Triumphrat

FunCrusherPlus

Hi everyone,

Does anyone have any tips or tricks on how to resync my carbs?

do I need to take the gas tank off? is there a way to keep the tank on?

thanks,

Marlo

TrumpetPlayer

I've done it with the tank in place, but it's a little tricky. The adjuster screw is hard to get at with the tank bolted down, and there is very little clearance. I use a Phillips bit from a multi function screw driver.

I'm thinking of pulling out the adjuster screw at some point to see if I can find a close match at the hardware store that will allow me to use either a hex key or a combination wrench to make the adjustments more easily and precicely than with a Phillips screw driver. The Phillips head sync adjusters are a dumb idea, but all Japanese CV carbs I've ever worked on have used them.

You can try unbolting the tank and propping it up at the rear. This will give you an extra inch or two of clearance. Also, the engine will be hot, so wear gloves.

I presume you alread have a set of vaccum gauges, a manometer, or a homemade (12 foot length of tubing zip tied to a yard stick and filled with gear oil or transmission fluid) sync tool.

Whisperinsmith

Here is a very valuable site. Carb sync pages are full of pictures.

http://members.bluefrog.com/~pwhitbec/

__________________
Life. Fill 'er up. It's all we got.

http://www.armchaircommando.org/benn...Bash/Home.html
Bennington, VT May 31, June 01 2008

moschika

and this is why i've decided to let the dealer do it. :wink:

after reading the link above, this gets beyond my skill level in so many ways. and fiddling with cars when i was younger, carbs were one of those things best left to people who know what they were doing - something me and my friends could not consider ourselves a part of that group, tho i'm sure some thought they did :razz:

GaryD

Every time this subject comes up I suggest that our fiends at Bellacorse or NewBonneville come up with a product to replace the phillips head adjusting screw; so here I go again.

__________________
Unsafe at any speed. First Terranaut.

Gohm

I either use a stubby philips screwdriver or my 90 degree offset motion pro tool to adjust the synch without removing the tank. Be sure to have the engine warmed up good and your idle already set.

__________________
Be a "weekend warrior" 7 days a week, 365 days a year!

My Photo Album

"A wink is as good as a nod to a blind bat" - MP

FunCrusherPlus

the dealer is charging $60 to re sync the carbs, for what seems to be a 30 min job, Newbonneville had the mercury carb tuner for $45 all this is, is adjusting the carbs by turning a screw...right?

Christov

Yes, once the carb stix are in place on the intake manifold the single screw is adjusted. This is adjusting the linkage between the two carburetors. One of the carburetors is fixed and non adjustable. The screw that you are adjusting is synchronizing the adjustable carburetor to the same reading as the fixed carb. In multi carburetor 4 cylinder bikes, there are usually 2 screws. The number 3 carburetor is fixed, and you dial the number 2 carb to the same as the number 3. The other screw is for 1&4 which are connected and adjusted by a single screw. Again, adjust the single screw for 1&4 to the adjusted readings of 2 & 3.
Piece of cake.

__________________
Fighting Terrorism Since 1861.

TrumpetPlayer

Once you get good at it, it's really more like a five or ten minute job. Yes, technically, it's just a matter or turning a screw, or at least that's the more important part. I usually do mine after coming home from a ride, since the engine is still at operating temperature.

1.) Put the bike on the centerstand (if you have one)
2.) Remove the vacuum caps on the intake runners going into the head.
3.) Place the tubes from the gauges, manometer, etc. onto the vacuum nipples, tubes, whatever, that the recently removed caps were covering.
4.) Situate the gauge.
5.) Put on gloves and grab the screwdriver.
6.) Start the engine.
7.) Let the idle settle for a few seconds, and look at the gauge. If you like what you see, stop the bike and undo the first three steps in reverse order. You're done.
8.) If you don't like what you see (gauges don't agree, mercury columns in manometer are not equal or close to equal), then get in there and turn the screw a little. If the indications even out, you went the right direction. If they got further out of whack, go the other way.

Make small adjustments. 1/4 turn is HUGE. Oftentimes 1/16th of a turn is sufficient unless the butterflies are really out of agreement.

With a mercury manometer, it's tough to get the two columns to be EXACTLY even with no fluctuation, so don't drive yourself mad trying to make it happen. If they are within 1/4cm to 1/2cm of each other, and fairly stable, that's quite good enough.

After each adjustment of the screw, blip the throttle slightly to settle everything and ensure accurate readings.

It just takes a little practice, but it's not rocket science. Compared to the potential frustration of syncing a four cylinder bank of carbs, the procedure on the Bonneville is a piece 'o' cake. Only one adjuster screw, instead of three. The only thing simpler would be a single cylinder engine.

JPS66

There is a nice carb vacuum unit from Morgan called Carbtune
Is it worth the money? That's a personal choice I think.
It certainly makes balancing the carbs a simple job although a better adjustment screw would help for sure. That little philips is a nightmare. :evil:
- J

__________________
"A bend in the road is not the end of the road -- unless you fail to make the turn." - Anonymous