Aligning the front forks

[Audi403]

Hey guys,

 

I found some interesting posts in the Hexhead section of this forum which have me questioning a few things. First, a little background info: I dropped my bike in my garage early 2022. I repaired the cosmetic damage and never thought much of it. At some point during the riding season I noticed when I took my hands off the steering, it had the ever so slightest pull to the left. Sometimes not even noticeable, to the point where I was questioning if it was just the road surface. But the prior riding season, whenever I took my hands off the steering, it tracked perfectly straight. This has me thinking maybe something got a little twisted.

 

Today, I replaced the fork seal on my left side fork. I had the single fork removed from the bike. I followed the service manual procedure to reinstall the fork on the left hand side. When installing the front wheel, I also followed the written procedure, which is to compress the front suspension a few times before torquing down the axle bolt and pinch bolts. I always felt this seemed like a waste of time, so I started reading into what the point of doing this is.

 

Well, I found something that got me thinking. I read this procedure recommended in the hexhead forum. The idea is that if the front end has been disassembled, this is required to align them properly. The member says instead of just bouncing the suspension before torquing the axle pinch bolts on the bottom of the forks, this bouncing should be done for the lower triple tree pinch bolts as well. He wrote this: 

 

"The rule of thumb I've used - work down. Loosen everything, then start tightening from the top down:

 

- Lower triple-tree first - then bounce bounce bounce

- Fork brace/bridge - then bounce bounce bounce

- fixed side of the axle - tighten nut and/or clamp - then bounce bounce bounce

- other side of the axle - usually a clamp bolt(s) on the bottom of the fork leg"

 

Has anyone tried this sort of procedure on a Wethead? One other question, is it ok to hold the front brake while compressing the front suspension?

 

I have a 2019 Shiftcam, but posting here since it's a more popular section, and are forks are the same as the Wethead.

[dirtrider]

8 hours ago, Audi403 said:

Hey guys,

 

I found some interesting posts in the Hexhead section of this forum which have me questioning a few things. First, a little background info: I dropped my bike in my garage early 2022. I repaired the cosmetic damage and never thought much of it. At some point during the riding season I noticed when I took my hands off the steering, it had the ever so slightest pull to the left. Sometimes not even noticeable, to the point where I was questioning if it was just the road surface. But the prior riding season, whenever I took my hands off the steering, it tracked perfectly straight. This has me thinking maybe something got a little twisted.

 

Today, I replaced the fork seal on my left side fork. I had the single fork removed from the bike. I followed the service manual procedure to reinstall the fork on the left hand side. When installing the front wheel, I also followed the written procedure, which is to compress the front suspension a few times before torquing down the axle bolt and pinch bolts. I always felt this seemed like a waste of time, so I started reading into what the point of doing this is.

 

Well, I found something that got me thinking. I read this procedure recommended in the hexhead forum. The idea is that if the front end has been disassembled, this is required to align them properly. The member says instead of just bouncing the suspension before torquing the axle pinch bolts on the bottom of the forks, this bouncing should be done for the lower triple tree pinch bolts as well. He wrote this: 

 

"The rule of thumb I've used - work down. Loosen everything, then start tightening from the top down:

 

- Lower triple-tree first - then bounce bounce bounce

- Fork brace/bridge - then bounce bounce bounce

- fixed side of the axle - tighten nut and/or clamp - then bounce bounce bounce

- other side of the axle - usually a clamp bolt(s) on the bottom of the fork leg"

 

Has anyone tried this sort of procedure on a Wethead? One other question, is it ok to hold the front brake while compressing the front suspension?

 

I have a 2019 Shiftcam, but posting here since it's a more popular section, and are forks are the same as the Wethead.

Morning Audi403

 

I usually tighten the upper fork nuts, then install the axle & tighten (no wheel on the axle) then tighten the fork clamps. Then remove axle & install the wheel. 

 

Typically fork alignment doesn't contribute to steering pull as a motorcycle is a single track vehicle.  The fork alignment is more to eliminate fork slider & bushing wear from side loading.

 

The front wheel would have to lean to effect steering pull. On the wethead that alignment is pretty well set & non adjustable.   

 

A worn front tire can cause a steering pull as well as more weight on one side of the motorcycle center line than the other. 

[Audi403]

1 hour ago, dirtrider said:

Morning Audi403

 

I usually tighten the upper fork nuts, then install the axle & tighten (no wheel on the axle) then tighten the fork clamps. Then remove axle & install the wheel. 

 

Typically fork alignment doesn't contribute to steering pull as a motorcycle is a single track vehicle.  The fork alignment is more to eliminate fork slider & bushing wear from side loading.

 

The front wheel would have to lean to effect steering pull. On the wethead that alignment is pretty well set & non adjustable.   

 

A worn front tire can cause a steering pull as well as more weight on one side of the motorcycle center line than the other. 

