Ok brief and to the point.

1. the Savage engine is very conservative. Low compression, small valves, mild cam timing, low horsepower @ low rpms

2. our rejetting is correct for power, long life, and smooth running - the stock jetting is way too lean.

3. There's no uneven burning, "rich and lean spots", fuel dumping, or excessive oil washing from either the rings or cylinder.

4. adding a "low-back pressure (loud)" muffler on a bike DOES NOT "make it run lean at some rpm and rich at others."

Our rejetting regimen corrects all 3 carb circuits and I can assure you my bike is jetted correctly and will last.

The reasons for these two engine failures are in no way related to what Mr. Engineer has posted. I've been modifying internal combustion engines for many years. I can assure you that free flowing exhaust and jetting for performance will only increase longevity.

911radioman wrote on 12/31/69 at 16:00:03:


That's a wonderful story, but too improbable as to the cause of rod failures. If the raw gas has diminished the lubricity of the cylinder wall causing aluminum microns to be scrubbed from the piston, a more likely result will be particles escaping out the exhaust. Anyways the steel piston rings are the first contact with the cylinder liner and any buildup of the wall causing excessive friction would more likely lead to a piston/ring seizure as opposed to transferring this heat down to the connecting rod in its oil bath.

Its funny how this guy can switch sides of the savage's design in the same breath.   I guess his engine design experience is based on riding different motorcycles thousands of miles.   Since when has that ever made anyone more qualified to make improvements to a motor?  I wonder if he is Japanese? haha

First praising the Japanese engineers

"is a typical American
idea that any guy with a screwdriver is a better designer than a bunch
of highly paid Japanese engineers"

and inserting his typical American idea to improve this engine that has been designed by highly paid Japanese engineers  he praised earlier

"The flamefront ignited by the spark plug has to travel all the way
across the monster piston bore to burn instead of explode. To minimize
this, the spark plug should be in the middle".

I am highly doubting this statement too  

there isn't enough length in the manifold to thoroughly
mix the droplets and let them vaporize

Im pretty sure if it wasnt vaporizing, it wouldnt be firing. 8)

Does a lean stock bike (his preferred savage) have more potential for engine failure than a properly jetted one?  I would think over the long term the stock jetted one with a free flowing muffler or k&n air filter would fail sooner than a completely stock bike or a bike with 152.5 and air filter with free flowing exhaust would .  I believe this is true  because its extra lean condition would make the temp higher as well as other things.  Even a stock bike runs extremely hot and in the summer it was almost frighteningly hot sometimes.    

This ain't rocket science he states.  Thank god.  I wouldnt let him come anywhere near my rocket  

He could always be secretly working for the EPA and make up this propaganda hehe.

Starlifter wrote on 12/31/69 at 16:00:03:


That is not my point.  My point is that if this is the case, why aren't bikes of all cylinder numbers and sizes failing because it is the same principle?

Heck, my bike is modified as well.  I'm not against these mods, just trying to figure out this guys thinking and wanting to share what he said with the forum here.  I'm not in agreement with him on it, save maybe one or two little points.

I think that one thing that this article didn't address is how much more perfomance is realized by the rejet and exhaust mod. After all we are only talking about a 15 to 20% increase in power, stock at around 30hp, mod at around 35hp. This power increase should be well in the safety limits built into the specs of the connecting rod no matter what they are made of. If the rods are that weak then there would be a lot more failures with nonmodified engines. After all the Savage is consitered an entry level bike and has been detuned for that reason. As to raw gas being introduced into the combustion chamber, well I haven't seem any raw gas being sprayed out of the exhaust which is where it shows up. Also everybody has been reading thier sparkplugs to insure that the fuel/air mixture is correct so the cylinder wall wash down theory really doesn't apply. I'm not going to argue the point that increasing the horsepower of an engine can decrease the overall life of that engine, I've been a firm believer in that for years. It just is a ballance between performance and engine longevity. We are not asking the big single to produce double or tripple the stock horse power, we are only bringing the engine up to power levels that have been shown to be reasonable by other engines of the same basic design. The author seems to have a problem with backyard mechanics who enjoy tinkering but without backyard mechanics we would still be riding horses and buggies. Just my .02 cents  

My opinion is this is: If you don't have the knowledge or a knowlegable friend to help you with the modifications then, NO you should not be doing them. I seen people bringing in there bikes saying "this thing ain't running right" or "it's backfiring to much". You ask them if they did anything to the bike, they say "yeah, I put on a set of drag pipes". Of course when you ask the other obvious questions about jetting and the air/fuel screw they act like they didn't even know the bike had a carb. This guys opnion about leaving the bike stock I think is just his own uneducated opinion. If the modifications you're doing are done right, there should be little or no affect on the reliability of the bike, If fact, eliminating the stock lean mixture alone should improve performance and engine life.