Aftermarket Header pipes cbr600f4 (1999)
Aftermarket Header pipes cbr600f4 (1999)
Hello all!
been trying to get rid of a flatspot that starts at 7k and clears at 8k for a little while now, I've shimmed the needle and this made no change to the flat spot, next I want to have a look at which jets are currently installed, bike runs,idles and everything else just perfect, this flat spot is to only issue.
Also ona warm engine if i rev it out in neutral the revs only go to 11k and bounce with a "bow,wow,wow,wow" kinda thing however in get and moving the bike will get to redline and after 8k it pulls really well, again it seems the be between 7&8000rpm.
So far I've shimmmed the needle, ordered a new fuel filter, checked all lines and vacuum hoses for leaks/kinks and none to be found, the only thing that isn't standard on the bike is the down pipes, they seem to be a solid unit and not multiple parts however there are no balance pipes between cyl 1,cyl2 and cyl3,cyl4, I suspect they may be early delkavic headers, is there any chance this could be the problem and if so has anyone with the same pipes found a way to tune this flat spot out presuming they are the cause? Sorry for the long post, any help would be appreciated!
Kind regards, Adie
been trying to get rid of a flatspot that starts at 7k and clears at 8k for a little while now, I've shimmed the needle and this made no change to the flat spot, next I want to have a look at which jets are currently installed, bike runs,idles and everything else just perfect, this flat spot is to only issue.
Also ona warm engine if i rev it out in neutral the revs only go to 11k and bounce with a "bow,wow,wow,wow" kinda thing however in get and moving the bike will get to redline and after 8k it pulls really well, again it seems the be between 7&8000rpm.
So far I've shimmmed the needle, ordered a new fuel filter, checked all lines and vacuum hoses for leaks/kinks and none to be found, the only thing that isn't standard on the bike is the down pipes, they seem to be a solid unit and not multiple parts however there are no balance pipes between cyl 1,cyl2 and cyl3,cyl4, I suspect they may be early delkavic headers, is there any chance this could be the problem and if so has anyone with the same pipes found a way to tune this flat spot out presuming they are the cause? Sorry for the long post, any help would be appreciated!
Kind regards, Adie
Welcome crew
Joined: Jan 2021
Posts: 2,575
Likes: 426
From: Preston, UK
Not sure about your potential carb issues, they ore other on here much more qualified to answer that question, shame you are having that issue.
As for the Headers, they were always a 'solid' unit with the connector pipes between 1&2 / 3&4 on the CBR and could Black Widow, Delkevic and I think M&P also used to make some. I spoke with Delkevic specifically when I noticed that they had removed the link pipes from their header and their statement was that it made no difference on the dyno tests that they performed!!! Not sure if Mr Honda would agree but that was their statement for what its worth.
As for the Headers, they were always a 'solid' unit with the connector pipes between 1&2 / 3&4 on the CBR and could Black Widow, Delkevic and I think M&P also used to make some. I spoke with Delkevic specifically when I noticed that they had removed the link pipes from their header and their statement was that it made no difference on the dyno tests that they performed!!! Not sure if Mr Honda would agree but that was their statement for what its worth.
Not sure about your potential carb issues, they ore other on here much more qualified to answer that question, shame you are having that issue.
As for the Headers, they were always a 'solid' unit with the connector pipes between 1&2 / 3&4 on the CBR and could Black Widow, Delkevic and I think M&P also used to make some. I spoke with Delkevic specifically when I noticed that they had removed the link pipes from their header and their statement was that it made no difference on the dyno tests that they performed!!! Not sure if Mr Honda would agree but that was their statement for what its worth.
As for the Headers, they were always a 'solid' unit with the connector pipes between 1&2 / 3&4 on the CBR and could Black Widow, Delkevic and I think M&P also used to make some. I spoke with Delkevic specifically when I noticed that they had removed the link pipes from their header and their statement was that it made no difference on the dyno tests that they performed!!! Not sure if Mr Honda would agree but that was their statement for what its worth.
Senior Member
Joined: May 2011
Posts: 1,988
Likes: 439
From: Mesa, AZ
Factory needles in carbs?
All factory jet sizes?
Factory mixtures had super-rich mid-range from triple-carburetion. Try one size smaller main-jet. This will end ho picking up some top-end hp as well.
All factory jet sizes?
Factory mixtures had super-rich mid-range from triple-carburetion. Try one size smaller main-jet. This will end ho picking up some top-end hp as well.
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