zipidachimp wrote on 07/22/21 at 22:46:37:I just finished reading a book about the Norton Manx 350 and 500 race bikes. The factory worked very hard trying to get more performance out of the bike, and each year they seemed to find one or two more HP. The book stated that in 1961 they were up to 53HP. The bike was a true race bike and had a very narrow rpm range where it ran well - it had to be wound up to make power and be competitive. They were able to find a few more HP - but only a few riders could use the extra power productively and keep the engine revved up where it made the extra power.....most riders were faster around the track with the 53HP engine.
The Manx engine is not an engine that can be ridden on the street from what I have read. It is a race engine and it has horrible manners when out in public. The engine has to be kept up in the power band to run well.
I believe the cylinder head is the limiting factor in the design of the Savage. When I look at the intake and exhaust ports of engines that make big HP they are smooth and straight in comparison to the Savage.
The DR650 engine is very similar to the Savage engine - but it was able to make 46HP in some countries (in some countries it was detuned to 34HP likely to comply with restrictions).
I believe Suzuki was engineering a small capacity Cruiser type motorcycle that was not a performance bike, and they intentionally designed it with good torque values and made it easy to ride. It is likely the Savage was designed to be a low HP entry level bike that was in compliance with the restrictions on power/size that are required in the places where the bike is sold in larger numbers (The US is only a small fraction of the world motorcycle sales). It is also very likely they didn't want to make if faster than their bigger and more expensive V-Twin bikes.
The Savage engine can be made to run really nicely and be noticeably more powerful if you follow Drag Bike Mikes excellent threads - but it will never be able to make the kind of HP that a modern performance engine can make. My Cafe' bike has a Wiseco Piston, Stage 3 cam, some head work, intake and exhaust improvements, and a lightened flywheel. The bike weighs about 320 pounds and accelerates about the same as an 883 Sportster up to legal road speeds.....and that is quick enough to satisfy my speed needs. Sport bikes can easily leave me behind - but I still have plenty of power to keep my happy and with my increased power and taller gearing I can cruise at 75mph easily.