Topic: Idle Mixture Screws - 6 turns out

[eurban]

Even if your slow jets are pressed in (I have heard that some of the 82s had screw in pilots) then they must be removed for proper cleaning.  Forget about what Clymer or Honda says on this one as there is no other way to get them clean after 30 years of use.  Feel free to search under "pressed in jets"; the subject of their removal and cleaning comes up all the time, particularly in reference to the 77/78 750 carbs.  You basically grab them with plyers (padded with leather if you like) and twist and pull.  You can then soak them in carb cleaner, followed by running a single strand of copper wire through them.  Clean the sideways passages as well.  Use spray carb cleaner to make sure that all the interconnected passages in the idle circuit are clear.  Gently tap back in the slow jet when they are clean. .  .  If you never pulled your slow jets previously, then it is very likely that they are the source of your problem.

[Hodgeman82]

Well, pulled the carbs today and started going through the process of cleaning the jets, etc.  I was glad to see that this '82 has the screw-in type slow jets.  Actually, everything looks pretty clean but I am soaking/blowing-out everything anyway.

My big surprise was that I came across two external hoses that were pretty much rotted off.  I would have never seen them had I not removed the carbs because they are located in-between carbs 1&2 and 3&4.  They are rubber "T" fittings that join those carbs.  Both lead away from the carbs and join to form another "T" which ends up connecting into the front of the air box.  Anybody know the purpose of this setup?  They crumbled right off of the fittings between the carb sets so I gotta think they were leaking air.  This could explain why all carbs were behaving equally bad and required the exact number of turns out.  Make sense?  Is it possible to replace these rubber "T" fittings without seperating the carbs.  The Clymer manual gives instruction for seperating 1&2 from 3&4 but recommends against seperating the carbs any further - looks like a real pain to do it too.  I'm wondering if the T fitting can just be worked on by getting one side on first and work the other side on from there.  Anybody had any experience installing these?

Another variation from the Clymer I saw is that they show a needle jet that drops in from the bottom of the carb that is supposed to be underneath the main jet holder.  Huh?  The only needle I have is the one that drop down from the vacuum cylinders right into the jet.  Doesn't make sense.

Thanks

 

[Hodgeman82]

I took the carbs off and gave them a thorough cleaning.  I also replaced those two T fittings for the carb bowl vents in between carbs 1&2 and 3&4.  Bench synced my carbs and reinstalled.  She started right up!  What a difference!  Runs like a new bike.  Even the sound of the exhaust is now deeper than before.  Idle mixture screws are now about 2 turns out - right about where they should be.  The bike accelerates much more smoothly and doesn't "search" when in that 2000-3000 rpm range. So, moral of the story is don't jump to the conclusion that a rejet is necessary before doing a good cleaning of the carbs.  Thanks to all of you for your advice to help me solve this problem!

One final question:  I saw no reference in the Clymer manual as to the proper distance between the accelerator pump shaft and the metal tang that it rests on when at idle.  I bent the tang so the shaft is just barely touching the shaft while at rest.  Is this OK?  I noticed the shaft was slightly depressed by the tang before I adjusted it.  Seems to work fine when I whack open the throttle - a very very small amount of blubbering at the onset but jumps the rpms right up otherwise.

THANKS!

[Soos]

Yeah....
That measurement is HARD to find.
Took me quite a while to find it.
(think i found it on one of the SOHC 650 websites)

But the specs should be 0.002 to touching for clearance on that accel pump tang.

Good to hear it's running right now!


l8r

[mrbreeze]

Glad to hear you got it figured out.Holy sh!t!!!!....when I first read this post,the first thing I thought was can those screws ...actually go 6 turns out???....Happy motoring!!!!

[Hodgeman82]

Hi - just a note from the guy who started this post in case others are still searching for this subject and come across this string of posts.  It's been a few years since I solved the problem and the bike is still running great with no adjustments.  Again, my problem was that I was NOT thoroughly cleaning the carbs.  DO NOT settle for using the spray type carb cleaner or even soaking parts in it or you are wasting your time. BUY THE CARB DIP CAN that comes with the internal basket and soak the parts overnight.  I bet I had my carbs off at least 3 times before I realized this is what you HAVE to do to make sure all that old varnish and corrosion are taken care of.  I've since used that dip can on several other carbs off other bikes and have one soaking right now, best purchase I have made over the years in regards to getting old bikes and other equipment up and running.  Happy riding! 

[lucky]

You have not mentioned if you are using a stock airbox and filter, Pods, open pipes etc. All of this can effect the mixture. You mention rejetting, however the mains have littile effect at idle. Unless you bought the bike new, it is hard to know what has been done to it.

Exactly...Not enough information!  Right on BobbyR.