I've been battling engine performance for awhile now on my PK-80 with 44T, 25:1 synthetic oil and 91 octane, my weight 180 lbs. It just didn't want to come up into 2 stroke rpm range unless it was going downhill. On the flats and particularly on a slight grade, it would surge between 2 and 4 stroke running. Steeper grade had less surging. Clearly a mixture issue, but without an RC engine-like mixture screw, it simply sucks! (hmmm, a Saito 4 stroke radial engine in-frame? Nice!)
Resealing manifold and carb, checking float, needle, and seat for debris, moving mixture needle clip into all four slots, matching intake/exhaust manifold ports didn't help. Scouring this site came up with nothing else to really go for.
So I took it on it's maiden voyage to work (20 miles one way) with an estimate 75 miles of break in roadtesting, and a few miles into the way back it just suddenly, miraculously, started to run consistently! No more surging, just smooth operation...nice!
I still wish it had more power on the hills, as even a very modest incline loses a lot of speed, but overall, much happier now. Wish I knew what changed!
I guess it is true, the firt 100 miles or so should be just ridden through without worrying too much about performance.
Resealing manifold and carb, checking float, needle, and seat for debris, moving mixture needle clip into all four slots, matching intake/exhaust manifold ports didn't help. Scouring this site came up with nothing else to really go for.
So I took it on it's maiden voyage to work (20 miles one way) with an estimate 75 miles of break in roadtesting, and a few miles into the way back it just suddenly, miraculously, started to run consistently! No more surging, just smooth operation...nice!
I still wish it had more power on the hills, as even a very modest incline loses a lot of speed, but overall, much happier now. Wish I knew what changed!
I guess it is true, the firt 100 miles or so should be just ridden through without worrying too much about performance.
