pods and jetting Question

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cabz
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pods and jetting Question

Post by cabz »

I am running my 73 GT750 with some new uni filters, the nice ones with the chrome end caps :) . when I first rode it it seemd flat when more than 3/4 throttle was applied. I adjusted the needle to a richer setting and that helped some . I have only one more clip slot to use so I dont think just adjusting that will be a total fix .
so my question is what size main jet should I get? how much more will be enough? everything else on the bike is stock except for the filters..
jaybob
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Post by jaybob »

You have to open up the carbs and see what you have and then go up one size on the main and see what happens. Due to different elevations, different fuels, humidity etc.... only trying something out on your bike in your area will work.
cabz
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Post by cabz »

jaybob wrote:You have to open up the carbs and see what you have and then go up one size on the main and see what happens. Due to different elevations, different fuels, humidity etc.... only trying something out on your bike in your area will work.
as far as elevations I am in fl , there aint none :)
and humidity mostly on the high side .

So do you think I might have to go more than one jet size up? should I get a few diffrent sizes or just the 1st oversize in line
jaybob
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Post by jaybob »

If you have the stock exhaust and it still bogs on wide open throttle after adjusting the needle, one size up on the main jet would be the next logical step. I don't think you would have to go higher unless you put on some chambers.

you can get the jets from Reproduction Decals or Sudco, or HVC cycle.

Now that you've made it breathe a little more freely you should consider a set of chambers. Add a little zip to the zang!!!
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tz375
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Post by tz375 »

Just for the record, at 3/4 to WFO throttle the main jet is the one that has most impact.

At high revs it's really only the main jet, so go up at least one size to be safe.

At low revs but lots of throttle the needle and needle jet also play a role. So start with larger main jets. Safer to be too rich and work back down to the right size. I'd order two sets - one up and two steps up and fit the larger ones first and try it out.

if it's fine at teh top end flat out and rich wide open at lower revs, leave the larger mains and drop the needle one step.

Just remember that the right main jet for wide open at low revs is not always the right main jet at wide open at high revs.
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H2RICK
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Post by H2RICK »

Absolutely right, TZ.
A guy MUCH wiser than me said the way to jet ANY bike is to start jetting at WFO at high speed, IOW, the main jet. Then work backwards from there with needles, needle setting, needle jet, etc.
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