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WEnt cruising at 55-65 mph for 70 miles today, did a plug chop and the plugs were somewhat sooty. Running NARKED, 140 mains, thruxton needles, no shims. Seems a 140 is already smaller than most NARKS use, so I need advice here. THe bike came with dynojet needles. Should I put them back in and put the clip up a notch, or buy stock needles? I estimated I got about 50mpg on the run.
 

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If it was me I'd go back to stock needles which in the manual for a 790 is nagb increase my main jet to 145 or 150 and start at needle pos 2.
 

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The dynojet kit is designed to run with the softer slide springs as well, and its nice you get so much adjustment on the needles, 5 positions.
I would use the dynojet stuff and experiment with the needle position.
The main jet would only come into play at full throttle, so unless you were running that way, the needle is the thing to play with...

50 mpg is good!
Was the bike full hot?

Brett
 

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stu,
The thrux needles will be a little rich, it will still run great way rich it will bog down.
The 140s may be a lttle lean mine has 150s and is a little rich 145s would be spot on for mine, but the 150s were close enough as were the thrux needles.
I would put all your needles and jets in a bag and take it and your bike to a dyno.
Its not the only way but it is the best way as it removes all trial and error.

Darcy
 

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Wow! 50 MPG!!!! That's really good. I get around 38-40 but I also run on average 80mph. Mabye I'll try to slow it down to see if it makes that much of an improvement. Hard to do though, taffic runs on average 75-80.
 
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