Thanks for the reply. The steps you listed are the same as the procedure from the service manual, which I followed. 

[Hosstage]

Bouncing the front end to help line everything up has been a common practice for as long as I can remember.

[Paul De]

3 hours ago, Hosstage said:

Bouncing the front end to help line everything up has been a common practice for as long as I can remember.

LOL, except on the Telelever front suspension end you better hold the rear brake instead of the front to get a proper  stroke of the stanchion into the slider when you bounce it.

[Audi403]

5 minutes ago, Paul De said:

LOL, except on the Telelever front suspension end you better hold the rear brake instead of the front to get a proper  stroke of the stanchion into the slider when you bounce it.

This is why I asked this questionin my post. The calipers are mounted to the forks. If the front brakes are held, the wheel is essentially fixed to the forks, and not going to move in relation to them. I think I'll use a tie wrap to hold the rear brake while I compress the front forks. It's too tricky to try and hold the rear brake and compress the front at the same time. Thanks for your reply.

[Hosstage]

I wasn't sure if the bike discussed had a telelever front end or not, I'm not familiar with them as far as service, nor a lot about design, my comments were directed toward a traditional front end. I should know better than to ever offer comment on servicing these bikes.

[Skywagon]

15 hours ago, Audi403 said:

I took my hands off the steering, it had the ever so slightest pull to the left.

 

I thought they were supposed to do that.  Every BMW I've owned pulled one way or the other when taking your hands off the bars even with cruise control on.  I've owned several.  Never had one track completely straight at all speeds.  I forget which way now but my old 1150RT bought new pulled pretty good.  There were some supposed cures of shimming the rear wheel, putting extra weight in one of the panniers, etc...but I never got it straight hands off.  My 1200RT will occasionally steer straight depending on speed...usually around 60mph, but it might hang a left or a right.  I can usually shift enough in my seat to hold it straight for a few seconds.  It doesn't matter if the tires are brand new or near worn out.

 

When I had my airhead with an adjustable steering tensioner, I could sometimes get it to go straight for a while..but not long.

[dirtrider]

6 hours ago, Audi403 said:

Thanks for the reply. The steps you listed are the same as the procedure from the service manual, which I followed. 

Evening Audi403

 

Then you did it correctly, you want the inserted/tightened  axle to control the fork spacing as that is the position the fork tubes will be in riding down the road. 

[Audi403]

Here's another thought, after bouncing the front suspension, does it matter if the front wheel is on the ground or in the air when torquing the axle bolt and pinch bolts? The owners manual says to lift the front wheel before torquing the axle bolt and pinch bolts. However, the service manual says after compressing the front suspension, to place the bike on the center stand to torque the axle bolt and pinch bolts. It's weird how the instructions differ depending where you look.

[Audi403]

A side note, I'm pretty livid with myself right now. After reassembling the bike and cleaning up, I realized I forgot to slip this little ring on top of the dust cap. The only way to get it on is to drop the fork again. I was rushing a bit to get the fork on last night as I had some plans I was trying to keep. 🤬

 

[Hosstage]

That's normally how I do it, disassemble, repair, re-assemble, see a forgotten part on the bench, mutter obscenities, disassemble, put that part on, triple check, re-assemble.

So don't think you're special just because you do it too!!

[Audi403]

All back together now. It took me about 1 hour to remove the wheel, drop the fork, install the silly ring on the dust cap, reinstall the fork and wheel, compress the suspension, and torque the wheel up.

 

[Audi403]

After compressing the suspension several times, I put it up on the center stand to torque the axle and pinch bolts, as per the service manual. As I mentioned before, this differs from the owners manual. It says to install the front wheel stand to lift the front wheel before torquing the axle and pinch bolts. Which way is correct? I don't know. If anyone has any thoughts on this, feel free to share them.

[Mike279]

Owner manuals tend to give general information you may need while on the road vs a service manual which usually gives complete detailed service information.  Who would say one way is wrong when both will work?  

[dirtrider]

On 1/22/2023 at 6:26 PM, Audi403 said:

After compressing the suspension several times, I put it up on the center stand to torque the axle and pinch bolts, as per the service manual. As I mentioned before, this differs from the owners manual. It says to install the front wheel stand to lift the front wheel before torquing the axle and pinch bolts. Which way is correct? I don't know. If anyone has any thoughts on this, feel free to share them.

Morning Audi403

 

As long as you originally installed the fork leg per the service manual then I seriously doubt that torquing the axle using either method makes any difference at all. You just want most of the weight off the axle (if possible) while setting torques. Even then it is probably going to be within the acceptable torque range either way. 

 

One thing about (U.S.)  BMW service & owner manuals, they are translated from German so often the translations are not exact due to grammar & word usage difference. I have seen Micro-switches translated as microphone switches & other things like that pop up regularly.