Welcome to our first "Ask a Mechanic" question where we answer your tech related questions and hopefully get you back up to speed and make your next ride your best ride.
Q: Even though it's not generally accepted among the professional mechanic community, is it actually ok to allow slightly larger tolerances then spec, and fix things the "cheap" way as long as it's done within moderation?
A: I'd say this is circumstantial, and depends on how one is defining "slightly" and what tolerance we are talking about. Tolerance is normally given in a range acceptable as any within that given range. Using things out of specified tolerance creates a safety problem for the operator/rider, liability problem for those suggesting anything be done outside of a given tolerance and a liability for those performing work outside of tolerance (the customer or mechanic).
It also leads to premature wear and other parts falling victim to subsequent wear. A good example here is that, yes, your brakes will work with new pads used on an old out of tolerance rotor, in exchange you risk your own safety, risk damaging other related parts and wear out those new pads faster. Always refer to your factory service manual for specifications and tolerances and make quality repairs that fall within those specifications for the sake of your wallet and safety. If you feel you cannot hold to these specifications due to mechanical ability find a competent, and reputable mechanic instead or if you can't afford it now, wait and save.
The same goes with, say a piston, that was slightly too small for the bore of a cylinder. You are wasting money as the piston will not last as long as it would if it were held to tolerance. It will also further wear your cylinder and can damage other components like your crank and rod bearings. Now, if you want to go 30 to 40 mph over triples, flying high and far throwing whips with something that absolutely positively works out on paper, but is more likely to fail, cause damage and potentially injure or kill you than using a part that is in spec - be my guest. But I'll take my chances with being in tolerance.
I mean sure I can ride without a helmet because I don't have the money or I'm cheap. I can also ride in regular shoes or work boots, but I opt for the protection. It's the same deal in this situation. That's not to say a cheap helmet won't suffice, but all helmets generally meet similar DOT or Snell tolerance or specifications, if you will, but a backwards baseball cap does not.
I am an advocate of being proactive and taking measures to prevent further problems down the road. The bubble gum Popsicle stick "just get me by for the weekend, or because I don't have the money" is an impatient and reactive measure that just eats away one's wallet. Be patient and do it right. Being cheap is far more expensive in the long run.