Crackin carb boots

[hank hill]

Hey guys, sorry if this has been addressed but I havent seen it. Im riding a hard tailed 650 with less than the stock amount of engine mounts and so it vibrates a bit. Im cracking carb boots like its my job and I need a solution to this. I have found after-market aluminum intakes for vm's and what not but cannot find anything for stock BS38's. Any help is much appreciated.

 

[weekendrider]

An L brace from the bottom of the breather to the top of the carbs?

 

[pristic]

That's a top idea Weekendrider. So effectively a bracket FROM engine NOT frame to the carbs. So they shake "together" right.

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[weekendrider]

Yes. But I got the tip from grizld1.

 

[5twins]

Are you using the stock sheet metal "shrouds" over the boots as intended? If not then that's probably why they're cracking on you. They need that extra support and will split in short order without it.

 

[grizld1]

Indeed they will, and unfortunately so will the JBM boots that are supposed to support the carbs with no shrouds or back support; they crack inside, right around the spigot stop. I think Don James' experience with lightweight mechanical carburetors on ultralight aircraft misled him on that score.

If you use a bracket for support, make sure to damp it against vibration with rubber washers, grommet, etc.

 

[hank hill]

Thanks for all the replys guys. I am not running the stock "shrouds" which is definitely not helping my cause. I will try and splint the boots and fab up some sort of brace soon, have a whole slew of other issues to work out lol.

 

[XSLeo]

Adding back in the missing enmgine mounts will help. It may save the engine case breaking around the rear mount.
Leo

 

[hank hill]

thanks for the tip leo. also, does anyone have a pick of this brace set up?

 

[cros36]

jbmindustries.com

 

[coughing skunk]

Have you looked at the tc bros intakes? Made of metal, so no cracking like the rubber ones. I've got nothing but good things to say about them.

 

[hard_y_rd]

I don't think they make em for 38's.

 

[NONclow]

On my '71 w/BS38's, I was able to use a standard carb top brace (connecting between the vacuum slide cover inner 2 screws on each carb) from a late 70's 650 w/ 34's, I welded two peices of 1\2"x1\8" flat bar to the top, angled to the rear bolt of the top motor mount (replaced by allthread), finished by two 5\16" washers attatched with accompanying rubber washers + locknuts.

P.S. my boots have been cracked for as long as I can remember (not rotten though...yet!)

 

[angus67]

I would really like a pic of a carb support. I have new boots, stock style 34's, and the cages, they haven't cracked yet, but I would like to get to this before they crack.