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Magnetti Marelli EFI - Reverting to Stock Settings?

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OK I know I should not have done it - too late, I have ...

Adjusted the throttle stop screw on a Sherco 300 EFI. The idle was too high at 2400, engine prone to "flame-out" on a quick blip of the throttle, a swine to start cold and tempramental when hot...

VDST diagnostics show no DTCs, ran all diagnostic tests; which everything passed.

Perfomed software TPS reset using VDSTS software form TechnoResearch. Same problems.

Have tried adjusting the air-bleed screw, which seems to nothing about from kill the engine around the 1/2 turn out point, richen it up any more by tuning it in and she dies.

Valves checked, exhausts were spot on, one inlet was 0.10 mm the other 0.24. Reshimmed to 0.15 and 0.16.

The bike is no better.

I want to be 100% certain that the EFI throttle settings are correct. Can anyone confirm that the procedure below is valid for the simple Magneti-Marelli system? I gleaned this from interweb searches and this seems to be the most common:

Unscrew throttle stop to make sure butterfly is fully closed.

Physically set TPS so that when powered on we see 150mV output.

Screw throttle stop back in to get 3.1 deg (angle from Sherco engine manual) - I found 105mV per degree, so that would by 315mV, PLUS the 150mV = 465mV.

Set air bleed to 1 turn out as a start point ( again from Sherco manual). If adjusted go no leaner than 2 turns out.

Anyone got better information , or can confirm that this is sound?

From a sound basic start position I can use CO analyzer, idle trimmer in VDST and air bleed to achieve the Sherco figure of 5% - Out of curiosity, any one know why they state 5% CO in the manuals, but CoC states 0.05% ??

I know I should in theory take it to a Sherco dealer, but l;ast one I talked to looked totally blank regarding EFI; and made a real hash of the PDI.

Edited by magwych

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