surging
 

Think I experienced the famous surging on the XT today.
Wasnt too sure what to expect reading other posts concerning this issue,
To me it seems the bike is saying open the throttle and get going.

tell us.. what year ye have, what model. whats yer mileage, an what exactly is it doin.... am only askin as ye need tae feed us wi as much info ye are experiencing....:088:

ok..tell us what ECU you have...to do this is very simple....

1. remove your seat
2. take your keys out of the side panel, and undo the top and bottom bolts on this side panel (you will need a 10mm socket).
3. Pull out the rear-most corner of your side-panel, so it comes out of the grommit.
4. now, slide your side-panel rearwards, so that the two "ears" come out of the petrol tank cover...and Voila!

Your ECU is the box nearest the petrol tank, just read off the numbers on the sticker. If you get stuck, have a look at the photos on this link....to show you what the ECU looks like, and the numbers needed.
http://www.xt660.com/showthread.php?t=8546

Ok, The surging I am experiencing is at slow speed the bike feels it has a flat spot and a little hesitant but as soon as you blip the throttle a touch its fine, another example would be kind of fuel starvation.
But all in all I take no notice of it now I have done a couple of hundred miles on the bike.
I have looked at the numbers on the ECU as requested and they read 5VK-8591A-11. Hope this helps and look forward to your expert findings.
The bike is a 59 model xtx with 2000 on the clock.

Not up on my reg plate numbers but that sounds newer than the 04/05 models which had a faultly ECU. They where replaced by yamaha but some people did find you had to fight a bit to get the work done.

Anyway normally the way i describe the surging of the XTR is that at a certain set speed and gear its like yamaha (or the emissions police) have tried to make the bike cut the fuelling (as you say stravation) even though you might be asking the bike to do part throttle stuff. But the only thing is being a big single your part throttle and them trying to cut the fuel mean in stead of the engine feeling as if its dieing or straving of fuel and leaving you with an on off throttle theyve tried to get round that and it can jump where its like on off on off throttle even though your keeping the throttle the same. Basically like the engines trying to pick up and then lets go again.

Sometimes its not a problem as if your on a road no one else around you either speed up, slow down or flick another gear. But mid corner, traffic, or people are just travelling at that speed where it happens can be a bit of pain.

But as you said most riders have got use to it and ride round it, most with out even knowing after having the bike for a while.

Be careful as the same effects on the XT can be felt by having a loose chain or the cush drive rubbers being worn (wear out quiet quickly on the XT due to the torque aka wheelie fun).

Yes Maxwell your description is pretty much spot on, and its true to say that once you have been riding the bike for a while you really dont take much notice.

sheedy..... i have had the same problem... but unlike you mines was a 06 model,, yours is a differnt model 09, wi lamba sensor... i thought theyd have it fixed by then.... take a half hour an read these posts,, most by me,, an answers by the guru on this site as well as a few others,, all waving there hands about... i have tried everything,,an guess what it was a TPS.. just saved ye a half hour an a whole 2 weeks o grief... but it may not be.... read ma post anyway.. an ye`l see me pulling ma hair out..litterrly.. then contact this guy in a new thread....KEV.. dont hijack mine,, as it may not get read...... http://www.xt660.com/showthread.php?t=14749 a hope ye get tae the bottom o it,,,john

Having read a load of posts and threads about the fuelling and fixes..... I decided to do two things to my 09 X. I hadn't noticed any significant issues with the fuelling, but I haven't done much town riding, where you'd notice small throttle openings and any surging / snatchiness.
So first I pull out the snorkel.... dead easy, just eased it out with a tug.
Second I did the CO1 change and upped my level by 8, from 17 to 25.
Then I rode into London for the evening through loads of traffic etc.... First thing I noticed was the increased noise and induction roar from losing the snorkel. Sounds great!
Second the bike FEELs a touch stronger in the lower revs. The snatchiness was more apparent riding through traffic, so I will up the CO1 by another 7.... totalling +15. It also stalled once with a pop at a set of lights, but I think that was just my blipping the throttle and feathering the clutch like a donk!
I think these two things have improved things, I just need to adjust a bit more to get the compromise right...... and it will be a compromise. I don't have the cash for cans, dyno time and PCVs etc..... so a K&N or DNA filter and a bit more playing will be as much as I can do.

Went another +7 on the co1, but it started to feel sluggish so dropped back -3...... Totalling +12 on standard setting and now feels just about right. Had a good ride out to H cafe in oxfordshire and it went well, started to flow on some twisties..... Feels like it could do with 6th gear mind!!! But lots fun at almost still legal limits!

Mech want tae improve things.. ioI have a K an N stage 1, an a DNA stage 2 fur sale ...pm me if ye want,, i also have a Kev mod that a dont need as well. furyer fueling ...the stages make a difference. let me tell ye in power an running... pm me if yer inetersted

Surging
 

Hi to all, I am a newbie to this forum so please be gentle!!

