Carb to airbox joints.

Can and do the rubber connectors from the carbs to the airbox shrink, as in get shorter? My '82 650 Seca is running lean and I suspect these may be the cause. They are fully fastened to the carbs but just barely making contact with the airbox. I don't believe for a minute they're sealing properly. I did order new ones and I hope they are longer. These are the original ones so they are almost 30 years old. The carb holders and gaskets are new.

On a somewhat related topic the carbs on my bike are off a 750. I replaced all of the jets with the ones that were in the original carbs. My question here is are the diaphragm springs and main jet needles the same?

And yes, the carbs are clean.

 

On the carb boots, they will definitely dry out and shrink over time. I bet if you put new ones side by side with the old ones, you'll notice a half in difference. And any little leak or crack in them suckers will make your bike run crumtastic.

 

Not only can they, but they do with age and gas fumes.

No, the needles are not the same....the springs should be...

you replaced all the jets, including the air jets in the top and intake?

 

If you are referring to the two jets under the diaphragm yes, I did. And by "intake" do you mean the two at the front on the carb? These were the same size so no, I didn't swap these.

 

Ok, I got the new joints today and they are a bit longer, but not by much. Nowhere near as long as they needed to be to properly seat in the airbox.
Then guess what, after owning this bike since it was new I see right on top of the airbox a 10mm bolt that allows the airbox to slide forward and back. Dang. Well a least I have nice new joints now.