Agreed! Rich is a wealth of knowledge.
Ric, you mentioned moving the LC inlet to the base? Why's that? The head is half the original (motor was a twin) so the water jackets flow through the head and cylinder just like stock. With a water pump moving everything and a pressurized system, it shouldn't matter where the inlet is located. At least that's what I'm thinking, but I could be wrong.
The crank is indeed becoming a bit of a sore point, but I half expected this so it's no big surprise. Rich has educated me a bit on what he's doing with the wider web crank and CR250 rod and that sounds like it may well be the way to go. I've had a few estimates come through and they're all sky-high. One of the reasons I decided to do what I'm doing was the fact that the RB25 kits are $1000 and used Rotax barrels are under a hundred all day long on eBay. I figured I could blow up, port, and otherwise abuse these things until I was blue in the face and still be into it for pennies on the dollar. A $1000 crank upsets this idea quite a bit.
That said, i will probably shift gears and go with a shorter stroke crank to keep the cost down and adjust the barrel configuration as required. The adapter plate is 25mm and needs to be machined anyways to get the port timings in line. I was going to assemble the rotating assembly and then machine the plate back as required. I assume a shorter stroke crank will need that little bit more taken off the plate.
As for the cases distorting while being welded, I'm with you on that. Made a fixture to hopefully keep this down to a minimum. Need to make another to keep the mounts from moving as well. Preheating and a slow welding pace will also help I hope! Gonna TIG the small stuff and where it's necessary to build up some material, I've got a spool gun for the MIG machine to really pile on the filler.
Rotax Lamby build-013 by
PotvinV8, on Flickr
Rotax Lamby build-012 by
PotvinV8, on Flickr
Rotax Lamby build-015 by
PotvinV8, on Flickr
Rotax Lamby build-014 by
PotvinV8, on Flickr
Adam, I need to check the clearance between the barrel and the frame but I was thinking of doing exactly as you mentioned if it is a problem. Great minds and all that...
-Ryan