Revs STILL Surge!

[Buildable]

I've owned my RC390 for one year now and loved every second of it, so much so that I'm going to keep the bike even after getting my full license. As much as I enjoy the bike its the little imperfections in it that drive me insane! The first things I did to the bike was fix EVERY little rattle. The one small imperfection remaining is the unsteady state of the bike. At idle the Revs surge between 1600 and 2400 even after warming the bike up and its not just at idle that this happens. Even driving at 60KPH the revs still surge and the bike jolts around. Making cornering and roundabouts pretty dangerous... I understand that around the 10KPH hour mark the bike isn't going to ride smoothly without using a little clutch but even at high speeds??

I read on the forums that a 15m idle can fix the issue. Unfortunately that didn't help at all, not even in the short term. I don't have a paddock stand though, could that be the reason?

Since that didn't work I read that a slip-on exhaust can help smooth out the ride, so I got the Werkes exhaust. No luck. Amazing sound though!

My third attempt was to install a power commander, which made a massive difference to the bike I highly recommend it, but STILL the bike surges way too much to be normal. The bike is running a BMC street air filter, Werkes slip-on and a PCV with Hard Racing's map.


So whats the next step for me here?

Do I need to take the bike to a tuning center (there are plently around in Melbourne, Australia. But cost $300-400 for a tune). I hear that Chad's maps are amazing and have sorted out the rev issues in the past so maybe the fuel table just needs to be adjusted a little?

Hopefully someone here with better mechanical knowledge than myself can see something I've missed.

 

[Treachery]

I'm not a pro, but that sounds like an air leak somewhere in the intake, confusing the O2 sensor. Anyone else think that's possible?


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[Buildable]

That very well could be it.

On deceleration the exhaust does make a popping sound and the occasional backfire. Maybe when I removed the stock exhaust, which took a LOT of brute force the manifold was damaged.

To find a manifold leak I need to bring the bike up to temp and then spray around the manifold with something like WD-40 then listen for any changes in the idle right?

 

[reenmachine]

+1 it sure sounds to me like you've got something going on completely unrelated to the tune. Perhaps it's a sensor issue (throttle position sensor, perhaps?) or a physical defect letting unmetered air in. If you've had to brute-force something the latter may be more likely.

I haven't use WD-40 but I suppose it would work. You'll get WD-40 all over everything though . Starting fluid/ether will work well and it'll vaporize away better. Investigate everything between the throttle body and the intake first, including the throttle body itself in case it's cracked, has a damaged butterfly shaft seal, etc.

 

[Buildable]

Possible Culprits

So I pulled the LHS fairing off to get a look at the whole pipe of the bike, i'm starting here because I think its the most likely cause of the possible leak. I sprayed from the slip on to the headers and found a few possible points where there may be a leak that I further investigated using a smoke gun.

I had an attempt to tighten the header bolts and managed to tighten one which had to be tightened a fair way, but I cant get to the other bolt. its impossible. Looks like my only option is to remove the radiator to get to it??? Or maybe get a mechanic involved. I've included a really bad photo of the header bolt that I cant get too. Any suggestions here?

The other possible location for a leak looks like this hole in the pipe. Some seriously bad welding... I've thrown in some some pictures of it. Should I get that bit welded again?

Will keep updating the thread as I go through the issue.

 

[Formula390]

Sounds like this could be a few possible problems:
1) Lean: So a lean condition can cause surging. That could be the map, or an intake air leak, not exhaust. The popping on decel is the lean condition / too short of an exhaust... but that's just the way it's going to be with the Werks exhaust. I wouldn't bother pulling the exhaust off to have that small pin hole welded up. There isn't any problem that pinhole is going to cause compared to the already massively short total exhaust length you are facing. Now, if you are having something else welded up already... then ehhhhh... sure... why not. I wouldn't do it just for that tho. To find any possible leaks on the intake, pick your RPMs up to around 1500 and aim your spray (I personally use carb cleaner vs ether, WD40, or whatever else) all along the intake track at all points between your airbox and the header. if the RPMs change, there's your leak. I would suspect that for your lower RPMs, but not the higher... so while this MAY be a problem, it's likely not your root cause.

