I'm bringing this thread back to life, as I believe that I have come up with a plan for my motor build, and I also have couple questions for the performance guys.
I've been speaking with a gentleman at M.A.P. Cycles, which I believe to be the leader in Brit Bike performance here in the States. I told him my plans of building, and the fact that no one here in the US sells performance RE parts, and quite frankly, I'm tired of sending my money overseas, paying twice as much for parts, when I should be supporting the struggling economy that I live in. After about 2 more weeks of research I have come to this conclusion:
I want steel conrods. I'm not wasting time or money on billet aluminum rods. I've seen too many pictures of them failing and taking out the engine. M.A.P. Cycle makes steel H-Beams for Triumphs, BSAs and Nortons. Upon my research, I have found that the BSA A10 conrods are damn near identical to the RE twin rods.
A10 Specs:
CtC - 6.5"
Small End Dia. - .75"
Big End Diameter - 1.8435"
Big End Width - .955
RE Specs:
CtC - 6.685" (I can't remember exactly, but this is what my memory is saying)
Small End Dia. - .75"
Big End Dia. - 1.8755"
Big End Width - .790" (measured on the crank journal).
Marino at M.A.P. believes that these will work well, and just need to have my machinist alter the big end of the rods to match the crank. If the RE rods are in fact 6.685" (6 5/8") then using the A10 rods will actually "stroke" the motor.
Upon the recommendations of Bullet Whisperer, I will be using Triumph T120 71mm pistons. Standard compression for the T120 is 9:1, but the dome of the piston is still 3-4 times bigger than the 8:1 RE piston. BW recommended using the Wiseco Norman Hyde pistons, as that is what he uses, but there's an issue with this. Even tho Wiseco is only a couple of states away from me, they will only sell those pistons directly to Norman Hyde. So, they will more than likely cost a small fortune by the time I have them paid for and shipped. M.A.P. Cycles sells a very nice forged piston set for $350 and appears to be very high quality. They also happen to sell a very nice cast piston for the T120 that is only about $120 for the set with rings. Marino says they are not as good as the forged pistons (obviously) but are "still a high quality piston, especially considering the price".
So, by going with the cast pistons and the steel rods I will only be spending about $600 for both sets. As compared to $1200 for making custom rods or pistons, or even $1000 for H's sub-par rods and pistons. Also, I'm going to figure out how to convert my clutch to a dry system to eliminate the slipping. I think the only real issue that I might run into is the alternator not getting lubricated. If it burns again, I'll just remove the charging system entirely and look into using a larger battery with a bigger reserve.
And lastly, the wheels. I'm thinking that because I want to race this bike, and I'm not concerned with either of my bikes being completely original, that I may be better off using the fork and wheels from the Chief for the Blackhawk. The fork is 1.25" wider than Interceptor fork that I have now, and the wheels are 16" which gives a little bit more options for performance tires. But, I'm not sure if this will have a positive or negative effect on the handling. If I do use the wider fork, I will have a custom billet fork brace made to help stabilize the front end.
All in all, my calculations say that I should be able to build the motor for $1800 or slightly less. then the only other items I will need is tires, a big tach and a cafe seat which should be less than $600 for all of that.
Forged Pistons
http://www.mapcycle.com/map/index.php/categories/engine/top-end/pistons/triumph-t120-tr6-650cc-forged-pistons.htmlCast Pistons
http://www.mapcycle.com/map/index.php/categories/engine/top-end/pistons/triumph-650-1958-later-piston-set.html4340 Steel H-Beam Rods
http://www.mapcycle.com/map/index.php/categories/engine/bottom-end/con-rods/conrod-a10-late-6-5-4340-h-beam-p-r.html