DIY Carb. Synchronizer

[badgertom]

Has anyone built their own carb. synchronizer. On the internet I find various home made units. I was planning to use 1/4 inch plastic tube
( reduced to 3/16 at the carb. for a tighter fit on my R65), 2 plastic bottles partially filled with partially 2 Stoke Oil. Does anyone recommend a better design that they have used? Thanks for any input.

[Barry]

I seen some balancers using bottles but a simple U tube manometer filled with ATF seems less messy.

[badgertom]

do you know if they used 1/4 tube and what liquid ( oil) was used. The design seems better, but where do I get the specs to build one?

[montmil]

I hang mine from a hook in the shop ceiling.

I also modified my $4.00 manometer by adding short bits of smaller tubing within the primary tubes. This tends to slow down the movement of the fluid and helps stabilize the often too quick vacuum draw.

Remember, balancing carbs MUST be done on a fully warmed-up engine. A ride around the block will give false results and only add to your frustration. Depending on ambient temps, ten miles or more will be necessary.

Place a large fan in front of the engine while tweaking the Bings. Try to get the work done within ten minutes or less so you do not overheat the engine.

Don't forget to balance the throttle cables, too. Use the friction screw on the twistgrip to set and hold revs around 3500-400 rpm.

[montmil]

do you know if they used 1/4 tube and what liquid ( oil) was used. The design seems better, but where do I get the specs to build one?

Photos show all you need. Nuttin' fancy about it. ATF, brake fluid, or my favorite... BMW fork oil.

[badgertom]

Thanks, I'll give it a try.

[Barry]

I used 6mm tube which is a little slack on the vacuum nipples but I found that sliding some copper olives over the end of the tube tightens them up nicely. You'll see in the pic I painted one oliver red (For right hand carb) so I always connect the manometer up the same way. As Monte said there is no real spec. If there any tips it would be make the manometer tall enough that you don't inadvertently suck fluid into the carbs from the vacuum being too far out of balance. Not that it's an issue for routine service sync's as they never get that far out. But if it was to happen ATF is a good choice as it will do no harm to the engine. 2 stroke oil would also be good for the same reason. Another tip is make the manometer tails plenty long enough so that they are not going to get draped over the hot exhaust pipes.

Yard sticks are most commonly used to support the tubing. Mine is a 4ft length of wall support bracket used  for slotted shelving. Just something I happened to have and all those slots were perfect for passing the zip ties through.

[badgertom]

Thanks again. I will try to synchronize the carbs this week.

[snowman910]

Could someone re-post photos of the vacuum take off points on the carbs, please?

[Barry]

The vacuum port is the nearest of the two protrusions the other being the mixture screw . This is a right hand carb and on the left carb the positions of these two items will be reversed.

[Luca]

Barry's vacuum port has a screw threaded into it, but US model bikes still sporting their emissions system will have rubber hoses slipped over the vacuum ports.

[Barry]

If the screws are needed they are M3.5 x 0.6  

[tunnelrider]

Hi guys, sorry to be jumping in on this thread but I've been using it to try and complete my first tune up and solve the problem of high revs at idle.  I made my manometer this morning using Barry's set up but hanging the guage up.  I put in 25cc of 2 stroke oil.  Setting the idle mixture screws at 3/4 turn from light seating as the Clymer says, it sucks out one side of the manometer.
Predictably this is the side with the poorest compression (both cylinders are 'poor' at 87psi and 62psi, can't fix it now as it's just turned riding season down here!).

My first question is whether anyone thinks it's worth carrying on trying to balance the carbs considering the difference in cylinder compression?  My second question is by turning the idle mixture screw in, should this basically increase or decrease the vaccum on that side?

Cheers

[montmil]

If memory serves, it should decrease.

You didn't say if you had added the very helpful 'restrictors' in the lines. Go back to the hardware store with a scrap of the hose you are using on the manometer. Buy a couple inches of tubing that will fit inside each of your primany hoses. Just takes an inch-long piece on each tube. I placed mine about six-inches from the ends that attach to the vacuum ports.

This will slow down the movement of the fluid that's currently helping you fog the neighborhood for skeeters. Perhaps try a slightly heavier oil if the restrictors are not enough.

You'll get there. Good fan setup.  [smiley=thumbup.gif] On my R65s, 3/4 open was too much. That's just a basic starting point.

[tunnelrider]

OK thanks for your tips Monte, I'll try out the 'restrictors' too.