Bill O'Neal2

[parrothd]

Bill, Got my parts today(Jon in evanston), was expecting next week!! Thanks!!

One question, the pop-off tester gauge only goes up to 30psi, I thought I read somewhere on here that some machines need the pop-off pressure near 40 psi??

[Bill O'Neal2]

Re: Bill O'Neal2

If it holds over 30 psi, you need not worry about it leaking at 40 psi. That is a genuine Mikuni guage, just like the one I use here. Don't sweat it.

[parrothd]

Re: Bill O'Neal2

Ok, whats the Bill O'Neal recomended settings for my 95xp 720?

pop-off pressure and hold what for how long?
High and low screws?
Which color springs?
Can I cut the springs if needed?(SBT aritcle says yes, thought no)...

[Bill O'Neal2]

Re: Bill O'Neal2

Ok, whats the Bill O'Neal recomended settings for my 95xp 720?

pop-off pressure and hold what for how long?
Emerse the needle and seat in gasoline or WD 40, Pump the guage up to the maximum, and wait 30 seconds to see if the guage drops pressure. If so look for bubbles. If not you are good to go.
High and low screws?
Factory settings of 1.25 to 1.50 for the low speed needles and Zero turns out for the high speed needles.
Which color springs?
Match or use the same springs that came in your carbs.
Can I cut the springs if needed?(SBT aritcle says yes, thought no)...

No, you do not need to cut the springs for any reason.

[parrothd]

Re: Bill O'Neal2

What psi should it "pop-off" at?

[Bill O'Neal2]

Re: Bill O'Neal2

According to the manual, 40-55 psi and it should be able to hold 24 psi sustained.

[parrothd]

Re: Bill O'Neal2

Sorry, guess I'm confused, if the pop off is 40-55 and the pop-off tester gauge only goes up to 30 how do I tell what psi it pop-ed off at?

[Bill O'Neal2]

Re: Bill O'Neal2

You need to trust me on this. If the needles do not leak (they are brand new and should not leak) and the springs are of the same size as stock, the pop off pressure will be right within oem spec for that carbureator.

The 30 psi guage is much more accurate than a 60 psi guage. That is why we use a 30 psi guage.

We have a Mikuni manual that tells us what size spring and needle combination makes whatever pop off measured in psi. We also have oem manuals for each ski that tells us what needle size came in the carbs.

We mainly use the PO tester to detirmine wether or not there is a problem from installing the needles and seats. We also use the guage to do many low pressure tests, like for the pump cone and check valves, where accuracy of the guage is much more important.

If you notice, the range of acceptable PO is 40 -56 psi. Not exactly a close science. So, if the needles hold a minumin of 24 psi for any length of time, and the correct springs are in the carbs to go with the oem specs for the needle/spring combination for that model carb on that model ski, the pop off pressure will be just fine.

[Danny Roszell]

Re: Bill O'Neal2

Bought the same gauge from Bill and had the same question. I found out he was right. Adjusting pop-off is not a tuning method. The needles either leak or they don't. As long as the needles are good, the spring is correct and the control arm is not overly bent, the pop off will be with in range.

You will most likely use the gauge more for oil changes for the pump than anything else which is just as important. All other pressure checks require 10 psi or less and the 30 psi gauge delivers the best accuracy.

[littlej72]

Re: Bill O'Neal2

How much would a carb tuning tool set run? and what do you recomend getting. I am an acura mechanic so not to knowledgeable on carbs but mechanically no problems. thanks.

[Bill O'Neal1]

Re: Bill O'Neal2

All you need is a pop off tester and an impact driver and a normal selection of hand tools.

[ski_guy]

Re: Bill O'Neal2

Hey Bill. I was wondering if you could tell me the correct spring weight for a Mikuni SBN triple setup for a 92 Polaris 650. I am having tought starts because of leaky needles I believe. Carbs were just rebuilt with SBT kits and needles/seats (1.2) and adjusters are all new. The kit came with 6 springs, I put the ones that were the same size/color back in and it still starts hard on water. I can watch the fuel leak into the carbs when the motor is off. My guess is that my pressure is too low and I need to increase to shut fuel flow off, but it would help to know the "reccomended" weight. I dont have a guage which makes it even more difficult to read. I've also heard that the SBT diaphrams cause a bit of a leak, is there any truth to this? Thanks for your help.

[Bill O'Neal2]

Re: Bill O'Neal2

I do not know what springs came in those carbs, but you might want to try the next size up to see if it stops your leaking needles. A pop off guage is for testing them before you install the carbs, sounds like it would have been a good investment.

[frankey01]

Re: Bill O'Neal2

Bill speaking off pop off gauges how much do you charge for them? They are mikuni of course correct?

[dontcare4urshyt]

Re: Bill O'Neal2

I rebuilt my carbs twice last year because the ski was loading up.. First time the filters were clogged.. it ran a little better but not perfect. Then the second time I rebuilt them i did it because I thought I screwed something up. I ended up blowing the motor. and rebuilt the carbs AGAIN over the winter but I bought a pop off gauge this time to find that my n&S were leaking at anything over 10 PSI causing my problems. changed the N&S, put in new SBT motor and now It runs PERFECT!!

Pop off gauge is the best thing you can buy when you doing your carbs. if you dont test the n&s your wasting your time.