Best Carburetor and Sprocket set up

[phantom]

so I'm on my last effort of purchasing an Athena 392cc big bore kit and a stock hot rods crankshaft for my RZ250RR hybrid conversion project but I do not know what carburetor size and best sprocket combo for it that I should get to pull the best possible performance out of my bike since it will be more on the road than a track.

[midlifecrisisrd]

To be honest the standard carbs will deal with the 392 no problem with a bit of jetting but Keihin PWK 28's are the weapon of choice

Gearing wise depends on what kind of roads you use

I'm on 17/41 at the moment (think 250 was 16/41) but if you are going to use motorways I'd go 17/39 as it tends to rev it's tits off

Steve

[phantom]

Aug 27, 2021 8:39:00 GMT 1 midlifecrisisrd said:

To be honest the standard carbs will deal with the 392 no problem with a bit of jetting but Keihin PWK 28's are the weapon of choice

Gearing wise depends on what kind of roads you use

I'm on 17/41 at the moment (think 250 was 16/41) but if you are going to use motorways I'd go 17/39 as it tends to rev it's tits off

Steve

Hi steve,

Thanks for answering back, currently looking at the Keihin PWK 28 as you have mentioned, any idea of what would be the best jetting settings for the PWK28?

The stock sprocket set on my rz250rr is indeed 16/41 might look and test both suggestions or sprocket you have mentioned and see which one will be a click to me.

[midlifecrisisrd]

Ask headcoats on hear about ballpark jetting as he messed around with a 392

Steve

[Tobyjugs]

Hello i'm using the same ratio as Steve on my 398, but i am also using 2.65 ratio primary gears. The jetting wont be extreme. What will be imprtant is the use of standard air box or pod filters as this will determine the needle type.

[phantom]

Aug 27, 2021 15:31:19 GMT 1 midlifecrisisrd said:

Ask headcoats on hear about ballpark jetting as he messed around with a 392

Steve

I'm still quite new on the forum may I get a direct link so I can PM headcoats?


cheers!!

[Gitram]

go up to the top of the page , click on "members" then search at the rhs, type in headcoats and then click on his name..

marti

[headcoats]

I never had a final setup I'm afraid but I did keep going up on the mains and was at 160 but my Lomas pipes killed the bottom end
You need pipes made for the Athena, zeeltronic and dyno time !

[phantom]

Aug 28, 2021 9:23:27 GMT 1 Gitram said:

go up to the top of the page , click on "members" then search at the rhs, type in headcoats and then click on his name..

marti

cheers thanks!

[phantom]

Aug 28, 2021 12:07:16 GMT 1 headcoats said:

I never had a final setup I'm afraid but I did keep going up on the mains and was at 160 but my Lomas pipes killed the bottom end
You need pipes made for the Athena, zeeltronic and dyno time !

do I need to change the reed cage or the stock one is good?

I'll have contacted someone a well known pipe maker on my origin country for a full titanium exhaust and some dyno tuning too and I'll be popping a new zeeltronic too