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Bottom Lug Tension
#788169 10/25/19 9:45 pm
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The bottom lugs on my 70 TR6C triple tree are a very tight fit to the stanchions. They require some spirited beating to drift out. I would like to be able to slip them out of the triple tree lugs while on the bike in the future by simply loosening the bottom pinch bolts and breaking the taper fit on the top lugs. I'm about to polish the I.D. of the bottom lug bores to get a decent sliding fit. Does anybody know a reason why they would not work? It looks to me like suspension loads would still be adequately transmitted into the lugs, bearings and steering head as long as the pinch bolts are tight. Any experience?

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Re: Bottom Lug Tension
TrophyGuy #788184 10/25/19 11:13 pm
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Try removing the pinch bolt and then carefully opening out the split in the triple tree using a large screwdriver.
Not in any workshop manual but extensively tested in the School of Hard Knocks!

Re: Bottom Lug Tension
Tridentman #788189 10/25/19 11:39 pm
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.
Open the Lower Split with a wooden wedge ... tapped in place .
It's more likely to stay in place
and less likely to leave evidence of prying .
.

Re: Bottom Lug Tension
TrophyGuy #788219 10/26/19 8:03 am
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TrophyGuy, I agree with you. While wedging works I see no reason not to carefully grind/sand the clamp ID, which is how I've done it for some time.
Every new bike I've ever worked on will drop their stanchions right out of the clamps when the bolts are undone. I thought it would work just as well on old bikes, and it does.
You'll be surprised at how little you have to nip up the pinch bolts before the stanchion sits tight.
It doesn't require all that much grinding either, but be careful not to overdo it of course. It transforms a job you used to dread, to one you'll enjoy doing.

Re: Bottom Lug Tension
TrophyGuy #788220 10/26/19 8:10 am
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The bottom lugs on my bike are tight too but I use something to open the slots as the others suggest.

I have never been able to break the taper at the top to take the legs out without disturbing the bearings/ headlamp assembly, etc. I am worried about damaging the stanchion threads. When I loosen the top nuts and try knocking the stanchions they don't budge. Is this supposed to be easy? I have had to do the book method of knocking the top yoke off and removing the whole fork assembly.

Dave

Last edited by dave jones; 10/26/19 8:12 am.
Re: Bottom Lug Tension
Stein Roger #788253 10/26/19 4:34 pm
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Originally Posted by Stein Roger
TrophyGuy, I agree with you. While wedging works I see no reason not to carefully grind/sand the clamp ID, which is how I've done it for some time.
Every new bike I've ever worked on will drop their stanchions right out of the clamps when the bolts are undone. I thought it would work just as well on old bikes, and it does.
You'll be surprised at how little you have to nip up the pinch bolts before the stanchion sits tight.
It doesn't require all that much grinding either, but be careful not to overdo it of course. It transforms a job you used to dread, to one you'll enjoy doing.


Thanks for the affirmation to what I had surmised. I'm going to open up those lug bores a little and let the pinch bolts do their job. Another benefit of having reasonably loose stanchion fits is that drawing stanchions into the lugs with a proper puller tool will be much less stressful on head bearings and triple tree arms. When using a stanchion puller I braced the opposite set of lugs with a long stud, washer stack and nuts so as not to put a big bending moment on the triple trees and bearings. Pulling against spring tension is plenty enough load for the bearings to take without the additional tension of a tight bottom lug. Loosening the lug bores seems more reasonable than wedging. I can see that Triuimph made the lug fittings to be wedged, but there is a lot of stout metal to bend to open a lug bore.

Re: Bottom Lug Tension
TrophyGuy #788323 10/27/19 10:33 am
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I always tap a wedge in from the underside, I do the same for assembly. A good tight fit on the forks is an asset....not a liability.

Re: Bottom Lug Tension
tridentt150v #788326 10/27/19 11:43 am
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Originally Posted by tridentt150v
I always tap a wedge in from the underside, I do the same for assembly. A good tight fit on the forks is an asset....not a liability.

It's difficult to argue the point but there's a difference between a sliding fit and a sloppy fit. As I said before, every newer bike, or even old "foreign" bikes I've ever worked on drops their stanchions right out when the pinch bolts are released. Unless rusted or molested of course. I too am reluctant to change the way I work, but sometimes I still do... thumbsup


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