Hey all, I think I already know the consensus of opinion here but I thought I would ask anyway. While at the shop talking to the "expert" he advised me to stick with stock because increasing engine performance would reduce engine life. He said the mods (most if them anyway) would cause additional heat and excessive engine wear. I was curious as to some feedback from those who've performed mods, have you experienced anything like this with you bikes?
Heat kills. Making power creates heat.
If you don't run a modified engine any harder than a stock engine, it's probably a wash...but then if you aren't going to run it any harder than stock, why spend the money?
If you want real answers, go enroll in a school of mechanical/chemical engineering. This whole combustion process is a lot more complicated than most people on sickle forums presume to know.
A few "truths" that appear evident from run of the mill testing is that stoich mixtures have the highest exhaust gas temperatures (EGT). This is because:
a) An efficient burn maximizes fuel economy
b) catalytic converters perform best at these temperatures
Also, maximum power is achieved rich of stoich.
If exhaust valves are the weak link (and based on the fact that mfgs are now using coolant systems targeting this area it seems plausible) then it stands to reason that running rich or lean of stoich would benefit a valve without the benefit of such directed cooling...like ours. Prolly not so great for the life of our catalytic converters though.
From what I can gather on the subject (and without attending a class that ain't so easy) EGT is not necessarily proportional to engine temperature itself. Thus, while richening the mix may cool the gas exiting the exhaust valve, it may still increase overall engine temp.
And then there's still other considerations. If you bought the extra power to run 110 mph down the road, you'll be getting a lot of cooling air to the engine to help dissipate the extra heat generated. If you bought the extra power to sit in a parking lot, spin your tires, and make blue smoke for amazed onlookers who are unclear of the effects of inhaling burnt rubber, then...not so much.