I currently have 5 Yams including a 2011 XT660X, and this is my third XT660, I luv em!! When I bought this one last summer it behaved perfectly for the first 4000 km and I really loved it, and I even told my dealer how much improved the engine management felt over my 2 previous ones (07 and 08). I had previously assumed that the surging was standard for a big single.......

BUT I recently noticed how poor the new one had become and it felt almost worse than the older ones had ever felt, surging all over the place and really tricky to ride in traffic! The flexibility had gone to pot and it would not cleanly pull 5th below 110 kph!! So I changed the spark plug which had very little effect, and then having read your forum I took the CO up by 10 points.

AMAZING!!! The bike will now pull top cleanly from 75kph like it used to, and has returned to being as sweet as it ever was. Thanks guys!! Simon

I hear the Kev O2 mod helps with surging. Never had any issues with surging despite some significant mods thanks to it!

Update from me: My 11 XT660X is still running great with the plus 10 on the CO plus removal of the snorkel. But guess what???? My last tankful shows an INCREASE of 10% in my fuel consumption, so now I get only 180 km to the fuel light against the former 200 km!!!!!!

But then I thought of the real reason........I am enjoying the bike about 100 times more than I was so the throttle is always wide open to hear the lovely induction noise, so I guess that the 10% is a small price to pay for the extra smile factor hehehehe.

And today my Stage 2 filter has just arrived from Greece so more fun is on its way!!

Thanks guys, Simon

Welcome to the XT modding addiction time

Quick update, never had any probs with surging, what evers there does not effect the ride and now 12000mls looks and gos like new.

Ok so just got my XT back from a service yesterday. The mechanic commented how the bike seems to have trouble maintaining a constant speed (i.e. surges). He thought it might be something to do with the throttle body but the bike was otherwise fine.

Anyway I get on to ride home and now I am noticing it quite a lot. I think it was a combination of heavy traffic and the fact that it had been pointed out to me. In the past I hadn't thought anything of it (see my post above).

I rarely do a lot of commuting on my bike so when I ride around on the weekend or at night I either have the throttle cracked pretty hard or I'm braking.

So it would appear that I have the famous surging issue too (2007 model).

Haven't read much into it yet (apart from this thread) but anything I can do to fix it??

-Stewart

There is a cure, you have quite a lot or reading to catch up.

http://www.xt660.com/showthread.php?t=14746&page=17

Thanks Kev! Will get on it ;-)

Ok so I have this O2 mod installed.

http://i.imgur.com/jis2L.jpg

Can I simply strap the 2012 O2 controller mod on in addition? If so, I'll place an order! :)

Sorry about that massive picture!! lol

That is one of my original O2 eliminators the bike should not surge with it fitted. Pm me & I will tell you how to test if the O2 eliminator is working correctly, you will need a multimeter.

What mods are fitted to the bike? What fueling device is fitted? What is the CO set to, what is the TPS set to? What fuel are you using?

There are a few things that make these XT's surge, the biggest one is the rear sprocket holder, there must be no free play in it when moving the rear sprocket back & forwards, the chain must be adjusted correctly, how many kms have you done on your chain & sprockets as a streached chain can make the bike surge?

Hi Kev, thanks for the response!

I didn't have any surging issues in the past. It seems to have gotten much worse since the service.

My mate has a multimeter I can borrow.

Mods include DNA Stage 3 air-box kit, MTC Cans and Power Commander V. I am using a fuel map that you sent me (I believe it was from your 07' XT).

No idea regarding CO or TPS.

I'm using 98 ULP. Usually BP or Shell.

Chain and sprockets have done 9,300km. I haven't checked them yet.

PM sent.

Hi Kev,

I read your comment about the chain. I'm wondering how to find out when the chain and sprocket should be replaced. I've done 35000 kms and the chain becomes loose very quickly after being adjusted. Advice on this would be appreciated.

Cheers.

I used to get around 25K kms on my XTX chain & sprockets.

35K on one set of chain & sprockets, amazing, time for a new set I would say.:smilies0349:

ok, thanks for that. will order a new set then. it didn't seem quite right for a while. so maybe next change will be a bit sooner i gues...

Back to surging, never really noticed any issues in traffic concerning surging, but this year I plan to change the air filtre to stage 2 and pipes to beowulf also cut back snorkel.
Might this cause surging or will it be fine.

To get the most out of a stage 2 air filter & or pipes you really need to add fuel, the XT's tunned run lean from the factory for emission control, when you add more air & don't correct the fuelling the bike will run even leaner.

We have proven in the past you can run these motors with a stage 2 filter with no fuelling device, but we have also Dyno proven you get an 2.2 more HP over & above the stage 2 filter when adding a fuelling device.

I always recommend fitting at least a fuel mod & if you have the funds an O2 controller or Optimizer to control the closed loop circuit, your bike will run so much smoother & have more HP & Torque with these mods.

Thanks Kev, Did wonder about the fuel side of things and will take your good advice.