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81 gs 750e, stock air filter, have a 4 into 1 exhaust, just put stage 1 jet kit into it, do i need to replace pilot jets? have spent lots of time adjusting idle mixture and got it sounding good, high speed is great, taking off from a light though, it misses and sometimes dies. every so often if i roll on the throttle from a cruising speed, it shows signs of a cough, not bad though. if i do need to replace the pilot jets, i dont know what size to get or if i can just adjust the screws (preferred) anybody run across this?
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How many turns out are they currently? "Normally" if they are more than 3 turns out it is recommended to go up one size. -
Have you adjusted the idle mixture screws using the "fastest idle" method? Did you do this with the engine warm?
Were all the screws set to about the same position (typically 2 1/2 to 3 turns)?
When you rev the engine and drop the throttle, does the idle go directly to the idle setting you have chosen, or does it hang high and then drop? Or does it sag low and then rise?
Does the main condition you're concerned about ("taking off from a light though, it misses and sometimes dies. every so often if i roll on the throttle from a cruising speed, it shows signs of a cough") get better or worse as the engine gets hotter?Comment
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The mixture screws are about 3 turns out, unsure exactly how many but I started from where the jet kit advised. The problem does get worse the more it heats up, if you stop and let it idle for a minute that it seems to be ok (could be affected by the load on the engine). It was really bad before I adjusted the idle, I backed each screw out until it got a little rough and then back inagain to where it smoothed out and it did make a big difference, so if I need to increase the pilot jet... First what size are the stock jets and what size should I put in. Its rideable now but if there were an emergency that I needed to get out of the way for, then I have a problem
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If you have got the standard airbox fitted and the only mod is a 4-1 then just stick the original bits back in the carbs. Adjust tickover by highest revs method and she'll be fine.79 GS1000S
79 GS1000S (another one)
80 GSX750
80 GS550
80 CB650 cafe racer
75 PC50 - the one with OHV and pedals...
75 TS100 - being ridden (suicidally) by my fatherComment
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To put the jet kit in, I had to drill out the lift holes in the diaphragm cylinder, can put everything back in and still be fine with the bigger holes you think?Comment
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A Stage 1 is fine for a pipe. You need to buy the pilot jets from Z1 or a Suzuki dealer, so just pull one and read the size. It may not even have the stock size in it any more, so I wouldn't trust what the Service Manual says.
I changed the pilots in my GPz and bought 2 sizes because of shipping charges.Comment
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Usually you can leave the stock pilot jets alone with this stuff anyway. The 1990 - early 2000's bikes had leaned out pilots for environmental regs, but your stock size should be ok.
Drilling the slide lets the slide respond faster, that is, it will go up faster AND come down faster. It's a response issue and should not have a big effect with your problem.
The fact that it gets worse when hot may indicate you may be too rich (too lean gets better when hot). If you were too rich on the low speed circuit, your idle would also want to sag low then rise when you blip the throttle. If you have that sag and are too rich, it is probably because your floats are set too high.
Suggest you read this site for more info: http://www.factorypro.com/tech/carbt...m_engines.html
Also, don't hesitate to call DynaJet. Tell them it's for carbs on an older bike and they will give you somebody who knows their stuff.
Good luck!Comment
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That is the site I used to tune my carbs. Lots of really good information there, not only about tuning but about how the carbs work.Originally posted by AJ View PostComment
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