V6Jon Posted July 25, 2011 Report Share Posted July 25, 2011 This weekend the Srad has had the carbs properly vac balanced (which improved things no end), however its not quite right and I am a picky fucker ! As I have never really played around with a bikes mixture before I though I would bounce my ideas of you guys before I fuck it up completely. For those that don't know it's a 1996 750, it has standard downpipes and silencer, and as far as I know it has standard needles / jets etc, however as it is about 15 years old there are no guarantees ! When cold the bike starts very easily (doesnt need much choke), and runs well enough throughout the rev range, but as it gets hotter it starts to get a bit woolly and wont pull cleanly from low revs. Once it gets past about 5k it revs up cleanly and smoothly still. To me this sounds like it is running slightly rich on the needles, and to cure this I need to drop them down to reduce the fuel getting through at low revs ? Also, never having messed about with this kind of stuff before how do I go about moving the needles ? I am guessing the I need to remove the 'top' of the carbs, and get to the inside of the vac slides where the needles are attached ?? Thanks Jon Link to comment Share on other sites More sharing options...
lorenzo Posted July 25, 2011 Report Share Posted July 25, 2011 Yep, You're right about how to move the needles and I'd say you are also right about them being a bit rich too. Undo the 4 screws holding the top of the carbs on and underneath you'll find the big diapraghm rubberand a massive great spring. You may, like me, have an extra o ring on one side built in to this rubber, but many don't so make sure you don't lose this, OK.Lift the main diapragm out and you'll find the slider on the end of it with the needle mounted into the base. Push the needle up and, making sure you don't lose the small spring from underneath it, you'll see the needle has a circlip and 5 slots. To make the carb more lean, remove the circlip then put it back on one clip higher, meaning the needle sits slightly lower in the slider. Some tricky types also put a 0.5mm washer beneath the circlip, which in effect give you a half clip setting, IYSWIM. It won't make a massive amount of difference to your running on anything other than a closed throttle and your starting, but make sure the pilot screws are about 2.5 turns out too. Have fun.... Link to comment Share on other sites More sharing options...
Alex_H Posted July 25, 2011 Report Share Posted July 25, 2011 Another thing to consider is that your emulsion tubes (the bit the main jet screws into and that the needle slides in and out of) are worn and oval, this can give you an overly rich running setup. Also make sure your air filter aint shit up and nothing blocking the tubes - a mate of mine once thought it'd look cool to fit some of that halfords vauxhall nova mesh to the front of his srad's intake tubes and complained about it running crap. Mesh gone, bike good, lol. Link to comment Share on other sites More sharing options...
scooby601 Posted July 25, 2011 Report Share Posted July 25, 2011 Did you check the valve clearances at any point? Could have a tight valve or two that are causing a leak when the engine warms up. Got a similar problem with my 600 srad that became more obvious after having the carbs stripped and cleaned. Had 3 slightly tight valves, hopefully new shims here soon so I can test if its the culprit. Link to comment Share on other sites More sharing options...
fran9r Posted July 25, 2011 Report Share Posted July 25, 2011 Another thing to consider is that your emulsion tubes (the bit the main jet screws into and that the needle slides in and out of) are worn and oval, this can give you an overly rich running setup. Also make sure your air filter aint shit up and nothing blocking the tubes - a mate of mine once thought it'd look cool to fit some of that halfords vauxhall nova mesh to the front of his srad's intake tubes and complained about it running crap. Mesh gone, bike good, lol. Definately this. New tubes and needles...a call to Allens should sort you. Link to comment Share on other sites More sharing options...
