95 XP (717) Needle / Carb Model?

[Tenacious D]

I have the manual and see that it calls for a 1.2 needle (which I now have, but is suspected of leaking) for my BN-38I dual-carbs...but I've heard others advise to use a larger size as a replacement, particularly, a 2.5 needle / seat.

Here are my questions on that advice, and one other general question about my carbs:

1. Is it more advisable to use the larger needle, though not OEM, and if so, what would the benefit / result be from doing so, if anything? Or, is it it simply best to stick with the 1.2 needle?

2. If I do use the 2.5 needle, what type of spring would be required to ensure for the proper pop-off, if even possible to do?

3. What is the difference between a "BN-38I" carb and that which the Mikuni guide shows as being simply a "BN-38" (without the "I"), if anything? Is there a real difference, insofar as replacement parts / kits are concerned, or is it simply a difference in nomenclature (meaning, Mikuni's listing it as a "BN -38" is intended to encompass all models of that carb, including the "BN-38I")?

Thanks, in advance, for any advice or suggestions.

 

[Dr Honda]

First... a 2.5 needle and seat will flow more fuel that the carb body can. Some people go up to a 1.5, but you are on your own with properly setting the pop-off. Personally... the factory specs work, so there is no reason to change the internal parts, unless you have a need. (like major mods)

1) No... it's not needed.

2) You are on your own... but with a 2.5, you would be down around an 18 pop-off.

3) On the 38... really nothing. They use the same parts. The "i" series is just newer.

 

[Tenacious D]

Thanks, Dr. H. That's all I need to hear on the 2.5

I've got a friend who is offering to give me two (2) 1.8's to replace my (leaking) 1.2's....could that work within spec, and if so, what would the spring need to be?

 

[Dr Honda]

Like I said... if you change the N/S... you are on your own to make it work. The bigger the N/S, the lower the pop off is going to be.

Seadoo never used a 1.8, so that's going to be tough. (and it's not a common size) If you were thinking about 1.5... then at least we could take the specs from another seadoo.

If I were to guess about the 1.8... it would be around 25. I can't tell you the spring because it never works out right. You have to just check the pop-off, and then adjust the springs.

 

[Tenacious D]

I'll stick with the 1.2 N/S.

If you couldn't make it work, there is zero chance that I could do so.

Thanks, again.

 

[Dr Honda]

I could make it work... but it's not worth the time and effort to tune it. And since there isn't a reason to just change the N/S size... we don't have "Known" specs for it.

We know that the OEM SeaDoo specs work. (not all brands are that way) I can rebuild carbs, off the ski... set everything to spec... and they will run just fine when they get bolted on.