ssray Posted June 18, 2020 Report Share Posted June 18, 2020 (edited) 1999 cbr600fx/f4 currently it has stainless downpipes and a std silencer, which I like as its stealth and I leave for work at 0500 It has the usual flatspot between 6-7k Would a dyno setup work to fill in the flatspot? The exhaust does not have balance pipes, the oe ones do, would adding balance pipes if possible help? The dynojet kit is about £140+ dyno time Would just a dyno setup be cheaper? Ta Ray P.s not ridden since March so it may be to fast for me anyway Edited June 18, 2020 by ssray Quote Link to comment Share on other sites More sharing options...
ssray Posted June 19, 2020 Author Report Share Posted June 19, 2020 Emailed bsd : , thanks for the email. What we normally do the carb bikes is run them on the dyno first to see what the fuelling is doing. Then we can assess whether we need to fit carb repair kits and adjust the jets to fuel the bike correctly. The approx. cost would be around £250 with parts, regards Gill. 1 Quote Link to comment Share on other sites More sharing options...
marvin Posted June 23, 2020 Report Share Posted June 23, 2020 Just buy a secondhand set of OE headers. 1 Quote Link to comment Share on other sites More sharing options...
ssray Posted June 23, 2020 Author Report Share Posted June 23, 2020 1 hour ago, marvin said: Just buy a secondhand set of OE headers. But rust.... Quote Link to comment Share on other sites More sharing options...
firebeast Posted July 16, 2020 Report Share Posted July 16, 2020 I would stay away from dynoshite kits personally,, my very old one had arrow headers and jetted etc but it didn't get shot of it fully so wouldn't bother. Factory Pro if they ever did a kit however, could be worth contacting to see what Marc says about the biike,, his carb tuning guide is well worth reading,, on the cheap,, putting an extra shim, or maybe two, under the needles, get valve clearances done if needed, adjust the mixture screws to see if that helps or not after trying the shims first and do a decent carb balance. Get rid of the emissions junk , if still there, as its useless. Being stock, if it ran a touch rich, you could maybe go down one size on mainjets and slightly richen up the mixture screws to see if it helped or not.. Bet you haven't still got the original cam chain tensioner in it as well. 😄 1 Quote Link to comment Share on other sites More sharing options...
lorenzo Posted July 17, 2020 Report Share Posted July 17, 2020 (edited) While you may improve it with a dyno session (I say may, 99% certain that a decent dyno guy like BSD will), it'll never fuel the same on differently designed headers. The thing to bear in mind with the dyno session is that you'll probably not have adjustable needles in there, which you're going to need if you're looking at getting the mid range sorted out, so budget for those too. That said, £250 with parts, from a reputable place like BSD who'll do the job right, that's decent value for money. Edited July 17, 2020 by lorenzo 1 Quote Link to comment Share on other sites More sharing options...
ssray Posted July 17, 2020 Author Report Share Posted July 17, 2020 Currently thinking that it's not really worth it, blackwidow f4i headers have the balance pipes, now on ebay watch list, would mean using the f4i link pipe as well or wait till my insurance is up next year and get a fireblade like I should have, no flatspot then and as I prefer torque over revs Quote Link to comment Share on other sites More sharing options...
firebeast Posted July 17, 2020 Report Share Posted July 17, 2020 (edited) On 7/17/2020 at 8:46 AM, lorenzo said: While you may improve it with a dyno session (I say may, 99% certain that a decent dyno guy like BSD will), it'll never fuel the same on differently designed headers. The thing to bear in mind with the dyno session is that you'll probably not have adjustable needles in there, which you're going to need if you're looking at getting the mid range sorted out, so budget for those too. That said, £250 with parts, from a reputable place like BSD who'll do the job right, that's decent value for money. Problem is that looking back, dynojet needles/kits a lot of the time weren't well designed and tbh, if people spent a bit of time looking into basic carb tuning, using just the factory Pro tuning guide, it's easy enough to get them a lot better without dyno work, just a plain old ass dyno, spend a few quid on the right tools and have a go at learning more. The headers won't solve the flay spot imho, it never went fully on mine,stock or racing headers etc, just a trait of that model. Some of the dj kits made a few bikes worse.. The other issue is they use their own jet sizing so swapping jets meant buying theirs to not get things confused.. They are just greedy twats imho and didn't put enough effort into making their kits top notch.. The tuning advice isn't very good either. Shimming the needles, maybe take a coil of the springs, workout the best mains, then go down and work through the rest properly and i bet it would be half decent. Another fix is change the front and or rear sprockets, but it's never gonna have dollops of torque, the f3 had more,, but at least it will pull harder and quicker.. Just ring the crap out of more and enjoy the nimble chassis. Mine had ohlins in the rear mind which was nice at the time.. Edited July 19, 2020 by firebeast 2 Quote Link to comment Share on other sites More sharing options...
CRM Posted July 18, 2020 Report Share Posted July 18, 2020 the delkevic pipes for these were known for a big juicy flat spot., the stock pipes are perfect, and with the stock can will be silent and smooth. I would try and source a set of OE pipes if you can 2 Quote Link to comment Share on other sites More sharing options...
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