Bonneville America Forums Forums Technical Forums Performance Mods Bell mouths-velocity stacks

Bella corse has aluminum fitted for Thruxton,scramble,t-100 but not for speedmaster or America.Jenks Bolts has them , they are rubber universal mount I think; to be used in conjunction with uni-filter,spun-shaped stack smooths air flow into carb. Is anybody using these? 7bhp at 4500 rpm , can raise jet size by 5 pts. Of course AI out , etc.

As they're meant to replace the snorkel, I question how well they work with the air filter in the way. It would seem the air filter media would defeat any gain obtained from the venturi. I could be wrong.

If they fit right on to the carb inlets,
Like so



I'd have a set.

I beleive speedblastr was referring to this
http://www.bellacorse.com/bce064.htm

http://www.normanhyde.co.uk/. These go into the air box inlet.

i already spray painted mine silver/chrome. am i good to go?

I see.

I still wonder if the filter media discounts the venturi effect, as the filter is between the venturi and the carb inlet. Maybe not.

Some K&N filters have a venturi inside. That may be among the most practical means of having a venturi, yet still having filtered air. A lot of old school Trumpet guys would slap a venturi right onto the carb, with no filter beyond a little screen, (if that) much like these:




I don't imagine it was much of a problem on sunny days. Then again, when I clean my filter...

I was thinking of putting pancakes on mine,but the thought of 600 mi. long trips with a giant sucking sound roaring through my ears, made me think of another way, however, undoubtedly freaking the system adds bhp to the crank. My thought on this thing since I have the airbox de-snorkeled ; In conjunction with Bell mouth and the UNI filter to provide the lung with _unturbulent air.I also have given the thought about drilling out too,(or removing resrictor plate)furthermore, I'm a little concerned about mid-throttle ride-ability ,whether as a side effect,that it maybe compromised. Since the lung is an integral part of the engines breather system.

I never looked into those. I just assumed they went on the back of the carbs. I can't see any advantage inplace of the snorkel except the bigger opening and you don't need one of those to get that.

The theory is it smoothes the airflow. It does have less restriction than the stock down tube (a.k.a. snorkel), since air does not have to travel to the bottom of the air box then back up and through- but I'm with you Ian, I doubt the efficiency is anything like the gains with open pods.

Steven- my experience in slowly chopping away at my air box is that the midrange falls off with the stock needles. However, either shims, TBS needles, Thruxton needles or a combination of the above cures this.