Front fork stictchion

Just got my Mk11 850 on the road, now the fun begins ironing out all the little isues. I have a 73 Trident as a yard stick and notice the front forks on the Commando are very stiff, in their action. They were overhauled with the covenant conversion carried out. I have just stripped and rechecked the action, I skimmed the extra bush form the covenant and also fettled the main fork bush and piston bush to make sure a free action without side play. But I now notice the fork seal is the main culprit. The seals are standard Norton items. Is there a trick seal out there that seals but slides easily?
I have the no leak type in the Trident and the fork action is nice and supple, and I have the progressive damper seals.
My bench tests pinpoints the main seal as the major sticking point, not he dampening system.

Any help out there?

Cheers Richard

Richards, Leak Proof Brand is the way to go. PM me when you really want to fix them for good. Much better that the Triumph front end. Also check your lower tripple tree with a striaght edge. They can be bent back with some care.

forks

Hi Norbsa,

So do the no-leak type offer less resistance?

And what's the scoop on doing up these forks?

Cheers Richard

leak proof seals

Greetings,
Not trying to start an arguement here, but, I felt I had to put in my two cents. In the many years that I have worked as a bike mechanic I have never seen those "Leakproof Seals" work like they are supposed to.
Theoretically they are supposed to be a floating seal, IE they are supposed to be able to move up and down in the holder...well they leak,
and they leak alot. The only way I've ever seen those damn things work right is if you install them with some kind of sealant/cement like "Honda
Bond" smeared around the outside diameter.
Maybe they work better on Norton style forks, but, I'm skeptical.

GB

There must be some kind of seals out there still that do not leak...for a long time. I bought some said to be leak proof...in 1981...and I have in the meantime had the forks apart a couple of times and those seals were just put back in again...and still don't leak. 25 years is a good reference, I'd say..... :wink:

Yes they float. That aviods a lot of wear. Like HeWho says we have some that are going after 20 yr's service. They need and work in oil. If you go this way you must file some shallow groves into the top of the high hat bushing to get some oil flowing in under them. They are soft and pliable. Be sure to check your lower Yoke.
I build kits for the Commando's do a search under my handle you will find lots of old posts.

Fork seals

Thanx Norbsa and others,

Well the leak-proof brand has worked a treat in my Trident, it has not leaked in a couple of years hard service, also in the Trident application I found the seal did not offer too much resistance to fork up and down movement.
Norbsa I do not believe my stiff fork action is due to missalignment, because when the wheel is out and I pump the sliders up and down with the springs removed the action is t-i-g-h-t. Remove the seal and they slide nice and easy.
Now I measure the stanchion at 34.5mm and the bore of the slider at 47.5mm is this correct or are the sizes an imperial odd ball?
When I showed the seal that was fitted to a bearing mob, they commented the seal would be very tight on a 34.5mm shaft, I agree.
I am wondering if my supplier of the seals has a batch of slightly off size unts, they were bought as standard commando.

Any idea's would be appreciated

Richard

No Leak seals

Well I have ordered a set of no-leak type that are quoted as low stiction.
So I will report back on their performance.
Norbsa I will take on board your thoughts and mill in some oil drain holes in the base of the fork seal retainer, to ensure oil circulating in the seal region. If these things work as well as they have in my Trident I will be be happy. Seems like the seal dimensions are such that ordering aftermarket could be tricky.

Wait for a report?

Cheers Richard

No Leak seals

Well I have ordered a set of no-leak type that are quoted as low stiction.
So I will report back on their performance.
Norbsa I will take on board your thoughts and mill in some oil drain holes in the base of the fork seal retainer, to ensure oil circulating in the seal region. If these things work as well as they have in my Trident I will be be happy. Seems like the seal dimensions are such that ordering aftermarket could be tricky.

Wait for a report?

Cheers Richard

Interesting thread because the latest std Norton branded seals I fitted 5000 miles ago are also very tight and without the action is a lot better. On the road its not noticeable to me.
Had a lot of problems with minor leakage and I kept replacing seals. They lasted 6 months and the leaks were back so I took a closer look. Oil was coming up the seal OD not the lip. Was worse on one side but I refitted both with a little RTV and have had no more leakage.....just a thought.

no leak fork seals

In reply to keith,
I have just fitted no-leak type and the fork action is not restricted as it was with the std type seals. I think the trick with roadholder fitment of the no leak type is care in getting the seal into the slider, past the internal treads, without damage. I managed this by using a heavy plastic bag, I cut the material in a strip lubed up with plenty of grease, and slipped the plastic between the trheads and the outer lips of the seal, then pushed it in with hand pressure. Seals are in, and I expect not damaged. The forks really slide up and down, befire they were as stiff as!

Cheers

Richard