more powerrrrrrrr!

[adyf]

just wondering has anyone run inlet venturi with individual pippercross sock foam filters,then cut front of airbox to get more air in?possibly with cold air feed, had ramair foam filter on a corolla car venturi size of kfc bargain bucket ,know it had injectors and loads of other sh1t i fitted but it made a huge difference to power and throttle pickup ,any thoughts ,trying to get more top end? cheerz ady f

[lloydie]

you want more power for little money !!
try doing these to name a few but these work i know coz its what i got innit
http://www.vtr1000.org/phpBB3/viewtopic.php?f=9&t=18341
http://www.vtr1000.org/phpBB3/viewtopic ... 30&t=24101
http://www.vtr1000.org/phpBB3/viewtopic ... 31&t=21761
http://www.vtr1000.org/phpBB3/viewtopic.php?f=9&t=21663
single sock filter dont work on the vtr

[Miff_UK]

you want more power for little money !!
single sock filter dont work on the vtr

As I'm in the middle of trying this, can anyone explain why these dont work ?

I have K&N style filters fitted on home made spigots bolted to the back of the carbs ( pics soon)

The bike runs fine up to 1/2 throttle and then bogs down really badly, running out of fuel at 70 miles, so i'm gessing it's massivly rich above 1/2 throttle, perhaps the Slides are running too high?

I have run the Carb 'breathers to fresh air rather than the airbox and suspect this is the problem, should there be a bit of vucuum to contol the slide height.

The jetting is the same as it was before, i would be suprised if they need to be smaller with more air flowing through the filters .

any advice appreciated

Miff

[lloydie]

3 off the air jets are on the outside of the inlet part of the carb this is why you need the airbox .
If you manage to get it to work let us know how you did it

[VTRDark]

That's why the only way to do it properly is to have some Keihin FCR carbs.
And IIRC they have an accelerator pump on them which help with the fuelling to compensate for the unstable air flow.

(:-})

[Miff_UK]

3 off the air jets are on the outside of the inlet part of the carb this is why you need the airbox .
If you manage to get it to work let us know how you did it

I have isolated the three air jets outside the inlet tract, but they currently go to fresh air. Do they need to go to a vacuum (as in the airbox), fresh air or blanked off ?

Miff

[VTRDark]

There is a pressure drop inside the airbox from the outside atmospheric air pressure. Pistons pull in air on their intake stroke, creating a low pressure pulse in the air box, as more air is pulled in from the outside.

Strangely enough in the HRC carb set up, they block one of the air holes in the top of the carbs. IIRC I think it's the main jet. But those air inlets need to go to the airbox where the pressure differentiates from the outside pressure.

If you want more top end then you need some kind of ram air set up like the Moriwaki's. Or install High comp pistons, two short stacks amongst other mods. Maybe you would be better off increasing the airbox size and installing some ram air tubes.

Have a look at the pics on here. http://www.vtr1000.org/phpBB3/viewtopic ... ng#p148377

(:-})

[Miff_UK]

Cheers, it's not more power that I'm after, it's purely cosmetic, I have stripped most things under the tank, Plastic heat shields, water header tank , and the K&Ns look great. I'll post some pics shortly

Miff

[8541Hawk]

Strangely enough in the HRC carb set up, they block one of the air holes in the top of the carbs. IIRC I think it's the main jet. But those air inlets need to go to the airbox where the pressure differentiates from the outside pressure.

The HRC set up for these types of set ups was to plug the main air bleed and run a smaller main jet ( from the 140s to 160s depending on the state of tune )

They also had a needle with a fatter mid-range.

The down side to this set up is is really only works on the track. The bottom end will be shite and will make it hard to live with on the road. Though you will get a real good top end hit ....

[Miff_UK]

today I put the airbox back on, but leaving the carb 'breathers' in fresh air, which worked OK, so the issue must be those three brass 'jets' . My next idea is to re-fit my K&Ns and see if I can pipe the jets to the filters for some level of vacuum. These carbs seem to be a weird design !!

[lloydie]

Yep more air you give them the richer they run !!!!!

[8541Hawk]

today I put the airbox back on, but leaving the carb 'breathers' in fresh air, which worked OK, so the issue must be those three brass 'jets' . My next idea is to re-fit my K&Ns and see if I can pipe the jets to the filters for some level of vacuum. These carbs seem to be a weird design !!

They are not a "weird" design, just real big CV carbs and are like nothing else to set up.

Those "three brass jets" you talk about are the air bleeds. The one that is causing you trouble is the "main" air bleed. It should be the center one, but as it has been a while. The way to check is to take a light and look. It is the one that ties to the main jet\emulsion tube.

You can plug it and run smaller mains or I would give something like a Flo-commander http://flo-commander.com/ a try to see if that could sort out some of the problems,.

[VTRDark]

Would the flo commander work without an airbox? I thought the object of the flo commander is to balance out the unstable air flying around inside the airbox, which then gives a steady flow of air which then emulsifies better with the petrol. And I agree, nothing wrong with the carbs they are nice and basic, just abnormally large and hard to tune.

(:-})