Pop off pressure

[mikidymac]

No they just go in the plug from the sending unit.

The fuse is actually soldered to the circuit board inside the sender. It is actually a small black diode looking thing and printed on the circuit board next to it is “F1” hence it’s name.

You can see it bridged with solder on the far right.

 

[andrewterri]

Thank you. I really appreciate you going out of the way to help me.

 

[mikidymac]

No problem.

 

[Chester]

According to the chart you posted with the spring weights. If the way I am looking at it is right then starting with the far left, shiny silver 65gr, dull silver 95gr, black 80gr, and gold 115gr. The mikuni rebuild kit I got has the shiny silver and dull silver. I used the dull silver and got about 38 psi if you average both carbs together.

Actually, the way you have them is not in order. The silver on the left is 65g, the dull silver (reverse wound) is 95g, the black one is 80g, and the gold one os 115g.

Chester

 

[Chester]

No, from your picture left to right.
115,95,80,65.

The long silver one is 65g and the gold one is 115g.

Chester

 

[andrewterri]

That is just a picture on found on google. Still thinking 38 psi on 95gr spring is awful low. Does that sound right to you mikidymac? I am going to do some research and see what springs mikuni includes. Pretty sure it's 65 and 95gr. I didn't know about them being wound the opposite and so telling them apart by color is difficult. Carbs competed and sealed up so I can't check.

 

[mikidymac]

The long silver one is 65g and the gold one is 115g.

Chester

Are you sure Chester? THe mikuni chart says the long one is the 115gm and measures exactly 16.55 and is the longest of all and the shortest one is is the 65 gm measuring 14.95. I don't see how the longest spring with the heaviest wire could be the lowest pressure?

 

[Chester]

Yup, I'm positive.



Chester

 

[mikidymac]

So then Chester is this chart wrong

It shows the long spring as the 115gm at 16.85mm?
I see as there is some kind of misprint as it shows conflicting part numbers and colors from the popoff chart to the measurement chart.

I don’t see how the longest spring can have the lowest pressure. Since the weight gets progressively lower with the measured length on all of the other springs.

The shiny silver is the 65. There is no gold anymore and is now platinum so the 115 is more of a chrome like in my picture.

I am not trying to say you are wrong Chester I just want to make sure I have it correct so I don’t give out bad information.

 

[Chester]

Hmm, interesting. Those 2 charts conflict. I've seen mistakes in the Hot Products catalog before. The pop-off pressure chart is the right one. It appears they changed the colour from gold to platinum for the 115g one. If I have time, I'll check the ones I have in a loose carb and post the results.

Chester

 

[andrewterri]

why do none of these charts have information for a 1.2 needle. mikuni did use them after all.

 

[mikidymac]

 

[andrewterri]

My number are way the heck off. I got like 20psi on the shiny silver and I'm sitting at 38psi on the 95gr dull silver. I tested about 20 different spring combinations and after being covered in wd-40 my numbers were consistant. Could be the aftermarket N/S? thought I was ordering mikuni but they were not.

 

[mikidymac]

Honestly I would not trust any of the aftermarket carb parts. You should be getting close to these numbers.
@minneonka4me should be able to get you the correct parts but I am not sure why Nick hasn't responded to you. Maybe he is actually getting some R&R.

 

[andrewterri]

he might be. The carbs passed the pressure test the pop off is just low. being low it will cause a rich problem if anything so I thought I would try it since it is already together and I don't like reusing gaskets if I open it back up. In the fall I am sending the jugs off to Full Bore for the top end boring and will change the N/S then. That is what I am thinking, what are your thoughts about doing that?

 

[AdamXP800]

Am I the only one that doesn’t check pop off and have never had a single issue? Running the correct springs with correct needle and seats and my carbs always perform exactly as they should. I sometimes think people get carried away with pop off readings

 

[AdamXP800]

And always use OEM mikuni parts

 

[andrewterri]

Should work if everyyhing else is good. My problem is the carbs were so corroded I really could not tell what springs I had. Even with mikuni parts my pop off is not what it should be. Tested the ski last week in 32 degree water without flame arrestor and ski ran awesome. Very responsive with pop off on the low end. Hopefully with the flame arrestor on the increased manifold pressure won't cause it to flood.

 

[mikidymac]

Don’t run it without the air cleaner it can cause it to be lean enough to seize.

 

[AdamXP800]

The flame arrestor is actually very unrestrictive

 

[AdamXP800]

Hence if it won’t run without it, it won’t run with it

 

[andrewterri]

Thank you both for the info. I will no longer start/run/ride without it on. luckily I only ran it for about 60 seconds on the lake just to test the jet pump so I know if there are any problems there. I got my screws in that I needed and hoped to finish the ski after work today but left early with a kidney stone. Hopefully tomorrow after work I will have it together. Than just waiting for summer (hurry the h*ll up)

 

[mikidymac]

The flame arrestor is actually very unrestrictive

Actually the stock air cleaner assembly is restrictive and the stock ski is jetted to account for this. Without an air box or with aftermarket air cleaners you have to increase your jet sizes to account for the increase in air flow.

 

[andrewterri]

wont this increase in pressure cause a pop off pressure on the low side to flood? The ski did not flood, however, I only ran it for a short time, I was thinking that once I put the arrestor and air box back on it might cause the cabs to run rich. i.e... the jet does not have enough spring pressure to overcome the manifold pressure thereby not closing off the needle and flooding the engine.

 

[mikidymac]

It will not cause it to flood. It might be a little rich but that is safer than being lean.