Head stock / forks movement??

[ian tomo]

Doing a spot of maintenance, and noticed that I had a slight play in front fork forward / aft movement. Probably about 1/2" movement at the wheel with the front end jacked up. The play seems to be mainly from where the upper and lower part of the forks join, with minimal play in the head stock bearing. Can somebody shed some light on this? Is this a normal wear and tear symptom? Planning on changing oil to higher viscosity in the interim as it has never been changed. (2000 ST1100 ABS/TCS)
I cleaned and greased HS bearing this year, with the intent of replacing with taper roller bearings this winter. I never noticed the play in the forks then, but that doesn't mean it wasn't there.
Thanks folks

Regards Ian

 

[vinny]

Ian, the fore/aft play in the forks is not normal. If you took it apart to grease the bearings, they were not tightened properly. You may now have a little "detent" after tightening them. The fore/aft movement probably pitted the race. If you are going to visit this issue, now is the time to upgrade to the tapered roller bearings. My two cents worth, YMMV.

 

[Art Franz]

minimal play in the head stock bearing

The play you have in the head stock bearing is as Vinny mentioned above - it is unacceptable, and, personally I fully endorse his recommendation with regard to repair.


But it sounds as if you have another problem here as well. The movement in the forks is unacceptable as well. The bushings in your forks are worn out, and need to be replaced. With that amount of movement in the forks, it's also possible that there may be some damage to the inside of the fork leg as well. After you get the new bushings on the fork and tube, check for movement before you put the spring in. In my experience, with the fork fully extended with new bushings you'll be able to 'feel' a bit of movement, but as soon as you compress the fork, that movement will disappear. Continue to check fore-and-aft movement along the length of the fork's stroke (still without the spring in) and it should be zero, paying particular attention to the area where the fork would be when it is in use while riding. This will test if there's wear inside the fork leg (the aluminum part) or not.
How many miles on the bike? Are the fork seals leaking as well? Have they been leaking for a while? Just thinking here - I've never heard of forks having that much movement before, I wonder if the forks were allowed to run out of fluid, and the resulting wear with no oil in them is why they're so loose.
Let us know what happens.

 

[ST1100Y]

With that amount of movement in the forks, it's also possible that there may be some damage to the inside of the fork leg as well.

+1... 1/2" sounds a LOT, quite likely that the inside of the fork bottoms is now 'barrel shaped' (oval, wider in the center then on top and bottom) as the worn bronze bushings were grinding the aluminum away (I guess metal flakes showed in the drained fork oil??...) if so: new fork bottoms (or low mileage used ones in top condition). Once that front end is rebuild the restored front wheel guidance will make it feel like a new motorcycle again. The bronze bushings are wear parts and require frequent replacement. An interval of oil change like every 20, and new bushings/seals every 40Kmiles sounds OK to me; we'll see the opinion/experience of other US riders on this, as the conditions over there might vary from over here in 'the old world'

 

[broc11]

I wonder should I be thinking of changing the fork bushings/seals as well? I was just going to change the fork oil to 10 weight motul. my bike has 41,000 miles now and I suspect forks have never been touched since new.
I have a new shock on the way and the suspension guy reckons I should change to progressive type fork springs,though some say straight rate are better.
I must check my own forks for movement as well,maybe I should replace the headstock bearings while I'm at it too.

 

[nhdiesel]

41k isn't a lot of miles. You could have worn bushings, or they could be like new. I bought my bike with 26k, now has 92k on it, and when I had the forks apart last month the bushings looked great. New seals & oil and they are working great. I check for fork movement every time it's on the lift or jack, and everything is still tight. With that mileage I'd say to check them well when apart and see if they need bushings. I can't say about the 1100, but the ones for the 1300 are very cheap- though if you start with the "might as wells", as in "I might as well replace xxxx since it's cheap and I'll be in there anyway..." there are a lot of parts that can add up.

 

[Art Franz]

I wonder should I be thinking of changing the fork bushings/seals as well? I was just going to change the fork oil to 10 weight motul. my bike has 41,000 miles now and I suspect forks have never been touched since new.
I have a new shock on the way and the suspension guy reckons I should change to progressive type fork springs,though some say straight rate are better.

Even if you suspect the forks have never been serviced, if it was me, I'd pull the forks, take them apart, and replace bushings and seals. I just did mine this spring on an 05 1300 and the bushings weren't real bad, but showing signs, so if they're showing signs, new ones will be better.

When I rebuilt my forks this spring, I went with 10 Motul synthetic, and I found it too stiff. However, at the same time, I changed the fork valves to RaceTech Gold Valves, so that might make a difference. Keep in mind, that fork oil viscosity's are not standardized - a 10w in one brand might be a 15 or 20 in another brand. And they might end up with different weights from one 'batch' to another from the same manufacturer or different factory. Just today, I changed the oil to a 5w same brand and bought from the same store.

Lots of info on this topic, I'm sure, on this forum. Go to the home page, click on forums, scroll down till you find ST1100 front forks, and you'll find just about anything you'd like to know about your front forks. Might have to do some reading, but well worth it. And you'll be proud of having done it yourself - I sure do.

 

[Bigmak96]

You will be well served to replace the head bearings with the tapered ones rather than the stock round bearings. I would hazard a guess that your forks cold use a rebuild as well. You will be very happy with the difference.

 

[ST1100Y]

I can't say about the 1100, but the ones for the 1300 are very cheap...

Ditto on the 1100... and their a lot cheaper as a set of new fork bottoms; so precautionary replacement (at slight signs of clearance and/or discoloration indicating the Teflon coating been worn off) does make sense...

