home made carb synchronizer advice needed

[drax71]

I already made one of these as a sealed system and it works well. However I find if I run the bike too long (over 20 sec) I get alot of bubbles in the lines . I can't find any leaks to the atmosphere so I assume the bubbles come from the quick movement of the fluid. Right now I run the bike for a few seconds quick adjust and shut off then set up on the next carb to repeat. Do I need restrictors or just heavier oil?? Currently I run the lines direct to the carbs on a inline 4 with regular 10-30 weight oil.  

Anyone with experience. Thanks

Great site BTW

[Flashmo]

Might be the oil, I filled mine with ATF, and there are no bubbles.

[M.Brane]

 Same here. My ghetto carb stick is filled with ATF, and works fine.

[drax71]

Thanks guys, I changed over to ATF today and it works without the bubbles ?? Don't know why - I will assume the thinner ATF is allowing the bubbles to pop.  who knew!