Billet crank case for 650

Dr_C · October 4th, 2020, 04:08 AM

Hi fellas!
I'll be designing some billet cases for my supermono engine this winter. It will be taylormade to my specifications (DOHC-head, big bore, taller conrod, larger mains and a cb in front).

In this process, I will also have the possibility to make cases that fit an OEM setup with kick, e-starter and all those comfy gadgets. They will propably cost less than 3000€, just to guess a round figure. If anyone out there is seriously interested in a set, please drop me an email with what improvements over the OEM you would like to see! More mtrl around the liner to allow a thicker steel big bore liner? More mtrl around the mains/bigger mains? Space for a larger oil pump? The current 3D model (see pic) is reflecting the 2001-2003. I'm not sure what is different on the 2004-2008, but I'm sure you know that better than I do! So, If you have this terrible itch and money burning in your pocket, send Santa a mail: mats.clementz@gmail.com

Taffy · October 6th, 2020, 03:12 AM

Hi Mats

If I were changing them I would try and make the sump 3-4mm lower (I know the frame underneath is close though.....

A long stroke goes through the back wall to the gearbox but I felt they gave more space for the 3/4th gear than was needed so that material could have been on the back face of the geabox divide instead of the inside.

the long strokes knock through the two engine mount bolt holes, not a lot can be done about that but perhaps it can be done beforehand ready.

that would then allow a 85mm stroke the same as the Husky 701. check out the centres on the Husky rod and copy. use the husky cylinder head and injection system.

But the con rod is too short so maybe the cases could be taller by 8.8mm plus whatever onto the throw of the crank?

a change to the KTM 53 chain would make the above figures different.

the 2004 plus have an oil squirt inside the cases on the left feeding out of the horizontal gallery. a must?

looking at the top of the casesaround the front under the exhaust port area you have just two 6mm coolant holes. later these went to 'smiley slots' to fit the exact shape of the head gasket.

what would you do about balancing?

perhaps now that the Husaberg clutch slave is no longer available it might be best to go straight to a later KTM set-up?

Taffy

Dr_C · October 7th, 2020, 12:55 PM

Nice wish list, Taffy! But you are not interested in a set, are you?

If somebody wants billet cases (only one, so far) we will together find out what is the desired combination of improvements. I have no use for "close to OEM"-cases and not really any feel for what people would like to achieve. The cases I'm doing for myself will be more "blue skye thinking"!

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Taffy · October 8th, 2020, 02:21 AM

The advice was free Mats.

Taffy

Alfy · October 8th, 2020, 01:27 PM

Why don't you consider having the houses made through 3D printing? For 1 couple it would be cheaper in my opinion ...

Goose916 · October 9th, 2020, 02:42 PM

In awe of this ambitious endeavor! I lack the engineering prowess to provide anything of use to you Mats, but you can bet your ass that I am totally subscribed to this thread. If I do have a suggestion worth considering, I will surely let you know.

Dr_C · October 10th, 2020, 04:19 AM

Originally Posted by Alfy

Why don't you consider having the houses made through 3D printing? For 1 couple it would be cheaper in my opinion ...

Maybe, but I'm good friends with a guy who is machining all the trickiest alu stuff for the swedish supercar manufacturer Königsegg. He has four of them 5-axis CNC-mills and software for simultaneous control of all 5 axis. As far as I know, you will still need to set the halves up in a mill and machine all bearing seats, sealing surfaces, oil pump position and bore for the liner.

Taffy · October 10th, 2020, 07:00 AM

difficult to imagine how you could go from 62mm mains to 72mm which I believe is the next 'port of call' (sorry about that sailor!) the right would perhaps take one where as the "isthmus" between the mains location and the intermediate shaft housing would be 5mm less. but what if the bearing house for the intermediate shaft could be made much smaller? it is a 6905 bearing at present.

the other thing I experimented with was a cam chain that went from the head to the crank with the lower cam sprocket inside the primary gear. I did a lot of lot on this and part of the trouble was that the chain needs a fair bit of space at the crank. So I went to the KTM 53 chain which helped.

the main on the left wants virtually no back wall for the bearing, and that weakens that area. I've done 80% of the work but theguy I sponsored had a chance to get a Fi Husqy at the time and was gone. project incomplete. If you want to borrow the cases and extended liner etc as something to bounce your drawings off - you're welcome.

The intermediate shaft was then no longer doing; cam, water pump and balancer but just w/p and balancer. you wouldn't even have the balancer there! so that leaves the waterpump?

Taffy

Alfy · October 10th, 2020, 07:08 AM

Yes and no ... That is, I have been working for 13 years on 5-axis milling machines and I know how much processing time it takes to shape an aluminum block and how quickly you can make a bearing seat, a centering pin or a plane of assembly. Looking at the shape of the crankcases will take a long time to get the shape you want, and a small part will be needed for tight tolerance machining.

polska · October 14th, 2020, 06:55 AM

Hello Mats. Perhaps this would be good idea. Dedicated threaded ports for the installation of the oil cooler or external oil filter. Oil return spray nozzle onto cam chain.