XJ750 Pilot Mixture Adjustment

I’ve recently bought an 83 XJ750 and am having considerable
difficulity with carb adjustments - specifically 1 & 4 are doing fine,
2 & 3 are running rich.

I’ve had the carbs cleaned, replaced the needles and jets, had the
carbs sync’d (vacum tube) twice, checked all the rubber boots for
cracks, have made multiple float level adjustments and checked the
levels against with what the manual says they should read on a tube,
and while each adjustment nets some little bit of improvement I am
quickly coming to the conclusion that the previous owner may have
tinkered with the pilot mixture adjustment screws.

Unfortunately the Haynes manual says little more than "these are
pre-set" and "do not touch", and dealers mutter archane words about
horrible and dire consequences when asked. I would like to know what
the factory pre-set is so I can check to see if that is what they are
set to but this information seems to have a higher classification than
most mortal riders can hope to attain, even Mr. Google has been of no
help to me.

I have considered checking where 1 and/or 4 are set and seeing if 2 &
3 are at least in the general neighbourhood - is this a workable plan?

Does anyone know what the factory pre-set is?

Thanks

M

 

the factory setting of the pilot mixture screws is usually about 1 tur
out from bottom.
That is too lean but used to pass emission regulations.
The optimum setting for the XJ750 is between 2 and 2.5 turns out fro
bottom.
So pull out those little rubber caps and bottom each screw carefully
There's a tiny spring in there so don't reef on it. Just gently botto
it, then carefully turn each one out to between 2 and 2.5 turns. You'l
like the result...
thx,
baz

 

Why are you responding to threads that are a year old? It's far too
late to help the original poster, he;s never going to read your reply,
so why bother answering an old thread?

 

Generalize much? I still have articles I posted in 1999 earmarked in my
newsreader. If someone posts a follow-up to one of them, I'll see it.

In any case, a follow-up to an old article may still help *someone* who is
searching the archives for information, if not the OP. As long as it's
topical and relevant, why get your shorts into a knot? Frankly I find the
belated responses a lot less annoying than your whining about them.

-Scott

 

I seriously doubt that reading late follow up posts to a thread that is
even a month old ever does anybody any good.

Threads that go on and on and on become more and more trollishly
argumentative than informative, and they waste the time of people who
are actually interested in helping the original person who had the
TECHNICAL problem.

When the OP *never* responds to any helpful advice whatever, all effort
expended in trying to help him/her is wasted.

So why dredge up old posts?

 

I'll be darned, here it is 2015 and your antique post helped me out on something I forgot.
Thanks for posting!!

 

Now it's 2017 and the reply from 2006 helped me set the pilot mixture after a rebuild. 2 turns back is great!

 

Because it helps people like me out... Aside from your trolling dickhead messages this forum has been UBER helpful to me.
I literally have the tank resting half on bike half on my knee while I'm juggling tools just so I can tell you to stop being a dick... Rofl

 

Idiiiiiiotttttt. Back in the cage troll.

 

WOW, it's 2020 and you got another kick in the nuts...
Thanks for the post, it helped me.