T500 Tapered Head Bearings

[GT Tim]

I think the thickness of the bearings will be the issue. I am afeared that I will have to have the steering stem milled down so the retaining nut will seat because if I am not mistaken the stem shank is higher on the GT than the T in relation to the frame race.

If there isn't an off the shelf solution of bearings or a shim to take up the difference, does anyone have the dimension of how much material has to be milled off and threaded for the nut to seat?

Am I making any sense?

[Suzsmokeyallan]

This might be a situation like the buffalo, some of those stems are cut down more than others.... It would therefore be safe to say taking down the top section of a Titan shaft about 10mms should be more than adequate...
Further threading should be minimal, if required at all.

[GT Tim]

This might be a situation like the buffalo, some of those stems are cut down more than others.... It would therefore be safe to say taking down the top section of a Titan shaft about 10mms should be more than adequate...
Further threading should be minimal, if required at all.

Allan,

The GT 550 / 750 triple tree, stem and all is going into the T500 frame...or did I misunderstand you?

To me it sounded like you have it the other way around. Sorry if I am confused.

Someone here must have done this before and knows what needs to be done.

[Suzsmokeyallan]

Well it sort of went both ways,,,, technically a brain fart moment on my behalf, anyway,,,,,,,,,,,,,
I have a Buffalo stem and a Titan stem available for measuring right now in front of me and it looks like you'll need to cut the threads for the top locknut on the Buffalo one down at least 15mms more to match the way the Titan one looks.

[Wayne Meuir]

Another approach that has been done in the past if you can't find bearings that work is to press the Stem out of both lower trees, and then insert the T500 stem into the Gt550 lower tree. This will have you using the GT550 front end mounted to the bike with the stock stem. A bushing may have to be made on a lathe to make it fit correctly and the welding should be done by a pro, but its been done quite often with good results. I don't really know what mods would have to be done to make the upper triple work, but I would not expect it to be very difficult.

Also, the Chinese All Balls bearings are fine. When I was working on one of my bikes I called Pro Flo about a set of stem bearings and the guy running Pro Flo siad that is what they used in all the bikes they were rebuilding for customers and they had never had a problem with them. He felt the only diference in them and the Parts Plus ones, which he also was selling at the time, was the price. These stem bearings are not subjected to high speeds, so they will probably last forever unless allowed to rust.

Wayne

[debby]

I pulled the front end apart on mine and I think I found the problem. It still had the OEM loose ball bearings (dry as a bone) but it was missing a bearing race! The outer race for the top bearing was not there. The flat surface of the adjusting nut was pressing directly against the balls.

Surprisingly, the three races that were still there all looked in good condition with no brinneling or anything. All would be well again with that missing outer race replaced, and some cleaning and regreasing. But the parts are NLA, so I guess it's time to do the tapered bearing installation.

On the stock forks the Kaw bearing goes on top and the GT bearing goes on the bottom. No grinding required on the stem. Not sure about the stack height yet. I'll have to do some measuring.

The other thing I noticed is the forks only have 3-1/4 inches of travel! That seems pretty pathetic. Did the DPO put them together wrong or is that really all there is? Maybe I should put that GT550 front end on after all. I have a spare one!

Debby

[diamondj]

I pulled the front end apart on mine and I think I found the problem. It still had the OEM loose ball bearings (dry as a bone) but it was missing a bearing race! The outer race for the top bearing was not there. The flat surface of the adjusting nut was pressing directly against the balls.

Surprisingly, the three races that were still there all looked in good condition with no brinneling or anything. All would be well again with that missing outer race replaced, and some cleaning and regreasing. But the parts are NLA, so I guess it's time to do the tapered bearing installation.

On the stock forks the Kaw bearing goes on top and the GT bearing goes on the bottom. No grinding required on the stem. Not sure about the stack height yet. I'll have to do some measuring.

The other thing I noticed is the forks only have 3-1/4 inches of travel! That seems pretty pathetic. Did the DPO put them together wrong or is that really all there is? Maybe I should put that GT550 front end on after all. I have a spare one!

Debby

I probably have a spare upper outer race if you want it. I prefer the roller bearings but I know folks that say the ball bearings are better provided they are greased and tightened correctly.

Do you have the Kawi and GT bearing placement reversed? The 30mm ID Kawi bearing should go on the bottom of the triple clamp assembly and the 25mm ID GT bearing on the top...

3-1/4 inches seems about right for the stock T500 fork travel. Consider they have an outer spring only with a free length of 5 to 6 inches....

