OK, now that the bike s built and running I have decided to delve into the finer things of Vision Zen...carb tuning.
I am trying to figure out the optimum settings and need some help.
I have an updated 82 carb and updated airbox.
What should the jet sizes be for the top jets (front and rear) and the side Jets (front and rear)
Also, the previous owner removed the plugs from the idle screws and presumably adjusted them himself. What is the recomended starting point for each screw for adjusting.
Presently YICS is removed and ports plugged.
Thanks for the help.
David
Hey Dave.
I have been using 135's for the main air jets (top) and keeping the stock 122.5 main jet (front) and 127.5 (rear)
Idle settings... much debate, but start with 2.5 turns out from lightly seated (front) and 4.5 turns out from lightly seated (rear)
hope this helps a bit.
Yup, use Superflys jetting numbers.
assuming the bike runs, you've already got your inital pilot screw settings, they are just to get the carbs to a point where it'll start & idle.
one at a time, adjust each pilot screw in untill the bike starts to idle rough, you'll hear it. then back the screw out 'till it idles rough again.?center it between these two points.. do this with both screws. you'll have a 'dead zone in the middle'.
synq the carbs
ride the bike, if you have a flat spot when warmed up, turn the pilots in 1/8 turn each then ride it again. if you discover later on you still have a flat spot, but only when the bike is cold, go in another 1/8 turn.
--Lucky
Thanks for the quick replies
ok, Im confused now. I thought the pilot screws were supposed to be seated tight and the idle screws were the ones that were supposed to be turned in and out. All four of my pilot screws are turned tight.
David
Pilot & idle??? there are only 2... (pilot)
on an 82 the pilot screws are the 2 flat blade screws in the tiny holes located just above the intake boots on the left side rear of each carb. any other screw should be tight, but NEVER tighten the pilots, you risk destroying the seats they sit in...
i'm guessing your thinking the drain screws are adjustments as well, they are tapered at the end & have an o-ring, but they are not adjustments, they should be tight. they are the phillips head screws located next to each plastic drain fitting.
--Lucky
Dave, Lucky calls them pilot screws, I have always used the term mixture screws. These are the 2 screws (1 on each carb) that sit on the left hand side of the bike , in the bottom right corner of the carb. Hope this helps.
Jim
Superfly
What did you gain using 135's in your carbs, just wondering.
Jim
Power!
This jetting really works great with aftermarket pipes (mac's)
Pilot is a Yamaha or carb manufacturer term, but they are mixture screws. some carbs have more than one mixture adjustment, so i just say that for clarity sake.
The 135 (pilot air) jets seem to smooth out the acceleratin & there is a positve effect on power output, but i have no dyno tests to back this up. ?i think Jason M. does though...
You are right Lucky,? I was searching through the old posts one day, and came across this:
http://ridersofvision.net/forum/index.php?topic=1951.0
great reading, and I noticed a difference after I switched out the main air jets.
And I agree with Luckys comment about using Velcro for the Carbs!!! ;D
Looks like Dave got more info than he may have wanted. I am going to try the 135 's and see what happens. If I can just keep the rear mixture screw from falling out of the carb with only 4.5 turns.
jim
the pilot screw shouldn't fall out at 4.5 turns, is the rubber o-ring on it? strech the spring a bit if you need to.
OK, the results are in.
You all are great! Went with 135's on top and 122 and 127 lower and the pilot screws are set at 2.5 front and 4.5 rear.
Starts on first crank and idles at about 1500 until warm and then drops down to 13 to 1400. Runs solid now and with the improved airbox there is no stumble when she is warmed up. Slight hesitation when cold.
I ordered new boots and gaskets from DGY today and that should take care of the mechanical part for now.
I'm also signed up for the MSF basic riders course for the weekend after this coming one...then I can get my license and insurance and ride outside of my subdivision...oficially. (snuk a few trips outside)
David
I was experimenting with the flapper door also, to keep it partially open, and that helped out also.
