Bonneville America Forums Forums Technical Forums Performance Mods FCR Filter Clearance

I got my FCR's from Carlos(TPUSA), installed on bike and found that one side of the foam filter was scrunched into the frame.

So I invested in 2 1/4" silicone turbo tubing or pipe so no part of the filter is touched anything.. Below are pic's of my handy(?) work.






I've been following "Threads" on FCR's for a while now for tuning info and had run across a comment about air filter alignment or filter clearance.

It dawned on me that the "cylinder side"(of carburetor) aluminum(screw in) adapters would adjust for it.
Since ya have to screw them in to the carburetors as part of the assembly,Screw both in. then screw one out to "turn" the carb's so it's even on both sides or that the filters clear everything.
Once installed in the rubber boot, and secured, It's not going to move.

I screwed mine all the way in with one drop of blue lock-tite. So I'm done for now.

I do not believe that one turn(say, 1/16th on an inch) will screw up air flow a significant amount.

If people out there are having filter clearance problems with FCR's, this adjustment would probably solve the problem.

It would have saved me $100 of trial and error. And the end result as you see above.


Below are pic's of my tablet set-up with the Innovate dual AFR's(tablet not shown).
Left. Right. Throttle position, and RPM.

Video to come when temp's are bearable.

Thanks for your eye's,,,,,les

I'd like to know what effect the long tubes have on power & drivability as compared to direct-connecting the filters.

I only got a chance to run the bike 3 times after install when the black ice season started.

I'm sure there are turbulences created because of the two 45 degree turns before the carb's intake.

Never having FCR's before, there is no way for me to tell ya if I lost any performance because of the "pre" bends.

Drivability,,,,it hauls azz.
Super smooth idle.
Instant acceleration.
Zero vibration, ok, vibration is greatly reduced.

One problem though,had to change to a stronger clutch spring.
The carbs seemed to cause quite a bit of slippage.
Something about a power increase.

Bellacourse has a nice pic of the adjustable aluminum adapters

I'm sure that a person can turn these in and out to help center the carbs for proper filter clearance

http://www.bellacorse.com/images/bce070rx600.jpg

It seems that the common component in most of these FCR threads with fitting issues is the manifolds. Just throwing this out there, but it looks like these manifolds are intended for the bonneville type bikes and the angles are not quite right.
So have you looked at altering the manifold to correct the fit issue? From the pictures it looks like your carbs are both higher and farther back then where mine are with the stock manifolds.

I'm in agreement with you that they were originally to fit on a Bonneville.
I did have to shoe horn these in delicately.
They are higher and longer.
Higher makes a more straight in shot for the fuel to reach it's destination.
Longer? I believe length adds earlier torque increases.

Tweaking the angle would need to be done by a machinist cause of the O-ring groove you would be removing to change the angle would have to be milled in again.
Length would be easier but ya still have to have the O-ring groove milled back in.

Length helps to maintain fuel air velocity to a point. The fuel air mixture can stay in motion after the valve closes if it has a place to go. Other wise it has to stop. Its easier to speed something up that has slowed a bit than to start something that has stopped.

web page
Spendy stuff, and an idea to steal, I mean copy with an absence of malice..

with these you don't need tank pads as how could you use them? Nope not in my future.

Lester,

Could you tell us what the settings are for your FCR's. Jets and needles so others can compare.

Looks good.

Settings are only rough because of black ice interruption.

FBR 5th slot from top.
Main jet. 138
Main air. 200
Slow jet. 53(or 52, not remember)
Slow air. Left 1 1/2. Right 1 3/4

AFR at idle was around 12.7
Wide open throttle is 13.1 to 13.7

Everything in between still needs adjusting, but was on the lean side. 14.0 to 15.0

With the "new" tablet set-up, life will be good,,,when warm weather arrives.