SJ nozzle boring 101

[ags0702]

What is the stock nozzle diameter?
What is the recommeneded bore diameter?

I was messing around tonight with a spare nozzle and started doing some filing on the inside and I liked how it was coming...will post some pics tomorrow.

 

[#ZERO]

The stock reduction nozzle is about 83.2mm in diameter and if you make it around 85.6mm you can take it down to the stock bilge siphon fitting before it starts getting real thin.

 

[Rickster]

My trim nozzle is at 85mm, and my other nozzle is at 86mm.

I have heard going to 87mm but I was not that brave....

 

[Ericfox]

I was told 85mm is about all you want to go... I have 85mm bored reduction nozzle and a wetwolf freestyle cone on one of my blasters. It works nice. For the $ it is a good modification...

I have not bored my superjet's nozzle, but I have dremeled away the old bilge outlet and filled the hole with some JB Weld. Saving the boring for another season....

 

[Mouthfulloflake]

Ive got a pro-tec nozzle ( no straightening fins) that is bored to 87mm.

that coupled with a WW cone, and a 12/15 concord gives massive off-idle hit, BUT it cavitates once the engine gets into its power band more.

I will try it this year with a steeper impeller and without the ww cone.

it has noticeably more bottom end than my 85mm stock nozzle.

My trim nozzle is at 85mm, and my other nozzle is at 86mm.

I have heard going to 87mm but I was not that brave....

 

[crammit442]

The stock reduction nozzle is about 83.2mm in diameter and if you make it around 85.6mm you can take it down to the stock bilge siphon fitting before it starts getting real thin.

The stock nozzle is 81ish mm. You can find metal reduction nozzles from other yamaha boats that are 83ish, but not on superjets.

 

[ags0702]

Here is the progress I've made with a file, pics are a little hard to see.

I measured the exit diameter at 3-7/16" or 87.3 mm.

 

[Mouthfulloflake]

make it easy on yourself and get a sanding drum kit from a cheap tool store, and use your drill!

for reference, mine was a more complete kit for cheaper from harbour freight, zillions of uses.

http://toolsandmore.us/index.asp?PageAction=VIEWPROD&ProdID=1307

 

[Rickster]

Or take it to a machine shop and $30-40 later you have a nice uniform bore....

:439: