So my Grande has been running great for some time, but recently has started doing the following:
After a few minutes of running, low end is gone. Not in the normal sense, but say from a dead stop you can give it as much throttle as you want, and it sounds like its four stroking and just kind of creeps along. Vary up the throttle position, nothing doing. Then if I pedal a bit just to get it to like 5mph or so it springs to life, winds out, takes off, and zips up to 50mph. The low end is there, it just never gets there until you pedal it up to a few mph.
Point gap is just over .4mm, like .43 or something, though I have tried .406 with the same result. Plug chop looks good. Compression reads between 150 and 160. Condenser is not tested but is a brand new (like 2 weeks) external Borg-Warner 126. Carburetor is so clean you could eat out of it. Clutch and drum are de-glazed.
Setup as follows: 64 Malossi, Multivar with 4gr weights, 13.13 w 78 jet, Malossi filter, Malossi belt with yellow spring installed in rear, 9.5:1 gears, cut DMP crank, 13mm intake, case matched. Appreciate the help!