skrapiron -FSO wrote on 02/06/08 at 05:04:59:And AGAIN... Since you failed to read the first TWO explainations:
The stock performance you get is NOT the fault of Suzuki, the Savage or anyone involved in the production, distribution or sale of the motorcycle. The reason you recieve a castrated thumper in the first place is due to stringent clean air regulations!
The bike has NO pollution contols. In order to meet emissions standards, the engineers had NO CHOICE but to reduce its performance by restricting the engine.
Your gripes about the header, cam, exhaust and bore are bogus! yes, the bike would perform MUCH better than it does stock. But it would NOT MEET modern emissions standards. THEREFORE IT COULD NOT BE SOLD!
If you want that kind of performance, YOU, the end user, will have to make the modifications (and suffer the consequences if ever subject to emissions testing). It's your bike. Do what you want.
BUT Don't continue to make broad statements like the bike IS UNDERPOWERED (No matter what we say). It may be underpowered TO YOU. That does not mean that WE find it underpowered. That's the difference between FACT and OPINION....
Actually no, I chose again to ignore your ‘explanations’ as they were bull.
Put it like this. I’m a chartered mechanical engineer, I’ve worked automotive industry, oil industry, been a military engineer the last 16 years, and I’ve built and modified an awful lot of bike and car engines (mostly V8s) over the last 25 years as my hobby/weekend business involves that kind of thing. I’ve had to struggle sometimes to get cars through emissions, and that’s often come down to cam profiles being too radical – you go for a lot of overlap, and you get a lot of hydrocarbons coming out the pipe (which can be harder to deal with than CO). I understand a lot about emissions and regulations (and, as an aside, I’ve known that there are 2 TDC positions for a bike when you’re setting the valves since I was about 12 years old, unlike some of us).
What makes you think it Suzuki had to restrict the bike so much to get it through emissions? Wrong I'm afraid. Why isn’t the Virago 535 only 30hp if that’s the case? It costs a little more, but it’s not smothered in emissions kit.
You seem to think it would be prohibitively expensive to mod it and get more power while keeping emissions down. Wrong again. Crankcase air recirculation would cost pennies. Ignition re-curve would cost pennies. Producing a different cam profile would cost zero – they’ll have loads of development profiles available to programme into the grinding machine anyway. The compression ration doesn’t need to be that low, and the header diameter could be better.
The first big restriction in the exhaust port is due to the spring seats sitting deep in the head and blanking off part of the port – that’s just down to Suzuki engineers concentrating on the engine’s looks and profile more than gas flow. Better valve train design could have removed that obstruction in the casting.
There’s also a deliberate cast-in restriction to the exhaust port orifice. That’s a factory restrictor. As well as limiting flow, that will cause some premature scavenger wave reflection which will worsen emissions, guaranteed, not improve them.
The only thing that would be emissions-dependent would be jetting, needle and mixture screw setting, just like it is on every other bike.
When the Savage was launched emissions weren’t the problem they are now. 2006 EPA standard for a Class 3 motorcycle is 1.4 grams per kilometer of HC + NOx (Hydrocarbon + Oxides of Nitrogen) and 12 grams per kilometer of CO (Carbon Monoxide). Suzuki could easily achieve that at virtually no cost for a Savage to produce another 10 or so hp. The limit from 1980 to 2006 was 5g of hydrocarbons – that’s a piece of cake to achieve, so blows your emissions claim out of the water.
There are plenty of other, simple bikes (twins admittedly, but they’re hardly going to cost more to sort than a single) which produce much more specific horsepower than the Savage, and sail through emissions regs with hardly any emissions equipment on the bike. Believe me, that little engine could produce more factory power and pass emissions if Suzuki had wanted it to.
So why does it only produce what it does?
Remember that the Savage, like many Japanese bikes, is built for the Japanese and European markets as well as the US. Its design and application are very dependant on their markets. What really IS more than coincidence is that there’s a European law for power limits on young riders with less than 2 years of experience which limits them to less than 33bhp. There are similar rules in other European countries. The advertising banners for the Savage in the UK whe it was launched were covered in references to it meeting the learner power limit.
That’s why the bike is only 31hp.