another jetting ?

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Eddie
To the on ramp
Posts: 280
Joined: Fri Oct 19, 2012 9:57 am
Country: U.S.
Suzuki 2-Strokes: 1974 gt750, 1963 superhawk

another jetting ?

Post by Eddie »

ok, well i had replaced the stock pilot (47.5) with a 50.00 and it actually smoked at idle, and not black smoke, so i thought it was ok. I rode around the neighborhood a few times never getting over 50mph and i checked the right plug and it was rich, so I moved the needles to the middle notch where the book says and i took it out on the highway, I was running about 70-80 and checked plugs again and they were lean, so rich at idle and lean at top end. I replaced the pilots because it was really lean down low but now its rich and it was the next size up, so now im thinking i will go back to stock pilots and put one size bigger main in and see what happens, what do you guys think? or maybe i should mess with the airscrews , or fuel screws whatever, the book says 1/4 turn and other books say 3/4 turn , I know to turn them till you get a smooth good idle, but the bike is still lean at top and I had the needles on the second to last notch, i know i have asked this before but I just dont want to go bigger on mains and then its way to rich, maybe just go back to stock jetting? if i keep the new pilots it will be rich at low speeds but when i take it up to speed it will burn the black off and plugs look lean so it could be ok as long as i hit about 70mph now and then , do your gt750's look really lean at low rpms?
Eddie
To the on ramp
Posts: 280
Joined: Fri Oct 19, 2012 9:57 am
Country: U.S.
Suzuki 2-Strokes: 1974 gt750, 1963 superhawk

Re: another jetting ?

Post by Eddie »

sorry for the long post ill make it short, I have a rich condition down low, and a lean condition up high, so i can leave the 1 size bigger pilot and move the needle on the last clip to make it richer up high, or put bigger mains in and go back to stock pilot , which is what i think im going to do..
GT750Battleship
Road race school
Posts: 841
Joined: Tue Feb 19, 2013 2:45 am
Country: Australia
Suzuki 2-Strokes: Suzuki GT750A 1976
Location: Sydney New South Wales

Re: another jetting ?

Post by GT750Battleship »

:( Hi,if anything if I putter around in traffic,or ride her slow,then take out a plug,it's more rich than lean,my needle clip on number 4,runs as sweet as a nut...never fouls plugs,starts right up on the choke,even after sitting for a month.. :lol:
Cheers,
GT750Battleship.
GT750Battleship.
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tz375
Moto GP
Posts: 6211
Joined: Mon Nov 03, 2008 10:47 am
Location: Illinois

Re: another jetting ?

Post by tz375 »

Go back to a 47.5 pilot and if the top end is lean, try a larger main jet.

Reading plugs at idle is more or less not going to work because the plug is too cool to burn off deposits.

And remember that the mixture screw is OUT for RICHER and IN for LEANER. The opposite of most carbs
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