Good GasGas 2 stroke mechanic near Portland Or

[jostby]

Quote:
Originally Posted by lineman12345678
I re-jetted it with DDK needle middle position 178 main and 40 Pilot... I am only a half turn out on the fuel screw. The farther I go out on the screw it starts to blubber.

I run 48 pilot with 180 main (and LTR needle) on my 250

[lineman12345678]

Thanks. I was thinking about trying the 42 pilot also. With the 40 I can run it 1 turn out but 1/2 turn is much better. I think the 42 will work the best. Are you counting the needle clip position from the bottom up or top down?

Originally Posted by MattR

It's an air screw (not fuel screw), as you turn it out then you adding more air and leaning the mixture. Since you can only go 1/2 turn out, it indicates that your pilot jet is too small.

Leave the needle clip @ 3 position (middle). Then go after the pilot jet to get it correct first. You should try to be in the 1 to 2 turns out range. This allows you adjustment flexibility in the future for temp/humidity changes.

Approx. same air/fuel mixture, I would try the 42 pilot.
Current setting: 1/2 turn out air screw @ 40 pilot.
New setting: 1 turn out air screw @ 42 pilot.
Note: pilot jet influences the 0 to 1/4 throttle range.

AFTER the pilot jet is good...
Then I would investigate the needle clip position. The needle clip position influences a broad range from 1/8 to 1/2 throttle. If too rich, more clip up 1 notch (2nd position). If too lean, more clip down 1 notch (4th position).

[webmaster]

It's also important that you back out and reset the idle screw - if you have it cranked in too far you are starting to "pull over" from the needle/main too early. Where is your idle screw set now? If it is cranked in to the point of coil bind on the spring - then it needs to be backed out.

jeff

[lineman12345678]

Yes it is compressing the spring a bit. I will back it out when I switch it to the42 pilot. Thanks

Originally Posted by webmaster

It's also important that you back out and reset the idle screw - if you have it cranked in too far you are starting to "pull over" from the needle/main too early. Where is your idle screw set now? If it is cranked in to the point of coil bind on the spring - then it needs to be backed out.

jeff

[webmaster]

I this weather - I would go with a 45 pilot and then turn down the idle. I would go with the LTR needle - one clip position up from center.

What fuel & mixture ratio are you using, etc. Are you running a race fuel or pump gas? You would go leaner for a race gas with a lighter specific gravity.

jeff

[webmaster]

By the way, if you want to make the carb easier to dial in - consider having the Ron at RB-Designs do his carb mod on your keihin. And to make it run cleaner (greater efficiency and throttle response) - having the squish dialed in by Ron too. He is located in Portland (actually Bonney Slope) - so is relatively local to you.

jeff