Raptor Forum banner
1 - 5 of 5 Posts

·
Registered
2003 Raptor 660, .05 over bore, FMF slip on, Fullflight +2 A Arms
Joined
·
63 Posts
Discussion Starter · #1 ·
So I just got my 660 running and after getting used to it, it’s not the same adrenaline rush as when I first started riding it. So I am wondering, what can I do to get a little more power out of my bike? It’s got a fmf slip on, 0.05 overbore, stage 1 cam, and a k&n filter with the filter lid on.

141541
 

·
Registered
Joined
·
3,136 Posts
Get rid of the airbox lid(which means you need an adapter and your choice of aftermarket air filter) and use a filterskin.
A small k&n style clamp-on filter for the crankcase breather tube(because that end of the hose went into the airbox lid).
A DynoJet stage 2 jet kit(the only way to buy their needles), it comes with several main jets.
Buy two #25 or 27.5 pilot jets
The DJ needles have a different taper and make more power than stock and gytr.
Buy a pair of Vito's fuel screws with adjustable thumbwheels machined on.
3 turns cc is ballpark/good starting point.
Stock fuel screws can be difficult to adjust once the carbs are on.
You'll thank yourself later.
Search here for 3mm Clear Tube Method.
Set the floats and trim the stops.
Everything in both 660 carbs should be set the same, except the main jet, the right carb's main will always be one size larger than the left.
These little things really wake up the engine, and it's much more responsive.
A -1 front sprocket will make it more agressive. Speed limiter mod will allow a few more mph on top end.
Stage 3 cam has much better mid and high range than stage 2 and 1.
Go up to an 11-1 or 11.5-1 piston, to make low end power stage3 cam does not.
But, even without the cam and piston, the carb tuning makes a very noticeable improvement...and you'll learn jetting along the way.
 

·
Registered
2003 Raptor 660, .05 over bore, FMF slip on, Fullflight +2 A Arms
Joined
·
63 Posts
Discussion Starter · #3 ·
Can I install Vito’s fuel air screws while the carbs are on? I was thinking about going up to a 686 or 719 when I get a couple more hours on it. (Approximately 6 hours on the cam and new top and bottom end). I also thought about the air box lid delete but after my first ride there was so much mud on top of the lid I figured it might not even be worth it unless I clean it after each ride.
 

·
Registered
Joined
·
3,136 Posts
Yes, you can install Vitos fuel screws with the carbs on.
As long as your airbox lid is on, you won't be able to get much more power out of it.
 

·
Premium Member
Joined
·
131 Posts
Have your head ported and +1 valves before you spend money on big bore kits. The head in a raptor is the bottleneck. All the cc's in the world do nothing if the head can't flow.
 
  • Like
Reactions: Sixpack577
1 - 5 of 5 Posts
Top