Bonneville America Forums Forums Technical Forums General Tech 2011 Speedmaster still has flat spot. Help!!!

Guys,
I am almost at wits end with this one so I need one of the gurus here to point me in the right direction.

I have a 2011 Speedmaster and since new (even before any changes were made) there has always been a hesitation just above idle that can cause you to stall the bike when taking off from stop. The revs start to come up, but when you start to load the engine up by letting out the clutch, It seems to have a flat spot in revs and if your not onto it quick enough by applying a lot more throttle, you can have a very embarassing moment as she stalls. Also if you blip the throttle between downchanges, there are times when a blip does nothing to the engine revs at all.
Now I have made some changes but would like to point out that this has always been on the bike since new and even after changes. I feel as if im chasing my tail with this problem and may be looking in the wrong area for a fix.
Changes to date have been:-
Fitted Aftermarket Silencers
Remapped to 20456 with Tune ECU
Removed SAI and plugged heads. (SAI solenoid and piping to airbox is still in place although plugged).
Balanced TB
Reset TPS
Done 20 min tune
Tried setting TPS to 3% to fool ECU (didnt really work) so back to 0%
Disabled O2 sensors at one point but no real difference so back on again

Another part to this story is when I took the bike in for its first service. (only Aftermarket silencers fitted, nothing else done at this time). They serviced the bike and balanced the TB. They reloaded map 20455 (which is standard tune). After they took it for a test ride, the mechanic commented on the flat spot. I said "yeah its always been there and im used to it".

I think going down the path of changing fuel maps, replacing TPS etc should not be required as I think it may be a simple fix. The issue I have is that the dealer may not be to keen on helping me since I have done some of these mods, and warranty may be an issue.

So my question is, has anyone else experienced this problem with the EFI 865 engine and if so, how did you go about fixing it.

I would just like to hear some thoughts and hopefully get on top of this so I can enjoy riding my new machine.

Thanks Trev10

Hello Trevor and welcome to the site. Unfortunately I'm one of the carb fellows but this issue has cropped up a couple of times before. I think the other fellows with the problem ended upping their idle speed to address the issue. Have you checked the obvious issues like intake leaks that might cause the bike to run too lean at idle.

You might want to reinstall your oem equipment and bring the bike to the dealer and complain. A lot of fellows have the EFI bikes and don't have this issue. If the dealer can't fix the flat spot, go up the complaint chain.

Hi Trev,

Where do you live? You don't even specify a country. On the off-chance you lived near someone we/they could compare EFI bikes with you.

There are several possibilities/actions that I can think of...

1. It might help to compare your bike with another 2011. I say this because the EFI does have what we call a snatchy throttle - but it is definitely not a flat spot. There are threads that discuss the snatchiness and resolutions here and over on the RAT forum. But I suspect you are talking about something else.

2. When I first had my 09 bike I stalled it 2 or 3 times taking off from stationary. In each case the engine was cold, also the idle was too slow (it should be at 1050-1100 rpm mine was about 900rpm) and more than anything, I was not giving it enough throttle and not riding the clutch enough. These engines torque curve starts to kick in above 2500rpm - they will labour (and maybe stall if cold) at less than that. If you are used to riding a low revving v-twin (like I was) you might need to get used to using higher revs.

3. You don't mention what, if anything, you have done about your air intake. With freer flowing pipes you should go to K&Ns or UNIfilter for more air to balance the freer flowing pipes.

4. If I am way off with these suggestions then you definitely need to get the dealer to resolve it. The mechanics' "just get used to it" attitude is WRONG. They don't all do this. Either he is setting the bikes up wrong (everytime!!!) or he's lazy. Take it back to the dealer. The AI removal won't affect performance AT ALL. The tune 20456 is the correct tune for TORs and aftermarket pipes so don't change back to 20455 or you run the risk of being too lean.


I repeat - aside from the snatchy throttle (which is just jerky in off-on throttle situations) - they don't do this flat spot. In fact they have an incredibly smooth power-on curve right up to the rev limiter. Check out my dyno curves in the performance forum
- click here - it's the dyno pic with SKIP'S PERFORMANCE on the chart. You will see how smooth the power delivery is and notice that the curves only start recording about 1600rpm.

I hope this helps.

EDIT: It just occurred to me that because the 2011 has different mapping to the 09 and possibly the 10 that your flat spot just might be tune related. TuneECU identifies your map as designed for up to 25% ethanol - which IS different. But regardless, Triumph wouldn't deliberately ship a bike with a flat spot like that.

2nd Edit: I realized that my link to the dyno charts and saying mine is the first chart on the page may not be true for everyone. I am choosing to display 30 posts per page - if you have your preferences set differently then the chart I am reffering to will appear elsewhere!!! My chart is the one by SKIPS PERFORMANCE.

I agree with Richard, however there was a time when I experienced what you describe. This was after I installed free flowing exhaust and did not bypass the O2 sensors, causing the bike to run in "Closed Loop". I sorted this with the tuneboy program. I am not familiar with tune edit sorry. I would also remove the tank and see if maybe there is a kink in a fuel line or something.Run a good injector cleaner through it as well.
Good Luck

I think Richard has got it right, I bought a 2010 Speedmaster late last year and had a bit of a problem with the bike stalling at times when I went to take off after I was stopped somewhere usally at a set traffic lights not very good at all.

So I took the advice I have read here and on another site turned up the idle speed and gave the bike more revs when I take off and so far so good, but in saying this I have stalled it a couple times and I know it is my fault just not giving the bike enough revs, because I have came off Harleys with there low down torque you don't need to rev as hard and sometimes I just get it wrong but the more I ride my Speedy the better it will get cheers.

I had this problem with my 2008 speedmaster, I turned up the idle speed and had no problems at all...

I think we're talking to nobody ... Trevor registered, posted this question and has never been back to the forum - as far as I can tell. Some people ...

In reply to Richard, even if Trevor has never been back, the info still helps others. My husband has a 2010 Speedy and has had the same problem, so I will be passing this info on to him. Thanks to all for the input.

Shouldn't judge Trevor too quickly. Maybe something happened to him.

Welcome to the Forum Fuzzydragon.

Yeah, you're both right - and I'm glad it's helping others. It's disappointing though when you go out of your way to help someone and they don't even bother replying. Ah well - I gotta be bigger than that.