Carb adjustment help needed!!!

So I have my bike running pretty good, but have run into a little confusion. Cylinders 1, 3, and 4 all run very well and at the proper temp with the carb mixture screws 2 and 1/4 turns from bottom. Cylinder #2 runs cold(probably not even firing) unless the mixture screw is about 6 turns out, at which point the cylinder starts firing and the pipe gets hot. Is this just a dirty pilot jet? I have not run a compression check to see if #2 is low, but the engine does not smoke, and it seems like it runs fine at 6 turns on #2 and 2 1/4 on the rest(although I can smell that it is running rich).
Any help would be awesome!!!

 

So I popped my carbs off yesterday, and found my problems(I hope all of them!). The carb boot on #2(my problem cylinder) was split wide open and causing a huge air leak. Also, the tiny spring that forces the #2 and #4 butterfly valvse to stay in sync with eachother was missing. This caused #2 to be dead at idle(wich explains my cold pipe), and only about 1/2-2/3 open when the other carbs are wide open.
I hope that this info can help if anyone is having the same problem!

 

I have an '86 that I will also probably have to pull the carbs off of for at least a good cleaning. Those old rubber boots made me a bit nervous cause I didn't want to tear one. Did you replace it with a new one? If so, where did you get them?

 

I had dreaded pulling the carbs for some time because of the intricacy of the setup, but it actually wasn't too bad. I took off the upper choke linkage first, then removed carb #1. #2, #3 and #4 have linkage that is pretty much impossible to remove on the bike, so those carbs came out hooked together. As far as cleaning them goes, they weren't really any more complicated than other constant velocity carbs internally.
Before reinstalling them, I replaced the bad boot with a good one from a parts bike that I have. I don't know if they are available from Honda, but shouldn't be too hard to find at a salvage yard.
I "synced" the carbs visually before reinstalling them, just adjusting the butterfly valves so they were all open equally(probably not the most accurate method, but it seems to have worked and I can't imagine trying to do it with them on the bike).
Putting the carbs back on was much harder than taking them off. On my '86, the carbs have bolts that hold them together at the bowls for ease of installation, but the '84 carbs are only held together by the aluminum plate to which the airbox attaches. I put the airbox plate on the carbs to hold them together during installation, but had to remove it to push them into the boots, and then replace it. The hard part here is that the small spring that syncs #2 and #4 is only held in by pressure(poor design), and can easily fall out while you are pushing the carbs into the boots. It is only fully secure when the boots are tight and the airbox plate re-attached.
The best piece of advice that I can impart is to make ABSOLUTELY sure to have rags stuffed into the carb boots before trying to pull the carbs from the frame. There are two small springs, and several tiny aluminum washers that seal the carb-to-carb fuel lines that can easily fall off and drop down the intake ports, through an open valve, and into the cylinder(which would really suck)!
I hope that helps!

 

Ok, I want to sync the carbs with a sync tool etc, but I have no clue where to hook up the tool.. Where are the vac lines the carb sync tool mentions? Where are the adjustment screws?

I am such a newb to carbs...

 

You do want to remove and replace the carbs as a set. Failure to do so can result in broken fuel tubes and bent linkage.

Here is a link to carb rebuilding:http://users.rcn.com/kochc/moto/carb/carb.html

The rubber boots should still be available from Honda. If not, boiling them (don't let them touch the bottom) can soften them up.

- For the '85-'83 carbs, install the carbs to the aluminum plenum (air box).

- Now slide the carb assembly into the engine. Attach the throttle and choke cables and adjust. Rotating the carb assembly makes it easier to install the cables.

- Now slide the boots into position. (carbs go in first, then the boots)

- Position the boots like so:


- Stand on the rider pegs and push directly down while slightly rocking in a circle. You may have to take a dulled, thin straight screwdriver to "help" the lip of the boot slip over the carb intake.

Note about bench syncing.
- Loosen the idle adjustment until it is not touching.
- Take a 3/32" slip of copy paper and use it as a feeler gauge to synch the carbs. Just put the slip between the throttle plate and the bore. Be sure it is furthest from the throttle plate shaft. If not, your adjustment will be off. Sync carbs 4, 3, 2, 1 in order. Then turn your idle adjustment in 1 full turn from touching.

This will get you in the ballpark and result in a good running bike. Doing a carb sync with the carbs on the bike will improve throttle response, smoother running and better mileage.

The vac lines ports are on the actual engine block. On each cylinder, right below the "fins" you should see a phillips screw. Remove it and insert the brass "extension" tube that the vacuum line attaches to. Bear in mind these screws are usually stuck pretty good.

The sync screws are located on the underside of the carburetor. There are three. You synchronize cylinders 1,2 & 3 to cylinder 4 - which has no adjustment. The manual will show you which screws adjust which cylinder. Motion Pro makes carb sychronizers, and so do other mfrs. I got mine (mercury - no longer available) from JC Whitney. Be sure to get the "extension" tubes for multi-cylinder Hondas.

Adjusting the screws is always difficult due to the coolant tubes being in the way, close quarters, and the very hot engine.

 

Thank you so much... Extremely informative!

 

Ok, I am cheap... Will this work? i am looking for an easy way to sync the carbs... it is about 1/4 the price of normal adjusters. Obviously not as accurate but could possibly work. Plus you dont need to remove any of the vac screws etc...

Ok, I will call myself lazy

 

Kind of hard to attach it to the carbs don't ya' think?