Author Topic: Intake tube (manifold?) suck? (Read 3037 times)

billster · « **on:** August 11, 2005, 11:51:01 PM »

Kneeling next my '03 B12N listening for a valve sound I noticed the intake tubes (ummm..between the carbs and head) are collapsing and expanding in rhthym with the intake stroke. These are that thin-walled? Anyone else notice this? Wonder if this affects performance or is a result of too tight an airbox/filter. This thing's sucking hard! Stiffer aftermarket tubes?

Cheers
The Billster

Red01 · « **Reply #1 on:** August 12, 2005, 12:24:37 AM »

It's normal. Don't know of anyone that's changed to anything stiffer.
Even the more powerful GSXR1100 engines were known to do this.

billster · « **Reply #2 on:** August 12, 2005, 05:07:12 AM »

Just seems strange. Can only imagine what they do at full load/rev. Danke schoen.

Der Billster

ray nielsen · « **Reply #3 on:** August 12, 2005, 10:18:23 AM »

It's most visible at idling RPM. At higher engine speeds the impulses are closer together and the motion is actually reduced.

On my Kawasaki W650 the carbs moved back and forth maybe 1/4" or more at idle -- didn't hurt a thing in 38K miles!

I suspect at high mileage the rubber will fatigue and the boots will require replacement -- hope they don't cost a fortune.

billster · « **Reply #4 on:** August 12, 2005, 06:33:00 PM »

Thanks....I'm sure it's not a problem but never saw that before. Wondering if more solid tubes that don't collapse would enhance the pursuit of free breathing.

Cheers.
Billster