TRITON, at last...

hudson29 · Feb 24, 2011

You mentioned using Norton rear wheel, hub & brake. Was this Commando gear? Will it fit on the Featherbed swing arm as is or will it need some modification? What will you need to do to get the Suzy front brake to fit your forks? Is the axle the same? I'm watching your project with an eye to a future one of my own.

Paul

Webby03 · Feb 24, 2011

No, in true Triton tradition, you want to drill as many hole in it as possible so it resembles a piece of swiss cheese. The resultant weight saving will gain you 0.00002 MPH, unfortunately the drag from the air vortexes around the holes will make you loose 0.00003 MPH :mrgreen:

Webby

Webby03 · Feb 24, 2011

Triton Thrasher said:
What's the downward-pointing keel on the head steady for? Splitting the wind?

I think it stops the coils from touching and vibrating against each other.

Webby

Webby03 · Feb 24, 2011

hudson29 said:
You mentioned using Norton rear wheel, hub & brake. Was this Commando gear? Will it fit on the Featherbed swing arm as is or will it need some modification? What will you need to do to get the Suzy front brake to fit your forks? Is the axle the same? I'm watching your project with an eye to a future one of my own.

Paul

Hi Paul,
A stock commando rear wheel should fit. When building a Triton there is no right or wrong way to build one, it's a bitza so you can use whatever parts you like. (I, for example have used a Triumph conical rear hub)
The advantage with the Norton wheel is it bolts straight on. If you were to use a Triumph hub, either you sleeve down the bearings so you can use a Norton spindle, machine down the Triumph spindle to fit or open up the slots in the swing arm.
The other advantage using the Norton hub is it is fitted with a cush drive (on a Triumph motor the cush is in the clutch center) This gives you a wider choice of belt drives if you want to fit one (QPD or BNR for example).
Both the Triumph and Norton rear wheels should have almost the correct offset to bolt right up, I found mine to be 3mm out, but that's because I'm being too fussy!
A Suzy front brake will fit between the standard road holder forks provided they are the later short ones with 7 3/8" between centers. If you're using a 4LS front brake (in fact it's a twin 2LS) you only need to true the rim central to the hub, so nice and easy.
As for the spindle size, I can't comment as I don't know the spindle diameter but generally you just need to get one machined up. (Jean dr is the one to ask, he had one fitted to his café racer)

I hope this helps

Webby

grandpaul · Feb 24, 2011

I put my suspension and wheel parts in a dark corner of the garage with pictures of unicorns, leprechauns and fairies next to the stack, hoping that when I come back to check on them, they'll all bolt right up.

...actually, it's about time I started test-fitting some of that stuff.

I know the Commando rear brake torque lug DOES NOT fit straight into the Featherbed swingarm. I also know that the Suzuki wheel assembly is going to take some fiddling to fit the Ceriani forks.

Foxy · Feb 24, 2011

Its there for "just in case"!? :mrgreen:

Triton Thrasher · Feb 25, 2011

Webby03 said:
Triton Thrasher said:

What's the downward-pointing keel on the head steady for? Splitting the wind?

Click to expand...

I think it stops the coils from touching and vibrating against each other.

Webby

But but vibrating against the plate is just as bad!

Carbonfibre · Feb 25, 2011

grandpaul said:
This is the unmarked 750cc kit that is a drop-in to the 650 cases with zero modifications-

Venoila pistons-

Worth bearing in mind that head gasket problems are pretty much assured if you have a 9stud 750 conversion. This being the main reason the factory 750 Triumph motors used 10 stud heads, and were largely trouble free.

Its also worth looking at how far the gear box sprocket centerline is from the swinging arm pivot, as the relationship between these 2 points is pretty important, and can greatly affect the finished bike.

willh · Feb 25, 2011

Carbonfibre said:
Its also worth looking at how far the gear box sprocket centerline is from the swinging arm pivot, as the relationship between these 2 points is pretty important, and can greatly affect the finished bike.

I take it you mean in Y being height. I'm interested in what you have to say about this. I have to make new plates for my special, ( not enough clutch clearance), and was wondering about dropping the height of the transmission to have the sprocket centerline below the pivot. Makes sense to me as the chain run is tight on top and loose on the bottom.

Sorry for the highjack Granpaul.

Will

hudson29 · Feb 25, 2011

Thanks Webby & GrandPaul for these very helpful threads. I'm sure I'm not alone in watching to see how such specials are created. The fact that later Commando bits will bolt up to the old Featherbed frame really simplifies things for building a sort of baseline from which to work.

grandpaul · Feb 25, 2011

If I have issues, I can always install a simple dirt bike chain tensioner. I've seen one that was done with a skateboard wheel & spring!

Webby03 · Feb 25, 2011

willh said:
Carbonfibre said:

Its also worth looking at how far the gear box sprocket centerline is from the swinging arm pivot, as the relationship between these 2 points is pretty important, and can greatly affect the finished bike.

