The velocity stacks are going to cause a venturi (sp?) effect going into your manifold/throttle body. The result is it sucking more air in. If you dont increase fuel, a "leaner" condition exists. It sounds like your already on to the fix. By increasing fuel in the mid to high ranges, youre taking care of the most noticable "lean" condition. The more you twist the throttle and open up the air intake, the leaner the bike will run with the velocity stacks. This is the simple mans explination and its not all inclusive, but I hope it helps.

Dave

 

Check your plugs first to be sure the mix is to blame.

 

A little info on venturi theory. Venturies actually restrict air flow. What they do is speed up the velocity of the air because of their restriction( same amount of air going through a smaller hole). Thats how carberators pull gas through the jets, by the suction created from the venturi. I am not familiar with either the Barons BAK or the PR BAK other than pictures I've seen. The one that is the less restrictive will be the leanest runner. Is the PR BAK kit one that narrows down smaller than the throttle body opening? That would be an added venturi. If it just gradually narrows down the flow of air to the throttle body opening, than it is a smooth gradual transition of air flow that has to narrow down into the throttle body. This smooth reduced transition can set up a positive breathing flow that allows the engine to breath better which could possibly draw more air into it. Not because of venturi, but because of the tuned air flow. Now that I've got us both totally confused I'm going to go have breakfast. Seriously though, can anyone elaborate on the PR Bak kit for us? KC.

 

The velocity stacks with the PR kit fit over the throttle bodies and have the same internal demension as the throttle body on the throttle body side. They are larger on the filter side. In other words the PR velocity stack does get more narrow but not smaller than the throttle body because it starts out larger. The Barons BAK does not have velocity stacks just filters that mount directly over the throttle body.

 

One of the selling points for the PR kit was that you don't need to adjust the fuel delivery. They said so right herehttp://www.rswarrior.com/forums/topic.asp?TOPIC_ID=9965&SearchTerms=PR,air,kit

 

Ok the PR BAK with velocity stacks definetly caused a leaner mix than the Barons BAK. I bumped up the PCIII 1 bar in the mid and high range and the engine smoothed out. Tried bumping up 1 more bar but that was too rich.I believe the PR Bak is giving better performance than the Barons. I hope to get a custom map for my setup after the recall mods.

 

Modit2thmax, when they did the back to back testing they didn't adjust anything but allowing more air in will always require more fuel otherwise it just won't run right.

 

quote:Originally posted by oly

Modit2thmax, when they did the back to back testing they didn't adjust anything but allowing more air in will always require more fuel otherwise it just won't run right.
I know that. In fact I said so in that thread. They insisted that the fuel wasn't changed. But who's gonna believe a shadetree mechanic like me over the GODs of Warrior racing? It sucks that people have blind faith in them just because they've won a bunch of races. I guess they don't know everything after all.

 

My bike sure didn't run right without increasing the fuel. Now that I have it adjusted it is running better with the PR kit than it did with the barons.