Would it help the early model 82 to leave flapper box slightly opened. (Early model without updates)
the trick for the early 82 airboxes (non vacuume) is to epoxy 2 nickles onto the flapper.
Betcha most of you didn't know that one, lol
Lucky....Rubber O-Ring on the mixture screw? I didnt know there was one on th 82. When I pulled it apart there was not one there on either carb.
I will look at the spring and see if has compressed at all. Thanks
Jim
Lucky-Epoxy two nickels to flapper? >:( To add weight or to keep it from closeing completely? ???
Damn Lucky, I havent read that one in a long time! ;D
Would that extra weight on the door keep it closed more? I liked keeping the door part way open.
What I did was take the top off of the airbox, and loosen the 2 screws the hold the vacuum pump assembly (there is some adjustment in there) if you manipulate it ever so slightly, you can set the door part way open. I did this a few days ago, and finally got rid of that last little bit of stumble on my 82 carbs...
CrazyJ, You might have to pry it out, it is in there! there is a spring, a little metal washer, and a little o-ring that go over the screw.
...to make sure your Vision is always worth at least $.10.
:)
Greg
Now that is funny! ;D
Hope my wife does not read this post. Will tell where to put my V and my Ten cents. Oh well, at least it's Friday
the nickle trick is only for the early NON-vacuume operated airbox flapper doors. what it does is cause the door to open a bit later.
the o-ring is the first piece to go into the carbs followed by the washer, spring &then the mix screw. it's easy to miss. pull it out with a pick or a bent paperclip.
--Lucky
Well, was a silly newbie thing causing the idle problem. In my haste to get things done, I inadvertantly mixed up the jets. 122.5 and 127.5 on the front and 135's on the back. They need to stamp them numbers bigger...or I need new contact lenses. Replaced all the jets today along with the boots (compliments of DGY), boot gaskets, and hoses and she sounds wonderful. No more rich gas smell either.
First official ride is to work tomorrow morning.
Wish me luck.
David
David -
It's usually something simple. Even on the new jets, those numbers are hard to read. I use a good light & magnifying glass to make sure of jet sizes. Wouldn't even try to read them with my contacts but my glasses work well for me. I couldn't read them any better 10 years ago, either!
Good luck on that first commute. It gives a whole new perspective on the work day. 8)
H2O
Oh boy, I am so excited to share this with you guys, you can appreciate (I hope).
Last spring, as I was putting back together a set of carbs from (I can't remember how many) spare ones, I tried reading the jets' sizes. Ended up bringing all of my jets to work - a natural sciences Museum, with a nice digital microscope hooked up to a computer and projector. So on the 3rd floor of Canada's Nature Museum, on a large screen, my work colleagues were able to contemplate the numbers on tiny jets from Vision carbs. And call be a freak. What a feeling.
I guess a magnifying glass could work too... but a microscope is more fun.
Lou
i usually rub a little something over the numbers, like a tiny dab of dirty grease. it seems to help. Radio shack sells a hand held lighted microscope that helps.
mayby we shoulld call ourselves the BROV (Blind Riders of Vision), lol
Quote from: louthepou on August 19, 2005, 10:09:31 PM
Oh boy, I am so excited to share this with you guys, you can appreciate (I hope).
Last spring, as I was putting back together a set of carbs from (I can't remember how many) spare ones, I tried reading the jets' sizes. Ended up bringing all of my jets to work - a natural sciences Museum, with a nice digital microscope hooked up to a computer and projector. So on the 3rd floor of Canada's Nature Museum, on a large screen, my work colleagues were able to contemplate the numbers on tiny jets from Vision carbs. And call be a freak. What a feeling.
I guess a magnifying glass could work too... but a microscope is more fun.
Lou
Ha!!!!? I just found a small paint booth with an air compressor/air tool hookups and exhaust vents and really nice overhead lighting at my place of employment.? It looks like it has not been used for a very long time....? ?I am going to have to fire that baby up, replace the exhaust filters and see where it takes me.....
Chris F.