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**mro** · 05-09-2008, 11:37 PM

So... after synk'n em did you adjust the pilot screws?
After which you need to synk em agin....

mro

**ross** · 05-09-2008, 11:49 PM

hey there mro....i read about resetting them on a previous thread....i reset them all to 1-1/4 turns......they seem to run fine....i thinking 3 is completly shut as the main carb idle screw is barely touching the plate it screws into.....i got idle down to 1k rpm.....pretty smooth also.....can get to 50 mph in one block in 2nd gear (don't want 2 scare the neighbors!!!)....i know this is something simple...just my brain cells are fused into one big jelly mold of information...thanx again...ross

**prometheus578** · 05-10-2008, 12:12 AM

"Man, you're way off..."

You're not to the point of offering beer, BBQ, etc... so I'm not to the point of giving you answers.

Ok, now that that's out of the way.

the screw between 1 & 2 opens/closes 1
the screw between 3 & 4 opens/closes 4
the screw between 2 & 3 opens/closes 1 & 2
3 is the carb all the others must be sync-ed to

This is correct.

if this is true, then to open 3 up so it fires correctly, you must turn the main carb idle screw in and re-sync off 3

This is not.
Consider #3 the master carb. All carbs must be "in tune" with it, and what ever #3 then does, all the other carbs do the same.
You can not "open #3 up so it fires correctly". Number three opens and closes by the large, main idle screw. When you turn that screw, it's connected to #3... and when #3 then moves, all the other carbs move "in synch" to that.
Once all the carbs are in synch... dickin' with the idle screw opens or closes all carbs at the same time. There is no "synch" adjustment for #3 alone.
#3, if you want to look at it this way, and even if you don't, is for idle speed adjustment only.
If #3 is running cool, and by that I imagine you're saying the pipe is not as hot as the others... that's an internal carb issue. something is plugged and you're not getting fuel, or the pilot screw needs to be tweaked.

everytime i got it close i had to unscrew it some to get the idle to go back down....

I'm not quite sure I understand your meaning.
Again, the idle screw adjusts the "idle" of all carbs at the same time. It works by moving on carb#3, and all other carbs follow suit.
I offer that you should set all pilot screws to1 1/2 turns out, and re-synch the carbs, adjusting the big idle screw wheel if the idle drops too low or too high. (this opens and closes all carbs at the same time)
Now, with all carbs synch'ed... if #3 still is a problem, it's either a vacuum leak or an internal issue with that carb.
What's the spark plugs look like?

There is no wisdom in errors, but much knowlege to be gained from them.

**prometheus578** · 05-10-2008, 12:19 AM

"I have this synching feeling..."

I take it then, that you don't have a carb synch tool and are trying to synch by ear.
As you say... If three is completely shut, then you are not in synch and the engine is running just offa #'s 1, 2 and 4.
That explains why... with you "trying" to adjust number 3, the idle revs up. Yes, you're finally opening up number three to an idle position, but all the other carbs are then way past their idle positions.
You need to fire up the bike, and adjust #'s 1,2 and 4 down a bit. As they come down, the bike will want to die, so you must up the idle... by turning the main screw that will open #3.
You will be synching back a forth for a while till everyone gets on line with #3's new idle setting.

**ross** · 05-10-2008, 12:47 AM

hey there prom....thanx for the feedback....if i was gonna offer anything it would be wild times and wilder women....but then that's just me....

have violated every orifice found in each carb with carb cleaner and air.....

i see you agree with me in theory....3 is set by the main carb screw......if that screw is totally unscrewed and you tried to sync the carbs from that setting, 3 would run cool....as the other 3 cylinders are running to keep idle....

pilot screw tweaking???...put 4 new ones in before i started.....clean as a whistle...i will turn the pilot screws out to 1-1/2....also throttle cable is loose at carb connection so i know that is not hangin' up....not too loose, but enough to show slack....

i was just thinking that if you tried 2 sync the carbs after a rebuild and messed up the main idle screw adjustment, that with 3 completely shut and 1, 2, & 4 open would you not get a cool reading on 3....i might have a 1/2 turn on the main idle screw before it is completely not touching 3 idle plate....ross

**prometheus578** · 05-10-2008, 01:08 AM

Yes, with #3 completely shut, it would get little fuel.
Now, if you have a synch tool, what I suggest is....
Back off the main idle screw.
Slowly screw it back in, watching the linkage. When it moves a little that means that #3 is open. (what the other carbs are at, who knows.)
Try to start the bike... being ready to turn it off quicky if the idle's too high.
If it won't idle, turn the screw in a little more, opening #3 up more(but at the same time, all other carbs, will be opening more.
Once you get it to idle, start closing the other carbs.
As the other carbs close, the bike will starve and want to die... so one must raise the idle more to compensate. Eventually, you'll get to the point where all carbs are about the same.
It's much easier with a synch tool. No guess work involved.
If you don't have a synch tool, you'll be chasing your tail for hours.
About the best thing to do would be to pull the carbs, set #3 open a bit and use the bread tie method to bench-synch the rest.

**ross** · 05-10-2008, 01:18 AM

hey there prom...check out the $64,000 question thread....yes, i do have a sync tool.....used the bread tie method and was way off....but then again not sure.....could of messed it up when i adjusted the main idle screw back down....just has me thinking.....thanx for the advice....with stupidy comes wisdom....ross

**prometheus578** · 05-10-2008, 01:35 AM

"I'm sorry, Ross."

I was following that thread for a while.
As many other "bigwigs" had chimed in, and their advice was good, as usual, I sort of drifted away to stick my nose elsewhere.
Never saw those last pics that you had posted, and such.

**skids** · 05-10-2008, 07:24 AM

I hope that you set the synch (or tried) when it was close to idle speed. I would definately see about leaks around the manifold boots. Be careful with wd40 as it WILL catch on fire with a hot engine. That brings up another question which you must forgive me if I haven't read all of the leading threads (I am lazy), the engine should be at normal operating temperature before you try and set the pilots and the synching. Check your choke operation and make sure that none of the linkages have disconnected. I agree that spark plug readings can tell you a lot. A propane torche can cave you a bit of money and time as you can burn off carbon and fuel fouling for retesting. Leaky float? Bad float level? Wrong pilot jets? Broken off pilot screw? Plugged screen at float valve inlet? Breather hose plugged?

**ross** · 05-17-2008, 08:53 PM

sync-ing problem solved....

hey there folks....i finally got the "rebel devil" synced up right....i know there are many ideas, methods, and theories about which is the right way....so far i have found this works best.....at least it is the most consistent and now the bike runs really good.....gas mileage is better also....

i originally bought 1 vacuum gauge from harbor freight and tried my best....ran good, but knew it had more in her....

talked 2 the mechanic and he mentioned about using 4 gauges to get the correct reading....

there was the issue about making sure the gauges all read the same.....decided that if all is to be calibrated off #3 then i should calibrate all the gauges off of that carb......needless to say that the 3 new gauges read really close to each other and that the original one i purchased was 3cm Hg off....figured in the difference and got them all to balance out....

to control the pulse of pressure from the motor i used cheap air hose valves from a fish tank.....eliminates the need for an expansion chamber as i had previously used in "the $64,000 question" thread.....

needless to say she is running pretty good...hoping 2 get her back on the road 2morrow and check her out.....i do want to thank all of you that have put up with my silly questions, but i promise you that your answers did not fall on deaf ears and now those thoughts are etched in the stone tablets in the rear of my service manual....thanx again...ross

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