Velocity Stack attempt.

Hi huys, just thought you might like to have a glance at what ive been up to over the week end.
I made myself some custom V/stacks out of some ally spray tins (because of super thin walls) pressed over various cone shaped items to get ther trumpet end. With a diameter only 1mm larger than ther TB inside diameter, it makes it a near as damn perfect fit. only modds i had to do was to the air box by opening out the holes for the rubber stacks by 1mm all round to allow for the extra 1mm of ally.
The dimentions were taken from the factory pro V/stacks from america (1x70mm & 1x35mm length stack) that you can buy for around £110 of ebay.
I have yet to ride it to see if there is any noticalbe differance in the midrange claimed by factory pro's stacks.
Ino its not as well made as their stacks but i thought id have a go anyway for the cost of £0.

Good effort.

[mikerj]

To really see an advantage from this you'd need to get the fuelling sorted.

ino, i plan to get the fueling sorted this summer at some point to go with everything else.then she is finally complete.

untill i find something else to add or modify ^_^

Are those measurements for pointys or do they do curvys as well?

Might knock something up on the lathe.

[johnnyrod]

Is the idea of these to optimise the oomph in a particular part of the rev range rather than hoping for more everywhere? Presumably the dimaeter and length are what it's all about, a bit like a zorst? They're a bit of a black art to me.

i presume thats the reason for the two diferent lengths, so u get an average gain all round. well thats my understanding. were as if you have the two 35mm ones, the gains are more focused at the top end as factory pro claim on thir website.

these measurments were originally designed for the poiunty and have no idea how it will affect the curvy as carbs are strange and complex things to get right to give you the desired performance. however, by all means have a go. the worsed thing that can happen is that you might need a bigger jet to cope with the faaster moving air due to the function of the stacks.^_^

I know on pointys 35/70 is midrange and 35/35 is top end.

I need to go to the dyno anyway as Im running lean with all my mods and bigger jets are deffo needed.

BTW are the measurements total length or how much it protrudes into the airbox?

considering the engine is the same practicly, i guess the measurments can be the same. entirely up to you.its the entire length. from were it leaves the TB or carbs in your case ^_^