Intake boot leak that won’t stay away

[Woodstock1976]

1979 special with bs38 and pods
I’ve gotten new oem boots off of eBay and oem gaskets
Fully installed no issue with a bracket to support the carbs from moving once on the bike. On install I did the spray test while running and no change in rpm. Go for a ride and when I get back they are both leaking again. Redid the whole process with gasket sealant and exact same results. No issue initially then after 10 minute ride I’m leaking again. Any ideas?

I now have a set of JBM industries boots, clamps, and gaskets along with non vacuum petcocks (to work with their boots) on the way. Any tips would be greatly appreciated

 

[willis]

Don’t over tighten the clamps. Get them snug and just a touch more. If you over tighten you can deform them and cause leaks.

 

[Jan_P]

1979 special with bs38 and pods
I’ve gotten new oem boots off of eBay and oem gaskets
Fully installed no issue with a bracket to support the carbs from moving once on the bike. On install I did the spray test while running and no change in rpm. Go for a ride and when I get back they are both leaking again. Redid the whole process with gasket sealant and exact same results. No issue initially then after 10 minute ride I’m leaking again. Any ideas?

I now have a set of JBM industries boots, clamps, and gaskets along with non vacuum petcocks (to work with their boots) on the way. Any tips would be greatly appreciated

I would check the screws holding the flange against the cylinder so they are tightened to spec
And of course other clamps
Myself would use some sealant both sides of gasket If not solved but others here disagree on that part

Straw on spray test hot ?

 

[willis]

JBM states their boots don’t need the gaskets. But they still sell them anyways. Go figure.

 

[Woodstock1976]

JBM states their boots don’t need the gaskets. But they still sell them anyways. Go figure.

Should I not use them?? If it helps to not use them I won’t I just want the leaks gone

 

[Wingedwheel]

Can you pin-point the leak?

 

[mike in idaho]

Are the throttle shaft seals in good shape?

 

[Woodstock1976]

Can you pin-point the leak?

Leak is directly between the boot and the engine each time. I was having issue leaking around the clamps but I fixed that

 

[Wingedwheel]

Why did you replace them in the first place? Same issue?

 

[Woodstock1976]

Why did you replace them in the first place? It seemed the right cylinder was running lean and I tracked it down to the crack

 

[Woodstock1976]

Originally my right cylinder was running lean when I first got it running. Fully cleaned the carbs and inspected them thoroughly and on reinstall noticed the boot on the right had a crack. And then the left one wouldn’t seal around the carb body after that. Seemed they were on the way out

 

[Wingedwheel]

Got pics of your set-up? I’ve had leaky boots from cracks and bad clamp ends but I can’t say I ever had one leak by the gaskets.

 

[Woodstock1976]

Got pics of your set-up? I’ve had leaky boots from cracks and bad clamp ends but I can’t say I ever had one leak by the gaskets.

I don’t it’s all torn back apart now waiting on the new boots from jbm. But it’s bs38s, oem boots with the barbs, oem gaskets, and I used oem style clamps and I also tried hose style clamps that had sleeves in them. Spray test with the straw gave me only leaks from between the boots and the engine.

I have new non vacuum petcocks also for the new boots with no barbs

 

[Wingedwheel]

Good luck and keep us updated.

 

[Woodstock1976]

Question are the metal shroud pieces that go over the boots necessary? This bike didn’t have them when I got it but I was thinking getting a used set to help if I needed them

 

[Wingedwheel]

I believe they were supposed to help support the carbs at the boots but I’ve run either way and as long as the carbs are mounted cirrectly, mine have been OK.

 

[gggGary]

Have you checked the head flanges are flat?
Enthusiastic bolt tightening can raise an edge around the holes

 

[Woodstock1976]

Have you checked the head flanges are flat?
Enthusiastic bolt tightening can raise an edge around the holes

I’ll double check with a straight edge but they look flat to the eye

 

[willis]

JBM advises not to use the metal shrouds on their boots. The already have metal imbedded inside them.

 

[Woodstock1976]

JBM advises not to use the metal shrouds on their boots. The already have metal imbedded inside them.

Thanks