Here's a collection of the kinds of things lifelong, professional mechanics don't believe and that make them laugh when forum "experts" espouse them. I'm sure you'll find these insightful and provocative. Unlike forum authorities, real powersports professionals...

1. Don't install head gaskets without sealing them

2. Don't regard 140 psi compression as good enough

3. Don't replace all the jets in a carburetor when rebuilding it

4. Don't fail to remove all the jets when rebuilding a carburetor

5. Don' believe carburetor rejetting is either needful or beneficial in nearly as many instances as forum "sages" do, and certainly not in connection with ethanol

6. Know that in most cases jet kits do more harm than good and that they exist as coverups for more fundamental problems

7. Realize ethanol does not harm rubber carb parts, cause corrosion, or cause leanness

8. Don't believe individual air filters change engine performance by altering CV carburetor slide movement--that's a myth

9. Don't insist a computer is better than a wiring harness

10. Don't advocate aftermarket air and oil filters

11. Don't measure piston clearance with a feeler gauge

12. Don't believe aftermarket big bore pistons demand more fuel

13. Are very aware of Honda valve recession

14. Don't lap valves, especially as a replacement for a valve job

15. Don't prefer LED replacement bulbs

16. Don't use dime store (bargain table) screwdrivers

17. Know that Honda valves up through the mid-80s cannot be refaced

18. Are aware that Honda's replacement valve guides are oversize

19. Don't value a bike's sound over almost anything else about it, and especially more than maintenance and durabilty

20. Don't gravitate toward the kickstart ethos

21. Don't regard exhaust modifications as more impactive on the engine than intake ones

22. Don't regard user forums as the ultimate clearing houses of maintenance advice

23. Know that far too many popular modifications are in reality band-aid fixes for maintenance shortcomings

24. Know that while carb sync is a frequent way to solve a hanging idle, it is far from the only way and not even the most effective way.

25. Disdain the extemporaneous unqualified advice that characterizes online venues

26. Don't overuse plastic cable ties

27. Don't slavishly endorse resistance tests as part of electrical troubleshooting

28. Don't denigrade everything factory

29. Don't go out of their minds when they discover a 50-year old factory bulletin

30. Understand the pitfalls of honing in-service cylinders

31. Don't regard racers and engineers as more credible than career mechanics

32. Don't advocate aggressive cylinder finishes

33. Don't promote Marvel Mystery Oil

34. Are aware that aftermarket "Hy-Vo" type cam chains are inferior to their Honda originals

35. Know that these same "Hy-Vo" cam chains are problematic in terms of wear and adjustment

36. Know that Honda never had an official paint coding system

37. Don't use Phillips screwdrivers on Taiwan-spec flat blade screws

38. Don't use #2 Phillips screwdrivers on #3 Phillips case screws

39. Are not caught up in the JIS screwdriver nonsense

40. Know that larger than specified valve clearances improve engine performance

41. Don't regard Honda's idle drop procedure as a valid tuning tactic

42. Don't believe in the "master carburetor" theory of multi-carb synchronization

43. Don't regard carb synch as a once or twice in a lifetime adjustment

44. Don't ignorantly assume a Honda bulletin nececessarily applies to every example of the subject model

45. Know that aftermarket replacement steering-mounted vintage model Honda keyswitches are junk

46. Don't believe valve adjustment an infrequent need

47. Well understand the role of ignition service in engine performance

48. Don't regard a carburetor that takes more than a half hour to rebuild as being "difficult"

49. Know that aftermarket electronic ignitions are not superior to Honda Kettering ignitions

50. Don't claim that Sta-Bil will hurt the fuel system

51. Don't ignore or downplay the three most fundamental vintage Honda maintenance needs: silicone brake fluid, Sta-Bil fuel preservative, and wiring harness and canon plug repair or replacement

52. Know that valve recession is the first hurdle in rehabilitating any vintage Honda engine

53. Understand that the aftermarket replacement parts industry is largely adversarial, deceptive and destructive

54. Don't foolishly accept aftermarket sales assurances that their products are "from the same vendor as OEM"

55. Know how to properly adjust their clutches and lube and adjust their drive chains

56. Don't slavishly, unthinkingly promote Viton o-rings

57. Don't insist that carburetor felt seals affect engine performance

58. Don't foolishly blame low cylinder compression on the compression tester

59. Don't prefer cylinder compression uniformity over average compression

60. Don't over-use thread locker and anti-seize

61. Don't like worm-drive hose clamps

62. Don't espouse modification as more important than, or even as a supposed form of, repair

63. Never attempt to detect vacuum leaks by spraying aerosol

64. Don't ignore the industry's most powerful troubleshooting tools such as the exhaust gas analyzer (EGA) and the more/less air test

65. Don't disdain silicone brake fluid

66. Don't regard valve-to-piston and deck height and cam profiling as unimportant and unknowable "black arts"

67. Know that the CB500/550's cam chain requires help during tensioning via the screwdriver slot

68. Don't advocate indiscriminate use of gauze type air filters

69. Don't adjust the CB350/400 four's cam chain with the engine running

70. Don't promote carburetor jetting kits over proper maintenance

71. Don't put sealer on cylinder base gaskets

72. Own thread pitch gauges, as well as other more sophisticated measuring tools

73. Don't fail to understand the need to oxidation-treat the gasoline in their carburetors

74. Understand about JASO MA, recognizing it as the single most important aspect of motor oil relative to powersports

75. Don't overuse their rear brake

76. Don't regard many models of 70s and 80s Hondas' as-designed not charging at idle as a defect

77. Use real-world dynamic charging, ignition and starting system diagnostics, not the simplistic, inconclusive static methods promoted in media

