Petcock vacuum line keeps coming off!

[jtolbert]

Anyone ever had their petcock vacuum line keep coming off the petcock? The tubing's the right size. It's fairly thick tubing, but it seems pretty pliable/flexible. Is there some "stiff" vacuum line I should be using?

Right now I've got a worm clamp around the vacuum line, but that seems like a hack to me.

[Pearson]

Anyone ever had their petcock vacuum line keep coming off the petcock? The tubing's the right size. It's fairly thick tubing, but it seems pretty pliable/flexible. Is there some "stiff" vacuum line I should be using?

Right now I've got a worm clamp around the vacuum line, but that seems like a hack to me.

Hey, what are you riding, year et al.

I'm riding a '78 750. Have not had this prob. at all but if a clamp works, don't worry about it. Ride it. Lot worse probs. for a bike our age, eh?

[mortation]

By rights ALL tubes, including fuel and vacuum are supposed to have circle clamps

[Guest]

Try a 1/4" vacuum hose.

[earlfor]

Yep, vacuum is 1/4", fuel is 5/16". I will bet you ten bucks to a doughnut he has 5/16" on both of em. hehehehe

E.

Try a 1/4" vacuum hose.

[jtolbert]

I have 5/16" fuel line on the fuel line and 1/4" vacuum line for the vacuum. Give me some credit here.

Where can I find these circle clips? None of the local auto parts stores seem to carry them. I'll try Farm & Fleet tomorrow.

[bwringer]

I use zip ties -- the clamp is not needed to create a seal. It's simply there to keep the tubing from expanding enough to slip past the fitting.

But you really ought to try a different brand or style of tubing -- some just fit tighter than others.

This problem arises because the fittings are 6mm (vacuum) and 8mm (fuel). 5/16 inch translates to 7.94mm, so you can use 5/16 tubing on 8mm fittings with no worries. In fact, this is close enough you can easily use a 5/16 wrench on an 8mm nut.

However, 1/4 inch is 6.35mm, so 1/4 inch tubing is very often a bit loose on 6mm fittings. In our metrically retarded country, it's close to impossible to find metric tubing, so we're mostly stuck using 1/4 inch. You have to experiment with different brands and styles of tubing to find one that fits correctly. I've found that fuel hose rated for fuel injection use seems to fit a little tighter and works well for vacuum fittings.

The pretty clear blue 5/16 polyurethane hose from CRC2 works well for the fuel fittings, and doesn't even need a clamp, but the 1/4 inch version doesn't work at all for the vacuum fittings.

[txironhead]

Yep, vacuum is 1/4", fuel is 5/16". I will bet you ten bucks to a doughnut he has 5/16" on both of em. hehehehe

E.

You owe someone ten bucks!\\/

[earlfor]

Heh heh heh You would not have been the first. :-)

E.

I have 5/16" fuel line on the fuel line and 1/4" vacuum line for the vacuum. Give me some credit here.

Where can I find these circle clips? None of the local auto parts stores seem to carry them. I'll try Farm & Fleet tomorrow.

[mortation]

I have 5/16" fuel line on the fuel line and 1/4" vacuum line for the vacuum. Give me some credit here.

Where can I find these circle clips? None of the local auto parts stores seem to carry them. I'll try Farm & Fleet tomorrow.

Let me check the garage in the AM. I ordered tons of these and I will probably never use em. They are like $.99 ea from the dealer but let me see what I have first.