The benefits of threadlocker on motorcycles are undeniable. Some of the most interesting thoughts, tips, and tricks are at the end, so don’t stop reading too soon.
Threadlocker on Motorcycles – The Good
First and foremost, it provides added resistance against shock and vibration – locking and sealing threaded fasteners together. This is obviously a very important job on motorcycles (especially old motorcycles like “Cal“, where vibration might as well be his middle name).
Additionally, it provides rust and corrosion resistance, which can be very helpful 5-10 years down the line.
Threadlocker on Motorcycles – The Bad
Then, there is the inevitable bad with threadlocker on motorcycles. Removing a nut or bolt that has been installed with theadlocker. Some of this depends on the grade of threadlocker used during install. The most common types during automotive applications are blue and red. Some facts about each.
Blue: Dubbed as “removable” on the package, this threadlocker after installation and curing (about 24 hours), is supposed to be removable with regular hand-tools. By hand tools, our friends are Loctite are referring to a breaker bar or lock torque wrench set to the loosen setting. In rare instances where hand-tools don’t work, the recommendation for disassembly is localized heat on the nut or bolt to approximately 482 degrees Fahrenheit (250 degrees Celsius) and removal while hot. According to the specification sheet on the Loctite website, Blue Loctite has a breakaway torque of 70-150 lb-in or 5.8-12.5 ft-lb and a prevail torque of 25-60 lb-in or 2.1-5 ft-lb.
Red: Dubbed as “permanent” on the package, the specifications clearly state that once cured it can’t be removed without heating up parts to 500 degrees Fahrenheit (260 degrees Celsius). Essentially this is meant for stuff you really don’t plan to take apart more than a couple times over the life of the vehicle. Red Loctite has a breakaway torque of 150-300 lb-in or 12.5-25 ft-lb and a prevail torque of 200-355 lb-in or 16.6-29.6 ft-lb.
Tips/Removal – Threadlocker on Motorcycles
Really, the “Bad” when it comes to threadlocker is ever having to remove a fastener that was previously installed with threadlocker. As discussed above under the specifications, the real trick to removal is heat. Like most adhesives, threadlocker on motorcycles can be loosened or weakened with certain chemicals, but the issue is how to get the solvent into the spaces between the nut and bolt such that it has a chance to do its job. Soaking the entire assembly (nut and bolt) could help if left overnight or a couple days, but it is unlikely that the part you are working with is off the bike in such a way that soaking in a Tupperware is even possible. That said, if you have clean access to the fastener, acetone is an excellent solvent for Loctite adhesive. Moving on to our discussion of heat.
Nothing does it better than a good video. Soup-to-nuts (pun intended) this covers the myths that are out there on the internet about the application of heat while removing fasteners installed with threadlocker.
Video Summary: For those maybe stuck at work with the boss hovering around, here is a summary of the video such that you don’t have to watch it to get the punchline. Basically, the author of the video puts together 4 test nut-bolt combos with red threadlocker and then tests 1) a soldering iron, 2) hair dryer, 3) heat gun, and 4) propane torch for the application of heat. Final result? The soldering iron and hair dryer could not provide sufficient heat to weaken the threadlocker. The heat gun got the job done after about 4 minutes of heat application and left no damage on the bolt. The propane torch got it done in about 1 minute, but scorched the bolt some.
Bottom line – a heat gun is a great way to apply localized heat and will get the job done with a little patience.
My second tip is regarding the removal of left-over threadlocker sitting on your bolt after it has been removed or anywhere else that you now have access to, but with some leftover threadlocker sitting there. The two best solvents for threadlocker are 1) threadlocker – put a little on and wipe it off. Threadlocker when still wet will dissolve old threadlocker and 2) acetone as mentioned above.
And my final tip on threadlocker goes back to the torque and heat specifications above. Obviously, you don’t want to overdue it with your choice between blue and red (i.e. use red threadlocker in a place that blue is enough). However, the breakaway torque of blue (5.8-12.5 ft-lb ) is rather low and probably too low for most motorcycle engine specifications. If a fastener needs Loctite, it is hard to imagine not needing the extra strength of red (12.5-25 ft-lb). Given the difference in “loosening” heat listed for both, 482 degrees Fahrenheit versus 500 degrees Fahrenheit, I think you are going to be applying heat either way and the difference in temperature is rather small.
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