Triumph Rat Motorcycle Forums banner

1 - 20 of 29 Posts

·
Registered
Joined
·
27 Posts
Discussion Starter #1
After removing my AI, I started to notice one pipe bluing a bit more than the other. Pulled the spark plugs and one side's burned a bit hotter than the other too. Decided to sync the carbs.

I've got a California bike, so it's got an evaporative loss system. General instruction (for all bikes) in the tech manual says to take the rubber caps off at the take-off points on top of the intake manifolds. My bike (2006 Bonnie, purchased new) has vacuum hoses here, not rubber caps.

lt also says (in bold) that for California bikes, I should disconnect the evap loss system hoses from the *carb* take off points and plug the hose ends.

So, two questions:

1. The *carb* take off points - are these located on the carbs, facing up, about three inches behind the intake manifold take-off points? (I assume this answer is yes, but I just want to be sure).

2. Should I be connecting the vacuum gauges at the intake take-off points and just plugging the vacuum hose that I pull off the *carb* take off points to do the test? If this is the case, then what happens to the vacuum I'm testing for, once the vacuum hose is off the carb (when I pull the hose off the carb, doesn't that screw up the vacuum)?

And no, I haven't been drinking...yet.

Thanks for the help!
Jim
 

·
Registered
Joined
·
1,499 Posts
Just put the plugs on the carb "take off" points and do the vacuum reading on the intake manifolds.The balance will be out cause the A.I. runs off the vacum from the left manifold.After setting up corectly reverse the hoses on the cylinders(left to right, visa versa) to allow for any inacuracy in your gauge.
I would be tempted to take the Californian evap ststem off and just put plugs back in afterwards,I sure no one else will know. :)
 

·
Registered
Joined
·
3,588 Posts
1. Yes
2. I can't tell any difference on mine between the intake and carb take-off points for balancing the carbs. I believe I would do the balance with the vacuum hoses disconnected; therefore, it would be easier to use the vacuum takeoff ports where the hoses were connected ( I believe that's what amanger said). Once you pull the hoses off the carbs, you have disabled the AI and CA emissions systems--don't worry about it for the carb balancing. What you are doing is setting the carbs so the slides are working exactly the same amount for a given throttle setting. Since you have the CA equipped bike, your vacuum between the two carbs is probably closer to equal when the system is connected than ours is with only the AI system connected to only one carb. Good luck with the adjustment screw--not the easiest to adjust and could be much easier if Triumph had used a hex or Torx screw with more threads/inch (still having a hard time thinking in terms of mm and pitch on metric screws).

Pipe blueing: I have never read where anyone has said their pipes blued the same on each side--with or without the AI system (doesn't mean it hasn't happened). I have read where many have said the left side (if my memory is correct) blued more than the right side. If I were going to worry about pipe blueing in any way, I would have the headers black ceramic coated and forget about worrying.

Larry
 

·
Registered
Joined
·
226 Posts
Just out of curiosity, what readings did you get? I got an average of 27-28 psi at idle with a el cheapo gauge taken at the intake manifold, with the other plugged while the test one was hooked up.

My bike has been missing at 4-5 in high gear at light throttle settings, plugged the plugs and they were black!
 

·
Registered
Joined
·
5,557 Posts
I don't think you need to be too concerned with the specific vacuum reading (how hi/how lo). What you're concerned with is that they both read (or can be balanced to read) the same at idle.

Now if there was a vacuum leak in one of the manifold rubbers, or one of the vacuum plugs was split, you'd probably see excessively low vacuum on that carb.

But if everything is buttoned up and there's no leaks, balancing simply assures that both carb butterflys are essentially open the same amount relative to each other, and that both carbs are 'seeing' the same amount of draw or vacuum from the engine.
Bob
 

·
Registered
Joined
·
27 Posts
Discussion Starter #6
My take too on this is that the pressure level isn't important, just that they're balanced. But since ya asked, I'll post tomorrow, when I actually do the work. (Got home too late tonight to get it done).

