Carb Adjustment

[cammyshade98]

Hi, last weekend I had my carb cleaned out by a mechanic and he set the idle screw / fuel air mix seemed okay but no whenever i take it past 6K Rpms's it starts to splutter and backfire. It goes fine if I take it slowly it just splutters when accelerating hard / going uphill. Which way do I need to turn the fuel mix screw and how much?

[cammyshade98]

Just to note the bike was sitting for around 2 months unused but was running perfect before the carb was cleaned and unset

[Rogerborg]

The idle mixture screw isn't going to have much effect at large throttle openings, and you shouldn't try to use it to tune for that as you'll wreck your idling.

Unless the main jet(s) has/have been changed, I'd suspect either the float height has been meddled with, or the needle has been moved.

What bike/carb is it, and do you know exactly what he did to it? And if it was running right, why did you get it cleaned?
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GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[cammyshade98]

I'll pop down and ask him. I think it may have something to do with the rain as it only happens when its been raining and I had it cleaned cause It was sitting for a 2monts doing nothing. I left it to idle for 30 mins outside work and it works fine now up to 10K revs? stange its a CPI SUV 125 (china shit)