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Dear XSives,
I'm posting this for fellow Xsive in hopes of getting more input and advice than what I thought of. SOME info is missing, and hopefully he'll post a reply with followup info to further assist us in his troubleshooting.
And here's my email "NON GURU" reply to him:
Hey there Morgzilla,
A few things left out of your info. What type of intake filter, Stock or Indy's? What sizes are your mains and pilots? Did YOU put in the Dyno jet, or did it come with it? Have you done an actual vacuum synch, or just breadstick tie? Are your plugs black and sooty, or bleach white, or somewhere in between? What are your floats set at?
With it studdering, it sounds like it's too rich! Also, from what I've read and heard, the Dyno jet kits have had bad jets, mostly the pilots which usually affects the idle and off idle range, but not full throttle!? Your pilot settings of only 1 turn out is slightly lean(with proper jets), but with faulty rich running jets could be reason for this setting vs. more turns out. The 4-1 pipes provide better flow, and so lean out the mixture, so usually you have to go richer, same for Indy filters vs. Stock box. SOME indy filters have bigger lip on mounting which partially obstructs ports on carb intake throat, but usually prevents folks from attaining redline period, no matter what throttle position, and you CAN get to redline, so doubtful that they are causing problem, but removing and testing without them on is easy check!
Having your needle set down also is compensating for overly rich condition, they control when the mains kick in, and when you hit full throttle, the slides rise up, and with the weaker springs of the Dyno kit, they usually rise up faster, and provide more fuel quicker, but if it's too rich, then it's dumping and choking/flooding, hence the studder!? Stock jets should be 137.5 for that year and carb, with 4-1, you should need only 1 or 2 sizes up, and with Indy filter, only another size up, so that's 3 sizes max for mains, taking you to 145. Your pilots should be 42.5, and many folks run with stock just fine, or go up to 45's max! If your floats are set too high, that can also cause an overly rich condition despite the jet!
If your pilot jets don't have the little holes on the sides, then they could be suspect! And, if your mains are not MIKUNI brand, no telling for sure what size they are, you can get genuine jets from Mike's XS, or Bike bandit for under $10.00 set of 4!
Finally, aside from carb issues causing this, timing could also be suspect, have you checked your ignition timing, and your vacuum and cent. advance mechanisms, and vacuum hoses going to the unit? I'm going to post your question to the group as well, and see what suggestions they come up with. If you can post a reply with the other info I asked for, then you'll get much better responses and troubleshooting suggestions! HTH.
I'm posting this for fellow Xsive in hopes of getting more input and advice than what I thought of. SOME info is missing, and hopefully he'll post a reply with followup info to further assist us in his troubleshooting.
I just purchased a 1978 xs1100e with 15k original miles and the bike has a 4 into 1 supertrapp exhaust of the era, dyno jet kit, and i have spent aprox32hrs trying to get the bike to run right, any help would be appreciated. bike runs fine at idle all the way up to redline at 3/4 throttle, if you go full throttle at 6500 rpms the bike studders, i have done the main jets, i have played with the needles, best postion 2nd from bottom, i have adjusted the air fuel screws, best postion 1 turn out,i have checked ignition wires and vacum hose and vacum,please help with any advice. thanks morgzilla.
Hey there Morgzilla,
A few things left out of your info. What type of intake filter, Stock or Indy's? What sizes are your mains and pilots? Did YOU put in the Dyno jet, or did it come with it? Have you done an actual vacuum synch, or just breadstick tie? Are your plugs black and sooty, or bleach white, or somewhere in between? What are your floats set at?
With it studdering, it sounds like it's too rich! Also, from what I've read and heard, the Dyno jet kits have had bad jets, mostly the pilots which usually affects the idle and off idle range, but not full throttle!? Your pilot settings of only 1 turn out is slightly lean(with proper jets), but with faulty rich running jets could be reason for this setting vs. more turns out. The 4-1 pipes provide better flow, and so lean out the mixture, so usually you have to go richer, same for Indy filters vs. Stock box. SOME indy filters have bigger lip on mounting which partially obstructs ports on carb intake throat, but usually prevents folks from attaining redline period, no matter what throttle position, and you CAN get to redline, so doubtful that they are causing problem, but removing and testing without them on is easy check!
Having your needle set down also is compensating for overly rich condition, they control when the mains kick in, and when you hit full throttle, the slides rise up, and with the weaker springs of the Dyno kit, they usually rise up faster, and provide more fuel quicker, but if it's too rich, then it's dumping and choking/flooding, hence the studder!? Stock jets should be 137.5 for that year and carb, with 4-1, you should need only 1 or 2 sizes up, and with Indy filter, only another size up, so that's 3 sizes max for mains, taking you to 145. Your pilots should be 42.5, and many folks run with stock just fine, or go up to 45's max! If your floats are set too high, that can also cause an overly rich condition despite the jet!
If your pilot jets don't have the little holes on the sides, then they could be suspect! And, if your mains are not MIKUNI brand, no telling for sure what size they are, you can get genuine jets from Mike's XS, or Bike bandit for under $10.00 set of 4!
Finally, aside from carb issues causing this, timing could also be suspect, have you checked your ignition timing, and your vacuum and cent. advance mechanisms, and vacuum hoses going to the unit? I'm going to post your question to the group as well, and see what suggestions they come up with. If you can post a reply with the other info I asked for, then you'll get much better responses and troubleshooting suggestions! HTH.
!
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