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flat spot under hard acceleration
Posted: Thu May 16, 2024 6:38 am
by Tom 2
Hi everyone
Bike hesitates on hard acceleration at around 3000 and 6000 rpms. runs fine other than that.
bike is a 2011 38000 miles.
Just bought and fitted 4 new coils thinking it was that.
Today going to buy some injector cleaner to run through the tank.
valve's in speck, exhaust flap working, Throttle Synchronization done by Bmw.
Any idea's please i'am stumped
Re: flat spot under hard acceleration
Posted: Thu May 16, 2024 11:47 pm
by Randyjaco
I had a similar problem with mine. I tried all sorts of fixes over several months to no avail. The final solution was replacing the fuel pump. The problem totally disappeared.
Re: flat spot under hard acceleration
Posted: Fri May 17, 2024 5:51 am
by jaapvanthoff
That can bee, + do not forget to change the fuel filter.
Re: flat spot under hard acceleration
Posted: Fri May 17, 2024 7:53 am
by Tom 2
Thanks guys.
Am I right in thinking this doesn’t have a fuel filter. Some kind of lifetime gauze in the tank.
If it has where is it how do you change it.
Will look into fuel pump price
Re: flat spot under hard acceleration
Posted: Fri May 17, 2024 2:45 pm
by Doctor T
Have you balanced the throttle bodies?
Re: flat spot under hard acceleration
Posted: Fri May 17, 2024 7:11 pm
by Randyjaco
I agree about the fuel filter. The stock one was crap. I got an aftermarket pump that came with a real canister fuel filter.
Re: flat spot under hard acceleration
Posted: Fri May 17, 2024 11:24 pm
by Tom 2
Fuel pump and strainer £51.76. Think I’ll order that for peace of mind.
Balance throttle bodies. Is that the same as throttle synchronisation?
Re: flat spot under hard acceleration
Posted: Sat May 18, 2024 11:38 pm
by Randyjaco
Let us know how it turns out
Re: flat spot under hard acceleration
Posted: Sun May 19, 2024 7:05 am
by Tom 2
Will do.
Out all weekend on her. Start taking her apart Monday
Re: flat spot under hard acceleration
Posted: Sun May 19, 2024 7:12 am
by Tom 2
I don’t have the correct tool to unscrew the top of tank. Do I need one or is there some trick or will it unscrew by hand. This is a new place on the bike I’ve not been
Re: flat spot under hard acceleration
Posted: Thu May 23, 2024 10:39 pm
by Tom 2
Update to my running issue
Fitted new fuel pump and filter. Took injectors out and cleaned and put back together.
Absolutely brilliant. The bike runs with no hesitation at any Rev range. Was definitely fuel problem. Although it ran a little better with the new coils. But that wasn’t the fix. Thanks to all