The Sumo velocity stack

Find the right velocity stacks isn't always easy, and play with the lenght and the size to achieve the right balance could be expansive. But I still want to play a little with the "character" of the bike and try to claw back some low and middle torque. 
So I start fabricating a first set of custom made ones...

 The difficult part is to find the right "cooking" temperature and time for the alloy hose. I ended up heating more one half  to make it flexible and keep stronger the other one (this explain the arrow).
Then squeez it on the mandrel with a lot of grease.

After some cleaning and buffing:

From 32 to 60mm, I think this is the max diameter before the metal starts to crack, but I'll try something longer.
A quick comparison with the original ones

These are some of the deads...I'll keep them to serve as warning for the future ones...

2 commenti:

ride4life ha detto...

li hai fatti più lunghi degli originali, ma tutti e 4 uguali?

Plan B Motorcycles ha detto...

Si, tutti uguali, con il punzone non si scappa :-). Una volta imbutiti li ho messi sul tornio per dargli una intestata e mi sono assicurato che fossero lunghi uguali (c'erano differenze di qualche decimo)