For our torque demon to be an interstate champ... Top gear has to be reworked so that cruising speed is at max torque.
Which it may be, but I hover around the max hp mark.  

Borracho wrote on 06/07/13 at 16:19:50:

You would probably be better off with a chain conversion and different ratios. You would loose bottom end torque and gain top speed.
Me, I'me perfectly happy the way it is. I consider the highway performance acceptable.

I agree- I have had 4 bikes in my life. A '37 Enfield 500 (great bike but would shake your fillings loose), a 50cc bike that was great around town but totally useless past the city limits, a Honda CB750 four, great on the highway but cumbersome in the city,(and a real pregnant dog to tune), and the S40, which straddles the overall performance of the 50 and the 750.
I had the opportunity to drive a friends CBX once and it scarred the poop out of me.

IMO a twin makes the most sense. A big single needs some kinda swinging balancer, thats mass that has to spin up, so its gonna rev slower, singles rev slower anyway, a twin can be built to balance out a lot better, no swinging weight, smaller dia/pistons = less weight = less rod stress = lighter rod, all that stuff adds up to quicker revs. Its easier on the motor to rev up than it is that big single.
Now, that whole bore/stroke thing,, hmm,, I guess everyone knows the square bore/stroke thing, oversquare revs fast as heck,,undersquare , long strokes & smaller bores, big torque,, & we are pretty close to square I think,.,.bore almost = stroke on our 650, right?

IDK Why they made it a big single or designed it to operate in that rpm range, but they did.. For my purposes its been a fine bike. Itll scat across town w/o makin the howling "Come get me coppers, Im FLYING!" sounds. If a guy was patient with it & rode it in its comfort zone he could go as far as he wanted to. Its not meant for high speed cruising. It will do 75, but I wouldnt recommend a real steady diet,like tryin to make a 3,000 mile run 5 days. Why does that hurt a motor to run it right near its max? Dang if I know,, just seems to gut them out way too often, I try to not run anything but the lawnmower at more than 80% of its max.,

DR 650 R 1993
Overall Length: 2 385 mm (93.9 in)
Overall Width: 870 mm (34.3 in)
Overall Height: 1 330 mm (52.4 in)
Seat Height: 890 mm (34.8 in)
Wheelbase: 1 505 mm (59.3 in)
Ground Clearance: 245 mm (9.6 in)
Dry weight: 166 kg (365 lbs)
Engine type: Air-cooled 640 cc single cylinder 4-stroke. OHC, SACS. 46 hp (33,6 kW)/ 6.800 rpm, 56,6 Nm (5,77 kg-m)/ 5.000 rpm.


The info above is from Suzukicycles.org
The engine layout of the '90-95 DR650 is pretty much like our LS650 bore/stroke/rpm wise.  The difference lies in the exhaust ports, which are more properly designed, and the camshaft which has a much higher lift & duration than even the Stage 3 camshaft.
The better exhaust ports and the cam profile allow the engine to breath much more efficiently than the LS650, and the result is more torque & hp production.
This is all stock factory stuff.

I personally don't think a few mild/moderate mod's in this direction over-stress the engine at all.  It still operates within the standard rpm range so piston speed is not an issue, and that IS a critical issue.  Engine components seem more than adequate to handle a power increase; the stock DR does so and I've not seen any of it's engine parts being heavier than the LS.

Anyway, the engine responds very well to the mild/moderate mod's of carb, cam, porting, cc & CR, exhaust, etc.  Still in the stock rpm range and the engine is just down right perkier.  It FEELS GOOD and wants to run.

It's also called the Suzuki "Sausage" for a reason... For what it is, a conglomeration of substandard bits and pieces mixed together in a seemingly random fashion... it's a pretty good mix.

Mine is just about ready for the scrap pile, electrical gremlins and the timing tensioner is about ready to let go. But that's 15 years of being beat on unmercifully. I usually try to have a real bike as my primary, keeping the Savage for what it does best, play b!tch to a better machine. And better is very subjective...