BTW, thanks for all the helpful responses. Makes it a lot easier to dive in and get it done...

Jim
 

·
Registered
Joined
·
296 Posts
Whats the current favourite device for balancing the carbs,
Here in the UK, Carbtune is recommended a lot.

Anyone still do it by ear?
 

·
Registered
Joined
·
1,499 Posts
15 ft clear fishtank hose same diameter as the vacum plugs(or slightly smaller) Find the exact centre,lenghtways,tape to a 4 ft bit of timber about 2" wide.Hang above bike height with loop at botom with enough liquid,preferably something that is nt going to harm your engine,ie. fuel injecter cleaner.Plug each end to manifold plugs.Start bike on fast idle.Adjust using very short screwdriver and much cursing till liquid is level on both sides of loop.Take off hoses and swap left to right.Takes about 15 min. Cost about $2-$5. :)
 

·
Registered
Joined
·
5,557 Posts
I use the 'fluid tube' you described, and it works very well.

If anyone here wants the plans, I'll post the link to a BMW Airhead site that provides it. I made mine a couple of months ago, and used it to balance the T100, W650, and will use it on the old Beemer shortly.

Bob
 

·
Registered
Joined
·
296 Posts
On 2006-06-28 05:50, ohiorider wrote:
I use the 'fluid tube' you described, and it works very well.

If anyone here wants the plans, I'll post the link to a BMW Airhead site that provides it. I made mine a couple of months ago, and used it to balance the T100, W650, and will use it on the old Beemer shortly.

Bob
Yes I'd like link to the plans please - perhaps we should make it a WIKI :wink: :wink:
 

·
Registered
Joined
·
296 Posts
On 2006-06-28 09:02, sweatmachine wrote:
I doubt the mechanic that pulled my AI did it
I think all this talk of AI removal affecting the carb balancing is pure fiction.

The balancing is actually done using the port on the left carb that the AI then plugs into (as well as the blanked port on the right carb).

So when the balancing is done the AI is out of the system and is not accounted for during balancing. Hence whether you reconnect the AI or not will not affect the balance.

Just my 2 pence worth :)
 

·
Registered
Joined
·
2,224 Posts
On 2006-06-28 11:29, ChrisV wrote:
On 2006-06-28 09:02, sweatmachine wrote:
I doubt the mechanic that pulled my AI did it
I think all this talk of AI removal affecting the carb balancing is pure fiction.

The balancing is actually done using the port on the left carb that the AI then plugs into (as well as the blanked port on the right carb).

So when the balancing is done the AI is out of the system and is not accounted for during balancing. Hence whether you reconnect the AI or not will not affect the balance.

Just my 2 pence worth :)
..................................................

Good point.
 

·
Registered
Joined
·
5,557 Posts
On 2006-06-28 08:03, ChrisV wrote:

Yes I'd like link to the plans please - perhaps we should make it a WIKI :wink: :wink:
For some reason - the URL no longer brings up the plans. I think I also saved them as a Word doc. If so, I'll cut and paste to my next post here. I can also provide a link to a cimmercial fluid loop that will show you approx what your completed unit should look like.

Bob
 

·
Registered
Joined
·
5,557 Posts
Sorry - the link is down and I have to post the entire article.

Here's the directions for building the fluid loop balancer. This came from a BMW riders' site. Remember, the directions for balancing a Beemer are more complicated than for our Bonnevilles, since the BMW must be balanced at (a) idle, and (b) at higher rpm. The reason for this is the fact that the BMW has a separate cable going to each carb, and they must both be pulling the same amount, or the carbs are out of balance at higher rpms. Although our bikes have two throttle cables, one is used to open both carbs, the other is used to assure they close. Summary - you don't need to balance your Bonneville at higher rpm, just at idle, say 1000-1100-1200rpm.

