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do I completely tighten pilot jet?

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do I completely tighten pilot jet?

PostAuthor: alaska1 » Wed Mar 13, 2019 1:24 pm

I have a 1993 that I just cleaned the carbs on. When I tried to start it, the only way was to twist the throttle. I did not pay attention to see if the pilot jet was turned in all the way or not when I took it apart. When I reassembled it, I screwed it all the way down. I am now thinking it needs to be 2.5 turns out?

Also, the air screw should be adjusted to make it run smooth, right? Am I correct that it is Needle, spring, washer, rubber o ring?

Thanks
Last edited by Jake on Wed Mar 13, 2019 3:20 pm, edited 1 time in total.
Reason: Moved to XV700 from XV750

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Re: do I completely tighten pilot jet?

PostAuthor: Flyingdog » Wed Mar 13, 2019 2:46 pm

alaska1 wrote:I have a 1993 that I just cleaned the carbs on.Thanks


A 93' what? If this 93' is your's, you oughta put it in your profile.

alaska1 wrote: I screwed it all the way down. I am now thinking it needs to be 2.5 turns out?


Probly why it won't start. Yes, 2.5 turns out from "soft seat" is a good starting point. Then go from there, with the pilot screw, to get the smoothest"idle".

FYI..the pilot screw controls "FUEL"..not.."AIR" for starting and idle'n. Your choke also controls fuel..not air as with conventional chokes.

alaska1 wrote:Am I correct that it is Needle, spring, washer, rubber o ring?


Yes..if you're talk'n bout the "pilot screw". Not to confuse the term 'needle' with the carbs' piston jet needle. Big diff between the two.
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Re: do I completely tighten pilot jet?

PostAuthor: alaska1 » Thu Mar 14, 2019 7:19 pm

Yes, the pilot screw, not the piston jet needle. The design between the Mikuni's on the 93 750 and hitachi's on the 85/86 is interesting. On the older bikes, the pilot jet is accessible from the bottom of the carb bowl whereas on the 93 it is not so. (at least I don't think so) I believe the only accessible screws on the bottom of the Mikuni's are for draining the bowl. ???

So does that mean that, (on the mikuni), I need to remove the bowls and loosen the pilot jet 2.5 turns and then fine tune with the jet accessible from the top of the carb next to the piston jet vacuum diaphragm cover? (At least that is what I am calling it).
Really glad this forum exists, these bikes seem to be a learning process.

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Re: do I completely tighten pilot jet?

PostAuthor: Cusstout 1100 » Thu Mar 14, 2019 10:19 pm

You can adjust the pilot screws with the carbs mounted on the bike; and you're right, they're much easier to get at on the HItachis than on the newer Mikunis. You'll need to adapt some sort of screwdriver to adjust them - I use a short straight blade screwdriver bit that "just" fits in the hole for the screw and I insert it into a 1/4" hex,1/4" drive socket that I have wrapped with masking tape with marks at each 1/4 turn so I can tell how much I've turned the screw. If you use that, shim the bit into the socket with a small strip of paper so the bit doesn't fall out of the socket. It's difficult but can be done. There will be a vacuum hose in the way on the left carb that I find easiest to move it out of the way to get at the screw. So, screw them into to a "soft seat", in other words, don't "tighten" them once you feel them touch the seat; then back them off the suggested 2 1/2 turns and go from there to get a good smooth idle. Once you've achieved that, you can play with them to get the best, smoothest operation through the idle to cruising range.
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Re: do I completely tighten pilot jet?

PostAuthor: Flyingdog » Sat Mar 16, 2019 1:22 pm

alaska1 wrote:So does that mean that, (on the mikuni), I need to remove the bowls and loosen the pilot jet 2.5 turns and then fine tune with the jet accessible from the top of the carb next to the piston jet vacuum diaphragm cover?


You might be confusing the pilot "screw" (#9) with the pilot "jet" (#17), that sits behind the main jet. Then you also have a power jet (#18). IIRC, some places also call this: Pilot Power Jet. #18 or #17 are set in their respective bosses and are not adjustable (other than size). Either/or... probly not a good idea to change these, other than cleaning. Unless you need to change the A/F ratio for whatever reasons. Cusstout is referring to "#9" assembly for that smooth idle/off idle adjustments.

https://www.yamahapartshouse.com/oempar ... carburetor
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