V6Jon Posted July 26, 2011 Author Report Share Posted July 26, 2011 Yep, You're right about how to move the needles and I'd say you are also right about them being a bit rich too. Undo the 4 screws holding the top of the carbs on and underneath you'll find the big diapraghm rubberand a massive great spring. You may, like me, have an extra o ring on one side built in to this rubber, but many don't so make sure you don't lose this, OK.Lift the main diapragm out and you'll find the slider on the end of it with the needle mounted into the base. Push the needle up and, making sure you don't lose the small spring from underneath it, you'll see the needle has a circlip and 5 slots. To make the carb more lean, remove the circlip then put it back on one clip higher, meaning the needle sits slightly lower in the slider. Some tricky types also put a 0.5mm washer beneath the circlip, which in effect give you a half clip setting, IYSWIM. It won't make a massive amount of difference to your running on anything other than a closed throttle and your starting, but make sure the pilot screws are about 2.5 turns out too. Have fun.... Thanks mate, looks like another chance to improve my skillz at removing/refiting the bloody airbox Will check the pilot screws too, just one question though . . . . Where exactly would one find them ?? Another thing to consider is that your emulsion tubes (the bit the main jet screws into and that the needle slides in and out of) are worn and oval, this can give you an overly rich running setup. Also make sure your air filter aint shit up and nothing blocking the tubes - a mate of mine once thought it'd look cool to fit some of that halfords vauxhall nova mesh to the front of his srad's intake tubes and complained about it running crap. Mesh gone, bike good, lol. Will have a look at the needles for signs of wear, but the bike has done less then 10K miles, and if it needs more then adjusting I will probably just do the best I can with what I have as I have a GSXR1000 Ti system to fit over the winter which will mean proper messing about with the mixture ! Besides, after the miles I put on it over the weekend and yesterday, I suspect I may have a more serious issure . . Link to comment Share on other sites More sharing options...
lorenzo Posted July 26, 2011 Report Share Posted July 26, 2011 Pilot screws are under the float bowls and are what's known in the trade as a right faff. Once you know where they are you can just about do them with the tank hinged back but it's much easier with the carbs off. Link to comment Share on other sites More sharing options...
lorenzo Posted July 26, 2011 Report Share Posted July 26, 2011 Also, if you do put the ti system on there you'll want to go up 1 on the pilot jets too. A set of 4 cost about £18 from allens from memory. Link to comment Share on other sites More sharing options...
V6Jon Posted July 26, 2011 Author Report Share Posted July 26, 2011 When you say 'under the float bowls' I presume you mean remove float bowls to get at them, not under them when carbs are on the bike ? Link to comment Share on other sites More sharing options...
lorenzo Posted July 26, 2011 Report Share Posted July 26, 2011 No, sorry, they're under, not in the float bowls, you don't need to undo anything to get to them, you just need eyes that see round corners and a well trained octopus to turn the screw driver. They are at about a 45 degree angle facing downwards and slightly recessed too. The one on the left is just about visable but the others are a nightmare. Of course, you can spend some cash and get extra long screws with thumb twiddlers on the end but where's the fun in that? Link to comment Share on other sites More sharing options...
V6Jon Posted July 26, 2011 Author Report Share Posted July 26, 2011 Cheers, I'll see what I can see . . . Then swear loudly and remove the carbs to see it properly Link to comment Share on other sites More sharing options...
V6Jon Posted July 30, 2011 Author Report Share Posted July 30, 2011 Kids at the grandparents for the night. Wife in garden getting pissed with Girly mates Time to head for the garage !! Seat off, tank off, airbox off, carb tops off one at a time and each needle dropped one 'groove', aribox on, tank on, seat on and out for a blat before the sun sets as I still have no headlight ! Bingo, fueling much improved, will pull from nothing up to the red line Cheers Lawrence ! Bike tucked up for the night, beer fridge being emptied as we speak Link to comment Share on other sites More sharing options...
Kayla Posted July 31, 2011 Report Share Posted July 31, 2011 Kids at the grandparents for the night. Wife in garden getting pissed with Girly mates Time to head for the garage !! Seat off, tank off, airbox off, carb tops off one at a time and each needle dropped one 'groove', aribox on, tank on, seat on and out for a blat before the sun sets as I still have no headlight ! Bingo, fueling much improved, will pull from nothing up to the red line Cheers Lawrence ! Bike tucked up for the night, beer fridge being emptied as we speak I'm glad you're sorted. Carbs are brill, but they're a sod when they're not Link to comment Share on other sites More sharing options...
lorenzo Posted July 31, 2011 Report Share Posted July 31, 2011 Cheers Lawrence ! Now remember other forum users, I got something right and helped somebody once, OK. Link to comment Share on other sites More sharing options...
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