Manometer comparison

[Grinder]

After 34 yrs I thought it was about time to sync the carbs. A friend had a mecury mano that had never been used, so we filled it up with the heavy metal and hooked it up. The tool was supposed to have restrictors in the lines but those were long gone so we tried it as is. It worked good and my carbs were pretty far off.

Not wanting to borrow his all the time I made my own following the info on the site. I used 3/16" clear tubing and ATF. It worked but the tops of the ATF columns seemed kind of blurred when in use. I had some 3/16" brass rod around so I made some restrictors for the lines. I made them about 3/8 long and drilled about 95% of the way through with a 1/8 bit and then used a #68 drill (about .030) for the last little bit. No special reason for the size, just what I had around. This setup worked much better, much more stable in use.

After setting the carbs with the store bought mano I hooked up the homemade version and found the columns to be about 1 1/2" off. I dialed it in with which took a very small amount of adjusting. The homemade version seems to be more accurate than the store bought version, I suppose because of the lighter oil.

Took the bike for a ride and there was a very noticible difference, much smoother through the whole RPM range. All in all $3.00 very well spent.

 

[azman857]

How many feet of 3/16" used?

 

[retiredgentleman]

Grinder;

Yes, the home made manometer is 13 times more accurate than one using mercury.

 

[Grinder]

I used about 12' but it really doesn't matter that much I wouldn't think. Make it what ever size you want. Some people used a yard stick to hold the tubing. I just copied the store bought version.

 

[hooktool]

You have to compare and calibrate each tube using the SAME vacuum port, store bought or home built. How is yours adjusted?

Nice. I bought one of the Motion-Pro versions for my 4 cyl bikes, but yours is about 97 bucks cheaper.

John

 

[Purplezinger]

You have to compare and calibrate each tube using the SAME vacuum port, store bought or home built. How can yours be adjusted?

John

Only if the tubes are separate, a U shaped manometer seeks it's own level.

 

[5twins]

I have an idea for a deluxe version. It will incorporate a plastic mayo or peanut butter jar at the bottom of the yard stick to act as a reservoir for the ATF. Two equal length brass tubes will stick out the top for the hoses to attach to and down into the fluid in the jar. I'm hoping the smaller I.D. brass tubes will dampen the fluid bouncing somewhat. I'm also hoping that drawing from a jar full of fluid will maybe stop one side from sucking into the carb if the sync is way off.

 

[Grinder]

The store bought mano has 3/16" OD tubes but the ID is only about .045 plus it was suppose to have restrictors in the hoses as well,so smaller is better I guess. I read elsewhere about a guy who made his own restrictors and he used a #80 drill which is about .013. I used what I had around(#68 drill). With the restrictors I put in my homemade version it jumps a little but works fine. I should have synced the carbs a long time ago, bike runs so much better!!