mods

This has been discussed before. The answer is more air flow does not significantly improve performance or mpg on these bikes. Some folks have installed K&N air filters toward that end, but nobody has posted before and after dyno runs for such a change. Seat of the pants feelings don't count. If however, making a change makes you FEEL like there is an improvement, have at it!

The reality is that computer management on fuel injected bikes has made increasing the power/mpg more difficult.

edit: Doug beat me to it by mere seconds. (And no dyno graphs to prove it!)
 
Starting to modify air flow opens up a number of cascading changes in order to have much effect. Opening up the front end does not do much unless you also open up the back end (collector and exhaust). Then there is the issue of air/fuel ratio, which may be somewhat dealt with by the CV carbs. Improving fuel economy is a worthwhile goal, but hard to do given the needed air/fuel ratio needed and the gearing that is baked in.
 
RR, you are pretty much wasting your time, money and effort in trying to increase the bhp by modding an 11. They are what they are. Service it well, put a nice new oem air filter in there and use whatever you can get out of it to its full. Could you extract more mower by extensive engine modification, of course, but then you could buy a 13 for less outlay.
Enjoy it for what it is and if 130 mph isn't enough......
Upt'North.
 
CV carbs are designed to work with a very specific air flow, including intake and exhaust restrictions. Increasing or decreasing it causes poor running.

The Nighthawk Forum constantly has threads asking how to make the engine run correctly after replacing the stock air-filter box with pod filters.
 
Larry Fine said:
The Nighthawk Forum constantly has threads asking how to make the engine run correctly after replacing the stock air-filter box with pod filters.
Click to expand...
Same on the SOHC group... getting jetting and needle positions right again (if at all) is an agonizing process...

Last year someone flat-bedded a 600cc Hornet to my shed...
"...only need carbs cleaned!"
"have you guys done anything to it??"
"naaah!..."

Cleaned, checked an sealed the carbs, new sparks, etc, hit the starter, runs like crap, tends to stall when opening the throttle...
Killed the ignition, grabbed my #2 Vessel, removed that "sports air-filter", stuck an OEM paper element in, hit the starter again: vrooom!

right, they haven't done anything to it...
 
Not to mention that CV carbs require certain back-pressure in the airbox (and Honda designs those airboxes that way). Adding holes would ruin these characteristics.
I’ve been playing with carbs on VT600. The only way to make it run again was returning everything back to stock.

if ST11 is too slow, hop on XX Blackbird for a similar price. It has luggage options too!
 
The biggest problems with air box modifications on the ST is that it by changing the restriction, the power band changes and of course jetting changes will have to be done, but the CV carbs react in such a way that it creates a dead spot off idle into the midrange of the power band. It may increase top end performance at full throttle but the bike will not be anywhere near as nice to ride and much more difficult to ride on twisty roads. The other thing is the intake noise increases dramatically. The tank shelter become a resonator and the sound is even worse. Getting the jetting right usually takes trial and error and having to take the ST carbs on and off would be a huge chore to make jetting adjustments to get it right. Just my .02. Some have tried modifications on the ST1100's back when they were fairly new. None that I know of were happy with the results.

Back when I was a bike mechanic in the 70's many people modified or removed the factory airboxes and replace the with small air cleaners. As much as they thought the bikes were faster(they sounded faster) the bikes did not run very well as the power bands were ruined.
 
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