UK sea level jetting????

[dibbs]

Hi Chaps
So I checked yesterday my settings, as I haven't looked since buying the bike last November! and they are:

Main jet 165, pilot 38, Air screw 1 1/2 turns out from closed, needle position 3 from top. (I know we will probably have different needles but mine is a N2ZW) is this set up fairly accurate for all two strokes at or around sea level, or will it be very bike specific?

Now these seem to be stock settings in the manual for my beta (apart from it says needle should be in position 2 in the book!) so does dropping the needle make the fuel/air mixture richer or leaner? and should we be changing jets for summer and winter riding? or is there a setting for all conditions?

What do you think?

[farmerpaul]

Hi dibbs,

Dropping the needle will make it leaner but only on the main jet. It depends on your type of riding whether, or not, that will make any difference.

I am pretty sure those are the same as my '16 300rr. The only change I have made is setting the float height.

[dibbs]

Thanks Paul. I'm a bit of a wobbler really so don't really scream about on the pipe much, or race! I only really use the bike for lanes and practice days I might try the needle on position 2 and see what that does! the bike seems to run ok with only a very very slight burble at start off! and I have no spooge at all, and getting about 60 miles a tank until reserve is needed. I guess I'm looking for the perfect holy grail set up but thinking does this really exist!

[farmerpaul]

If you not any spooge and it runs OK then I would suggest you have it set pretty good.

Your type of riding you are describing you are on the pilot jet and needle so as long as your pilot circuit is set right you should be able to allow for most temp changes in the UK with the airscrew.

[KB112]

Needle position does not affect your main jet. Needle position affects approximately 1/4 - 3/4 throttle. The needle is tapered, so dropping it to a lower clip will put a thicker part of the taper into the needle jet, limiting fuel, so you are leaner. Once you are past 3/4 throttle to needle is at the end of the taper, so at that point the main jet is limiting fuel and takes over control of fuel mixture.

[dibbs]

If you not any spooge and it runs OK then I would suggest you have it set pretty good.

Your type of riding you are describing you are on the pilot jet and needle so as long as your pilot circuit is set right you should be able to allow for most temp changes in the UK with the airscrew.

Ive been told this by another mate as well, so next outing I'm going to have a fiddle with this! probably only needs half a turn to sort it I reckon.

Thanks for your advice mate and to everybody else.

[dibbs]

Been out for a spin and gave the air screw another half turn out (now at 2 turns out from closed) and the bike does seem a bit crisper, so hopefully this is as near as I'm going to get it to spot on! I did notice that the air screw seems to be maxed out at 2 turns though there didn't seem to be any more adjustment left! anyone else found this?

[dibbs]

I did notice that the air screw seems to be maxed out at 2 turns out though, there didn't seem to be any more adjustment left! anyone else found this?

[farmerpaul]

Dibbs,

Normally the air screw will turn all the way out to the extent that it will completely come out of the carb body. Are you sure you have the right component?

[dibbs]

Yes! I will try again. Also i rang a dealer and spoke to the mechanic there and he sugested i go with 168 main and 40 pilot air screw 1 turn. As my current set up was too lean!