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Discussion Starter #1
my F3 675 has had a low down fueling problem since new,holding the throttle steady anywhere between 1000 - 4000rpm it surges , hunts and is worse when hot ,bad when riding slow in traffic, it has the latest map i think #63 , we can see it is running to rich when hooked up to a gas analzer, just had the upgraded FBW throttle grip and gear position sensor fitted but still the same , can anyone advise a cure ? thanks
 

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I'm on the same map - I occasionally get what you describe, but never on shorter rides. Needs to be out and running for at least an hour, maybe two.

Just had the dealer check the throttle body sync, which they say is in spec. They re-set the self learning parameters, which did nothing. Seems hard for them to replicate - as obviously they have not got time to take the bike out on two hour test rides.

Still not gotten to the bottom of it and I've had the bike for 2 years now.
 

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I suggest to check for an air leak around the inlet manifolds, yours wouldn't be the first to have one. While you're there get the air bypass screws checked, they should all be at least half a turn out from closed. Many F3s have come out of the factory with one or more of these closed, usually #1 cylinder.
 

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Mine was the same from new. I cured it by balancing the throttle bodies. They were well out despite the dealer saying they had checked them and they were OK. Number 1 and number 2 were 14 and number 3 was 18. It took nearly 2 full turns of the adjuster to bring it down to 14. Bike was transformed with balanced throttle bodies. Where abouts are you ?
 

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Discussion Starter #5
thanks squidger, yes you may well be right about balancing the throttles bodies i have heard about this before, the techs at my dealer are useless so i will do it myself i have access to the gauges i am from New Zealand
 

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I'm not sure what the scale reads in. Doesn't really matter though as long all 3 read the same. If you have 3 different readings just use the middle as good and adjust one up and one down. If 2 readings are the same adjust the 3rd to match etc. Best way to supply fuel is from the bike fuel tank as the fuel pump is bolted to the tank. I just disconnected my fuel tank to get at the rest then reconnected the tank and sat it about 6 inches behind where it normally sits to run the engine. I noticed an immediate difference. The bike revved cleanly. Throttle response was crisp and it even ticked over nicer. Absolutely no hunting. Before it was almost impossible to ride around town at 30mph in sport mode. If you really need to know the units of measurement I can check my vacuum gauges. Mine are the metal rod type.
 
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