Throttle body balance rod adjustment knob

[Pressureangle]

I'm going to make some. May check out a couple types of plastic, as well as aluminum. 

[docc]

You don't love yours for some reason?

(It's the same white knob on the V11, seen all blurry in the foreground of this image?)

[Pressureangle]

There was a request on WG for one like mine; I don't know if yours is the same, but it's a very simple part for us to make. If I can get a sample of your style, I'll throw them in the ring if it's a part that breaks much. My own is fine, I'll use it for the pattern.

[docc]

The V11 knob looks to have more extension on the thumb rests. These can be problematic if one hangs on the shock reservoir adjusting knob and chocks the throttle open . . .

[billgreenman1]

2 hours ago, docc said:

The V11 knob looks to have more extension on the thumb rests. These can be problematic if one hangs on the shock reservoir adjusting knob and chocks the throttle open . . .

Ohlins cruise control? Sounds a little scary...

[MartyNZ]

7 hours ago, Pressureangle said:

I'm going to make some. May check out a couple types of plastic, as well as aluminum. 

Huh.

I was thinking that I should replace mine by a nyloc nut, or a pair of plain nuts. I only touch it when checking the throttle bodies are synchronized. It's not something I would adjust while riding, so it doesn't need to be so big.

[Lucky Phil]

8 hours ago, Pressureangle said:

I'm going to make some. May check out a couple types of plastic, as well as aluminum. 

Forget the aluminium it'll be a loose sloppy mess in a few thousand klms. It's also needs to have a relatively high natural friction in the threads so it has an inbuilt stays where it's been adjusted to anti vibration design. Plastic is perfect for this and as I mentioned on another board Delrin would seem to be a good choice. I'd be interested in one or 2 myself in plastic but not aluminium. There's a reason the oem is plastic.

Ciao   

[GuzziMoto]

10 hours ago, Lucky Phil said:

Forget the aluminium it'll be a loose sloppy mess in a few thousand klms. It's also needs to have a relatively high natural friction in the threads so it has an inbuilt stays where it's been adjusted to anti vibration design. Plastic is perfect for this and as I mentioned on another board Delrin would seem to be a good choice. I'd be interested in one or 2 myself in plastic but not aluminium. There's a reason the oem is plastic.

Ciao   

And it isn't always because they are cheap bastards......

[Pressureangle]

57 minutes ago, GuzziMoto said:

And it isn't always because they are cheap bastards......

Well yes it is, because delrin wouldn't have broken by now.

[Lucky Phil]

9 hours ago, Pressureangle said:

Well yes it is, because delrin wouldn't have broken by now.

I'm willing to here about other plastic options.

Ciao

[docc]

So, the  original white knob is prone to breakage?

Mine is looking rather "chalky." I had thought it a polyamide ("Nylon®"), bet perhaps it is polyethylene (or HDPE)?

Wouldn't POM/polyoxymethylene/Delrin® be the better choice? Or too brittle?

"Just one word " . . . . . .

 

[Lucky Phil]

5 hours ago, docc said:

So, the  original white knob is prone to breakage?

Mine is looking rather "chalky." I had thought it a polyamide ("Nylon®"), bet perhaps it is polyethylene (or HDPE)?

Wouldn't POM/polyoxymethylene/Delrin® be the better choice? Or too brittle?

"Just one word " . . . . . .

 

Yes docc they get that way but seriously they are getting on for 25-30 years old now. I have 3 sets of Centauro/Dayton T/B's as well as my original V11 set and the adjusters are still functional. Not sure what the original is made from but the disadvantage with Nylon is it swells when subjected to moisture which A POM like Delrin isn't affected by. Considering the knob has a close fit in the pivot fitting and it needs to have some thread friction I considered Delrin a decent choice of material partly because it doesn't have the water swelling issue, is easy to machine and chemically resistant. Happy to be educated otherwise. Aluminium wouldn't have the natural thread friction and where it engages with the pivot fitting would be subject to fretting from engine vibration I would think.

Ciao   

[Pressureangle]

We regularly machine a number of different plastics, most of them custom high-density mixes. Some probably not compatible, for instance mixed with a Moly-based lubrifier. But we have straight delrin also. We'll get with the supplier rep to ask about specific properties required, and make the final choice with some advice and testing. 

[docc]

On close inspection, I can see the threaded portion extends about halfway through the steel block, that indexes the left throttle body, ending in a sort "collet" that capture the block.

So, I am seeing it's not jut a plastic knob with a threaded hole through it, but has an 11mm extension inboard with this four blade collet. This would have to have some tensile integrity (I'm sure there is a more accurate term) in order not to snap off. As such, it appears more likely a composite (like glass-filled Nylon) rather than a simple polymer.

Is it the collets that are failing on the original parts?

[Lucky Phil]

7 hours ago, docc said:

On close inspection, I can see the threaded portion extends about halfway through the steel block, that indexes the left throttle body, ending in a sort "collet" that capture the block.

So, I am seeing it's not jut a plastic knob with a threaded hole through it, but has an 11mm extension inboard with this four blade collet. This would have to have some tensile integrity (I'm sure there is a more accurate term) in order not to snap off. As such, it appears more likely a composite (like glass-filled Nylon) rather than a simple polymer.

Is it the collets that are failing on the original parts?

Good image and explanation docc. I've not experience one that's broken so don't know what the failure mode is.

Ciao