HI Michael, Pretty much seems everyone that gets Wassell is disappointed with it. Pretty much every part I've gotten from Wassell has low quality issues somehow. Just had to return primary chain tensioner. Pad glued on crooked & bends at end were terrible.
On the other hand AMAL
Premier has proven quite good overall. If you choose AMAL
make sure it has .019 idle jet. The new Premier is different casting & they do much better with the 019 jet. This has shown true on both Tigers & Bonnies. You can buy direct from AMAL
& they will assemble to your specs with all parts including top & banjo fitting. They didn't charge me extra. Email Phil at AMAL
. I found him easy to work with. I would start with the other jets & slide sizes Hawaiian Tiger posted.
Also float level on Premiere is above float bowl, not lower like earlier Concentric
. Don't lower it. Idle jets are easy to get & not costly, but I'd still start out with .019 idle jet.
I've found lowering compression ratio doesn't seem to effect mixture, meaning putting 7.1 pistons in unit 650.
I don't have experience with your motor, but I've found on T140 even going from 930 to 932 doesn't run as good overall. I've been personally involved with that.
I would tend to go closest to size of the original carb. Over sized carbs generally only work at the very highest RPM which is only good for racing at high speeds. Going fast on public roads it will often run worse pulling out of turns in real life speeds etc. The 932 on the T140 was disappointing. The price of Premier is not cheap, but worth it. However I see you want to get it right the first time. Smart move!