“A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.”-Douglas Adams
As above main jets make no difference to starting. I''m skeptical that jetting is your starting problem though, changing from an airbox to pods has negligible change to the airflow at engine starting speeds/idle speeds. I'd be thinking your carbs either need a good clean or that your valve shims need adjusting. How many turns out out are you pilots? These should be around 2.5 - 3 turns out.
fzr660/400: fzr400 3en1 frame, 3en2 swinger, custom single seat subframe, fzr660 motor conversion, APE adjustable cam gears, full D&D 4-2-1 exhaust, falicon clutch basket, ignitech ignition, R6 front end with tz250 wheel, ohlins shock, storz steering damper, tzr250 rear wheel.
weighs 166kg wet (25kg lighter than my stock fzr600).
Yeah, like Dru said...along the lines of valve clearance adjustment.
Tight intake valves (very very common) drop intake vacuum. This will make the vacuum signal at the carbs iffy at best. Especially on cold starts.
A very 'wet' starting mixture will compensate for the poor vacuum a little. Often, when the valves are tight it takes much cranking with full enrichment (enrichment is NOT 'choke', but people tend to think of the start circuit in the carbs as 'choke'). Once started, the engine will then struggle to 'clean up' missing a bit and fluctuating until the cylinders heat up and the enriched idle climbs.
Properly set up, and with sound mechanicals (good compression, good valve seal -i.e. adequate lash clearance), a cold start should be performed like this:
Full enrichment, key on, kill switch on, hit start button.....NO throttle (that's NONE, ZERO, DON'T EVEN TOUCH THE THROTTLE GRIP)
Engine should fire in the first few seconds, and the revs should rise within 10-15 seconds. Use the enrichment lever(back it off slowly) to keep the idle speed about 2k rpm until the engine is making heat.
The engine won't start until the valves are dripping with fuel (thus helping seal them-thus improving vacuum signal at the carbs).
You end up with an engine that wants a lot of enrichment to start, but is also very very prone to wet fouling.
It is common that people screw around with carb settings and chase problems back and forth, then clearance the valves and they need to go back to square one (usually leaning it out again-quite a bit).
“A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.”-Douglas Adams
