bartonmd Posted May 31, 2005 Share Posted May 31, 2005 actually, I'm sure he wasn't flying with it... I'm sure he had just put it on, because it didn't have a jet kit in the carbs yet... wouldn't run for shit I'm sure... Mike Edit: And actually... the difference in power between a full system and stock isn't that much, and you can just as easy get killed on a 600 as an 1100 anyway... whether it has a pipe or not... Quote Link to comment Share on other sites More sharing options...
slyxdevil Posted June 1, 2005 Share Posted June 1, 2005 this is true!! however i did notice the wake up .thats what i like to call it ..even on my gsxr 750 ..it was hard to wheelie it after pipe it wheelied with ease ..same with my xx not all bikes require jet kits alot of pipe companys are making their pipes /slip ons where no re jetting is required have you tried the 6 mm spacer for rear shock yet? what a differance and the mirror extenders work great too.. got sick of looking at my shoulders lol Quote Link to comment Share on other sites More sharing options...
PlasticxxHead Posted June 1, 2005 Share Posted June 1, 2005 hey guys.. Just got back from my FOURTH FUCKING TRIP TO THE PRO SHOP.... Well finally the bike runs good.. I had the Stage one dyno jet kit installed and the top end power and smoothness was a HUGE improvement.... BUT the low end ..1700-2000 rpm's had a massive lean spot.. I played with the air fuel idle adjustment under the carbs.. first way out like 4.. then in to three then 3.5 still a flat spot down low.. SSSOOOO.. I had the mech pull the carbs again and drop the needle from the 3 to the 4 position... idle jetts still at 3.5 turns out. and the bike runs well.. Not too rough an idle and the right amount of wrist turn and she is OFF... Thanks Andy for the multiple offers to help me out.. I'll ride out this season with the kit the way it is.. I may pull it neXXt year.. Quote Link to comment Share on other sites More sharing options...
slyxdevil Posted June 1, 2005 Share Posted June 1, 2005 hey pete i was gonna orffer to come up today and fix it ! glad to hear you gott it sorted .im suprised your pro shop with exhaust gas analyizer couldnt pick up on that .i could of told just by riding bike down street with choke on 1/4 of the way im sure i would of felt it getting beter u can only go so far with screws then its time to move needles 1 clip higher and try again but once u get it set it will ripp ..i had a few ball busters in my day and i called techs at dyno jett and they always helped me out ill never forget day i gott my bird ..i loved it on highway till i let off and rolled it back on and motor felt bogged down.. it was the notorious flat spot. there is a big article on that i sent it to you. its on the ixxra site it made me dislike riding my bike! once i got it sorted it was like my babys back and feel even more in love with my xx Quote Link to comment Share on other sites More sharing options...
slyxdevil Posted June 1, 2005 Share Posted June 1, 2005 Carburettor Flat Spot Earlier Blackbirds that had carburettors were known to have a notorious flat spot from about 5000 to 5500rpm. The reason for this flat spot (according to Mr.Honda) was the result of having to comply with the strict noise and emission regulations. This proved to be a major concern as the flat spot hit top gear at typical cruising speeds. This threatened the tital of the bike being a sports/tourer machine as it was not strictly speaking a ‘sports’ bike and the location of its flat spot hampered its ‘tourer’ status. So in 1998, Honda reworked the XX, giving it the ultra reliable fuel injector system nicked out of Honda’s works RC45 World Superbike racer, the legendary RC45 (RVF750), and a direct air intake pressurised air box. The result was a creamy smooth throttle response, and an awesome tug at 6000rpm upwards! Should you own a carburettor Super-Blackbird and want to sort out the flat spot, the ONLY way to achieve this is to fit either aftermarket race cans or a full system, and the get the bike dyno’d and re-jetted. When buying exhausts it is always better to pay that little bit more and get a well known brand that have a proven track record, such as MICRON, ERION AKRAPROVIC or YOSHIMURA. Then get the bike professionally dyno-runned and re-jetted, again, from a reputable tuning specialist. Quote Link to comment Share on other sites More sharing options...
bartonmd Posted June 1, 2005 Share Posted June 1, 2005 Just FYI... just adding the needles from the Factory Pro jet kit takes care of the flat spot completely on completely stock cans... and of course you want to richen up the idle mixture whether you do the needles or not... I believe it has more to do with the shape of the needle than the flow charactoristics of the pipes. Mike Quote Link to comment Share on other sites More sharing options...
Pete in PA Posted June 1, 2005 Share Posted June 1, 2005 Allright, lets get the facts right. 97 and 98 are carbed, 99 and beyond are FI. I have NO flat spots anywhere without a jet kit. I have my slide vac. holes drilled out to 1/8th inch, my pilot screws out 3 turns and my stock exaust cans have holes punched in the last baffle. I want to find someone near me with a FI bike to compare with. I belive I may have better throttle response than a FI bike. (stock, no power comanders and pipes etc.) Quote Link to comment Share on other sites More sharing options...
bartonmd Posted June 1, 2005 Share Posted June 1, 2005 true Pete... I have no problems with the throttle response... anything more than what I have would be too much... and I've ridden an PC/full Micron '99 (Travis's bike) and there was not a noticable difference between the 2. Also, I thought you had a Dynojet kit before and were unhappy with it (fuel mileage wasn't it?) and took it out and were now just happy with the holed slides and 3 turns out? Before the jet kit, I did have a lean stot about 5000-5500rpm, but only when accelorating through that area, not cruising... cruising was just fine... I immagine it has more to do with the lag from the small-ish slide holes than an actual lean mixture at that point in steady state... but the jet kit on mine fixed it completely, or I would have drilled slides too... Mike Quote Link to comment Share on other sites More sharing options...
