Have any of you got any better designs for the bering sleeve set up in the swing arms of the 77ish to 81ish KTM's as the double o-ring on either side doesn't look very substantial, In fact it looks almost Heath Robinson [xx(]. Also can anyone explain the proper workings of the original design as I don't really get it [?] [?]
Cheers
Chris.
If I understand your question correctly and correct in my belief, the O-rings are intended to seal off the needle bearings in the swing arm.
By the way, they are a pain to replace.
Tony
You are correct Tony, I also thought the o-rings were to seal off the needle roller bearings, It just looks like a totally rubbish design though as the two o-rings either side don't really seem to do a lot. All they do is just sit over the shoulder on the nuts and not really seal anything. The other thing is that the needle rollers work fine for the rotational axis but there doesn't appear to be any type of thrust bearing and the nuts just rub on the outer face of the needle cage or on the shoulder inside the swing arm, either that or I am missing something [?] [?] [?]
Cheers
Chris.
The design may have changed but my 73-75 type 250 swingarms have double o rings as well. Since you fill up the needle bearing portion of the swingarm with oil then, I can only assume those friendly engineers knew my wife would complain about the oil dribbled all over the garage floor. They ingeniously put the double o rings in there to save me from her wrath. Friendly fellows, those engineers.:D
Mike H.
seapupsan@aol.com
Chris, I have a better design. I use garlock plastic, turn it down into the right size bushings and press them into the swing arm in place of those "cute little needle bearings".:D
BTW, has anyone ever seen one of those "cute little needle bearings" still intact after a good summer of riding[?]
Raymond
Down East Pentons
Sounds like a reasonable idea Raymond as the adjusting nuts can then be made to bear on the low friction plastic face instead of the bearing cage or metal face of the swing arm. I also don't reckon by looking at it that the double o-ring on either side is going to keep out any water. I thought about a proper turned ptfe seal instead of the o-rings and wondered if anyone had done anything similar.
Cheers
Chris.
Are you sure you don't have things installed in the wrong order?
Should be needle-bearings pressed into swing arm, hollow "swivel tube" though the needle bearings, then double O-rings each side, then shouldered nut each side with the shoulder facing in. The shouldered nuts are torqued down very slight until zero side-side movement while rolling free on the bearings--only resistence being the O-rings friction.
Then that assembly is stuck in the frame, threaded bolt pushed through, and frame torqued down on the nuts/swivel tube. The swivel tube is fixed with the inside nuts acting as jamb-nuts to the swingarm bolt. Should be left with clearance between shoulders of the nuts each side and O-rings just inside the swingarm. I've re-bearinged 3, filled with oil, and never had one leak a drop--so I'd predict water would have a tough time penetrating.
Seems the biggest flaw is that the needles eventually get gummed and stop rolling, afterwhich the swivel tube grinds metal-to-metal and then the thing becomes just a complicated bushing. Most tubes are pitted and nasty, and no replacements exist on this planet. Plus, the needle bearings are a bear to get out.
Mac
And just what is the technique for removing needles which have become one with the swingarm [xx(]? Also, are replacement bearings available?
Keithuu
Mac,
Yeah I've got the bits in the right order but wasn't sure what it was that stopped the bearing tube moving side to side. I know you tighten the nuts till you have just eliminated the play but from what you are saying it looks like it's the o rings that stop it's sideways movement which doesn't sound like a great design. I was going to replace the rubber o-rings with turned ptfe washers so to speak as rubber isn't really a great thrust bearing material.
Keithuu the bearings are available through any bearing stockist here in the U.K. They are SKF HK2030 needle rollers.
Cheers
Chris.
Chris,
Chris,
I can scan and post how to adjust the nuts for proper side clearance if it would help. The Side of the needle bearing that has the bearing # on it is hardened and so are the ends of the adjusting nuts. that forms a thrust washer type set up when the swing arm side clearance is set up right.
If you check the oil level every so often then the needle bearings will last a lot longer. The double O rings do work well so long as the inside of the swing arm where they ride against is in good shape , not burred or damaged.
