Surging under steady throttle.

[fulltimer]

I have been noticing lately that when I am under steady throttle, often in 3rd or 4th gear, I get some surging. Not a miss and not very pronounced, but noticeable. Seems the most noticeable above 4000 rpm. We have been riding in New Hampshire and most of the time we are in 3rd or 4th gear due to the constant hills and curves. Running premium gas, not just one tank problem. Have been sensing it for the last couple of months. Runs great under acceleration and the surging is subtle.

Any of you had this problem with the 998? I have about 28,500 on the clock.

[Wrongway]

I've got the same thing happening on my 2011 with 18,000 miles on it.
fuel grade makes no difference and it's most noticeable with cruise on.

in the advanced search function just type in surge and select titles only. A whole lot of information about a very common problem.

let us know if you find a cure please.

regards
Greg

[loisk]

A few thoughts

vacuum hoses - easy fix - they can let air in, even if they look ok

spark plugs

spark plug leads - go funny if moved, eg, while replacing plugs

a batch of dirty fuel

clogged up fuel filter

They are the 'cheap' ones anyway...

[Chupaca]

Above things to check....if you have not changed your fuel filter or don't know if or when it was done you should start there. Crusing at steady speeds will let the deposits settle movement will give better flow. Run some seafoam with your gas to help clean up the injectors. Plugs and wires are more of a cut in and out surging is more of a fuel problem...when did you change your air cleaner last, another place to look...

[Wrongway]

I thought it was important to give an update on the surging that I reported on my 2011 RTS.

I've only had my Spyder for 2 weeks but have put 1800 miles on it already.

When I noticed the surging I added a can of seafoam right away because I've had great success with it but the surging continued.

After reading on this forum I realized that I had been topping up the gas tank to get as much fuel in as possible. After I stopped doing this, the surging stopped after 4 tanks of gas.
This isn't a scientific cure but just my experience so I'll no longer top up the tank after the automatic pump shut off.

regards
Greg

[Easy Rider]

Run some seafoam with your gas to help clean up the injectors.

Even better yet, you could use a product that was actually designed to be a cleaner......instead of a fuel stabilizer that is just marketed for that use.

Techron, Gumout and Berrymans B12 are MUCH better cleaners than SeaFoam.

[Easy Rider]

This isn't a scientific cure but just my experience so I'll no longer top up the tank after the automatic pump shut off.

I think the two most commonly reported fixes for this surging are:
A vacuum leak.
An evap recovery cannister clogged with liquid fuel.

The '11 I had for a short time did this too, along with a slightly erratic idle.
I don't know what the cause was because the dealer has it back now.

P.S. You can "top up" the tank until the fuel just touches the bottom of the cup in the filler neck but that last few ounces can be really messy because most fuel pump nozzles are almost IMPOSSIBLE to finesse a slow flow. I think just getting it close to the cup is the best plan.

[Grandpot]

My 2011 RTS suffered from that annoying surging for awhile. I tried fuel system cleaner, changed the MAPS vacuum hoses, and different grade gas. Nothing helped. Finally I did a canisterectomy. We have been surge free for over 5K miles. It's a simple procedure that will take less than an hour. Here is a link:
http://www.spyderlovers.com/forums/s...canisterectomy

[mcalva]

I'm sorry but I can't translate "surging".
When you talk about "surging", do you talk about that when you accelerate takes a time to respond and suddenly accelerates?
Thank you.

[Wrongway]

I'm sorry but I can't translate "surging".
When you talk about "surging", do you talk about that when you accelerate takes a time to respond and suddenly accelerates?
Thank you.

Fulltimer probably explained it best in his original post.
It feels like the bike is missing due to a bad spark plug or fuel starvation but when you give it gas there doesn't appear to be a problem.

Picture yourself walking into the wind on a very gusty day. As the wind gust hits you, it seems like you briefly loose your forward motion. The gust of wind passes and everything is good.

If I explained it well, that's great. If I didn't, I tried. Lol


regards
Greg

[Easy Rider]

I'm sorry but I can't translate "surging".
When you talk about "surging", do you talk about that when you accelerate takes a time to respond and suddenly accelerates?
Thank you.

That is one possible use of the term "surging" but not the most common one.
The situation you describe is most often called something like "uneven acceleration".

"Surging" most often means that the engine changes speeds without any operator input.
At steady throttle, the engine speed varies.

[mcalva]

Thank you very much. I think I start to understand the difference.