Click to expand...

I take it you mean in Y being height. I'm interested in what you have to say about this. I have to make new plates for my special, ( not enough clutch clearance), and was wondering about dropping the height of the transmission to have the sprocket centerline below the pivot. Makes sense to me as the chain run is tight on top and loose on the bottom.

Sorry for the highjack Granpaul.

Will

Hi Will,
Looking at your photo, I would say your gearbox is almost as low as you can get it. On a Triton the center of the gearbox sprocket is in line with the center of the swing arm spindle, you don't need it any lower (in fact it's not possible to get it any lower without removing the center stand lugs)
As for your chain, it's normal that it's tight on the top and loose on the bottom, all bikes are like that.

I hope this helps

Webby

Webby03 · Feb 25, 2011

Carbonfibre said:
grandpaul said:

This is the unmarked 750cc kit that is a drop-in to the 650 cases with zero modifications-

Venoila pistons-

Click to expand...

Worth bearing in mind that head gasket problems are pretty much assured if you have a 9stud 750 conversion. This being the main reason the factory 750 Triumph motors used 10 stud heads, and were largely trouble free.

Its also worth looking at how far the gear box sprocket centerline is from the swinging arm pivot, as the relationship between these 2 points is pretty important, and can greatly affect the finished bike.

Hi Carbon,
Yes, you are correct, the chain run is very important.
If you mount the gearbox (or the motor in the case of a unit) too high the chain will foul the upper motor attach tube, too low and it will foul the swingarm. You also don't want the motor too far to the rear of the frame, given that the weight distribution of a featherbed frame when fitted with a manx single is about 50/50, really you want about 60/40 with the 60 at the front. However if you mount the motor far forward then you will have issues with the long chain run, GPZs suggestion of a tensioner would get round this but I think the finished bike wouldn't look right.
So it's all about compromise, I did about a months research in books and on the internet to find the ideal motor placement and chain run, I'll be intrigued to compare my measurements to GPZs Dresda plates, if I took my measurements correctly they should hopefully be the same.

Webby

willh · Feb 26, 2011

Webby03 said:
....
As for your chain, it's normal that it's tight on the top and loose on the bottom, all bikes are like that.

I hope this helps

Webby

Hi Webby,
Thanks for that in sight :lol: What I meant was that it shouldn't be as much of a problem having the transmission lower than the swing-arm. A piece of nylon slider on top of the swing-arm near the pivot is all that's needed for protection. I actually will move another 1/4-3/8" farther forward and down to get the clearance I need at the clutch basket, lower the weight, and get more clearance up top. Just means removing the front mount lugs from the frame and welding new mounts where I want them.

Webby03 · Feb 26, 2011

Hi Will,
Sorry for pointing out the obvious

There is no reason why your idea wouldn't work, just check the clearance between the chain and swingarm with no weight on the rear and again with you sat on the bike.
My 94 Triumph Speed Triple has a slider on top of the swingarm, although the chain only rubs when the shocks are extended. I think the clearance is about 1/4" with the bike sitting on it's wheels under it's own weight.

Webby

grandpaul · Feb 26, 2011

My friend finally got his run of custom knives done for the NY show, so we got down to the spindle kit fabrication.

First, the template for the bolt plates-

Next, the the bandsaw with the 3/16" stock-

(I didn't get any shots of drilling the holes) Then came the grinder to dress them up-

Voila'

grandpaul · Feb 26, 2011

On to the lathe to turn down the threaded end-

The Left end will be trimmed down to length and welded up-

The Right end will be threaded, then trimmed to fit behind the Right side rearset mounting plate-

grandpaul · Feb 26, 2011

We can't thread the end of the shaft till Monday when he gets his lathe set up to cut threads, and we can't weld the other end till after the threading is done; so, this is it for today.

I need to modify all my wrenches like this one, no more having to search for where you set down the hammer!

Of course, when fabricating Norton parts, you should use only the finest Norton finishing materials...

Carbonfibre · Feb 26, 2011

Main thing to check with any type of special, is whether or not the chain tightens in a certain position over the travel of the rear suspension. If it does then the action of the suspension will be adversely affected, as will the overall handling of the bike.

This type of effect tends to be accentuated as the distance between the gearbox sprocket centre and the swinging arm pivot increases, and ideally these points need to be as close together as possible. The horizontal plane relationship between these 2 points is also important, and on MotoGP bikes the swinging arm pivot position is adjustable as is the steering angle.

However while the above things would be likely to have a drastic effect on a special fitted with a modern motor, producing maybe 150BHP at the rear wheel, they are not likely to be as noticeable on something fitted with an old Brit twin, and are probably just something most people are going to put up with!

grandpaul · Feb 26, 2011

Well, TriTons have been built using conversion plates similar to these for what, 50 years? I think any adverse effects are pretty manageable.