pilot 42 in 82 650 did WONDERS (stock 40)

granted, I probably didn't get the smallest passages Perfectly clean inside the carbs and who knows who does. RickOmatic once described a volume test for each pilot and main passage using vacume, graduated cylinder, and stop watch and I didn't do the test. But I ordered the next size up for my pilot circuits and it tuned (by ear and with the Colortune) so much better and runs like a dream. The carbs were cleaned at an old school local shop in an acid bath, then I heard on this forum that it may take multiple attempts to Really get them clean and there's a chance it would never happen lol ! anyway, i'm a happy rider today, the Canadian models have the 42's in them from the factory anyway - if I remember correctly cause of the altitude differences.

 

if it came from the factory jetted lean with a 40 back in the 80's, fuel changes today now using 10% ethanol require bigger jetting or at least significant adjustment of the pilot screw. doesnt it feel great when it runs much better?

 

Reallyyy. Excellent tid-bit, thank you. Just getting ready to rip into my 650 Seca, knowing the Canadian bikes had 42s and I'm only 18 miles from Canada...

 

With ya'lls help, I'm so awesome, and Proud

 

Pretty sure my 81 has 120 and 40 in the carbs... cant see anyone else ever have changed them, so I have to assume that was from factory.

 

my 82 750 was 120 40, and before i ripped the airbox out and chopped her up i cleaned the carbs and couldnt get it idling right with the screws out 4 turns IN STOCK FORM (that was for rick) until i upped the pilot.

as for my fuel post, 10% ethanol means that 10% of your fuel would normally need to be jetted 33% bigger as a very vague starting point. thats what we use when we change a race fuel engine to alcohol, to get the jetting in the ballpark before fine tuning. using that math a 120 main would need to be 124, and a 40 would need to be a 41.5

with my pods and open exhaust i am running a 125 and 42, i do not remember where the screws are now somewhere between 2-2.5 turns, and i do not run my machines lean because my race machines ON THE DYNO, WITH THE SNIFFER, have told me time and again that lean is less drive pressure with more damaging heat, and stoich to slightly rich nets the most power under the curve with nicer running temps.

 

good to know Zookie. I came back here post that once again my bike has no pulling power, sputtery, gotta tease, rev, half engage clutch to get going Again. 2 years with these carbs. Don't think I have a choice to do either 3 more acide baths and then after, new carb bodies, which probably won't happen. I have 9 bikes at my house right now, worked on about 17, and my XJ is the only one I want perfect and all the others get the glory. All my carbs have mixture screws set very different # of turns out - according to the Colotune plug - I tried to ignore that cause it always runs perfect directly after a tune (colortune and sync) but then falls off again.

Lastly, I notices last time I did a sync with the Carbtune Pro, the idle was highest when it was out of sync and got lower when the gauges were lined up. Should I focus on that issue instead of more acid baths? or maybe it's the same?

I've had this bike running good good better better best and even best, and it always seems to fall off. 2 YEARS and about 600 miles (nothing) doing this Sh*%. I feel like an idiot cause everything between the 2 tires has been rebuilt (except internal engine), cleaned, painted, all engine externals and valves adjustments. God Dammit, I friggin dropped it in my driveway, and a different day the tank fell off a box while i wasn't home, gas spilled down the front of the tank - bye bye paint n all these other bikes are like, hey, how ya doin, not so good? oh, too bad, see ya next time

 

have you checked your valve clearances? tight valves will kill you if you are trying to tune something in.

if you have no pulling power you dont need to pay attention to the sync or pilot circuit. what do the plugs look like after a wide open run through the gears then kill it without letting it idle down. do a plug chop for wide open. also, its hard to do on a cv carb but a part throttle plug chop could help as well.

 

Zookie, you wanna look at my bike? Please, By My Guest. I'll bring it there, what part of CT are you in? I did the valve shims, that was another 90 bux. you don't think it has something to do with all my mixture screws not being close the amount of turns of the others? today, i think I'm going to borrow a different sync tool - cause when my idle is highest the gauges are off, to get all the gauges the same, the idle goes way down...