Yes you need those spokes!!
Today I was cruising around on my motorized bike and the chain pulley came loose and went into my bike spokes. It tore up my chain and broke 4-5 spokes. Do I need those spokes or can I remove them and go without them?
I hope you weren't injured badly. Remember my advice on the first page of your smaller sprocket thread?
Your question above tells me you are in no way ready to go fast.
I don't mean to rag on you at all, I am just hoping you build a solid bike that you can ride safely. Take your time, enlarge your knowledge base and proceed in stages.
and one more yes to the need for all of your spokes.
If you dont like dealing with the stock part check out this,
http://www.ebay.com/itm/Bicycle-Cha...211804?hash=item1a12e5fbdc:g:dS8AAOSwhRxXKI4-
Just spend a bit more money it the problem will take care of itself automatically.
I might ask a friend to weld my stock down. Not sure yet and not worried about it yet.
Glad to hear you weren't badly hurt. You dodged a bullet there. I think Cylon posted a link to the best design for a spring tensioner.
One thing to remember is that a new chain will "stretch" which will contribute to possibly jamming the chain up in the drive sprocket cover.
If you can get the tensioner welded then that would be great.
I think the weak point in the stock tensioner is that it is prone to being pulled into the spokes. To make things easier for the tensioner I always que up the motor to the downstroke when I start up.
The best tensioner design, in my opinion is the arc tensioner available at Custom Motored Bikes.
Ideally, you would have no tensioner at all if you can get your chain length perfect.