Ask an Engineer

[bogan]

Do you have enough journals for that? Oldham couplers won't support the cam, so you need at least two journals on each side of it, if you're only doing the one cylinder you'll only have the end journal on the one side right?

[ducatilover]

Do you have enough journals for that? Oldham couplers won't support the cam, so you need at least two journals on each side of it, if you're only doing the one cylinder you'll only have the end journal on the one side right?

Ah, I see. Yup, journals are between the lobes, you can see where in the last pics.
I had my hopes up there, would work if I went for a big bang set up, but that'll root the rest of the engine...

[ducatilover]

Here be a pic of where I'll be chopping/joining

[Ocean1]

I was assuming it'd help reduce the risk of the cam twisting in the join (remember, I know nussing about engineering stuff)

If it's not needed, I won't do it

It's quite possible a mild shrink fit on the sleeve would hold the torsional load, but I wouldn't trust it. Oldham couplers would be nice, if yo ucould buy them off the shelf, (fair bit of work to make) and if you had room to swing them. You dont. The simplest way to form a mechanical drive that'll fit in there is to pin a sleeve radially through the shafts both sides of the joint. I'd use taper pins, nominal dia about 5mm. Pre-assemble the shaft and check run-out and timing before reaming for pins.

All you need to do that is a lathe and a drill press, easy. I've got taper reamers if you decide to go that way. And pins.

[pete376403]

Bore through the centre of the camshaft, cut the shaft and put a spigot inside, give it a decent chamfer then bronze the thing back together in correct alignment

H-D did this with the rocker shafts on the original XR750 motors to get the angles right after shortening the 883 cylinders, so it's not like it's never been tried

[Ocean1]

Here be a pic of where I'll be chopping/joining

What diameter is the shaft at the join? And what clearance does the standard shaft have from the oil runner?

[Ocean1]

Bore through the centre of the camshaft, cut the shaft and put a spigot inside, give it a decent chamfer then bronze the thing back together in correct alignment

H-D did this with the rocker shafts on the original XR750 motors to get the angles right after shortening the 883 cylinders, so it's not like it's never been tried

Yeah, it's an option. Think it'd work best if you made up a fairly substantial jig to keep it consentric.

[husaberg]

Cool, I'll have a looky and see what I can find about them!

As long as whatever I do is safe with revs (ZX6 pulls 15k, I can drop the limiter to 10k, but that's gay)

http://www.britcycle.com/Manuals/Bui...sh%20Twins.pdf
http://www.650motorcycles.com/270277updates.html
http://www.offsetcrank.com/thefirst.htm

Yeah, it's an option. Think it'd work best if you made up a fairly substantial jig to keep it consentric.

http://www.offsetcrank.com/bike_cams.htm

[Brian d marge]

Im worried about the loading , while its not reversed it is repeated and again while the movement isn't big , the frequency is high and fatigue may be an issue, as well as the interference fit remember it will be running around 100 deg c more or let , which will affect any interference fits
the last idea with the bronze with a sleeve seems the most sturdy , but until you have an idea of the loading .....

Do a free-body diagram , then a loading diagram this will help you making a decision,

just my concerns

Stephen

[Ocean1]

massively oversizes pic

Perfekt...

[husaberg]

Perfekt...

Did you have a look at the links it did them in an interesting way.
the one i can't find it the Triumph that an Aussie did to try out Phil Irving 76 degree concept

[Kickaha]

Did you have a look at the links it did them in an interesting way.
the one i can't find it the Triumph that an Aussie did to try out Phil Irving 76 degree concept

There's a Matchless twin sidecar racing in NZ with a 76 degree crank the owner made himself

[DEATH_INC.]

What about stainless TIG? When I searched for info on welding gearshafts and stuff for the trike it was the most preferred method I found....

[Ocean1]

Did you have a look at the links it did them in an interesting way.
the one i can't find it the Triumph that an Aussie did to try out Phil Irving 76 degree concept

Briefly. They seemed to have more issues with cams than cranks.

[Ocean1]

What about stainless TIG? When I searched for info on welding gearshafts and stuff for the trike it was the most preferred method I found....

Is a good way to manage gear shafts, but they're carbon steel. Looks like this cam is cast iron, and while you can bronze weld cast iron with a TIG it's not the tool I'd use.