4 stroking at cruise, is this normal?

mobicon

New Member
Sep 12, 2016
7
0
0
rochester ny
Got my bike running reliably now. Seems to have decent power and a smooth steady sound when under load accelerating or climbing a hill.

However it always starts 4 stroking when I'm in a steady state low load cruise on the straight and level. When I hit the throttle it smoothes right out and jumps to power, but then begins skipping again when the load drops off on cruise. This occurs at any speed under low load and constant speed.

I tried leaning the mixture, but it only got worse.

Is this normal? Is this wasting gas?
Thx
 

crassius

Well-Known Member
Sep 30, 2012
4,032
156
63
USA
some folks think they are 'leaning the mixture' when they reduce the oil in their oil to gas ratio of their fuel

usually, 'leaning the mixture' means reducing the fuel in the air to fuel ratio coming out of the carb

try lowering the metering needle in the carb and lowering the float level too - if this helps, then you'll know where the problem is
 

WECSOG

Member
Nov 10, 2014
127
2
18
North Alabama, USA
What Crassius said. In fact if by "leaning the mixture" you mean reducing the amount of oil in the mix, you are actually making it run richer.
And yes, 4-stroking at cruise does waste fuel. Fouls the plug, too.
 

crassius

Well-Known Member
Sep 30, 2012
4,032
156
63
USA
needle is easy to go back if wrong, try all the way lean - float level is also easy to undo, so try that leaner too

if you see no diff at all, it may be a flow problem with ports/exhaust, but a leaner main jet could still be tried
 

ZipTie

Active Member
Jan 8, 2016
750
48
28
Mpls Mn
if you are running a NT carb...I've seen this only once, but you could pull your air cleaner off so you can check and see that the choke is opening all the way. Some NT carbs have a janky lever that is made in 2 pieces and if the lock nut is loose the choke stays partially closed with the choke lever all the way open.