JBM Industries intake failure!

[rwingsfan]

Have always had great luck with the intakes for our xs 650's from JBM Industries, but after installing these and running them about 500 miles tonight they decided to go south. I am about two miles from home, running great, all of a sudden I feel a tweak, then a shudder, misfire and I start hear that awful sucking noise. She is running pretty lean I tell ya!! Was able to baby it to my garage where after stopping I see the right carb is completely disconnected and the left is hanging by about half the circle. Talk about air/fuel mix I will post pictures tomorrow of the intakes. This is not a bashing of there products, quite the contrary as I have had nothing but good luck in the past, but rather a isolated instance that shows even good parts can fail once in awhile. BTW I use nothing but unethanol premium 91-92 fuel.

 

[Patches]

The problem is dangling those carbs out there not supported in combination with all of the vibration. I always try to figure out a wat to relieve the pressure off of the rubber boots. But I agree, JBM makes great stuff.

 

[rwingsfan]

Hmmmm....he states right on his sight that one of the advantages to his intakes is they do not need to be supoorted and I have not supported them in the past. Don't know if I just got a bum set or what.

The problem is dangling those carbs out there not supported in combination with all of the vibration. I always try to figure out a wat to relieve the pressure off of the rubber boots. But I agree, JBM makes great stuff.

 

[Patches]

Hmmmm....he states right on his sight that one of the advantages to his intakes is they do not need to be supoorted and I have not supported them in the past. Don't know if I just got a bum set or what.

Ya, I remember seeing that too, but was a little bit skeptical, not calling the guy a liar or anything, it just seems like good practice (to me) to support the carbs some how. With the weight of BS38's and some pod filters that adds up to a good amount of weight sticking out there. I'm going to give a billet set a try on a bike. Not only for the strgenth factor but because they have extended length.

 

[hotdog]

Send it back, he might throw you a new one in return for the damaged part....new rubber for you, R&D for him...???

 

[Tomterrific]

I'm running two of my bikes with teh carbs unsupported. One is an SR500 with a 36VM which I bet is much lighter than the BS38s unspported on my '77XS. What are some simple, clever, easy to live with ideas to support teh BS38s on my XS?

Tom

 

[bluebikerblan]

Have always had great luck with the intakes for our xs 650's from JBM Industries, but after installing these and running them about 500 miles tonight they decided to go south. I am about two miles from home, running great, all of a sudden I feel a tweak, then a shudder, misfire and I start hear that awful sucking noise. She is running pretty lean I tell ya!! Was able to baby it to my garage where after stopping I see the right carb is completely disconnected and the left is hanging by about half the circle. Talk about air/fuel mix I will post pictures tomorrow of the intakes. This is not a bashing of there products, quite the contrary as I have had nothing but good luck in the past, but rather a isolated instance that shows even good parts can fail once in awhile. BTW I use nothing but unethanol premium 91-92 fuel.

Something is definitely amiss with how they were attached, clamped on, threads engaged, fit, size something.....I've been quite involved with this product, the maker etc. and this is the first issue of this sort I've heard of. Let's get some good pics of where how the failure occurred and track it to ground. Save everything....Don James will want to see it all too. Best, Blue

 

[bluebikerblan]

Hmmmm....he states right on his sight that one of the advantages to his intakes is they do not need to be supoorted and I have not supported them in the past. Don't know if I just got a bum set or what.

I hope you're not mixing up the question of supporting the intake end of the carburetors weight with the issues of clamping the carb holder rubber on the carburetor outlet flange......I assume you are using a standard automotive radiator hose clamp of some sort tightened around the carb holder intake?
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Good session with rwingsfan today....thing we have a plausible hypothesis as to what may have occurred to result in the failure. More examination, pictures etc. underway to confirm. Blue

 

[rwingsfan]

Ok Blue here are the pics. After talking this out I am convinced my failure was 90% operator error. These boots were from a original run and I think they were a bit softer in compound. I tightened the clamps a little over zealously I think. I have had some issue in the past with a intake leak, although never with JBM intakes. I used a wider radiator style clamp that has few slots. In my effort to be sure of a tight seal I tightened them to much. As was brought to my atten by Blue once these "pop" into there respective slots the clamp really only needs to be snug so that the carb movement does not disturb that seal. I kind of did the gorilla thing on them. Lesson is, if you tighten them enough to watch the rubber distort much, you've gone to far. Did make for a interesting ride home though!