 

[Brant]

+1... 1/2" sounds a LOT, quite likely that the inside of the fork bottoms is now 'barrel shaped' (oval, wider in the center then on top and bottom) as the worn bronze bushings were grinding the aluminum away (I guess metal flakes showed in the drained fork oil??...) if so: new fork bottoms (or low mileage used ones in top condition). Once that front end is rebuild the restored front wheel guidance will make it feel like a new motorcycle again. The bronze bushings are wear parts and require frequent replacement. An interval of oil change like every 20, and new bushings/seals every 40Kmiles sounds OK to me; we'll see the opinion/experience of other US riders on this, as the conditions over there might vary from over here in 'the old world'

Thinkin' your thoughts and opinions better fit the situation since your 'there' so to speak. Opposite side of the coin totally would be my location. Have absolutely no rust issues, 6-15% humidity at most, can ride year-round, and do majority of that on 10,000+ft. mountain twisties and high desert riding. With that, issues I don't see come up for some 20+yrs. can show their ugly head overnight in areas across the pond, east,west and southern areas here with humidity, coastal salt air, etc. If I lived in one of those areas and had an ST or other bike, the first thing I'd do would be to dielectic grease every plug-in connection, then remove swing-arm and have it shot with Line-X or similar bedliner material, and generally do alot of extra preventative maint. that I normally don't even think about for 10+yrs. at a time. The front fork/tripple tree situation here IMO needs to be addressed as it is at a stage of being a safety hazard to the rider and others.

 

[Brant]

BTW, a fork brace WILL resolve any future slide bushing wear......JAT

 

[ST1100Y]

Have absolutely no rust issues, 6-15% humidity at most, can ride year-round, and do majority of that on 10,000+ft. mountain twisties and high desert riding.

Wasn't thinking about differences in climate, but about terrain, road surface, riding style and that... frost beaten, patchworked alpine roads (some places even still have cobblestones...) combined with a pace on the harsh side requiring immediate, frequent and hard usage of brakes, etc... versus the smooth, stretched roads that go forever to cruise along... ;-) I still don't see forks living for 2 decades on your side of the pond, that's just too optimistic, but probably double the lifetime/mileage of what we see over here (same on brake pads or hub dampers; later see like 36Tkm/22,5Kmiles on my ST till significant sings of wear surface, 'clunk' at take-offs, shifting seems off ...). But I totally agree on the safety aspect of head bearings and condition of front fork, but issues for failing our annual MOT inspection epically... for good reasons...
Sure, frequent riding in bad weather will also drag more contamination into the fork oil, thus accelerate the decomposition/aging of the oil, thus impacts the wear on the bronze bushings, but I still think that suspension action/work caused by 'bad roads' is the influential factor there...

 

[Brant]

Wasn't thinking about differences in climate, but about terrain, road surface, riding style and that... frost beaten, patchworked alpine roads (some places even still have cobblestones...) combined with a pace on the harsh side requiring immediate, frequent and hard usage of brakes, etc... versus the smooth, stretched roads that go forever to cruise along... ;-) I still don't see forks living for 2 decades on your side of the pond, that's just too optimistic, but probably double the lifetime/mileage of what we see over here (same on brake pads or hub dampers; later see like 36Tkm/22,5Kmiles on my ST till significant sings of wear surface, 'clunk' at take-offs, shifting seems off ...). But I totally agree on the safety aspect of head bearings and condition of front fork, but issues for failing our annual MOT inspection epically... for good reasons...
Sure, frequent riding in bad weather will also drag more contamination into the fork oil, thus accelerate the decomposition/aging of the oil, thus impacts the wear on the bronze bushings, but I still think that suspension action/work caused by 'bad roads' is the influential factor there...

All things considered, U definitely have conditions that beat up on anything with wheels! As for forks and fork seals, The 32yr.old forks on my Yammy Venturer1100(XS11) only got changed a couple years ago still having the originals seals on them. Don't really figure on doing them again as they were OEM. Forks on both bikes stay shiney and have no pits or nicks in them. The ST's battery is also on its ninth year, and don't own nor will I ever own a batt. tender. That batteries life can give credit to the ST having a digital clock, since lead-acid wet cell batteries like to be 'used', not 'shelved'. I could go on and on with issues that never arise based on my location that plague others living in coastal, or areas of elevated humidity. Fuel left in tanks in those areas give issues that never happen to my motorized equip., even if left for a year without starting. I also don't use any kind of fuel stabilizer cept for the occassional 'if I remember it' once a year splash of SeaFoam in the bikes. So, definitely location, general climate, and road cond. play a huge part in what would be considered normal maintenance in one area could be an 'overkill' in another location. Least that's the way it is here in the States.

 

[ian tomo]

Thanks for the replies y'all.
I have only done about 2000 miles since greasing head stocks. Everything was torqued to specifications. I manufactured a tool that takes the torque wrench to tighten steering head nut. The bearings ran smooth after cleaning. the forks had no pitting and looked like new when wiped down. and no oil leaks at all.

The bike (2000 ABS CBS model) is ex police, and amongst the paper work was full service / fault history. The oil seals where replaced in 2007 at 16,370 miles. It only has 36,000 to date.
I think I will order taper roller bearings and fork bushes and seals and change out ASAP.

+1 on road conditions. Ours here on the Wirral in the UK are absolutely trashed. Pot holes and man hole covers everywhere. I get to check the operation of the traction control 2 or 3 times a week due to terrible road surfaces. Local councils priority is putting up 20 MPH signs everywhere, or flashy new LED traffic lights. Not resurfacing dangerous roads.

I will post my findings when I get job done.

Thanks again for all info
Ian