Also, keep in mind if your carbs are really out of balance, the one pulling the hardest can essentially pull all the fluid out of the loop. For that reason, use something that won't harm the engine. I used Stabil fuel stabilizer. The design calls for automatic transmission fluid.

Bob

Friday, 01 March 2002
Since joining the Airheads shortly after purchasing my first-ever Beemer in October of 2001, I've found the AirList to be an invaluable source of information and direct feedback as I learn my way around my new 1984 R100RS. One of the first things I do when acquainting myself with a new mount is a basic tune-up. Lurking on the Airlist provided a bunch of helpful tips to supplement (and correct) the tune-up info in the Haynes and Clymer manuals.
One of the slickest tune-up tips I came across was Tom Rowe's mention of a ridiculously cheap and easy-to-build differential manometer (vacuum gauge) for balancing carburetors on vacuum port equipped Boxers. I'd read about the Twin-Max (aprx. $80) and have used the $40 CarbStix on my 4-cylinder Hondas, but for less than $4, I was able to build a twin carb synchronizer that is 16 times more sensitive than my mercury vacuum gauges and can be assembled from common materials available at almost any hardware store. I built it and my R100RS loved it - it really smoothed out some bands of footpeg/bar/mirror vibration that the bike had, even after using the CarbStix.
I posted a 'Thank You' note for the idea on the AirList after I tried it and got even more valuable feedback from Jay Carpenter and a request from John "Beetle" Mailleue, ABC# 5657 to write a tech article for the AirMail. After spending some more time in the garage incorporating Jay Carpenter's ideas, I figured I'd go ahead and write-up a description of how to build and use the $4 Carb Synchronizer, because it REALLY works. Super cheap, super accurate, super easy to build and super easy to use - CLASSIC Airhead technology!
Credit for the original idea has to go to Marty Ignazito of the powered-parachute crowd, he came up with the idea to balance the twin Bings on a two-stroke Rotax and his original write-up is at www.powerchutes.com/manometer.asp. If you try this idea and like it, send Marty a thank-you e-mail at [email protected] This email address is being protected from spam bots, you need Javascript enabled to view it .
Here's the Materials List for the $4 Carb Synchronizer Tool:
• 20 feet of clear plastic (vinyl) tubing - inside diameter big enough to slip on the vacuum nipple of your carb (3/16" i.d. worked for my bike, but it's tight, maybe 1/4" i.d. might be better). 15 cents per foot in the plumbing section at my local 'big box' hardware store, Sutherlands.
• A yard stick - Home Depot sells an aluminum yardstick for under $2, but you can make a perfectly satisfactory gauge with a 3-foot piece of 1" wooden lathe for next-to-nothing. (For a 'professional'-looking gauge, I actually used a yellow aluminum 4-foot rule, but that was wretched excess at $5.)
• 3M/Scotch/Whatever - clear mailing/packaging tape. You should have some of this left over from the Christmas mailing season; otherwise around a $1 a small roll (and you won't need much).
• 2 short nylon zip-ties - You should have these in your garage. If not, buy them in bulk for cheap in the wiring section of Home Depot, Sutherlands, Ace Hardware, etc. - you'll use them and wonder why you didn't have them before.
• A tiny amount of automatic transmission fluid - Actually, just about any fluid works, including used motor oil, colored water, 2-stroke oil, etc. I chose ATF because I already had a gallon of it and (most important) it is really thin and is RED (which looks WAY cool as the indicator fluid against my fancy yellow ruler) and ATF won't hurt the engine if it accidentally gets sucked in the carb's vacuum port.
Building the Balancer
Fold your 20' of vinyl tubing in half and mark the center point. Lay your yardstick down flat on a convenient work surface (kitchen table or floor). Place the center point of the tubing at the bottom end of your yardstick (there is generally a hole at the top end of the yardstick - put the center-bend of your vinyl tubing at the opposite end of the yardstick from that hole). Carefully run the tubing up each side of the yardstick, making sure that the tubing makes a smooth, non-kinked bend at the bottom.
Use the clear packing/mailing tape to fasten the tubing in place on either side ( left and right ) of the yardstick. Thread the zip-ties through the hole at the top of the yardstick and snug the left and right side tubing to the respective sides of the 'stick with the zip-ties. You should now be able to hang your yardstick from the hole in the top ( I use a bungee suspended from a hook in the garage ceiling). The tubing runs around the perimeter of the yardstick and about seven feet of tubing hangs down from the left and right sides of the 'stick. I fold a piece of tape around each end of the tubing like a little flag and mark the left side with an "L" and the right side with an "R" using a magic marker.
Now, put one side of the tubing in the container of automatic transmission fluid and, using the other side of the tubing like a drinking straw, suck ATF fluid about three feet up into the tubing. Maintaining suction for a second, pull the tubing out of the ATF container and then raise BOTH ends of the tubing above the top of the yard stick. Temporarily fasten both ends of the tubing high enough that the ATF drains down to the loop at the bottom of the yardstick. I recommend leaving it overnight so that all the bubbles, etc. work their way out.
