hi matt,
i was just wondering, have you ever had any experience of making up a set of crankcases eg out of billet or maybe sand casted?

cheers juan...

i have made crankcases in the past, simple british bike cases manualy and modern ones using a cad program and a home made milling machine.

not realy worth the effort (or expense if somone else is making them) in my opinion unless you realy cant get ready made cases or making specialist racing parts.
_________________
Honda nc23 CBR400 AERO 1986, 1990 honda NC23 Tri-Arm, 1987VFR400 NC24 Rothmans Rep, NSR250 MC16 1987, CL250s 1983. Moto guzzi zigolo 110cc 1958. Fantic 50cc 1972. Suzuki Cobra Race bike 500cc 2t 1975 , GP125 1975. Triumph T110 1954. BSA Thunderbird 1955. Ariel VB 600 1952, 1990 MuZ 125 etz.

hi alan, i think thatsreally great that you were able to make your own cases i wish i could. what cad programs did you use? also what sort of cost was involved? and were they two stroke or fourstroke these cases?

cheers juan..

Haven't got around to machining a set of cases from billet. I did have some cases drawn up in a 3D model, but cost of development is a major issue, as I'd want it to work properly, not just work.

Never got into sand casting. Did some research, but what with machines, sand blasting, compressors and all other noisey stuff at my house I wasn't sure that the neighbours were quite ready for a casting foundry. Well, not yet anyway It doesn't actually look too tricky if you can get the right materials.

I take my hat off to anyone that gives it a go and makes their own cases, or whatever. I am in the process of making an engine from scratch, but it's not a two stroke, or a four stroke for that matter. Half of the prototype is done, but it's a slow process as I don't want it to interfere with other (TYGA) projects.

A guy on the RGV forum has designed a set of replacement crankases for the rotax tandem twin engine, positiniong the cylinders in different positions.

I suggested that if he used wax rapid prototypes this could form the basis for a lost wax/investment casting process, rather than milling out a £1000 chunk of alloy.
_________________
NSRless again...

the cases i made where for a 4 stroke british bike (a 1919 triumph 600cc) and a new set of crank cases for my batavus 50 as icracked the cases on it so were basic.

i used auto cad and then a program of theinternet to convert into a program and to test it out before mking them.

was a while back and i dont think i'll bother again was realy just to see if i could do it.

made £150 from the home made mill that i made originaly from breadboards and old printers then replacedthe breadboards with a stainless steel frame
_________________
Honda nc23 CBR400 AERO 1986, 1990 honda NC23 Tri-Arm, 1987VFR400 NC24 Rothmans Rep, NSR250 MC16 1987, CL250s 1983. Moto guzzi zigolo 110cc 1958. Fantic 50cc 1972. Suzuki Cobra Race bike 500cc 2t 1975 , GP125 1975. Triumph T110 1954. BSA Thunderbird 1955. Ariel VB 600 1952, 1990 MuZ 125 etz.