YOU WANT TECH, I'LL GIVE YA A TECH TOPIC!
'kay, here goes:
1) Does anybody know what size & just what kind of bung I should buy to utilize those fittings on the down-tubes of our headers? It would afford us a more reliable reading of what our air/fuel ratio would be via each carburetor (our cross over pipe prevents such a reading).
2) If I wanted to drill out my 2.5mm air hole to 3mm, should I AVOID from doing it by hand..... should it be done with a drill press instead?
3) I see that the steps suggested for variations of main jet sizes seem to be in 5 point increments.
(*e.g.. 105 for free breathing pipes, 110 with an added free flowing air filter, 115 with addition of a bellmouth, 120 when eliminating an air box baffle, 130 if the air box is replaced with pods) per Thruxton needles. My question is this:
I can go to a motorcycle shop and buy main jet sizes in all sorts of sizes (and I have lotsa jets now) In the world of Bonneville's Keihin's CVK, just what is "one full step" in jet sizes???
Now this is really weird.....
4) I'm currently running a 790 with the divider plate still in my air box (I ran w/o the plate in my BonnieBlack). The only other differences are a slight variation in my modified D&D cans, and my NH bellmouth having been powder coated a smoooooth and sexy gloss Black. Now, I just got the thing "sniffed" & Dyno'ed with some 118's in the Thruxton needle equipped carbs, and it was running waaaaay lean. It was running upwards to 17 (Air/Fuel), between 3500rpm & 4200rpm. 14 to 15.5 (Air/Fuel) from 5000rpm to 7800.
This baffles me because I may have actually been running smaller main jets in my BonnieBlack (sans it's divider plate)! How is it that my current bike seems to want a bigger main jet?!?!?!
5) So...... I had two size jets readily available with which to replace the 118's, some 122.5's or 130's. THUS my question, "what is a full step" in main jet size? I thought that because I was running soooo lean, that simply going from 118 to 122 wasn't enough to address my lean mixture, so I stuck my 130's in there (it's been raining, haven't taken her for a spin yet). In the meantime, I also concluded that my cold start problem was as a result of having the 40 Pilots still in there, so I bought some 42's yesterday. I'm NOT gonna take those carb's apart again (my hands are still chapped from all that gas from last night's switch out), until I have the bike sniffed with these 130's (that's assuming the danm thing'll start this afternoon).
So, to sum up.......
1) What size bung and what do I need to make myself a pair of sniffer sticks?
2) Can I just drill by hand, or find somebody with a drill press?
3) What's a quarter step, half step, or full step in jet sizes?
4) How many 'steps' would YOU increase from my lean running 118's, given my lean reading a couple days ago?
Speak among yourselves, share your thoughts, help me with some wisdom here guru's of things carburated.....
[ This message was edited by: FattRat on 2006-12-09 11:37 ]
'kay, here goes:
1) Does anybody know what size & just what kind of bung I should buy to utilize those fittings on the down-tubes of our headers? It would afford us a more reliable reading of what our air/fuel ratio would be via each carburetor (our cross over pipe prevents such a reading).
2) If I wanted to drill out my 2.5mm air hole to 3mm, should I AVOID from doing it by hand..... should it be done with a drill press instead?
3) I see that the steps suggested for variations of main jet sizes seem to be in 5 point increments.
(*e.g.. 105 for free breathing pipes, 110 with an added free flowing air filter, 115 with addition of a bellmouth, 120 when eliminating an air box baffle, 130 if the air box is replaced with pods) per Thruxton needles. My question is this:
I can go to a motorcycle shop and buy main jet sizes in all sorts of sizes (and I have lotsa jets now) In the world of Bonneville's Keihin's CVK, just what is "one full step" in jet sizes???
Now this is really weird.....
4) I'm currently running a 790 with the divider plate still in my air box (I ran w/o the plate in my BonnieBlack). The only other differences are a slight variation in my modified D&D cans, and my NH bellmouth having been powder coated a smoooooth and sexy gloss Black. Now, I just got the thing "sniffed" & Dyno'ed with some 118's in the Thruxton needle equipped carbs, and it was running waaaaay lean. It was running upwards to 17 (Air/Fuel), between 3500rpm & 4200rpm. 14 to 15.5 (Air/Fuel) from 5000rpm to 7800.
This baffles me because I may have actually been running smaller main jets in my BonnieBlack (sans it's divider plate)! How is it that my current bike seems to want a bigger main jet?!?!?!
5) So...... I had two size jets readily available with which to replace the 118's, some 122.5's or 130's. THUS my question, "what is a full step" in main jet size? I thought that because I was running soooo lean, that simply going from 118 to 122 wasn't enough to address my lean mixture, so I stuck my 130's in there (it's been raining, haven't taken her for a spin yet). In the meantime, I also concluded that my cold start problem was as a result of having the 40 Pilots still in there, so I bought some 42's yesterday. I'm NOT gonna take those carb's apart again (my hands are still chapped from all that gas from last night's switch out), until I have the bike sniffed with these 130's (that's assuming the danm thing'll start this afternoon).
So, to sum up.......
1) What size bung and what do I need to make myself a pair of sniffer sticks?
2) Can I just drill by hand, or find somebody with a drill press?
3) What's a quarter step, half step, or full step in jet sizes?
4) How many 'steps' would YOU increase from my lean running 118's, given my lean reading a couple days ago?
Speak among yourselves, share your thoughts, help me with some wisdom here guru's of things carburated.....
[ This message was edited by: FattRat on 2006-12-09 11:37 ]