Does anyone know the exact models we can pull camshafts from? I'm looking at a camshaft from an SP42B model. Looks like the older camshaft style but its a 90-91 model, not the 91-95 I believe we look for. Seems to be the older 640cc engine as well, not 644cc.

Is that going to make the bike faster? I drove the DR650, it feels way more powerful than S40.

Awesome thanks for that Sneeze! Looks like the camshaft changed when the engine grew 4ccs in 96', something I haven't seen mentioned here.

Interesting seeing a bit more history on the bike:
https://dr650.zenseeker.net/DR650History.htm

och, def check out DragBikeMike's series, almost anything you can think to do to the s40 he's done it. The DR650 gives the bike a bit more aggression as I understand it, about on par with the performance cams offered by Lancer but you can find them used from time to time. Been a hot minute since I've seen one crop up on ebay.

The DR650 cam has the same basic duration as the Stage 3 but it has a little more lift on the valves than the Stage 3, so it does provide a bit more power in mid-upper range.  However, the LS650 engine will never make the power of the DR650 because of the exhaust ports on the LS650.  The DR has straight shot exhaust ports while the LS has “crooked” ports which impede air flow. A stock DR makes 45 hp while the LS makes 30hp at the crank...a significant difference, and the stock DR has 9.5:1  CR, the stock LS 8.5:1CR.

The Savage can be made to run much better than stock but the physical difference in the exhaust ports just cannot be overcome by adding parts, it needs a redesigned head to do that.  DBM’s engine builds and road testing show that the Savage can approach the power level of a stock DR with a highly modified LS engine but also that when run hard it also suffers some engine damage, but if used under normal riding conditions it should be ok.

A performance carb, hi-comp piston and cam, with a better flowing exhaust, will improve the bikes performance and that can be done by a competent mechanic if you don’t feel your skills are up to it.

Thank you guys for all the info. This is not my first priority, if at all, to modify the bike - I was just very impressed with the DR650 performance. Incredible how much more powerful its engine is compared out ours considering the same displacement and single cylinder.