So far I've found all the answers to my maintenance questions by scouring the forum (a big thanks to you all), but I've finally reached an impasse.
With the help of the information supplied by David Raforth and his big brain, the carburetor rebuild went well and they're mounted up, ready to synch. Using a home-made water manometer, I've managed to get #1 and 2 synched with each other, and likewise 3 with 4, but when it came to getting the first two to match the last two, not happening. 3 and 4 are sucking harder than 1 and 2 regardless of any adjusting I do.
I'm assuming there's a vacuum leak somewhere, but I'm not seeing it. Any suggestions of where to look first would be appreciated.
Also, Dave refers to taking the idle mixture screws back to 2 1/2 turns, and adjust from there. Does this mean to totally back the screw out, and then turn it clockwise 2 1/2 turns?
Thanks all.
Oh, and pictures will be forthcoming, as soon as I figure out how to post them.
Are you trying to do 2 at a time? This is making the job tougher than it should be... I use a set of 4 gauges that was pretty cheap and worked like a charm. All 4 carbs right on the nose together with some averaging for throttle position... you just can't effectively do that without having all 4 gauges (or manometers if that's your fancy) to look at while you're turning screws and twisting the throttle. The reward you get in drivability is well worth the investment.
Side note: The gauges are not nearly as handy for the Keihins... they have no on-the-fly adjustment, so you bench align them with a fixed spacing for the slides. I'll try this and add using the gauges to guide my fine tuning of the slides. Should be just about the right amount of head banging for my taste. :dash2: :dash2: :dash2:
Frank
if its standard Fj carbs , wind in mixes till the just seat, then its undo 2.5 or whatever turns she likes
A lot of here guys like 3 or 4 turns out. You have three screws, left side to sync 1-2, right side 3-4, once you have the right and left pairs synced then use the center screw to balance the two pairs. This can be done with only a gauge for two carbs. Doing all four at once the best answer. Hope this helps.
Kurt
The mixture screws are set by running them in 'til they just barely seat (don't keeping torqueing on them, it'll ruin the screws, the carbs, or both...), then turned out 'til they pass the "Blip Test". Could be 2 turns, 3 turns, whatever it takes...
Typically someplace between 1.5 and 4 turns is the usual range. If you're not getting there and wanting more than four turns, try cleaning again (unless you ultrasonic'd or otherwise are really sure that things are spotless inside). If you're wanting less, then check the size of the installed pilot and go down a size (from 40 to 37.5, etc), but that'd be unusual unless you went from pods to the airbox, or back to a factory-type exhaust.
Quote from: Flynt on September 28, 2012, 09:44:51 PM
Are you trying to do 2 at a time? This is making the job tougher than it should be... I use a set of 4 gauges that was pretty cheap and worked like a charm.
My home-brew manometer measures all 4 at the same time, but it can be a chore keeping the water from being sucked into the bike!
Think I'll get 4 of the gauges on Amazon for $19 each.
Quote from: RichBaker on September 29, 2012, 04:59:27 AM
The mixture screws are set by running them in 'til they just barely seat (don't keeping torqueing on them, it'll ruin the screws, the carbs, or both...), then turned out 'til they pass the "Blip Test". Could be 2 turns, 3 turns, whatever it takes...
I'm the original owner of this '86 FJ, and as I delve deeper into the mechanics of it (the carburetor being the "Holy Grail" as it is the most intimidating to me!) I'm finding evidence of incompetent mechanicsmanship from the dealer I purchased it from, as I've suspected since day one. (lots of stripped screw heads, missing screws/bolts, etc.)
Two of the mixture screws are pretty boogered up from gorilla tactics and I'm afraid of tightening them til they barely seat. I haven't searched for replacement ones yet, but it looks like it's come to that.
Quote from: mich1jon on September 29, 2012, 08:50:41 AM
Think I'll get 4 of the gauges on Amazon for $19 each.
That's going to be ~$80... for ~$100 I got a rack of four gauges, each with an in-line throttle valve (critical you have these to dampen the needle vibrations), all mounted on a nice hanger, with 4 lines and 4 each of 5 different fittings to connect with (none of which we need). I also found this on ebay, but Randy has it now for $106...
http://www.rpmracingca.com/proddetail.asp?prod=Carb%3A4gage&cat=24 (http://www.rpmracingca.com/proddetail.asp?prod=Carb%3A4gage&cat=24)
You'll use this thing a bunch, especially as you're getting the carbs dialed in. Then I would synch anytime I was taking the tank off because it is so easy. Good tools have a way of making some tricky jobs easy... This is one of those times.
Frank
Randy (rpm) has a kit for the carbs, I think it does all four. http://www.rpmracingca.com/proddetail.asp?prod=carbkit&cat=24d (http://www.rpmracingca.com/proddetail.asp?prod=carbkit&cat=24d)
Hope this helps?
If you need some help and are coming north let me know.
