What causes surging with closed throttle

[Whit]

Most every two-stroke that I have seems to surge when going downhill with the throttle closed. Is this a problem with my carbs or something else? ///Pat

[ja-moo]

It's kinda how they work, but a lean mixture will agrivate the effect.

[netbikes]

getting the carbs perfectly balanced will help a lot.

cheers.chris
www.netbikes.com.au

[johnakay]

my old T500 use to do it a lot and I had it perfectly balanced!
got round or should I say got rid 60% of it by having it run a little rich.
again an advice from one of the guys on here.

every body who I spoke to who owned two stroke have said(shows) that most of them do and that is the characteristic of these bikes.
nothing to worry about better to run rich then lean.
if you run it to lean then theres a chance of a holed piston!

[Vintageman]

Pat,


Here's one thing to check too, I had this problem on my Yamaha R5. I was researching on the aircood-rd.com club and one person said something about pilot jet too small. Yeah right.... my bike was all factory specs on jets. Finally I went 1/2 turn out on pilot air screw instead of the 1 1/4 turn and the problem almost went away. So I increased the pilot jet and completely gone. Most posts stated it is week clutch dampening springs or rubber dampeners and I am sure on these old bikes they are week, but too lean causes things to oscillate. If your surging is kind of bucking when throttle full closed consider this.

[oldjapanesebikes]

If this is for a GT750, take a look at service bulletin GT-36

[muzza]

they all surge as mentioned. Reducing back pressure helps...get some chambers!

Running a bit richer is my cure, raise the slide a notch.

cheers

Muzza

[netbikes]

I learnt many years ago to slip the clutch just a tad as you change down to reduce rear wheel bounce, as a side benefit it also reduces 2 stroke surging, go figure.