78. Are very aware that Honda's official manuals have never provided any systematic charging or ignition system diagnostic methodology

79. Know that Honda to varying degrees stopped providing effective repair information in their manuals sometime in the late 1960s

80. Know how to stop brake squeal

81. Don't disdain soldering as the correct wiring repair method

82. Disdain Scotchloks and other wire crimps

83. Know the proper steering bearing adjustment method

84. Know about best practices for finding oil leaks

85. Know that most forum "experts" wouldn't pass an entrance exam to a mechanics school

86. Would never install a relay instead of repairing or replacing the wiring harness

87. Don't favor fitting supposedly superior aftermarket tapered steering bearings over properly maintaining the original ones

88. Don't insist that aftermarket valve guide seals are best

89. Are not confused about so-called "matched" or wearing-together engine and carburetor parts

90. Don't endorse premium fuel in 70s Honda road bikes

91. Aren't silent about such things as hazard flashers, center stands, and onboard ammeters

92. Don't advocate using Pine-Sol for carburetor cleaning

93. Believe in adequate and frequent tire pressure maintenance

94. Don't treat 70s Honda bikes as if they're throwaway "beater" just-transportation cars

95. Don't use or promote aftermarket oil filters and control cables and electrical parts and engine seals and gaskets

96. Don't believe a hone can take the place of a cylinder boring machine

97. Don't promote honing Honda brake cylinders

98. Don't endorse using brake cylinder hones on engine cylinders

99. Understand the technicalities of piston and cylinder wear

100. Are not ignorant about oil consumption

101. Are not "YouTube experts"

102. Don't regard abrasive blasting as a carburetor cleaning method

103. Avoid abrasive blasting engine parts

104. Don't believe ultrasonic cleaners clean parts by vibration

105. Don't believe aftermarket valve springs are necessarily better than OEM

106. Don't prefer aftermarket valve guides over the original

107. Have always known about the evils of carb rebuild kits

108. Shake their heads at forums' complete ignorance of the benefits of factory special tools

109. Don't regularly change their views on things when reality sinks in and then act like they always knew the truth (many of the items listed here have been and will continue to filter into forum posts, with the posters acting like they knew them all along)

110. Have always known about grinding brake discs instead of turning them

111. Are not adamant about 120 degree spacing of piston ring end-gaps

112. Don't insist racing carburetors work better than the stock ones

113. Don't reuse drain plug washers until they curl up like potato chips

114. Don't advocate "soaking" clutch plates

115. Don't slavishly embrace aftermarket exhausts

116. Don't promote retention of a Honda's air intake oil separation device

117. Don't believe an aftermarket exhaust necessarily increases engine power

118. Don't use sealer on oil seals

119. Don't regard aftermarket ignitions as superior to OEM

120. Are very aware that o-rings require grease

121. Are aware of where o-rings got their name

122. Aren't ignorant about the relationship between fuel hose and hose clamps

123. Don't "dis" factory Honda fuel hose clips

124. Aren't unaware of proper canon plug maintenance

125. Don't kick-start their machine while it is leaning on the sidestand

126. Don't think engine parts must be milled in order to make gaskets not leak

127. Know that cheap replacement valves are a poor choice for shim type engines because they don't permit a proper valve job to be done

128. Don't confuse preignition with detonation, Kettering with CDI, and magneto with energy transfer

129. Avoid recamming drum brake operating arms

130. Don't advocate the use of hammer-type impact drivers

131. Don't value chrome, powdercoat, polish and paint over mechanical rightness

132. Don't endorse using colorized wiring schematics

133. Don't remove valve springs with a hammer and socket

134. Don't advocate abrasive-cleaning spark plugs

135. Don't check spark with the plugs out of the engine

136. Regard adjustable wrenches and Vise-Grips as among the most unwisely-used tools

137. Don't whine about Honda bulletins not being published for consumers

138. Don't believe running an engine out of fuel will prevent carburetor varnishing

139. Don't recommend simple carb draining as a means of preventing varnishing

140. Know of the principle of unintended consequences and how it applies to most "upgrades"

141. Are very aware of Honda's long-published error of 12 foot-pounds torque for a 6mm bolt

142. Don't unwittingly advance Honda's frequent gasoline octane number error in its vintage manuals

143. Know better than to use silicone sealer anywhere on an engine

144. Don't use abrasive means of removing old gaskets

145. Don't simply mill down a cylinder assembly's protruding cylinder sleeves

146. Know that installing 2.2 ohm ignition coils on a 70s SOHC Honda four will not result in electrical issues

147. Don't believe that 70s SOHC Honda four charging systems break even at 2000 (or 3,000!) rpm

148. Avoid using Neway valve seat machining tools

149. Don't believe braided steel brake hoses necessarily improve brake function (see unintended consequences above)

150. Don't prefer vintage Honda block-sipe and ribbed tires over modern high performing tires

151. Don't pry engine parts apart using screwdrivers

152. Don't hammer on engine cases to separate them

153. Don't regard the 60s-70s CB450 twin's all-steel clutch pushrod as equal to the later bimetal version found in the final year 450 and the 500 and the 500 four

154. Don't tie down a trailered bike while it is still on a stand

155. Know that WD-40 will make your engine's cylinders rust faster than will engine oil

156. Are very aware that there is no such thing as piston and cylinder and valve and valve seat "break-in" or "bedding-in"

157. Avoid tapered valve guide machining pilots because they result in non-concentric valve seats