Stops at 2000 RPMs

[davepol]

Hi

I noticed couple days ago that sometimes when rpms are going down (I rev it and then let go) it stops around 2000 rpms for couple seconds and then it goes down a bit to a normal rmps when idle (around 1200). Other then that bike works perfectly fine, it revs well, there is no loss of power, just this issue from time to time.
Thanks for any advice,
davepol

[squiggy]

The three things I remeber from here are:

vacuum leak

carbs set too lean

and

out of sync carbs

[davepol]

The bike is 3 years old (9200miles) so I think carb sync would not be a bad idea, especially since I have never done it before Can out of sync carbs mess up anything on my bike?
thanks again,
davepol

[md86]

Out of synch will just make it run & idle a little funky .
Throttle cable binding or misrouted or done can cause crap like that , too . So can crap in the carbs .

[squiggy]

Throttle cable binding or misrouted or done can cause crap like that

If the RPMs rise when turning from steering lock to steering lock then definitely misrouted cables.

[davepol]

Hi

I guess I found the issue. First I checked if the throttle cable is correctly routed. It seemed like it was (rpms stayed the same while turning the steering). I don't suspect any junk in the carbs, I try to stay away from poor quality gas and as far as I remember I never left old gas standing in the bike.

But since it's winter (at least here in Michigan), I try to keep the gas tank as full as possible. So the last time I went for a ride I filled it up to the brim. That's when it started to happen. When a little bit of gas was gone (good weather made it possible to ride the bike for a few days) the entire problem was gone.

So correct me if I'm wrong but I think that overfilling the gas tank can cause similar issues. But I don't understand why

thanks,
davepol

[md86]

There's a drain/vent in the rim (that little hole you can see ) . Overfilling should NOT cause an issue . I overfill mine more often than not (I cna often see a few drops of gas come out the overflow : ) , and it never causes it to act funny .

[davepol]

That's right, there is a hose that should drain the excess of the fuel. Well it's ok, now, I haven't use the bike for almost two months before I went for the first ride, so maybe that have something to do with it, the most important thing is that it seems to be ok now

thanks,
davepol

[davepol]

Could it be a choke cable (getting stuck)?

[HexKrak]

The three things I remeber from here are:

vacuum leak

carbs set too lean

and

out of sync carbs

vacuum leak - Seems the most common culprit. Spray wd-40 around the carbs and when the idle goes up you've found your leak.

out of sync carbs - Second from what I've seen.

[davepol]

Hi

What is vacuum leak? Does it mean that my carbs are not connected to the engine tight enough and the air somehow gets through?

thanks,
davepol

[md86]

Kinda ... means are gets in somewhere it should NOT .

[davepol]

One of the screws in the valve/head cover is messed up, I put some silicone around it, but I think the air still can get through easily. Or is only a leak somewhere around carbs?

thanks,
davepol

[ModernJoker]

a vaccum leak is air going in where is shouldnt be, or coming out where it shouldnt be in reference to the intake. if it is comming out where it shouldnt be in the exhaust system, it is called an exhaust leak. your carbs might not have a good seal, or somewhere else may be leaking. however, a vaccum leak would make the engine run funny throughout the rpm range, but most noticably would be near idle. so it might be your problem. but if the bike set for an extended period of time, and is carburated, then you very well may have some varnish buildup. doesnt matter if you buy good gas, it still happens. if it isnt causing you any problem other than being slightly annoying, why worry about it?

and i may be completely wrong with what i've said, but i've built a few automotive engines, including 2 inline 4 cylinder engines and the concepts are basically the same. Someone please take pity on me if i am wrong and you feel the need to correct me.

[davepol]

It's only slightly annoying so I will just do the carb sync and that's it. Idle is fine, acceleration is perfect, only thing is that when it's in neutral and I rev it to higher rpms coming back it hesistates around 2000, it doesn't stop it just slows down a little and then comes to idle at around 1100 rmps.

thanks,
davepol