Author Topic: carb synchronization question (Read 5478 times)

shrike · « **on:** July 13, 2007, 01:30:02 PM »

Hello,
Does anyone have a link or can someone share their experience when synchronizing the carbs on a B12?
I just got my morgan carbtune and I'd like to do this tonight. I know I would need a fan, engine at working temperature and from what the booklet says the idle should be set a bit higher.

I will also check to see how my air filter looks before doing that.

Anything else I should know?

Thanks.....

pmackie · « **Reply #1 on:** July 13, 2007, 03:44:08 PM »

I did mine without a fan, using my new Morgan Carb Tune. Took less than 5 minutes, so bike did not get too hot.

Since it was my first time using the Morgan, I started playing with it when the engine was cold. Pretty simple. Once I had it roughed in, the engine was warm, and it only took 30-60 seconds to balance things. I started at 2000 rpm, and checked again at 1200 idle once finished.

The hardest part is getting the tank off, finding something to block it in place so you have fuel to the carbs and still have access to the adjustment screws between the carbs. I set mine cross ways approx where the seat attaches and used a longer fuel line that I had handy.

Some guys say they can balance with only the fuel in the carb bowls, and likely once you get familiar with the proceedure you can, but for your first time, you will need to have fuel to the carbs.

The Morgan Carb Tune is pretty slick. Just follow their instructions on setting it up.

Good luck

bikeb4cage · « **Reply #2 on:** July 13, 2007, 04:02:19 PM »

For what it's worth, I had trouble getting at the clips and caps for the carb sensing lines with the carbs installed - I have a stage II, so it was easy to pull the carbs back from the inlet and remove the clips/caps/install the lines...and then reinstall.

Jay

shrike · « **Reply #3 on:** July 13, 2007, 09:02:44 PM »

guys, that piece of crap does not work. The idle always fluctuates. The manual calls for 1750 RPM. I can't get it. Even if I go for 2000 rpm I can't get it. It goes high and then the RPM drop to close to 1500 RPM.
Also when the engine is coldd I hear some backfires in the air box. I don't know what could cause this. Can it be the valves that are not properly adjusted. I think I will have to open it up again. I know I checked them many times after I adjusted them. I can't explain the backfiring unless the bike is waaaaay too lean but I never touched the carbs. Also the backfires when cold situation seems to get worse and worse.

shrike · « **Reply #4 on:** July 13, 2007, 09:09:46 PM »

One more thing. Backfires seem to be in the airbox. Also when carbtune is plugged if I give it gas it takes time for the RPM to drop.

Red01 · « **Reply #5 on:** July 14, 2007, 11:56:49 AM »

FWIW - mine (Holeshot Stage II pod kit) still backfires a little when cold if you try to ride it before it's warmed up. They aren't booming backfires, more like little sneezes. I figure I must be jetted a little leaner than most because I still have to use some choke to start it.

shrike · « **Reply #6 on:** July 14, 2007, 01:10:28 PM »

Quote from: "Red01"

FWIW - mine (Holeshot Stage II pod kit) still backfires a little when cold if you try to ride it before it's warmed up. They aren't booming backfires, more like little sneezes. I figure I must be jetted a little leaner than most because I still have to use some choke to start it.

Mine does the same thing but because of that I can't synchronize the carbs. What trick do you use to synchronize them. Right now I took the carbs off. I took the plugs off the A/F screw and I measured the settings. They vary from 2.5 to 3.375 about turns out, so I will leave them like that for now . I won't touch them

Red01 · « **Reply #7 on:** July 14, 2007, 02:27:20 PM »

To be honest, I've never synch'd them. I've got a synch tool (mercury type), just never have bothered taking the time.

My A/F screws were all over the map when I did the jet kit. One was completely closed! Set them all to 3.5 turns out when I did the kit 6 years ago and since it was and is running well, I've never gone back in and futzed with anything.

shrike · « **Reply #8 on:** July 14, 2007, 06:11:45 PM »

Well, the carbs were dirty. there was like a brown jelly on the bottom of the bowls. So I guess that's varnished gas. Now I ran into another problem. One of the diaphragms is torn. So I got to wait to buy that before synchronizing the carbs

Daytona · « **Reply #9 on:** July 14, 2007, 11:00:11 PM »

Quote from: "shrike"

guys, that piece of crap does not work. The idle always fluctuates. The manual calls for 1750 RPM. I can't get it. Even if I go for 2000 rpm I can't get it. It goes high and then the RPM drop to close to 1500 RPM.
Also when the engine is coldd I hear some backfires in the air box. I don't know what could cause this. Can it be the valves that are not properly adjusted. I think I will have to open it up again. I know I checked them many times after I adjusted them. I can't explain the backfiring unless the bike is waaaaay too lean but I never touched the carbs. Also the backfires when cold situation seems to get worse and worse.

You have the air box or filter housing all sealed up rite? Air to the carbs is very important. Dirty filter makes no diff your just syncing all carbs together. I like the PO mans system! If you have 4 lines your syncing the carbs to the tool, not to each other. Don't use the enrichner to elevate the rpm. Diaphram needs to be changed but makes no diff when not running faster than 2K rpm. Its got to Idle smoothly or sync won't do any good! Its the last thing just to fine tune. TPS set rite? Why did you have to remove the carbs to get at the tips?

Daytona · « **Reply #10 on:** July 14, 2007, 11:12:47 PM »

Daytona · « **Reply #11 on:** July 14, 2007, 11:23:07 PM »

Did you look at the sync threads? It covers it all.

shrike · « **Reply #12 on:** July 15, 2007, 12:55:24 AM »

Quote from: "Daytona"

Why did you have to remove the carbs to get at the tips?

Thanks for the input. Yes I read about the synch threads over here but also on the net, in the manual for the bike and in the manual for the synch tool. On my old Nighthawk I tried a tool similar to yours but all the oil went in the carbs. Got a bit smoky so I decided to buy the Carbtune this time.
The airbox should be tight, I never opened it. Well I did but yesterday only so I don't think that was the problem.

I am not sure I get your question about the tips? If you mean to the stubs on which you plug the tubes for synchronizing then I did not take them off for that. I took them off after trying to synchronize and as the idle speed was very rough because of those backfires I then decided to clean them. There was a bit of brown-red gunk in them.
I adjusted the TPS to the 76% value but that did not change anything so I put it bacl to the 81% it was set at from the factory. I'll put it back though to 76% before trying again to synch them.
I'll check the airbox again to see if everything is fine but I will wait to buy the diaphragm before trying again

Daytona · « **Reply #13 on:** July 15, 2007, 01:10:05 AM »

Your on the rite track then. The cleaning will or has to do some good. Like i said it has to be running good for the sync to make it just rite. If the fluid gets sucked in the system which doesn't take much! I use colored water. This is the most touchy i found! When you get it within 1" with water its spot on. I just crimp the hose and adj till it stays in the loop. Gages, etc always cause me to have doubts if they are correct, tube has carb / TB pulling against each other is just fool proof. Good luck. When you get it smooth it will all be worth it! It will make such a diff, even when you say its running great.

shrike · « **Reply #14 on:** July 15, 2007, 11:35:08 AM »

Did you have to make like a restrictor on it? I am thinking maybe that was the problem when I tried that method the first time.

I cleaned the carbs but now after speaking with someone i might have made another bad move. I also dumped the float needles in carbcleaner and if I am not mistaken the are rubber tipped. Should I change them now?