Once the ATF has settled into the bottom of the tubing, the balancer is almost ready to use. If everything has gone according to plan, you should now have a nicely graduated rule hanging from the ceiling with a thermometer-like tube running up both sides, with the red "thermometer" fluid about half-way up each side at identical heights. Cut a piece of black electrical tape just long enough to cover the width of your ruler and use it to mark the height of the fluid. Your super-accurate Carb Synchronizing Tool is now ready to use.
Synchronizing the Carburetors
BEFORE attempting to adjust the carburetors, you MUST have the other basic systems of the engine working properly: ignition properly adjusted (timing spot-on, advance mechanism operating properly), valves adjusted, compression within specifications, air filter clean, pollution lines leak-free, etc.
Warm up the bike with a ten-minute ride. Park the bike next to the Carb Synchronizer. Loosen the throttle cable adjuster lock nuts with a 10mm wrench and slack off the throttle cable adjusters until there is absolutely no tension on those cables - they should be loose. Disconnect the vacuum tubes that run from the carb nipples to the airbox (or remove the blanking screws or plugs from the vacuum ports, this varies between bikes - check your manual) and connect the right and left Carb Synchro Tool tubes to the respective nipples. Pick up a straight-blade screwdriver that fits the carburetors' throttle-stop screws and start the bike.
Synchronizing the Throttle Stop Screws at Idle
Unless you are incredibly lucky, the red fluid will begin to move, rising on one side of the ruler and dropping on the other. The fluid rises on that side of the bike where the throttle butterfly is more closed, which raises the intake vacuum. Gently turn that side's carb's throttle stop screw in (clock-wise) until the fluid movement stops, then just a touch more, until the fluid moves back toward equilibrium. As the fluid approaches the balance point (which you have marked with the black electrical tape), turn the throttle-stop screw counter-clockwise and STOP the fluid movement right at the balance point. Now check the tachometer for idle speed. If the idle speed is between 900 - 1100 RPM, you have the throttle stop screws perfectly balanced for idle speed. I like a 1050 RPM idle speed. If your idle speed is too high or too low, carefully adjust BOTH throttle-stop screws until the idle speed is within the 900 - 1100RPM range and the Carb Synchro fluid remains STOPPED at the balance point. Check to be sure you still have slack in both throttle cables. If so, the idle throttle stop screw synchronization is complete.
Important: the bike should NOT idle in the garage for more than 5 to10 minutes after being warmed up without a 'cool down' ride around the neighborhood or use of a BIG, high-speed fan, blowing cooling air over the engine.
Note: At this point, you may wish to adjust your Pilot Mixture Screws. Since this is not an absolutely necessary part of synchronizing the carburetors and is covered adequately in the various shop manuals, I will not address it here. If you do the Pilot Mixture adjustment, re-check the throttle stop screw balance and idle RPM and re-adjust as explained above.
Synchronizing the Throttle Cables
Now you must synchronize the throttle cables. Amazingly enough, neither the Haynes nor the Clymer manuals discuss this procedure, yet it is essential to smooth running, vibration-free highway-speed operation of your bike. Both throttle cables should still be slacked-off and their lock-nuts loose and the twist-grip will have a bit too much free-play as a result of loosening everything up for the idle adjustments. Carefully turn the throttle cable adjusters counterclockwise until MOST (but not ALL!) of the slack is removed from the cables, then spin the throttle-cable lock nuts down (clockwise) until they just BARELY seat. Re-check - there must STILL be some slack in BOTH cables. You should still be able to move the cable adjusters and lock nuts easily with your fingers. Start the bike. Idle speed should be the same as you have originally set it. Turn the handlebars to either side. Idle speed should not change. If idle speed or balance changes, you have TOO much tension on the cable(s) and must dial in some slack. If everything checks out, you are ready to synchronize the throttle cables.
With the engine running, slowly roll the throttle on until the engine speed picks up to 2500 RPM. Hold it there and check the Carb Synchro fluid. If the fluid is moving (as is likely), turn DOWN (clockwise) the throttle cable adjuster on the LOW side of the fluid until it stops, then moves back toward equilibrium, while holding the RPMs at 2500. As the fluid reaches the balance point, turn the throttle cable adjuster counter-clockwise and STOP the fluid movement as it reaches the black-tape-marked balance point. Snug the throttle-cable adjuster lock-nuts and re-check the balance by rolling on the throttle. If the fluid does not move from the balance point as the RPMs come up, shut off the bike and tighten the lock nuts. Re-check, including turning the handlebars to either side. If the fluid remains balanced, you now have perfectly synchronized carburetors. Disconnect the Carb Synchronizer Tool, reconnect the bikes's vacuum hoses (or replace the vacuum port screws/plugs) and go for a test ride.
I think you'll find, as I did, that well-balanced carbs make for a smoother Beemer.
Click here for a drawing of the balancer. It's a bit big, 89k, so download only if needed.
Hugh Kenny #6051
Cheyenne, Wyoming