Kurt
Not to take food from Randy's mouth, but the Morgan Carbtune is also a really nice piece for about the same $$ as Randy's. It uses stainless steel rods and works really well. I have it and really like it. I kno others do as well. Don't let the international shipping cost or times bother you. I paid about $100 for it including shipping and it was delivered to my doors about 5 days after I ordered it. Easy peasy.
http://www.carbtune.com/ (http://www.carbtune.com/)
All that said, I really don't know much about Randy's in contrast, but knowing Randy from here to be a stand-up guy who understands quality, I have little doubt that his is also a good unit.
Dan
+1 on the Morgan :good:
They're that good all your mates will want to borrow it
Now if I can just find mine.....
Thanks for the options, but unfortunately I already ordered the ones from Amazon (they should be here tomorrow). I'm saving $3o, but the dampening feature Randy's has would've been nice to have. I'm quickly running out of riding season and really want to see the garage in my rear view mirrors. :good2:
Without some sort of damping valve or restriction, the gauges will be worthless. They will flutter wildly and be totally unreadable and unuseable for synching.
DavidR.
If you need some restriction you could make something. Let me know if I can help.
Kurt
if I recall correctly, from an article I read...... you can use small tie wraps cinched up on each hose ...
Tony
When I had a set of gauges, I used small hose clamps and wire nuts to constrict the vacuum lines and provide damping. However, for $30 more the Morgan Carbtune is a much better solution.
DavidR.
just go to a pet store and buy 4 fish tank pump valves , same thing as fitted to my synch gauges but much cheaper
Quote from: fj11.5 on September 30, 2012, 02:46:42 AM
just go to a pet store and buy 4 fish tank pump valves , same thing as fitted to my synch gauges but much cheaper
So, I gotta ask...how do you calibrate the air valves? How do you know how far to open or close them?
Quote from: Pat Conlon on September 30, 2012, 08:23:33 PM
So, I gotta ask...how do you calibrate the air valves? How do you know how far to open or close them?
Pat, you Non-conformist!!! Rebel!!! Anarchist!!!! :ireful:
Ok, how the hell do you set the fish valves??? More buffer/restriction from one or more will alter how it looks and behaves according to to the other vacuum tubes.
You don't "calibrate" them. Their whole purpose is to damp the wild swings of the needles or fluid column. So, you turn them in just enough to minimize (not stop) the movement.
Arnie
Quote from: Pat Conlon on September 30, 2012, 08:23:33 PM
Quote from: fj11.5 on September 30, 2012, 02:46:42 AM
just go to a pet store and buy 4 fish tank pump valves , same thing as fitted to my synch gauges but much cheaper
So, I gotta ask...how do you calibrate the air valves? How do you know how far to open or close them?
Quote from: Pat Conlon on September 30, 2012, 08:23:33 PM
How do you know how far to open or close them?
Mine are like Randy's offering. You close the valves down to control the range of the needle vibration. At full shut they don't move obviously. Open a little and they move a little. When you have them open the right amount, the needles are bouncing minimally and all needles are moving rapidly up and down the range as you blip the throttle. Hard to describe, but works easily and no advanced skills required. Don't know a thing about the Morgan however. Sounds like it damps the pulsing with weighted rods?
Frank
thanks arnie, that's exactly how they work, at least someone is thinking outside the box
Ok, gotcha. The Morgan has small inline jets you place in the clear tubing at the prescribed distance to the unit.
I have a set of gauges like rpm sell, , same type of valves fitted as the fish tank pump type , as I have both types to compare them ,, also have a motion pro think they are the same as Morgan carb tune , with the tapered screw to dampen / slow down vaccume
Excellent feedback! The extra $30 would have been worth it (I'll have to read Amazon's return policy) but it sounds like I'm probably about to increase my knowledge on vacuum dampening.
Here's you first lesson (everyone else pay attention also).
DampENing means to wet something.
Damping means to slow something down.
DavidR.
Quote from: SlowOldGuy on October 03, 2012, 09:47:44 AM
Here's you first lesson (everyone else pay attention also).
DampENing means to wet something.
Damping means to slow something down.
DavidR.
lol that is funny and true :)
Quote from: SlowOldGuy on October 03, 2012, 09:47:44 AM
Here's you first lesson (everyone else pay attention also).
DampENing means to wet something.
Damping means to slow something down.
DavidR.
Here's your first lesson.
Your ends with the letter "r".
:)
BURNNNN :lol:
So I can't type, sue me. I also always spell "the" as "teh" (I think my fingers are usually ahead of my brain). I saw that eror, but my edit period had already expired
Which is why I don't correct people's typing.
However, I think I effectively communicated the concepts, which was the main point.
DavidR.
Quote from: SlowOldGuy on October 03, 2012, 05:03:51 PM
So I can't type, sue me. I also always spell "the" as "teh" (I think my fingers are usually ahead of my brain). I saw that eror, but my edit period had already expired
Which is why I don't correct people's typing.
However, I think I effectively communicated the concepts, which was the main point.
DavidR.
So I just gotta ask, how many times did you re-read that before you actually posted it? (Just to make sure there were no issues?)
:)
I mis-typed teh again. :-)
When I get a chance to do this at work, I want to get in and get out quickly. Thus the spelling errors.
DavidR.