Jim

[debby]

I'll have to post a photo of all the parts. Maybe some of this stuff is from another model?

The stem is about 25 mm except at the very bottom where the lower race sits. It might be 27 mm but doesn't look anywhere near 30 mm. The area where the bearing race sits is only about 7 mm tall.

The collar on the adjusting ring, where the upper race sits, is 30 mm OD however. Bearing can't sit directly on the stem there because it's threaded.

It also looks like the triples may be bent. I noticed after I took the fork legs out that the left headlight bracket was a loose fit but the right one was clamped firmly in place. So I need to figure out some way to check the triples too.

Debby

[Suzsmokeyallan]

Ok lets get a bit technical now,, if the stack height is off a bit you can do this alteration.
Once you know where the rollers ride you can safely grind a portion of the wide taper section off so the race goes further into the head tube.
To do this, you need to place the race into a lathe, then run a cut off wheel up against it using a dremel moto tool with extender cable mounted in the tool rest, spinning in the opposing direction.
It will take a while but it can be done with a few repeated passes and a few cut off wheels.

[debby]

if the stack height is off a bit you can do this alteration.

Hmm. You could do it maybe, but I could not. It would be a job for my machinist.

I don't know if the tapered roller bearings are worth the effort on the stock forks though. Those forks and triple clamps are the flimsiest I've ever seen.

Seems to me the stock ball bearings are fine for the job, if all the pieces are present, greased, and properly adjusted. Of course all the pieces are *not* present on mine!

Debby

[Suzsmokeyallan]

Well Debby i never plan on riding my T500 at high speeds since its brakes and suspension is just too antiquated to keep up to the engines output.
So its more of a cruise bike with an occasional 'blast' if the road conditions (a long clear straight) allow for some carbon clearing.
Plus i want to keep it as stock looking as possible, so the front end has to stay, i'll just live with the pathetic suspension legs/brakes for now.
If you can get the top bearing race you need from a member here, then get new ball bearings and grease the assembly and reinstall..
Its always a good rule of thumb to remember any bike you ride, to keep in mind its limitations and just where those limitations are, even if some are rider induced as well.

[Suzsmokeyallan]

Its nice when you have the thing stripped down in front of you so here it is. The Titan is funny cause the top race does not sit on the stem as with a GT it sits inside the large top adjusting ring on a lip. This large adjusting ring also acts as a dust cover with integratededge lip for stopping water from pouring into the top race.
The bearings needed to convert a Titan to a tapered roller setup are a pair of 48mm OD and 30mm ID with a stack of 14mm,,,, so the kit 22-1012 is it.

[diamondj]

Allan

I've been wondering about the correct bearings for a T500 - It's been a while since I've studied the stock T500 triple clamp set-up. After digging through my spares boxes I came across a '72 lower triple with the top adjuster nut still in place. You're absolutely right - both the lower and upper bearing should have an inner dimension of 30mm. There's a 6mm tall collar on the bottom of the steering stem for the lower inner race and a matching collar on the adjuster nut. I even found an earlier adjuster nut that has the bearing cup as part of the nut with the whole thing threaded to fit the upper steering stem! So it looks like the H1/H2 set of bearings would be right for a stock T500 triple clamp assembly.

Jim

[GT Tim]

OK let me attempt this again as I didn't pose the question correctly the first time.

-Can a complete '72 GT550/750 front end be put on T500 frame? W/ tapered bearings?

-Has anyone put a '72 GT550/750 complete front end on a T500 frame? W/ tapered bearings?

-Are the fork tubes for the '72 GT550/750 too large for the triple tree of the T500?

-Can anyone who has put a 4LS set up on a T500 tell me how they did theirs?

Thanks in advance

[Suzsmokeyallan]

Tim come on in and sit down lad, i have all your answers,,

1 A complete GT 750 front end with trees can fit into a Titan frame, the bearings are the same OD as the Titans at 48mm so a set of bearings for a GT will work in the Titans headtube.
2 You will put one set on a Titan, so who cares if anyones done it before, live life on the edge and be a pioneer.
3 The Buffalo tubes are 35mms versus the Titans 32mms so they are not the same diameter as the Titans,,and the Buffalos are also a bit wider apart in the trees.
So you have to use the trees from the Buffalo, AND the Buffalo fender too obviously for a total transplant.
Even if you could use the Titans trees you have no way of clamping the top of the Buffalos fork legs as the Titan didnt use a clamp.