TLDR: can't find VHST needles or pilots in north America and shipping from Europe cost $80+ USD for a single jet or needle. Cold weather is a requirement in my location, so unfortunately the VHST needs incremental changes via jets and needles.

Also no reply, no support from Polini tech. I hooked up a WideBand O2 sensor and confirmed, it needs pilots and needles to fully optimize the tune in cold and hot temps (like 30F &100F). My Keihin runs great, requiring at minimum 2 main jets, 3 pilots, 3 needles to cover about -2000 to +8000 ft DA assuming you want it to run good in any of those conditions. If you want to be anal like me, with increased resolution (like ol' dirt bike manuals with jetting charts) you can have it run great in any of those conditions, however you will need a few more jets and a couple more needles. An interesting observation is that the main jet doesn't actually change much, the needle is the most important for PPG and the pilot second to ensure a proper idle.

Old notes before the Wideband 02:
Hot EGT headed past 700C at cruise rpms, that's with a richer drilled pilot & the stock needle raised, and the main jet isn't even in the picture. More details keep reading.

No Dellorto VHST carb parts support in USA let alone proprietary carb needles from Polini THOR. In Cold weather 0°C 32°F and up into the 40Fs and (-) Density-Altitude, the EGT is too high around cruise rpm with the stock needle raised, all I want for Christmas is a set of Dellorto Needles for a fair price including shipping.

In cold weather it idles very lean with the mixture screw turned out all the way like it's going to start leaking turned out, and still lean, verified by a colortune never got yellow until pulling choke. Idle hangs after hot run up in cold weather, for a while 2600-3200 rpm even hunting, but you can blip throttle 4 times, hop twice, blip it good 1 more time, lean left and stay, and it'll idle down.

Pilot jet is drilled to 0.50 mm, stock is S38, this richer idle will actually allow the engine to idle down now consistently. Richer confirmed by colortune again, it will for sure turn yellow past 2 turns. Also Main jet is good, 75-100% throttle EGT falls off headed for below 600C (based on rate of change), my landing gears were giving out too much thrust boys.

I got a genuine Keihin PWK 28 to trial for cold weather operations, along with full quality tuning sets for Main jets, Pilot jets, & Needles costing less than 33% the price of a Lectron / SC2 and more advanced PWK tuning parts are in stock in the USA or cheap fast shipping from the East. I also got a Mikuni square metal fuel pump.

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