Remove all that air filter tubing malarky.

[peterrose]

A few weeks ago I took off al thoses air filter tubes, boxes crap that come off the air box. Couldn't really see what good they did.

Anyway, I soon found out that without them the bike didn't pull so smoothly through the rev range, it would surge every couple of thousand revs and wouldn't pull past 8500 revs even in 4th.

I refitted them a couple of days ago and bingo, smooth acceleration right up to the 9500 red line in 5th and didn't get the chance to max it out in 6th but it was pulling well at 135 mph.

So just to let you all know, don't remove all that air tubing stuff, it upsets it.

My question is WHY or HOW ? Would it be the constant velocity carbs need a certain amount of resistance to create a bigger vaccum in order to lift the diaphrams ?

Pete

[oldndumb]

Smart of you to figure out that the rough running would be remedied by restoring the hoses to their rightful places.

[peterrose]

Originally Posted by oldndumb

Smart of you to figure out that the rough running would be remedied by restoring the hoses to their rightful places.

Why yes, oldndumb. I have not got to where I am in life so far by not being smart.

I have also realised that this is the second thread of mine you have replied to today, that must make you one of my biggest fans.

I'll send you a fan club membership pack, just fill in your direct debit details for the membership fee asap, thankyou.

Pete

[oldndumb]

Two replies qualifies me as one of your biggest fans!?!

Don't know if I want to pay for member ship in that club. Not very exclusive, is it?

Now, If you sweetened the deal, I might reconsider.

[3banger]

Engine intake systems have a lot tuning designed into them. Manufactures spend a lot of time designing air box volumes, velocity stack lengths, air filter area/size and resonators. In general at lower RPM’s you will want longer overall flow paths for the intake. At higher RMP’s you will want shorter. At each RPM there is an ideal intake path length that will produce the highest volumetric efficiency (best breathing). Most engine intake systems are balance to give the best volumetric efficiency over the RPM range of the engine. The latest Yamaha engines have intake runners that are actuated to be either short or long depending on the engine RPM.

A lot of times garage mechanics like my self see all of the intake “malarkey” as simply an air restriction and eliminate it. I have made this mistake as well. This usually results in a HP gain way up at redline but large performance penalties in the mid and lower RPM ranges and effects the overall drivability of the engine.

[Calliway]

I think I would like to know why a little friendly ribbing gets people knotted?

I always find it funny when we as consumers think we know better then the engineers who spent millions developing the machines we drive....

Do we open up the hoods of our cars and go "Look at all this rubbish" and start pulling hoses off?

Some times the best lessons learned are ones that we learn for ourselves so I do appreciate posts like this and ask all weekend warriors who start pulling hoses learn from others lessons.

Cheers.

[Triple Ripple]

A liitle bit off the question but it may help. I am reading Sportbike Performance Handbook by Kevin Cameron (MBI publishing -- I do not know if it is still in print as it was first printed in 1988). He gets right down the minute details of how to get more speed.

Flat torque curves are a result of the engineers moving the peaks around from the many parts of the engine system that help to increase torque. Changing one part may move its contribution up or down the rpm curve and its impact (increase or loss)
cam timing -- is a compromise as the valves close too late at low rpms and too early at high rpms for optimal cylinder filling at all rpms
exhaust pipe resonance -- at some rpms it adds torque and at others it will create a flat or low spot
intake system -- its length creates waves that bounce back and forth and has an rpm range where it works best and helps create a torque bump
sealed air box -- also has a resonance effect that puts its bump into the torque curve

An easy way to understand the resonance effect is the note you get when you blow across the top of a bottle. Adding water to the bottle raises the note at which the air in the bottle resonates. Unplugging the hoses to the sealed air box may drop the resonance to a point where it is no longer possible to get any resonance.

[lemansnz]

Originally Posted by Calliway

I always find it funny when we as consumers think we know better then the engineers who spent millions developing the machines we drive....

I think it goes something like this.

I hear or read ...I forget
I see...and I remember
I do...and I understand
I stuff up.... I understand how and why.

[KitNYC]

All else aside, this is probably a thread for the T3 forum...

Cheers,
-Kit

[HiVel]

Do you have a relative (same name) in the Colonies that played baseball and liked to gamble?? He was not too smart despite being very good at what he did for a living-maybe you are related?

have fun anyhow!!