zipidachimp wrote on 09/19/23 at 22:22:15:Spent the last 2 years riding around with a 152.5, felt pretty lively. Took the exhaust off last winter and found lots of black soot around the joint at the head. Went back to a 150 this year and surprise! Same liveliness ! More is not always better !
Cheers!
An engine that is a bit too rich runs smoothly, starts easily...and fools you into thinking things are great (when they really aren't).
An engine that is a bit too lean is often not smooth or steady as you open the throttle to accelerate or hold a steady throttle to cruise. They can also pop and backfire more than normal.
A properly jetted bike runs so much better than one that it too rich or too lean. There may still be some popping/banging while decelerating, as a closed throttle while slowing down or downshifting creates a lean condition....sometimes the stock carbs TEV just can't overcome that, and a more open exhaust makes the situation more noticeable.
When I first started jetting the Savage I went to the extremes to see the limits. I put in a main jet and rode the bike, then kept putting in bigger ones until I could feel the engine starting to choke under full throttle......then I put in smaller ones until I could feel it was too lean. Now I just reach for a #150 as it has proven to be the proper main jet for my 500'-800' elevation. I have ridden the Cherahala Skyway with this jet to 5,000' elevation and it still runs OK - however if I lived at that elevation a smaller jet might be in order. The #50 or #52.5 pilot jet are in the correct range - use the one that results in the mixture screw being 2-2.5 turns out for smoothest idle (must turn the idle speed down to around 800rpm for this adjustment). Then fiddle with the needle spacer to get smooth acceleration at partial throttle......keep adding washers until you feel a surge and uneven acceleration - then take out washers until the partial throttle acceleration becomes smooth.