P11 loose steering head

elefantrider · Jul 5, 2018

On a new bike to me, I have discovered it has an incredibly loose steering head. Before I tear apart the head stock, what could cause this?

The bottom and top fixations seem tight but if you hold the front brake lever, the entire fork will pivot front and back.

Makes for a very interesting riding experience and especially when you grab the front brake!

PS.
I am surprised that on this particular bike the front brake is rather powerful, I can almost lock the front tire (new knobbies).

Ron L · Jul 5, 2018

Sounds like it may be missing the ball bearings in the top or bottom races (or both)

elefantrider · Jul 5, 2018

Thanks Ron,

Do they fall out or get easily out of place somehow? It does not look like they can fall out so maybe I will find them dislodged in the stem.
I see this seller on ebay has the balls in case of need.

https://www.ebay.com/itm/TRIUMPH-BS...K-3-16-BALL-RACE-MATCHLESS-ARIEL/272112143561

Bernhard · Jul 6, 2018

Balls also wear oval, check with a micrometer, the cups wear out with the steering at the straight ahead position and you can usually knock them out and turn them 90 degrees in the opposite direction to one another and use plenty of grease.

p400 · Jul 6, 2018

I had loose steering head a while back and I tightened up the top attaching nuts. It felt good and smooth after adjusting. I felt a little guilty not tearing into it to inspect, but it has been fine.

elefantrider · Jul 6, 2018

Thanks P400. Will try that but mine is really loose.
Will order replacement balls just in case. I don't see how the race cups can wear out. They are thick metal. The cups should clean up unless they are pitted, in which case I would replace. Will know when I get them out.

Removing those top 2 nuts will allow the center axle to drop out and then the fork can be removed?
Any tricks putting it back together with the balls?

Ron L · Jul 6, 2018

elefantrider said:
Any tricks putting it back together with the balls?

Grease and Patience. The smallest movement will drop ball bearings which will roll down the main frame tube. I bought the balls by the bag. They are not expensive and very easy to lose.

jerrykap · Jul 8, 2018

Guys, I've done this job a few times already. Most recently on the Patrick racer. If the basic adjustment doesn't solve the issues? I recommend removing the fork tubes and disassembling the steering head to service the bearings...it's a fiddle-some job that's much harder with the fork legs still attached. Think of it as an opportunity to get everything right in the front end.

C-ya, Jer

Ron L said:
Grease and Patience. The smallest movement will drop ball bearings which will roll down the main frame tube. I bought the balls by the bag. They are not expensive and very easy to lose.

mdt-son · Jul 8, 2018

elefantrider said:
Thanks P400. Will try that but mine is really loose.
Will order replacement balls just in case. I don't see how the race cups can wear out. They are thick metal. The cups should clean up unless they are pitted, in which case I would replace.

True enough, the cup and cone are thich metal but I believe the races are not hardened, and the bearing balls cause pitting which will cause obstruction to steering rotation and possibly crushing of balls. If cup and cones are visibly worn, just replace them. They are available from the AJS/M Owners Club.

-Knut

elefantrider · Jul 8, 2018

I tightened the center big nut which removed a lot of play.
BUT it upon closer inspection, the play was also coming from left fork leg to tube transition BECAUSE the leg is cracked almost ALL the way down the side. Did not notice that before!!

Will post a picture later.

Going to order new stanchions/tubes, head races and balls. I have all the other wear parts in my spares stock.

Anyone have a spare left side fork leg which is not cracked??

elefantrider · Jul 9, 2018

batrider · Jul 9, 2018

Happens when water gets in there and freezes. When you re-ball the bearings make sure to count the balls. I think there is space for an extra one on each race. They do like to find their way into the frame tubes. I used a greased toilet paper tube inside the headstock to prevent this. Fit perfectly!

elefantrider · Jul 9, 2018

Are the left and right side fork legs the same (same part number) and interchangeable?

elefantrider · Jul 9, 2018

batrider said:
Happens when water gets in there and freezes. When you re-ball the bearings make sure to count the balls. I think there is space for an extra one on each race. They do like to find their way into the frame tubes. I used a greased toilet paper tube inside the headstock to prevent this. Fit perfectly!

When you soft mallet off the top yoke, do the balls all want to pop out of place and down the tube? How do you prevent this before you are able to insert the toilet paper tube?
By holding the headstock completely perpendicular to the ground?

mdt-son · Jul 9, 2018

batrider said:
Happens when water gets in there and freezes.

True. The crack is due to circumferiental stress, which will occure as a result of internal pressure. The only possible explanation is freezing water.

-Knut

mdt-son · Jul 9, 2018

elefantrider said:
Are the left and right side fork legs the same (same part number) and interchangeable?

Yes. Complete fork sliders are 022794, 2 off. New or s/h available from AMC Classic Spares (UK). In the US, try Baxter Cycle.

-Knut

p400 · Jul 9, 2018

I believe hard landings could cause this, pothole hits, wheelies and the like.
This Teledraulic design is not really, in my opinion, able to handle the"off road" possible use of this P11.
Teledraulic is a vintage design carried for years.

elefantrider · Jul 9, 2018

It happened after I hit a few speed bumps at 30mph last week. Rather sure the crack was not visible before that. But the fender stay boss was already cracked on that same one.

mdt-son · Jul 12, 2018

p400 said:
I believe hard landings could cause this, pothole hits, wheelies and the like.
This Teledraulic design is not really, in my opinion, able to handle the"off road" possible use of this P11.
Teledraulic is a vintage design carried for years.

Teledraulic forks were used in heavy 500cc scrambles in the 50's and 60's including jumps and hard landings with no ill effect as far as I know. P11s were entered in scrambles events as well.
However, I just discovered that Mike Patrick's old race bike was retrofitted with Roadholder sliders, so maybe his forks did suffer from slider cracks. We will probably never know.

The alloy is now 50+ years old and it will be affected by fatigue.
Ideally, oil pressure on the compression stroke affects the bottom of the slider only, but with a worn slider and bottom bush 021495, compressed oil will leak by and excert radial pressure on the slider's upper part as well.
http://www.rocbo.net/technique/norton_workshop/103.html

In addition, there is the mechanical load trying to bend the slider, but that load will not generate hoop stress cracking as seen in the picture above.

-Knut

batrider · Jul 12, 2018

elefantrider said:
When you soft mallet off the top yoke, do the balls all want to pop out of place and down the tube? How do you prevent this before you are able to insert the toilet paper tube?
By holding the headstock completely perpendicular to the ground?

If there is old grease in there then they will probably stay in place. It is hard to prevent them from falling in even when trying to be careful. I would just plan on replacing the balls and probably races.

I had a G80CS which had been sitting outside a dealer's shop for years and one of the lower legs was cracked just like that. BTW have done plenty of wheelies, woods and road riding with the scrambler and never had a problem with the Teledraulics or the bearings. I don't think they are inherently bad.

P11 loose steering head

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