Penny-tech carb sync tool

[kevbo]

Originally Posted by Randy

i hooked it up to my mityvac and it held a good deal more vacuum than it will ever see in it's normal useage.

If you have a mity vac, you can use it to pull the glue into the leak. Done that a lot using JB weld.

[Caribou Bentspoke]

Good job Kevbo, I have an even better way to adjust the filters (needle valves) to zero them so to speak.....
Start the bike and stabilize idle, then zero each tube, using the same cylinder on the bike. If idle is stable this is 100 percent accurate, in fact many commercial vacuum gauges are calibrated just this way. You would have to mark the spot on the tube. Some of the commercial ones I have used had lines marked on the glass tubes, and you just picked a line. On a inline 4, I always use #1 cyl, and calibrated all tubes to that, at a constant idle.

bentspoke

[fixer]

kewl, i gotta build one for my KLR!

[Randy]

Originally Posted by bentspoke

Good job Kevbo, I have an even better way to adjust the filters (needle valves) to zero them so to speak.....
Start the bike and stabilize idle, then zero each tube, using the same cylinder on the bike. If idle is stable this is 100 percent accurate, in fact many commercial vacuum gauges are calibrated just this way. You would have to mark the spot on the tube. Some of the commercial ones I have used had lines marked on the glass tubes, and you just picked a line. On a inline 4, I always use #1 cyl, and calibrated all tubes to that, at a constant idle.

bentspoke

i'm not quite clear on your procedure. with this design you can't hook up one tube at a time or else all of your fluid would quickly be sucked out . i used a T fitting and a short length of hose connecting both vacuum tubes together then hooked it to one TB. to double check your "zero", just use the balancer as you would normaly then just reverse the tubes to opposite TBs. if the reading stays the same it's balanced.

[Cauldron]

I have one for a KLR that I will sell you dirt cheap.....

[kevbo]

The function of the valves is to slow down the response to vacuum changes, NOT to reduce the vacuum. The valves need to be set with both sides connected to the same vacuum (or even low pressure) source that is changing.The valves should have NO effect on a static (constant vacuum, constant rpm) reading unless one is completely closed, or you have a leak on the instrument side of the valves.

The "first principals" design gaurantees that this setup is zero'd at all times.

[Caribou Bentspoke]

Originally Posted by Randy

i'm not quite clear on your procedure. with this design you can't hook up one tube at a time or else all of your fluid would quickly be sucked out . i used a T fitting and a short length of hose connecting both vacuum tubes together then hooked it to one TB. to double check your "zero", just use the balancer as you would normaly then just reverse the tubes to opposite TBs. if the reading stays the same it's balanced.

Yes I see what you mean, I did not notice at first that they were interconnected. I wonder if one would be accurate if each side was separete, and had the fluid level at the exact same height on each side.

Bentspoke

[kevbo]

Originally Posted by bentspoke

I wonder if one would be accurate if each side was separete, and had the fluid level at the exact same height on each side.

Bentspoke

You can do that with a shared water resivoir (vented to atmosphere) at the bottom. This is how mercury carb sticks are made.

The problem is that when you chop the throttle, the vacuum can go to over 20"Hg(mercury) Since water is much lighter than quicksilver, you'd need an instrument about 25 feet tall.

Connecting the tubes at the bottom means the instrument only needs to indicate differences, so the high sensitivity goes from being a bug to a feature.

[maduko]

Thought I'd share a photo of the design I came up with. I opted for a hanging tool that can be eaily be stored 90% of its life. It can also hang from the handlebar if need be.

[dirtymartini]

Ia there any reason why you used 2" PVC...Just wondering, I have about 10' of 1" 1/2 laying around....

[sharkey]

I just left out all the plenums and valves and used 5mm (3/16" I think) hose ... no fittings, no chambers, no valves, 5mm hose fits straight onto an airhead's vacuum ports, fill with 20W-50 motor oil and it's pretty stable but still reponsive enough to see the smallest turn of the screws ...

http://zoic.org/sharkey/moto/r100gs/redneck.html

-----sharks