Fast? I've got a high revving warmed up 250 racing twin  I'm overhauling for street duty, and it will handle the roads around here better than the Savage does. Ceriani front and rear suspension, tls drums on both ends (no sudden failure of a crap single piston caliper pushing against an improperly heat treated rotor).

Touring? I had a GS750T with a Windjammer fairing equipped with a cigarette lighter...

General purpose? Had a 1999 VN800A with full rear fender conversion that looked better, was a LOT faster, better seat, better brakes, bigger gas tank, 50+ hp at the rear wheel (heavily modified)... Had a stock 2005 VN800B (Classic) that was such a p.o.s. it makes a stock Savage seem like a Cadillac (or better yet, a real LaSalle or a high end Packard)...

Offroad? Yamaha XT500 and the racing spec Honda CL72 250 Scrambler turned TT bike. I'll take the Savage offroad, but it doesn't much care for it...

The Savage is a great commuter bike. Set of small saddlebags, better seat and the proper handlebars turns it into a perfect utility bike. But, for all intents and purposes, it's an antique with a later ignition swapped in. Suzuki would have been doing all of us a great service by running a 1960s Honda style cam in real bearings... more aggressive profile and no chance of tearing up the head section castings due to the inferior oiling system and weak sister oil pump.

I've corrected most of the obvious compromises on mine so it fits me and does what I need it to do. Tall bars, better rear shocks, heavier fork oil, full rear fender, higher flow exhaust, manual petcock with a real inline fuel filter, bigger headlight with infinite adjustability... cam chain tensioner will be swapped out in September, failure prone switches and safeties deleted, wiring harness being shortened and armored...

Hop it up all you want, the engine design (not to mention the miniscule fuel tank) relegates it to commuter or toy status. I still like my Savage, but I don't trust it as far as I could throw it.

I was going to reply to Dave, but read on...

Then I was going to reply to Serowbot, but read on...

Then I was going to reply to JOG, but read on...

...and I'm glad I did, because wise old Lancer nailed it on the head !

Like the say in merrie olde Englande, it's "horses for courses".

The only things the Savage and the DR650 have in common is the brand badge on the tank.
Else, the Savage is a wet sump, low revving, low specific hp air cooled engine.
ENTIRELY BY MISTAKE it has a 4-valve headm had they equipped the Savage with a simple LARGE valve "2V" head, and quite possibly a better location for the spark plug, they would have done a better job.

My Savage's sweet spot for highway criusing is around 4000-4500rpm, but I prefer to stay around 3800-4000 which equates to 55-60ish.

Beyond that speed... the engine is quite capable, but the bike is not designed to cruise at anything Beyond 60-65mph.
Not with those pull back bars and forward controls.

As for "the best racing bikes yakk yakk yakk", I am sorrym, that is nonsense.

The best racing twin to be a 750? PL-E-E-E-ZE !!!
Hasn't anyone ever heard of DUCATI ? 848, 899, 998, 999, 1098, 1099, all the way up to the latest 1198cc screamer (if you can call the Ducati's growl a scream, it's more like the bellowing of an enraged bull !!! )



The same applies for APRILIA...



(Aprilia Tuono pictured with KTM SuperDuke)

The same applies for BMW's "HP2"... quite possibly the only factory bike other than the Ducati 1199 Panigale with a chronometer for lap times built into the instrumentation



Even the new, revived, resuscitated Norton Commandos are quite impressive scorchers...



Enjoy some Thunder !



Privateer on road legal Ducati 999 lapping Monza... see tach clocking 9500rpm!



This is a Superstock Panigale 1199 lapping Imola  
(see how his handlebars snake all over the place in accelleration... )



Ducati Monster S4RS at a track day

AND NOW...
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FOR SOME RIVETING ACTION ( !!! )
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