I have yet to use the new MAP conrods but hope to soon. But I have been using their products since the early 1990s. I have used many of their Unit Triumph belt drives for both myself and shop customers when I was still running a shop. Other parts as well, They have been a staple for both stock and customs for a long time.
(They have some very informative tech papers on stage tuning, cyl heads, valve train and general racing and street performance they used to publish and include with their catalogs. I asked last year if they would dig them out and publish them or offer them for sale, Still super helpful material,, The carb tuning stuff is something I used to photocopy and hand out to customers, saved me loads of grief, and educated end point user is a wonderful thing)
I think it would be great for you to post up pix and details of your build and be a help to others.
As to balancing, thats a complicated topic. There is a auto based shop in Gresham Oregon we have used, and they are well respected in the Race car and hot rod community, They did fine on several builds a few years ago. We had another guy, Dan Halls 5 point automotive who also did Dynamic balancing and specialized in British bike cranks and rods as well (Many shops wont touch them) but he passed away and the guy who took it over was a disaster.
So my preferred guy is an old Oregon Hippy who does airplane propellers and industrial applications. No website and has a small specialty shop up in the hills But I usually boxed things up and ship to him, but I have a cabin we visit so we pass right by.
Its name is E.V Lewis Dynamic balancing and he does the bike stuff on the side as there is not enough of it to run his business on. But he is well regarded in the vintage Bike community and many shops secret weapon. So on balance factor, He can discuss that and advise, But goes about it differently than many discussions you will see. You can find the percentage %s hotly debated on many forums, But my experience is dont get hung up on specific numbers. You DO want to record and keep a journal on all your specs, weights and numbers so, lets say down the line you have to replace pistons? Just consult your specs and you can deal with it.
But heres what I do. I box up everything that will rotate, after the rods are machined/resized, Journals ground or polished and Crank has been checked (Cracks, straightness, tolerances) then the pistons, pins, clips, rings and even the sludge trap plug (On some models there is a plug on the side of the crank). Optional is clutch basket, or Alternator rotor
(On some models that rotor is a huge weight flopping around on the end of a crank and can unbalance the whole she-bang,, Ernie charges generally $10 to balance them and worth it. Some come back with 3-4 dimples, others are so out of whack they look like a swiss cheese grator on one side) Some people balance trans mainshafts and layshafts and timing gears but thats a big OCD.
Now, Ernie will ask a series of questions. What type of frame, RPMS you generally ride at, and takes measurements. He fixes Rocking couple (Which is a complicated topic, but its a vibration wobble in laymans terms) but then corrects your weights and then moves the worst vibration to where you rarely run at RPM wise. Low, or high...
Now, some cranks and Rot. assys balance easily, Some are a real PIA. But sometimes,, there is a real problem. Early BSA Cranks have pretty full crank flywheels and cheeks,, LOTS of material to work with. But later Triumph and Nortons the cranks are cut down, and you remove weight opposite where you have the imbalance, But sometimes there is no material THERE. (Nothing to machine/drill) So he calls and runs my options. A few times we had to add what is called Mallory metals, which he machines a hole, plugs it with super heavy Mallory metal (Ballast) and tack welds it into place. Thats the only way to balance some cranks. I think I still have some photos of some Norton and Triumph ones,, Ill look. But years ago, we experimented with a BSA A65 and tried out the Capt Dirt suggestion.
Ill add this here, but if you feel its too off topic to your discussion Ill remove it.
Capt Dirt used to build some super competitive TT and Flat track BSAs, He told me the Unit Twins had the best cyl heads and better than Triumph or Nortons. He also liked the BSA cams, and correctly pointed out the stock A65 cams profiles are what Triumph copied for their race/sports models. But Capt said the BSA had too heavy of a flywheel. So, besides the oiling system mods and the rod mods I explained he said go out and weigh the lightest Triumph twin crank and then match that on the BSA and you will have a rocket ship.
So Triumph played with crank weights up and down over the years, Part of their vibration was also manifested in frame design (A real problem on the duplex mdls 60-62) but I think 1966 was the lightest cranks,, I would have to check my notes to be sure so dont quote me,, But IIRC it was around 16-17 pounds total weight. BSAs we measured were around 22-24 pounds? So, in late 69 to 73 BSA had 3 different flywheels and weights. (including the A70 twins, the A50 and 2 weights for the A65) So I have NOS flywheels so we picked the lightest one, and had it machined. We COULD NOT get it to the target weight but I think we got around 17-18? Which was a lot less than the stock weights. But Ernie had a heck of time balancing it. But he succeeded (He found the project FUN!
).
So, there was some blueprinting issues with the cases as well (Cases were out of whack, both crank and cam center lines as well as the cyl deck) We also used a SRM 357 Cam and some other tweaks. So I built the motor and it went into a hard tail bobber frame. The owner freaked out a little bit. It revved like a 2 stroke and was freakishly quick. Zero to go to jail MPH super fast. (We geared it for the street not the track) So it was a super fun bike. But,,, not good for long distance cruising or relaxed putt putt in the country. It was a beast. I enjoyed the project and well learned a lot. However I dont think for most bikes super light cranks are a good idea. The BSA Unit is a good all around plodder and hooligan blasts, so the heavier crank works well.
I have pictures in my office of that build and on my list of things I want to put up here that might be informative.
I have no input on other balancing shops besides my regional ones. But I have a friend in Alaska who builds a bike every winter and he ships his bottom ends to Jaye Straight? Brittech. I never dealt with him so no opinions. Maybe others can advise.
My old guy, Dan,, felt Ernie was too cheap, He felt he should charge more. Dan was anywhere from $125 to 250 depending on difficulty which is fair. Ernie was much less,, $75 to $150 in most cases, and add ons such as timing gears and alternator rotors were cheap,, often $10 per part. Prices might have changed since and problem projects scale accordingly.
But Ernie, Should anyone want to use him, Is located in Creswell Oregon not far from Interstate 5. He will meet in town or at the small airport, But can do shipping as well. #541-895-2287
