Front End Wobble

I don't know how tight they need to be but it would seem to me the the additional 1/8 turn should have been enough. Maybe not. I put the twisteroo to the top nut on the old Yamaha & it wouldn't come out of a turn on its own (over did it I guess). Had to go back & take some torque off. Maybe the manual would shine some light.

I know that when I put my Rocket on the centerstand, the fork is loose enough that it swings side to side without "any" resistance. In fact, when its up on the stand and I let go of the handlebar, the front fork will swing fully (the the stop) to one side or the other on its own when I push down on the luggage rack to lift the front tire off the ground. I usually block the frame to hold the front tire off the ground for easy cleaning of both wheels & I can't make the front fork stay straight. It always wants to swing to the side.

See ya.

A little more techinical....

I've been following this thread as it progresses. So here goes.

According to the illustrious triumph Shop manual the procedure for adjusting the steering head or headstock bearings once you have exposed the top nut and adjuster nut is:

-Tighten the adjuster nut (bottom nut) to 40Nm.
-Slacken the adjuster nut fully
-Re-tighten the adjuster nut to 6Nm.
-Loosen the adjuster nut by 90 degrees (the manual says there will now be some free play present)
-Hold the adjuster nut in that position while tightening the locknut to 40Nm. Insure that the adjuster nut does not move while tightening the locknut.

Check to see that all free play has been removed and the steering can freely be moved from lock to lock without any signs of tightness.

Basically, with the exception of torque settings that's the same procedure for setting end play on wheel bearings on big trucks.

What is happening there is the clamp nut is actually pre-loading the adjuster nut by taking up the play in the threads between stem threads and the adjuster nut. The pitch and the fit of the stem threads in relationship to the adjuster nut is a known tolerance, for example a Class 2 fit, so the clamping action of the top nut actually moves the lower (adjuster) nut a known distance removing any play.

If you want to get really old school, the end play can be measured by what's called 'starting torque'. That is, how much lateral force it takes to put the assembly in motion measured in Inch Pounds or Nm. You obtain a starting torque measurement by using a spring scale and comparing the reading to the know constant provided by the builder.

It's just a lot simpler and less time consuming to use the pre-load method. One thing I'd check is the quantity and condition of the grease in the headstock before making any adjustments. In as much as they (the steering head bearings are tapered rollers on both ends), good quality uncontaminated grease is needed. There isn't much in the way of seals on the headstock and repeated washings can and will contaminate the grease leading to rust and a less than frictionless action with the bearings.

I suspect that if I ever did a bearing check on my Rocket, I'd remove the stem entirely and drill the frame head for a Zerk fitting so I could pump fresh grease in regularly.

I'll probably re-pack those bearings at some point, but that requires additional work, such as lifting the front of the bike high enough to remove the front end assembly and removing a bunch of other stuff. Maybe when it gets really cold. Next time, I'll get off my butt and take one of the nuts with me to find a socket to fit and use my handy torque wrench.

For now, she's riding pretty darn good though. I tried to get the shake going on my way to work this morning again, and did notice a very tiny amount of shake at 40MPH, didn't notice this with my hands on the bars, but when I let go, I could see it at that speed, but that was it. Shake is gone at any other speed, and she's riding steady again.

I've seen this happen on other bikes, but it's usually bikes that are really old (with ball bearings), or that have spent alot of time with the front wheel in the air and coming back down, but either way.. it's an easy enough problem to fix..

Thanks Flip and all. Good advice. Will a trigger pull scale work

I have her scheduled to go into SLC Triumph dealership tomorrow to get fixed. Like I said, it is still under warranty so it's going to be on their time and dime.

Yes, mine is still under waranty too, but my dealer is 90 miles away so I have a hard time getting the bike there and picking it back up..

HeR3tic said:

Thanks Flip and all. Good advice. Will a trigger pull scale work

Click to expand...

Most certainly but you'll need the 'starting torque' figure from Triumph. I don't know if a dealer will have it, it's not listed in the shop manual. When you pre-load a wheel bearing on a big truck, the axle has a tabbed metal retainer that you use to hold the nut so it don't rotate as you apply torque to the clamping nut and in the case of Dana axles, the clamping nut actually ratchets on so you can preload the clamp nut by ratcheting it down without turning the adjusting nut but it takes a special socket. Probably the best way to retain the adjustment nut would be to get the appropriate sized spanner (open end wrench) and grind it to the width of the adjustment nut and then employ a socket to apply the clamping torque to the top nut while holding the lower adjustment nut stationary. I suspect that Triumph has the appropriate thin jawed spanner for a price of course.

All my lathe spindles and milling machine spindles in the shop are pre-loaded exactly the same way but have a pre-load collar that is engaged with a hook spanner acting on radial needle bearings. That removes the end play from the spindle. The radial play or what's called TIR (total indicated runout) is handled by the tapered roller bearings that also get pre-loaded when you remove the end play. Most of those bearings are continuously lubricated with pressure lubrication or constant drip feed.

TMI! TMI! Really do appreciate thorough explaination. REALLY! You might look into being an instructor

I'm familiar with the retainers. It has always been a remarkable invention; all by itself.

Starting pull torque I'm talking 3#s favorite

HeR3tic said:

TMI! TMI! Really do appreciate thorough explaination. REALLY! You might look into being an instructor

I'm familiar with the retainers. It has always been a remarkable invention; all by itself.

Starting pull torque I'm talking 3#s favorite

Click to expand...

Rocky:

I am an instructor licensed by the State of Ohio and the Department of Homeland Security for teaching the masses not to be asses.......remember. By the way, my permit number is 6998.

I could never teach a shop class though I've been approached. Way too much OSHA crap and I never wear safety glasses or ear plugs and all that crap. You can abstain from all that in your own shop. there has even been a number of times I've gotten a good sunburn from welding in a Tee shirt.

Well... after a 700 mile trip last weekend, including about 10 miles of gravel road, my front end is back to wobbling. So it's coming apart this week to fix it right, grease the bearings, buy the right socket and torque the nut to the proper specs, clean everything up while I'm there.. and back together.. and pray the wobble is taken care of...
My bike is under warranty... but my closest dealer is 90 miles away and by the time I get the time to take the bike there, I can already have it done.. and I need to get it done for the Harvest Classic this weekend..

Meanwhile, I have to settle for a girl's bike... the wife's Trophy 1200...