PS - here's a link to a commercial unit. Your home made one will look like this, except you won't have (or need) all the fancy scales. All you're attempting to do with this device is to balance to where the columns of fluid are at the same level.

Link to commercial unit
 

·
Registered
Joined
·
1,499 Posts
On 2006-06-28 11:29, ChrisV wrote:
On 2006-06-28 09:02, sweatmachine wrote:
I doubt the mechanic that pulled my AI did it
I think all this talk of AI removal affecting the carb balancing is pure fiction.

The balancing is actually done using the port on the left carb that the AI then plugs into (as well as the blanked port on the right carb).

So when the balancing is done the AI is out of the system and is not accounted for during balancing. Hence whether you reconnect the AI or not will not affect the balance.

Just my 2 pence worth :)
ChrisV wrote the above,and I can see what your trying to get at but you have nt looked at the big picture.




I think that is why you find 2 vacum attachments on each manifold.When the carbs are balanced with the A.I. installed you use the rear attachments.
If you unplug the A.I. to balance there is no vacum to operate the valve and the bike wont run properly,that is why you cant just remove the vacum hose for the A.I. and bung the attachment,it would be much easier to do that though.
:-D :-D

[ This message was edited by: amanger on 2006-06-29 02:44 ]
 

·
Registered
Joined
·
1,032 Posts
Once synchronized, how many of you do like I do and connect the vacuum ports together with a piece of hose?
I've been running this way for over a year now and have had no synchronization/carb problems that I'm aware of. An old "Triumph Head" suggested that I do that and I've seen some older twin carbed Brit bikes at a local shop with a similar setup.

Shorty
 
1 - 20 of 29 Posts
Top