess with the tuning. Leaking popoff is a very common problem that causes all sorts of issues you just can't tune out. I personally like to verify carbs are clean and working properly before I try to tune them.

There is no harm in adjusting the screws as long as you don't get to lean overall at high rpm. Make sure you know where your screws are before you mess with them so you can put them back.

Remember, your low speed effects the high speed. If you lean the bottom, you are also leaning the top. Be sure not to just lean the bottom to fix the hesitation while skipping retuning the top, then burning up your motor.