get lose Posted March 22, 2009 Share Posted March 22, 2009 what would be the cheapest way out for me. i have a 93 yamaha yzf 750sp with 39mm flatslide carbs that i was going to take out and rejet! only thing ive done is clean the carbs and put back on the bike to make sure it ran! and i dont know anything about sycronizing the carbs, but was told that there is a tool to do so! and since i clean the carb and all the jetts once it should be less difficult for me to rejet it right! Link to comment Share on other sites More sharing options...
pilninggas Posted March 22, 2009 Share Posted March 22, 2009 syncronising carbs is a series of adjustments to make sure they are working together - if they are out of sync each cylinder of the engine will be trying to rotate at a different speed and so the idle and off-idle throttle will be poor. What you are trying to do is set the static opening of the throttle butterfly of each carb, so that all 4 carbs create the same vacuum. the tool for doing this is a set of 4 vacuum gauges (you can use a set of 2 and do each side and then the centre), which allows you to see the vacuum of each manifold (and therefore the adjustment of each carb) and using the manufacturers baseline vacuum (i guess around 200 mm Hg for a yzf 750, though you'd need to check in a workshop manual), adjust all four carbs so the vacuum is the same +/- 5mm Hg. On standard carbs you would use a screwdriver, however i have never adjusted flatslides on a big-bike, so i can't say for certain that it would be the same. having an fzr1000 (very similar to the yzf), i can tell you to budget a couple of hours if you have never done the job before. the access for the vacuum is below the carbs and is a pain to get to. you will also need an auxilliary tank to supply fuel while you are setting the vacuum (i have in the past used the bikes tank, sat on foam on a workmate with a metre of fuel pipe). Id read up a bit on flatslides if i were you, i cant claim to be an expert on them, but they have a steep transitional off-idle character and therefore may be a tricky to balance/syncronise. good luck. Link to comment Share on other sites More sharing options...
get lose Posted March 23, 2009 Author Share Posted March 23, 2009 what would be the cheapest way out for me. i have a 93 yamaha yzf 750sp with 39mm flatslide carbs that i was going to take out and rejet! only thing ive done is clean the carbs and put back on the bike to make sure it ran! and i dont know anything about sycronizing the carbs, but was told that there is a tool to do so! and since i clean the carb and all the jetts once it should be less difficult for me to rejet it right! do u know what the idle/air screw is suppose to be set at! on mine are set at 1.25 turn. is that about right! Link to comment Share on other sites More sharing options...
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