Welp, here is my first question. The cams I have require shim on bottom (under the buckets). I have long assumed that I could use a nice set from a 650/750 engine, but have recently been advised that the stock followers cannot long withstand high lift cams.
What say ye experienced engine builders?
That is BS.
I recently put together a 1327 drag engine with "good" stock 650 buckets. I asked my engine guy who has built many hundreds of drag engines if they would be OK for .460-.480" lift cams, his answer was yes. He did mention when you get to .500" lift and over that is when you would need them mostly for the high spring pressures involved because they are made out of 8620 hardened steel. Drag engines target 110-120 PSI seat pressure, street engines 80-90 PSI so quite a bit of a difference on the force generated back onto the cam lobes.
My 650 based alcohol injected drag bike is running +.440" lift cams with stock 650 buckets. A few bucket top failures but that was attributed to lack of proper oiling due to alcohol contamination. On that bike I was also using 20W50 car oil because it was changed out after every outing (lack of Zinc = not good)
I am currently putting together a 1197 street motor using 750 buckets, cams are .425" lift. I don't expect any issues.
I have also logged a lot of street miles on stock 650 buckets with .400" lift cams with zero issues.
APE says you have to use aftermarket buckets over .410" lift and titanium retainers - also BS, just want you to spend extra $$
All my builds use stock 650 retainers, titanium is only for serious race engines.
If you use assembly lube on the lifters and cams before start up using good quality conventional (non synthetic) motorcycle oil there should be no issues.