Carb holder clamps....variable idle...

[TomRodgers]

Anybody out there ever replace carb holder clamp screws? After pondering the funky idle of BlackSunshine last night after sync'ing the carbs, i cant help but think its getting air in it somewhere..( i did not do the spray and pray technique ) to verify, but will do that tonight/tomorrow. The carbs return mechanically to the stops at idle quickly, but bike drones on at higher rpms for a long time, and never to the same 'idle' location. The #2 and #3 holder didnt seem to snug up very tight, and further inspection shows some slightly worn phillips heads..... off to hardware store after work today. In one of the other posts, what/where exactly are the advance springs? in the timing cover on the left side of bike?

[randy]

Tom, the spray and pray technique can be messy, if you have one, you might try a propane torch (UNLIT!). Open the valve and let the motor suck in the vapor, that will identify the air leaks, if any. Also, I see by your signature that you ave a 4-into-1 with stock pilots. Could be running lean? Mixture adjustment is part of the synch process, but you may already know that. The advance springs are under the timing plate in the advance mechanism. That mechanism could just be sticky, while you have it out, lube it up. If you dismantle it to lube it, be careful to orient the rotor in the same position as it came off. It's possible to re-install the rotor 180 degrees out. DAMHIK!

[foreda]

Hmmm

Did you try removing the vacuum advance line? I know you know you know this but is the vacuum advance line connected to the number 2 carb?? Diaphrams checked for pin holes?? JAT

[TomRodgers]

Diaphrams 'looked' okay. vacuum line is hooked up to #2, but that line is looking old and dry. i may have to tear into the the timing cover and check things out. i know it is smooth and VERY responsive to acceleration. raps up the rpm range without hesitation or anything. i had two turbo fans on the thing last night, ran it for almost half an hour, and plugs had a nice tan color to them. i did have to back the idle mix screws out a pit to keep the thing from spitting.... but to have the idle go from 1100 rpms and pulling even on the guages (carbtune), rev it up to about 7grand, and have it SLOWLY come back down to 2200 rpms....and no lower....its weird. im stopping to pick up better clamp screws today. it was acting a little funny....1 to2 and 3 to 4 seemed hard to get adjusted evenly. whole thing could be a leak on 2 and 3. will update after i tighten the sh!t out of them!!!!

[foreda]

#2

Pull the vacuum line off of the #2 and pressure test. That may be where you're leak is. JAT

[TomRodgers]

Pull the vacuum line off of the #2 and pressure test. That may be where you're leak is. JAT

okay..... just how does i doo dat?? pop it off the #2, guage the tube while running... what should it be??

[foreda]

Test

okay..... just how does i doo dat?? pop it off the #2, guage the tube while running... what should it be??

Just pull it off of the # 2 and clean the hose and suck on it. I know it sounds dumb but it works. You should pull the left side cover to observe the advance mechanism. When you pull a vacuum on it, it should stay.
Das how I do dat!!

[TomRodgers]

lemme guess...if it moves when i suck on it ( no comments from the plethura of monkies in the peanut gallery!!!) then something is broke? if it stays put the springs are okay?

[CatatonicBug]

lemme guess...if it moves when i suck on it ( no comments from the plethura of monkies in the peanut gallery!!!) then something is broke? if it stays put the springs are okay?

If it moves when you suck on it, that is a good thing, and when you stop sucking, it should go back to where it was (springs at work).

[randy]

If it moves when you suck on it, that is a good thing, and when you stop sucking, it should go back to where it was

There's at least a dozen jokes in there......

[TomRodgers]

ive never had that cover off before...is that bit of hose easy to replace if needed? or is it...complicated?

should the sucking be done while running or no?

[DGXSER]

The hose is easy to replace if needed, just pops through the back side of the timing area there and then straight up to the carb port.

As to the sucking and running....well..I was gonna say something about a rule of running with stuff in your mouth and all...but...The vacuum advance is mechanical and it will move when vacuum is applied to the tube weather or not the engine is running. Of course that assumes the tube is not deteriorated and leaking, which I have not seen on one of these yet.

[cywelchjr]

That bit of hose should be easy to replace, I plan on replacing mine next weekend (or sooner if I can get around to getting the right hose sooner.

You should do the suck test without it running, you just want to make sure it pulls up and stays there. If you have a might vac, you can use that to do the test and then you can test for actual amount of advance applied by it if you have the bike running, but the suck on it, I would do without it running.

[TomRodgers]

Update.... Tried out the colortune. think im making progress.... get a nice blue flame most of the time, with the occasional white flame....but the beast is idling now. much better than it has before. now gunna sync it up. probably shoulda checked but the thing had different plugs ....1 and 2 were the same...3 and 4 were the same... replaced with all 4 the same, and revs right up, AND back down like it should. question is...is it uncommon to have to back the mix screws out 3 complete turns??? to start off with, i turned them all in until stopped...gentle i was... backed each out 1.5 turns. then started beast up...each one had to be turned out another full turn to keep from having continuous white flame. another 3/4 turn makes them start to burn a lot of yellow. backed it off a bit, and only occasional yellow flame... according to instructions..this is dead on. but 3 turns out??? seems odd.

[CatatonicBug]

Completely normal to have 3+ turns out after a colortune. I'm at anywhere between 3 and 4.5 turns out across my 4 carbs. Remember you need to be just at the edge of blue, just barely touching the lighter color. What you should do is synch the carbs first, then colortune, then synch again immediately afterward.