I'm looking at my 97' Mazdaspeed Competition Parts Catalog and Noticed that Mazdaspeed use to sell/make race/upgraded Grose-Jets(Needle and Seats) for the 12A Nikki.
Page IN-3 (Intake and Exhaust Section)
Part # 0000-06-7311
Fits 72-85, 'Replaces stock carburetor needle and seat. Provides consistent fuel metering and fuel flow under all conditions, even with high "G" cornering loads.'

Does anyone have any of these? Or know if they still sell them?
Thanks,
-Crispin

 

there was a tread about this last week, they haven't been available thru mazda since something like 2004

 

also, unless you have modified ignition components, some mild porting, and perhaps a performance exhaust, these could easially flood the engine. more fuel on a stock engine is a bad idea any way you look at it..

 

Monster Port, Wasted Spark, and Open Exhaust. So I should be good to go.

That sucks that they don't make them anymore.. I didn't see the thread that someone posted.

 

The grose jets aren't necessarily made to flow more fuel. Their purpose is to replace the unreliable needle and seat setup found in most carburetors. The needle and seat setup is very prone to sticking as many of you know. When this happens the result is a flooded carb. The grose jet uses two ball bearings, so you never have the issue of them hanging up and flooding the carb. It is more of a reliability modification, than a performance increase. You wouldn't gain any additional performance from them. Just a more reliable setup.

They are also better in race applications where you will see rough driving conditions that could disturb the delicate needle/seat setup.

 

Actually Dave, grose jets are a replacement for the needle and seat assembly. They use ball bearings instead of the tapered needle, so it seals better and there is less chance of it sticking.


Edit:

damnit somebody beat me to it

 

Perfectly said. +1.
I think I may have found someone who has them, I posted this same thread in the 'Old School' section and, someone simply replied: 'I have them in stock.'

 

my fault, i read it wrong. i t was early in the morning and i hadn't gone to bed yet. thanks for adding the correction guys!

 

Grose Jets also fill up the float bowl *faster* and they don't spray fuel which causes foaming like a needle & seat does.