aftermarket triple clamp stack too high?

[Nibor]

hi guys,

I've fitted my IMA's to the bike ('97 Monster 750), with new All Balls bearings. however the total stack height with the bearings, bearing seals (top and bottom), steering head cover washer, and ring nut, means my headlight u-bracket mounted to the lower triple, no longer meets the top triple. as well, the steering head stem bolt has less purchase, due to the top triple sitting higher than flush with the top of the steering pin.

I'd like to keep all seals/covers on, to protect the bearings from contamination. can I ditch the ring nut which holds the bearings in? so the only thing holding the bearings/triples in would be the steering stem nut on top, as well as the top triple clamping force.

thoughts? other options?

see pics below of my current setup:


see the ring nut (black) and silver steering head washer (with bearing seal hidden), equates to the gap from the U-bracket arm plastic lug, to the opening hole in the top triple where the Dash bolt will drop through. 

[Speeddog]

can I ditch the ring nut which holds the bearings in?

No.

Are you sure you got both bearing races *all* the way into the top and bottom of the headstock?

Same for the inner race and bearings on the bottom triple?

[Nibor]

I froze both the outer races before knocking them in. helped them fit. then drifted in with the old race to ensure even contact. kept going until the sound clearly changed, indicating they'd bottomed out.

[stopintime]

I have the same U-bracket issue on my S2R with IMA triples. I cut the U-bracket a couple of mm.

[NAKID]

I have the same U-bracket issue on my S2R with IMA triples. I cut the U-bracket a couple of mm.

Looks like he has the opposite issue. His U-Bracket is too short, or rather, the top triple is too high.

[stopintime]

Looks like he has the opposite issue. His U-Bracket is too short, or rather, the top triple is too high.

Aha 

[Nibor]

i could just make some bigger spacers to fill it up, but my main concern is the steering stem nut not having as much thread to bite into. it still has a fair bit mind you.

[Speeddog]

How much engagement does the steering head stem bolt have in the stem?

You'll need to play the ring nut adjustment against the steering head stem bolt to get the bearing preload correct.

[Nibor]

How much engagement does the steering head stem bolt have in the stem?

You'll need to play the ring nut adjustment against the steering head stem bolt to get the bearing preload correct.

thats something else i'm unsure of, how tight to do the ring nut for the bearing preload. a certain torque? or until a certain amount of resistance in steering?

[SpikeC]

 While this is not a Duck, it is Italian....my Bimota top triple uses the top nut to tension the bearings. There is no nut under the triple. I tighten the top nut to 22nm, then back it off 20 degrees.

[koko64]

Hmmm.. Does the stem or top clamp have any feature that indicates said feature replaces the ring nut? If so try without the ring nut and measure it up. Any slop? bearings retained securely? If not then double check bearings are fully seated as SD suggested.

Does the IMA site give any instructions or clues?

[Speeddog]

Just for reference, I've got an M750 that's mocked up.
The end of the stem is about 5mm down in the hole of the upper triple.
All OEM hardware.

When you tighten the ringnut it's sitting on the upper flanks of it's thread.
Then you clank on the upper triple, and screw in the stem bolt, and tighten that.
It forces the ringnut down to the lower flanks of it's thread.
And that adds a good bit of preload to the bearings.

With the front end in the air, supporting no weight, the ringnut and stem bolt are worked against each other like locknuts.
Tighten it until you can feel a little resistance at the grip going lock to lock.
Ride the bike for a bit, check it to see if it's loosened up, reset as necessary.

[Nibor]

While this is not a Duck, it is Italian....my Bimota top triple uses the top nut to tension the bearings. There is no nut under the triple. I tighten the top nut to 22nm, then back it off 20 degrees.

as long as the top nut is tightened appropriately before the top triple pinch bolts are tightened, I dont see why I cant do this too? the top triple just becomes a funky shaped washer effectively, which is then also secondarily secured to the forks/stem with the pinch bolts.

then again, maybe this is why im not an engineer 

[Nibor]

Just for reference, I've got an M750 that's mocked up.
The end of the stem is about 5mm down in the hole of the upper triple.
All OEM hardware.

When you tighten the ringnut it's sitting on the upper flanks of it's thread.
Then you clank on the upper triple, and screw in the stem bolt, and tighten that.
It forces the ringnut down to the lower flanks of it's thread.
And that adds a good bit of preload to the bearings.

With the front end in the air, supporting no weight, the ringnut and stem bolt are worked against each other like locknuts.
Tighten it until you can feel a little resistance at the grip going lock to lock.
Ride the bike for a bit, check it to see if it's loosened up, reset as necessary.

this is definitely more than 5mm down! I may get a mate to machine up a longer top nut, so theres still plenty of good purchase, and just carry on. any reason this would not be a good idea? thanks for the tightening explanation too  my concern is its not a set figure, but "by feel". I'm yet to develop the feel for this particular step. good thing Koko64 is around the corner (hint hint)

[koko64]

  One mile exactly.