Head Bearings Maintenance For Triumph Bonneville And Others

[@paulbowyer5665]

Great videos John. No bullshit, no music, just useful inspiration.

[@Gringo_In_Chile]

Big fan of your channel. Your Triumph maintenance videos inspire me to take on jobs that would otherwise freak me out. Your videos have helped me keep my 2015 Bonnie T-100 in great shape after 40,000 Km.

[@tinderboxarts]

Great to hear, thanks!

[@kevincosby1632]

Excellent channel and info. Thanks

[@jackjohnson65]

Love your videos, nice job.

[@Gringo_In_Chile]

BTW, I have seen you replace parts that weren't that necessary to change out. But you did anyway because it was either time to or because you might as well since you took the time and effort. So, I was surprised that you did not change out the headstock bearings this time.

[@tinderboxarts]

These bearings were in great shape, and headstock bearings generally last a long time if kept greased. Unlike wheel bearings, there just isn't that much wear and tear on the headstock bearings. Plus, changing them is a difficult process because the outer races must be removed and the new ones pressed in. In this case, best to keep the old ones going.

[@ry4ncoughlin]

Hey great video. Do you know if the street scrambler 2020 year has the same size adjuster nuts? In some part drawings I’ve seen it says they are M30 but I can’t find any information to verify that

[@tinderboxarts]

I don't know about that model year, but I will say that Triumph and other manufacturers tend to keep parts like this the same over years and models if possible because it reduces costs. But, you'll really need to pull it apart to see.

[@kalled4662]

The manual states that you should lose the nut again and set it to 3 Newton. I dont know why but i says so. What do you think?

[@tinderboxarts]

That technique has been around for ages, on all kinds of vehicles and bearing types. The point is to first tighten the nut in order to fully seat the bearing. Then you back off slightly and re-tighten to a torque spec which is an appropriate pre-load. The same technique is widely used on automotive wheel bearings. Is it necessary? Well, much depends on your level of experience and the particular bearings. If you have extensive experience you probably have muscle-memory for the feel of a seated bearing and the pre-load of a bearing. If you are a beginner, though, this technique can be helpful. And, the type of bearing makes a difference too. A head bearing like this is not large and does not have a heavy load on it, so it's a bit easier to feel the pre-load. I have a Chevy 3500 work truck which has very large and heavy front discs/hubs. Despite my experience, on that vehicle it is very difficult to feel anything just due to the weight involved. So when I replace those bearings I seat them first, and then back off to a spec.

[@rocktriple]

Just out if interest, how many miles did your bike do when you found that loose head stock nut?

[@tinderboxarts]

I just looked at my maintenance records and it was at 23,673 miles. To be clear, it was loose but not to the point of being dangerous. If I had not discovered it then over time it would have led to more wear and eventually I would have actually felt the looseness in the handlebars.

[@dirkdiggler5164]

40 Nm is 29.5 ft/lbs. It didn't look like you made it anywhere near that tight. 29.5 ft/lbs is 2x as tight as you make a spark plug.

[@tinderboxarts]

Maybe it didn't come across in the video, but I wasn't using the factory method. The factory method wants 40NM, not at the end of the wrench where I was pulling, but with a torque wrench choked up closer to the nut. They have a special wrench with a square hole for the torque wrench and the hole is located near the nut end, which provides less leverage. I was seating the bearing by feel, which I have done hundreds of times in hundreds of settings. It's not difficult to feel when the bearing loses play and then to go a little tighter to ensure the assembly isn't cocked or misaligned. Then you loosen enough so that there is little resistance but no play. This identical method is used on truck and car wheel bearings, axles, bicycle bearings, etc.

[@dirkdiggler5164]

@@tinderboxarts Ah! thank you. 30 ft lbs sounded to me awful tight for that. The tool must make it effectively less. I'd think straight on the chin direct tighten, about 8 ft lbs sounds about right. Just a guess. I'm in the middle of doing that job. All the same but mine had the green grease on it