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K & N air filter advice.
Posted: Wed Nov 20, 2013 9:06 pm
by wullie3xv9
Hi all.

I've just purchased the appropriate K&N air filter kit (SU-7592) for my GK76a's stock airbox assembley & would like to clarify what size main jets, needle clip position & pilot jets are required if I fit the
larger of the two air inlet rubbers supplied. I'm assuming that no jetting / setting changes are required if I fit the smaller, stock sized inlet rubber supplied. (My bike has a Scorpion end can fitted to stock downpipes).
I've removed the carbs to check them over / clean them out, (they've already been treated to a set of Viton O-rings by its previous owner), so would like to know jets & settings before I rebuild & re-fit them.

Thanks in advance.
P.S. I've trawled through all previous posts relating to K&N filters but couldn't find a definitive answer.

Re: K & N air filter advice.
Posted: Tue Nov 26, 2013 4:28 pm
by rgvsp
I'd stick with the stock settings and then adjust if necessary. I have the larger air filter and kit exhaust and went with a larger main, adjusted clip richer and ended right back at the stock carb settings.
Re: K & N air filter advice.
Posted: Fri Nov 29, 2013 6:41 pm
by morris147
Get it set up on a dyno if you want it spot on....
Re: K & N air filter advice.
Posted: Sun Dec 15, 2013 6:34 pm
by wullie3xv9
Thanks for the replies, guys.

No definitive answer then?

I've removed the engine from the frame now so that I can give both of them a good clean up / check over & will check the valve clearences on the engine while it's out.
I'm now seriousley considering buying & fitting the less restrictive stainless steel down-pipes from Sandy Bike Spares via Ebay.
So, does anyone on here, with a non SP model GK76a, have a K&N filter with the LARGE inlet rubber fitted & a Scorpion end-can fitted to the above down-pipes?? If so, could they advise me please what size mainjets, needle clip position & pilot jet size to start with. Would 112.5 or 115 mains, needle clip moved from the middle slot to the 2nd from top slot & stock 47.5 pilot jets be a good place to start & then fine tune from there ??
Cheers.
Wullie.
Re: K & N air filter advice.
Posted: Sun Feb 16, 2014 9:53 pm
by stripes1976
ok 117.5 is a good place to start with the main jet on the dyno but always start rich and come down. I have always tried the 120 main as a base then usually drop to 117.5
For every 3 main jet sizes you increase you will need to go up 1 in pilot. If you dont you have a huge flat spot and bad running in the middle and low down.
Re: K & N air filter advice.
Posted: Tue Feb 25, 2014 4:35 pm
by wullie3xv9
Thanks for the info above, Mr Stripes. Can you confirm please that this is the jetting/settings to try with a set of free flowing stainless down pipes/headers, an old, round Skorpion end-can & K&N filter with large inlet rubber fitted. TIA.