Kiethuu,
The bearings are an HK 2030, i believe and they were still avaiable last time I checked. If you will do a search on posts you should find what folks have done to remove them. If the shell is not rusted away. you can use a piece of thread all 3/8 inch diameter and 2 hardend washers to remove them.
Hope this was some help.
John D.
One side remains intact (and I mean, really intact) while on the other the needles pretty much all came out with the inner sleeve, having grafted themselves to it. Yikes!! The interesting thing is that all four O-rings are in perfect condition, despite the dry, rusty environment. Or maybe that's why they're in good shape.
I soaked all the pieces in WD-40, etc., applied some heat, but as you are aware, there's no internal place to get a bite with any sort of extracting device. Aaaah, what is life without challenge, eh?
Thanks for the advice.
Keithuu
Thanks for the offer John. Kip is actually kindly sending me over a copy of some of the manuals he had for my year of bike so the information might be in that. If not,if you wouldn't mind doing that it would be much appreciated.
I see everyone posting about filling the swing arm with oil, Is it oil that goes in and not grease as I'm sure the exploded diagram of the swing arm shows a grease nipple on it. If it is oil, I take it it is mighty thick oil so as not to leak past the o-rings.
Thanks for all your advise folks it's great to be in touch with so many helpful and knowledgeable people :D
Cheers
Chris.
Kiethuu,
we used 2 ( for enough strength) thick hardened washers, ground a flat on opposite ( 180 degs appart) sides so we could turn them side ways to insert. The od of the washer was just large enough to clear the swing arm tube and still get a bite on the edge of the bearing when they are upright. The thread all ( 3/8 , 7/16, largest that will fit inside) and some washers and a socket finished the rig up. It works a lot like a wrist pin extractor does.
If you dont have the right size od washers you can use a bolt and nut to hold the washers together. Chuck the bolt in a drill. Clamp it lightly in a vise and use a file to cut the washer OD down to size.
If the ends of the bearing are too far gone then you have to use something to cut the outer shell length wise ( thin it enough so you can tear it) , like a dremmel and carbide bur. You can use a small hard screwdriver blade ( like the metal handled tool steel precision drivers used in electronics) to lift an edge then and collapse the shell inwards allowing the whole thing to be remove.Clean up any burs or dings you make in the removal and the new bearing will press back in , good as new. The bearing shell is hard . Its the outer race of the assembly.
Hope this helped some. Its not a fun job chuckle chuckle. If we check and keep the oil level topped off they should never rust up on us again.
John D.
Chris,
Our 1975 manual calls for " gear oil, transmisson lube or high viscosity engine oil". It sounds like any good 20 or 30 weight oil will do. Both plugs need to be out when you fill it to let all the air inside be displaced.
John D.
Nice one John, Thanks for the info.
Cheers
Chris.
John D. is right on the money...IF you can get the needle-bearing outside race out with the press or big hammer method, you're home free. I've never been able to free it up that way myself, and have a really big hammer in my toolbox.
After trying everything else, the only method that's worked has been the "cut and collapse" method. After knocking out the inner race and pins, I've used a hardened/carbide cutting bit (looks like a cone-shaped rasp)in the old drill to cut the channel down the wall of the race at least 2/3 the way, then pounded in an old screwdriver between the race and swingarm wall until it can be broken/driven out. That hardened race will shatter and pieces will fly, so do yourself a favor and wear safety glasses for sure.
You can't help but cut a trough in the swingarm wall as you grind through the thin wall of the race, so go light and careful and stay off the O-ring outer area. Won't hurt anything in the bearing area, as the new bearing has an outside race with plenty of wall to grip, but always hate to inflict permanent scars. I do my cutting on the "up" side of swingarm, on the theory that a potential trough on the high side won't end up an oil leak by-pass by mistake.
Definitely 30w oil or lighter, doesn't take much to gum the needles in the bearing. The O-rings will hold it. Same O-ring setup as on your shift lever which does a decent job of keeping the tranny fluid inside.
HK 2030 bearings, most all bearing shops have them. Mac