Speednumpty2 Posted July 4, 2012 Report Share Posted July 4, 2012 Currently streetfightering my super Blackbird (carb model). Bike ran fine prior to removal of fairing, however taking it for a ride for the first time this evening since removal of all the plastics. It feels fine in 1st gear but doesnt like throttle in any others? Seems to be misfiring or running waaay too rich Any ideas, I have not touched anything other than removal of plastics and fitting of straight bars and a different headlight plus relocation of oil cooler. Would it be likely to have something to do with the lack of fairing/ ram air? Link to comment Share on other sites More sharing options...
Alex_H Posted July 4, 2012 Report Share Posted July 4, 2012 I don't know exactly how this would effect your bike, but I know older carb'd bikes with ram air have big trouble if the balance tube that goes from the top of the carbs to the front of the ram air system gets disconnected, ie they won't rev. I'd be willing to bet its something along the lines of your ram air removal mate, might be a dyno job. Link to comment Share on other sites More sharing options...
Gregorious77 Posted July 4, 2012 Report Share Posted July 4, 2012 yep my guess is ram air too. you need it to be balanced. Link to comment Share on other sites More sharing options...
Alex_H Posted July 5, 2012 Report Share Posted July 5, 2012 Was thinking about this last night, sadly, and it might be worth looking at a fiche for an x11, see how its all plumbed in on one of those compared to your bike. Same motah innit, etc, I think. Link to comment Share on other sites More sharing options...
Speednumpty2 Posted July 5, 2012 Author Report Share Posted July 5, 2012 Thinking this may be the problem, however would it still be running fine in first if that was the case? Also the blackbird doesnt have true ram air, just feed pipes either side under the fairing, these are still as standard and all I have removed is the fairing in front of them Link to comment Share on other sites More sharing options...
Alex_H Posted July 5, 2012 Report Share Posted July 5, 2012 Did any pipes go to the fairing at the front? Link to comment Share on other sites More sharing options...
Speednumpty2 Posted July 5, 2012 Author Report Share Posted July 5, 2012 Update- having been out on a more scientific test ride. It runs really nicely at low speed in all gears 1,2,3 but once moving faster (above 40 at a guess as no speedo currently) it bogs down and doesnt want to rev. Looking at the inside of fairing and the 2 feed pipes to the airbox, I am guessing that it needs the opposite of ram air. ie an area of low pressure that would normally be behind the fairing. Next step is to cut the airbox feeds at an angle so the engine doesnt get over fed air at pressure... Link to comment Share on other sites More sharing options...
Speednumpty2 Posted July 5, 2012 Author Report Share Posted July 5, 2012 No connection between airbox pipes and fairing. Normally they sit in the space inside the back of the nose cone/ upper fairing but no direct connecting ducts etc. Link to comment Share on other sites More sharing options...
Speednumpty2 Posted July 6, 2012 Author Report Share Posted July 6, 2012 Running much better now with the air intakes cut at 45 degrees so they no longer face immediately forwards. Still a bit stuttery at the top end (65+ mph) but the problem is nowhere near what it was previously. Next thing will be a trip to the Dyno I reckon. Anyone recommend a decent dyno near Kings Lynn as the only ones I can find are Norwich way? Link to comment Share on other sites More sharing options...
Speednumpty2 Posted July 13, 2012 Author Report Share Posted July 13, 2012 All fixed now. Further to a couple of conversations to the extremely helpful guys at X bikes in Wisbech, it was suggested that I try removing the ram air effect as the carbs need a still air draw from behind the fairing. Then get dyno'd afterwards to adjust for mods. 1st attempt was to cut the air feed pipes at an angle so they didnt force so much air. Not too successfull 2nd attempt was to remove the air feed pipes (leaving just the holes direct to airbox) and taping the gap between frame and tank to stop air forcing in. Rode much better but still lumpy as hell and severely lacking top end. 3rd attempt was to shorten air feed pipes and blank the ends off completely, then drill umpteen 14 mm holes in the underside of both pipes for a non direct feed. Just tried it out and it feels better than it did as standard, loads of power and really smooth, no holes in the response and still pulling well in 5th/6th (on a private stretch of local dual carriageway obviously) Job jobbed, well chuffed with the result and eternally grateful to x bikes for the advice, will probably take it for a set up when funds allow but it is miles better than it was as standard for some reason. Really pleased with myself for fixing the problem by a process of trial and error. Now all I need next is a speedo of some description.... Link to comment Share on other sites More sharing options...
lorenzo Posted July 15, 2012 Report Share Posted July 15, 2012 Sigma push bike speedos are good for over 120mph.... Link to comment Share on other sites More sharing options...
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