I was wondering if mods such as pipe/filter/jet will effect the motor negatively over time? What about bore kits?

 

In my opinion they don't.......as far a boring, you run the risk of blowing up more when you are cranking the hp's out.......and once you've big bored, well you can't bore anymore.....

The big bore is probably the most at risk......and when you really get the hp flowing, then you are proabaly effecting the motor.....

As far as pipe,etc.....I doubt they hurt too much......

 

Not really for the pipe ect. For bore kits it will if you go very extreme in overbore or stroke such as 430cc kit for a 350cc, or similar. Most bore kits won't however, since they are usually smaller differences than that. You will experience more heat in the engine, so if you're running hot already you should find some means to better or more efficiently cool the engine such as oil coolers or better radiators. Heat transfer is one big factor in prolonging engine life, since you will start burning up the aluminum in the cylinder or on the piston. Cooling the engine by the above means is also a good idea if your engine is only air cooled. You will receive a fraction more power from running cool also.

 

Bolt ons - No, unless you screw up the jetting.

Internals - You decrease reliability just about every time you open that engine up and swap a part, so yes.