IcutMetl
10-03-2009, 04:21 PM
I was doing some tuning on my carb today, and made some pretty good progress. I currently have a bored 38a/s on a 67.5mm midrange ported 195+psi top end, open airbox, FMF pipe, airscrew 1.5 turns out, RAD valve, etc. You can def. tell that the meat of the power is in the midrange; it doesn't pull like a tractor off the bottom, and it's not ALL top end either. Seems to start fine, and will idle pretty damn smooth too. Never had a problem fouling plugs.
Started out with 175 main, 48 pilot, DDJ needle on middle clip. Ran good but there was something missing. Had a slight stumble off the bottom, and seemed to stall early. Choke would cause high idle instead of stall. Put a 50 pilot, then a 52- didn't see a HUGE difference either way. I don't have any leaner than a 48. Choke would kill engine, but it took a few seconds. Messed with airscrew- 1.5 to 1.75 turns seems to be the smoothest but hard to tell.
Played with my main a bit; tried putting in a 178- ran good with no sputter or bog, but felt flat on top- better with a 175; may try a 172 just to see what the plug looks like.
Played with my needle; started in middle, then tried 1 clip down (4th). Definite change; not better- had a sputter. Went to 2nd clip- much more responsive; better off idle response. Then tried 1st clip- best yet- I would like more off bottom response, but it's not a bottom end motor either. Throttle response is cleaner all the way thru and it likes to wheelie shifting thru the 1st few gears.
Being I'm at the top clip on my needle kinda makes me think I need something a bit leaner to play with? I have a CEG and a CGJ to play with; should I be looking for anything specific?
What do you recommend for my pilot? Hard to tell if richer did anything for me; didn't seem to affect it too much. Should I try a 45, or keep going richer.
I started out on a used plug, which was a milk-chocolate brown after a full-throttle shutdown. I typically gap around .018", and it definitely seemed to run cleaner on a fresh plug, but didn't have enough time to really burn it in.
I know I'm close...messing with the needle really helped it a ton. Just a little fine tuning and it should be breathing fire again. This massaged airstriker sure seems to suck the fuel down faster than my 38PJ did though!!
So what do ya think?? I appreciate the help!!
Started out with 175 main, 48 pilot, DDJ needle on middle clip. Ran good but there was something missing. Had a slight stumble off the bottom, and seemed to stall early. Choke would cause high idle instead of stall. Put a 50 pilot, then a 52- didn't see a HUGE difference either way. I don't have any leaner than a 48. Choke would kill engine, but it took a few seconds. Messed with airscrew- 1.5 to 1.75 turns seems to be the smoothest but hard to tell.
Played with my main a bit; tried putting in a 178- ran good with no sputter or bog, but felt flat on top- better with a 175; may try a 172 just to see what the plug looks like.
Played with my needle; started in middle, then tried 1 clip down (4th). Definite change; not better- had a sputter. Went to 2nd clip- much more responsive; better off idle response. Then tried 1st clip- best yet- I would like more off bottom response, but it's not a bottom end motor either. Throttle response is cleaner all the way thru and it likes to wheelie shifting thru the 1st few gears.
Being I'm at the top clip on my needle kinda makes me think I need something a bit leaner to play with? I have a CEG and a CGJ to play with; should I be looking for anything specific?
What do you recommend for my pilot? Hard to tell if richer did anything for me; didn't seem to affect it too much. Should I try a 45, or keep going richer.
I started out on a used plug, which was a milk-chocolate brown after a full-throttle shutdown. I typically gap around .018", and it definitely seemed to run cleaner on a fresh plug, but didn't have enough time to really burn it in.
I know I'm close...messing with the needle really helped it a ton. Just a little fine tuning and it should be breathing fire again. This massaged airstriker sure seems to suck the fuel down faster than my 38PJ did though!!
So what do ya think?? I appreciate the help!!