Hi, i have a Gas Gas 300 pro 2009, & since day one when i bought it off Sam Haslam it has done nothing but pink most of the time, i had the carb set up exactly how it is reccomended (according to GG UK), 125 main jet, 45 pilot, 3 slide, JJH needle with clip in the middle, doesn't seem to like that though, it was a bit chokey on bottom end & at one point it sounded like it was nearly completly out of fuel but had half a tank left in, had a look at the plug & it was really black & oily which i presume is a very rich mixture which has created this.

I dropped the clip on the needle one down & seems a bit better now but pinking, not when you rev the bike, only when you say are going up a hill or get to the top of a hill & blip the throttle, occurs more in a lower gear.

The bike either eats spark plugs or is pinking all the time, can never seem to win with it!!

Any Help would be Really Appreciated,

Cheers,

Ben.

You have adjusted the mixture screw, right?

Yep it's just about been turned everywhere possible, it's currently on 1 turn out as it should be, but still pinking.

Are you using super unleaded? If not this definitely helps.

Are you using super unleaded? If not this definitely helps.

I tried it at one point, but still pinking as i can remember, will give it another go though see if it helps.

Cheers

I'm running the same set up as you Ben and don't have problems. I always use 98 octane fuel, mix at 66:1 and store it in a steel, not plastic, container. Have had pinking problems in the past, even with super unleaded fuel, particularly when snapping the throttle shut at the top of a climb, or running on light throttle between sections, and that was due to an air leak on the intake side. Suggest you have a look around the reed block to crankcase and manifold joints and make sure there are no leaks. Hope you get it sorted soon. Dave

I'm running the same set up as you Ben and don't have problems. I always use 98 octane fuel, mix at 66:1 and store it in a steel, not plastic, container. Have had pinking problems in the past, even with super unleaded fuel, particularly when snapping the throttle shut at the top of a climb, or running on light throttle between sections, and that was due to an air leak on the intake side. Suggest you have a look around the reed block to crankcase and manifold joints and make sure there are no leaks. Hope you get it sorted soon. Dave

Thank you very much mate, very appreciated. will have a very good look through it.

you could try octane boster.

Try 3 to 3 and a 1/4 turns out, standard on GasGas carbs as its a fuel screw not an air screw.............has always worked for me!

AvGas

just a bit of learning, what is pinking? also i use standard 95 petrol and i noticed you mentioned using 98, does it make much difference?

just a bit of learning, what is pinking? also i use standard 95 petrol and i noticed you mentioned using 98, does it make much difference?

Full definition of pinking there for you mate. my bike seems to like it anyway.

http://en.wikipedia.org/wiki/Engine_knocking

Edited September 23, 200916 yr by GasGasben

just a bit of learning, what is pinking? also i use standard 95 petrol and i noticed you mentioned using 98, does it make much difference?

I will NEVER put low octane fuel in mine. Absolutely definitely makes a difference. I've done it in the past when I've had to, filling up in the sticks and no super unleaded, then forgotten all about it, and been reminded when the bike starts pinking.

It's maybe 40 or 50 pence difference a week - same with plugs -

Never really had much of an issue with it on my bike, only occasionally after a long run on the road it starts to knock slightly. I let the revs die off and it seems to go back to normal! Never changed the settings on my carb from when i bought it, it's an 07 which i got at the end of 06. I run Shell V-Power with a 50:1 mix. Very rarely run anything else, if i can help it.

Hi Ben,

On my last 3 PRO 300's fitted with a Keihin carb, they always run lean with the std factory setting and pink as you found out. I use Shell V power at 50:1, nothing fancy just high octane in this part of the world. You need a larger main jet, 127 or 128. Clip on 2nd notch from bottom, std slide I thought was 35 - can't remember. JJH needle is ok for the younger splatt attack lads, GJH needle gives vastly better low end control for more, er mature riders! 45 I find too rich for pilot, use a 40. Use an Iridium plug, won't foul up.

The Keihin has no internal fuel filter, best to have an inline one fitted. Give the carb a thorough clean out just in case. Pilot (air) screw on the Keihin should be around 3/4 to one turn out, DellOrto pilot is 3.5 to 4 turns out.

Ta ta, PeterB.