2) Throttle Position Sensor: You could have something going on there, but I would expect to see a warning light if that were the case.

3) O2 Sensor: Maybe. I would expect more issues that just that small amount of surging if your O2 sensor was going TU.

4) Bad ECU connection or faulty flash: You might try having your dealer re-flash the ECU, either with the stock maping, or my recommendation the Akropovic map. The Akro map alone (with stock exhaust) was worth 3HP and a buttload of torque (not as much as the airbox mod, that's still king of power gains). When I was doing my exhaust development work, during one of the runs the tech doing the pull shifted his weight to push a button on the dyno, and the bike started to buck and kick and surge and basically throw a hissy fit. We shut down and tried to figure out what was going on. I feared we broke something on the motor is was acting up so badly. We were futzing with this and that, and suddenly the bike wouldn't run at ALL anymore. So we did more checking and turned out that the plug for the ECU got bumped just enough to have a faulty connection. We re-seated the ECU plug, and threw a zip tie around the clamp to KEEP it secure, and presto... bike started and was acting fine again!

I'd be interested in what Chad thinks about this. Also, you may want to consider seriously consider putting in on a dyno and get your AFR graphed to see what's going on there! Bikes don't normally do this, and if it was doing it PRIOR to the mods, the mods you have done won't fix it, only hide/change it, and make it that much more difficult to root cause.

 

[Buildable]

Thanks for the reply Matt.

I see you don't favour the Werkes exhaust too much! I've had a serious issue with mine where the entire thing has faded and just looks awful due to it not having the correct packing... I love that sound though!

Tomorrow's plans are to replug the ECU and the O2 optimiser. Then start spraying around the intake track and see if we have a leak. Related to that, you say bring your RPM up to 1500? Mine idles around 2k on average according to the PCV, could this provide some more info on the problem?

I really want to get the Akra map onto the bike, but my dealership says its not available for my bike? I call complete BS they have sold cup bikes here before i'm going to call them again and keep asking. I think there was someone else from Melbourne, Australia on here who was having the exact same issue with getting the Akra map.

The bike has always had the unsteady Revs, before any modding. But it seems to have become more apparent after mods.

 

[msquared]

Looks like my only option is to remove the radiator to get to it??? Or maybe get a mechanic involved. I've included a really bad photo of the header bolt that I cant get too. Any suggestions here?

Remove the radiator, it is the correct way to get to these bolts per the repair manual.

 

[msquared]

I really want to get the Akra map onto the bike, but my dealership says its not available for my bike? I call complete BS they have sold cup bikes here before i'm going to call them again and keep asking. I think there was someone else from Melbourne, Australia on here who was having the exact same issue with getting the Akra map.

I feel your pain. My dealer has refused to put the map on twice.

The first time they claimed it was because without the Akra pipe the bike would get too hot and it would catch on fire.

The second time they said it was because they have to dyno the bike to install the map and they didn't have a dyno.

I know both excuses are bullshit. However, given they have had to replace valve cover gasket twice, and the valve cover once based on their mistakes(stemming from the first service); I am neither surprised nor particularly upset that they haven't flashed it.

 

[A1VW2NV]

Remove the radiator, it is the correct way to get to these bolts per the repair manual.

I used a 12" extension and a socket.

 

[Buildable]

Culprits

So I bought some carb cleaner today and went and sprayed around the bike. The only time the revs seemed to surge was when I sprayed the pinhole in the exhaust pipe. That was when the bike was cold, once the bike had warmed up it didn't surge again.

Now I noticed that I could see my air filter!!! (pics included) and being very stupid I sprayed it. Which killed the engine. Took 3 attempts to start it again but its running no issues. Going to take off the air filter box and resit it?

I took a video of the bike idling with my partner watching. Unfortunately in the video you can't really hear the engine skipping a beat. Partner says it sounds like its making a chugging noise similar to when you start up a truck and it get WORSE and louder as the bike warms up.

I've thrown in some more pictures of where their are some cracks etc.

 

[The Mariner]

I'll say from the outset that I'm no expert, so I'm OK if the acknowledged experts come back & shoot me down. I'm just trying to help a fellow Aussie.