Pete in PA Posted June 1, 2005 Share Posted June 1, 2005 true Pete... I have no problems with the throttle response... anything more than what I have would be too much... and I've ridden an PC/full Micron '99 (Travis's bike) and there was not a noticable difference between the 2.Also, I thought you had a Dynojet kit before and were unhappy with it (fuel mileage wasn't it?) and took it out and were now just happy with the holed slides and 3 turns out? Before the jet kit, I did have a lean stot about 5000-5500rpm, but only when accelorating through that area, not cruising... cruising was just fine... I immagine it has more to do with the lag from the small-ish slide holes than an actual lean mixture at that point in steady state... but the jet kit on mine fixed it completely, or I would have drilled slides too... Mike I'm glad to hear that carbed XX's are equal to FI. I am happy with my 3 turns out and enlarged vac. holes. Works for me. I forget who but I sold my dynojet kit to someone on this site. Quote Link to comment Share on other sites More sharing options...
flipy351 Posted June 3, 2005 Share Posted June 3, 2005 With the jets being 142 on the 2 centre carbs and 140 on the 2 outside carbys. Are the needles all the same or are the 2 middle carbs fitted with different needles than the outside two? Quote Link to comment Share on other sites More sharing options...
bartonmd Posted June 3, 2005 Share Posted June 3, 2005 All the same... the main jets only really affect the jetting at the upper end of the range at near full throttle. Mike Quote Link to comment Share on other sites More sharing options...
slyxdevil Posted June 3, 2005 Share Posted June 3, 2005 you would think they would be shimmed higher but they are not mike is right all same Quote Link to comment Share on other sites More sharing options...
flipy351 Posted June 4, 2005 Share Posted June 4, 2005 Q1 If needles are all the same then in stock form are the centre two carbys running too rich or are the outer two carbs to lean? Q2 If we change the exhast and make it free flowing then this would tend to cause the engine to run leaner. Therefore wouldn't it be a good idea to richen the outer two carbs? I suppose the real answer is to check the spark plugs. Any ideas on this anyone. Quote Link to comment Share on other sites More sharing options...
slyxdevil Posted June 4, 2005 Share Posted June 4, 2005 answer question # 1 the only reason the cener 2 carbs are richer is because they each have a cylinder on each side.. and would tend to get a little hotter as the 2 outside cylinders get more air threw fairings when riding and run cooler so to compensate honda gave the center 2 more fuel .as an attempt to cool it down. question # 2 answer no because if u richen up 2 outside carbs it will run to rich as all after market jet kits mostly stage1 has 140 on all cylinders because they find it to rich when stock and the center 2 arent really running that much cooler so its a trade off more power smoother excel a tad hotter not even noticable on temp gauge!! in most cases u go bigger on jets when doing full system but they found going snalller it runs best with free flowing exhaust Quote Link to comment Share on other sites More sharing options...
bartonmd Posted June 4, 2005 Share Posted June 4, 2005 The reason for the bigger jets in the center is part right, but it probably has more to do with the fact that there is water cooling around 3/4 of the sides of the side cylinders, but only about 1/2 of the center cylinders since they are saimese (sp) bore... And since they're siamese bore, they will tend to create hot spots if not run a tad rich... Like the small block 400 had siamese bore cylinders and would tend to cook the oil around the center cylinders and detonate more easily than a similar 350 (no personal experience, just from people who had them back in the day). So the center cylinders are richer to make up for the lack of cooling to them because of the siamese bore... This is why I just went 142 all the way across... Mike Quote Link to comment Share on other sites More sharing options...
slyxdevil Posted June 4, 2005 Share Posted June 4, 2005 my point exactly thats what i was trying to say but broke it down for dummies version..lol...not all know about siamese cylinders Quote Link to comment Share on other sites More sharing options...
flipy351 Posted June 16, 2005 Share Posted June 16, 2005 Thanks for explaining the reason why they run the different jets and the siamese bores. bartonmd Q. Are you running standard exhuast system? Q. Are you running the standard paper airfilter? Q What were your standard factory fitted jets? The standard jets here in Australia are 142 and 145. I believe in the US the standard jets are 140 and 142 Quote Link to comment Share on other sites More sharing options...
bartonmd Posted June 16, 2005 Share Posted June 16, 2005 Sly: I find that it's better to explain things the right way, and go farther in depth if someone has more questions rather than to say something that's not really true, but is easy to understand... then again, when I asked why the sky is blue when I was a kid, I was explained the atmospheric absorbsion theory instead of my dad saying "to match your eyes." Anyway, Flipy; 1. Standard exhaust system with 1" holes punched in the rearward most baffle... Had a set of slip-ons on the bike for a bit and bike ran the same with them as it does now, so I assume they flow about like a set of slip-ons. 2. Running a K&N filter (I wouldn't buy one, but it came in the bike...) 3. The factory jets in my bike were 140 on the sides, and 142 in the centers. I am now running 142 all the way across... Mike Quote Link to comment Share on other sites More sharing options...
slyxdevil Posted June 16, 2005 Share Posted June 16, 2005 very true mike .. just lazy typer i guess mine came with k and n air filter also was reading article that they actully make less power than stock filter bmc,k&n ect all the after market brands that last forever cause improper flow. so i wouldnt buy either. the 4 seperate ones for stage 3 is a differnt story that will make an increase in power. but ones that go in stock box rob power might be more in mid or low end but less on top by a few horse Quote Link to comment Share on other sites More sharing options...
flipy351 Posted June 17, 2005 Share Posted June 17, 2005 bartonmd Thanks for the info that gives me a good idea where to start my mods and in which direction. Quote Link to comment Share on other sites More sharing options...
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