Starace Velocity stacks for 821/939

Araitim · May 18, 2021

The 821/939 series now has some additional intake options. Dimpled velocity stacks coupled with the RSR filter housing it's sure to make a marked improvement. I will soon have a kit in hand, install them and report back. Pics are of Starace and OEM. OEM are rubber moulded one piece design. If you ever had them out then you know flimsy they are and how they meet up to the throtle bugy in a funky way inside

nickwst4 · May 19, 2021

Interesting; extra turbulence just where you wouldn't think it desirable. Or are they going for some kind of boundary effect? What's their take on it?

Nick

Araitim · May 20, 2021

nickwst4 said:
Interesting; extra turbulence just where you wouldn't think it desirable. Or are they going for some kind of boundary effect? What's their take on it?

Nick

There are a few different techniques used in this area to help atomization of the air n fuel. The norm used to just be to clean up the intake and exhaust runners then polish to help things flow better(port n polish) but over the years it has been discovered that on the intake side it is better to dimple or texture to help promote air/fuel atomization after opening/smoothing out the intake . It's still the norm to port n polish the exhaust side.

nickwst4 · May 20, 2021

Maybe before your time, but the BSA Gold Star motor had an Amal GP carb that was a wider bore than the inlet stub. Home tuners used to open the inlet tract and blend the two together, and wonder where all the torque had gone! Then there were the tuners who would actually reduce the inlet tract bore, in the interests of gas velocity that helped to stuff the cylinder at certain revs. All good fun!

Nick

gatdammit · May 20, 2021

I will say reseating the OEMs leaves you hesitant that they are mated correctly. I had to keep pressing the airbox, checking clearance and purchase, and started over about 5 times because it just didn't feel right. How is Starace doing these days? All those past order fulfillment issues laid to rest? I would still be hesitant to order from him.

Araitim · May 21, 2021

gatdammit said:
I will say reseating the OEMs leaves you hesitant that they are mated correctly. I had to keep pressing the airbox, checking clearance and purchase, and started over about 5 times because it just didn't feel right. How is Starace doing these days? All those past order fulfillment issues laid to rest? I would still be hesitant to order from him.

The fulfilmanet issue was many years ago, all have been corrected from what I read. He seems to be doing well. He is definitely testing new parts he is making . He has alos partnered with a few companies, Termi, CNC racing and Sprinter to name a few. I don't know for sure but I don't think those companies would partner with someone who is having issues with fulfilment. I do think that it's odd there still isn't a website. But as for him maintaining sales commitments, I believe that is a thing of the past.

Starace Velocity stacks for 821/939

Araitim

nickwst4

Araitim

nickwst4

gatdammit

Araitim

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