I have never heard of using a slip-on to try to cure the low RPM surging. I would have thought that given the surging is generally caused by running lean, adding a slip-on without changing the map would only make things worse, not better. I feel this is proven by the fact that when you just fit an Akra slip-on and/or do the airbox lid mod without also fitting a Bazzaz/PCV you should also get the Akra map as it's richer than the stock map.

If you have an intake air leak somewhere then that can explain what's happening, but as an idea why not try changing the map on your PCV ? Even though you have had it supplied by a quality supplier like Hard Racing, it's possible it's still not correct for your particular combination of mods. It's an easy thing to do, so why not try another map to see if things change/improve ? If no change is felt you can just go back to the original knowing that the map can be eliminated from the list of possible causes.

This one might be worth a try. It's not a perfect match to your mods but it's a place to start.

 

[reenmachine]

Well you've definitely got airbox problems as evidenced by that 3rd photo. The bottom half of the airbox being cocked down at that angle (if it's that making the gap and not the lid or the seam) could mean it's not securely connected to the throttle body. Air getting in through that interface could cause surging. Really, air getting around the filter via a path of less resistance in any way could cause your issue -- that's why when going to a low-restriction setup you need to remap to avoid running too lean.

I think you're close to finding your culprit. Go through the entire airbox assembly carefully and see what you find.

 

[Buildable]

Ill give my dealer a call when I can tomorrow and demand nicely the akra map and see if they have any ideas about resitting the whole airbox. I think connecting that back to the throttle body might be a little bit beyond my mechanical knowledge. I pointed out the leak last service and they said its probably just buildup from the washable air filter. Should I go at them at a bit over this?

Thanks for the map! Ill give it a go.

EDIT: Map was FANTASTIC bike had a noticeable difference in acceleration and handling. Seemed to make the exhaust sound a bit different too but that might just be my imagination. The engine is still skipping a beat though and the idle is all over the place but still a bit steadier. Highly recommend this map to anyone with a similar setup.

 

[Buildable]

So bike has done a day at the workshop and I have the culprit.

First up the company that did my first service on the bike did not replace / fit correctly the gaskets under the rocker cover when adjusting the valves in first service. So the engine is leaking oil... My mechanic has said it will cost 1HR labour plus gaskets to get it fixed which seems reasonable to me.

The major culprit is the BMC airfilter used in the bike. This may only be true for the Australian model of the bike. The BMC air filter is made from a hard plastic that does not compress this causes the two halves of the airbox to push apart causing the leak and cracking. The solution is to go back to stock or use a K&N air filter. I've ordered the K&N for my bike!

And finally my mechanic told me off for not getting a proper tune on the bike and just relying on a base tune. So bike is going to be booked in for a full tune on a dynojet dyno in a few weeks. If anyone in Melbourne Australia has a recommendation of where to take the bike i'm all ears. Otherwise ill be going with the Peter Stevens dyno in the city. STILL NO AKRA MAP AVAILABLE!!

 

[Ausracer]

Hi, buildable. The AKRA map is available in Australia. I had mine remapped about 6 months ago and am running the AKRA map with K/N filter and PCV from Commonwealth. My suggestion is to try ringing a few KTM dealers as the map is available. Its a pain for the dealer to re-flash as they need to hook it up to a booster pack as the KTM software will not allow the re-flash unless system volts are about 12.5 - 13 v or thereabouts. Chase some KTM dealers because the map is available here in NSW.

Cheers hope this helps.

 

[=maz=]

Map is available in WA as well mate.

 

[emphatz]

Purchased my bike in January (from Peter Stevens, Melb) with the Akra Exhaust, they also put on the Akra map for me, working a treat, I have a mate that works there, let me know if you need specialized help, the guys there seem to know what they are doing.(i'm based out in Seaford)

 

[Buildable]

I also got my bike new from Peter Stevens in the city. They guys at the service center always tell me the map is not available and has not been release yet. Maybe you could find out for me why they refuse to do it? Perhaps there is a genuine reason.


The guys at Peter Stevens have always been eager to help me out so I do trust them.

 

[emphatz]

Messaged my mate at Peter Stevens and he said that their Def is an Akra map available, when did you last speak to them??