Breva 750 Pinging

[Hugh Straub]

My 2007 Breva pings on hard acceleration.  The pinging apparently comes from the left cylinder only.  Because of my concern with plastic tank issues, I run 91 octane, no ethanol fuel.  Is the ping a mapping issue or an octane issue or both.  Non Ethanol gas in New Orleans is unbranded so I don't have a lot of confidence in purported octane ratings at independent stations.

I look forward to your views.

[Doppelgaenger]

I have had the Breva 1100 ping on the left cylinder only as well. Does yours happen only when the engine is properly hot? Being in New Orleans I imagine that the heat problem is more pronounced.

I seem to have mostly gotten rid of the problem by using Chevron fuel which is 92 octane up here in washinton state vs all other stations that only stock 91. It still pings here and there, I've just learned not to flog the engine when it's been sitting for a while. Ethanol does act as a octane booster so you might try switching to a higher quality ethanol gas. A fuel tank is going to be a lot cheaper and easier to replace than a blown engine.

I know that the fuel map can be updated for the Breva 1100 by Todd at Guzzitech and it will eliminate the issue. There are a few other solutions as well, but I don't know how many of them apply to the 750 since I don't know the small block engine. I don't know of a ECU reflash for the 750, but Mischa at Moto International told me that he could fix the problem at the dealership, he just didn't want to because it'll rob a bit of power if he does it, so your dealership may be able to help. You could also get it dyno tuned.

[mwrenn]

How long has it been doing it?  Is this a recent issue that just started?  Just thinking about plugged injectors, fuel filter obstructions, spark plug gaps etc...starting with the easy stuff you know. To answer your question, yes,  it could be a mapping issue, or too low octane gas. I have a spare ECU if you want to borrow it and plug it in.  It has a the stock map loaded for an 07 Breva 750.

[Muzz]

Is it an 1100 or a 750?

[oldbike54]

Is it an 1100 or a 750?

 Muzz , it is a 750 , maybe the Thunder win today has you a bit fuzzy  ;D

  Dusty

[Muzz]

Muzz , it is a 750 , maybe the Thunder win today has you a bit fuzzy  ;D

  Dusty

Duh duh duh.  ;D

Ok, so itsa 750. :D  I know mine will pink on our 91 octane if it gets loaded up a bit.  Certainly prefers 95 octane.  I don't think it has pinked on that; however, it never gets asked to accelerate from low down.

Dusty, (thread drift) saw what I think was a win from a few days ago; is that the one or have they pulled off another as well?

[oldbike54]

Duh duh duh.  ;D

Ok, so itsa 750. :D  I know mine will pink on our 91 octane if it gets loaded up a bit.  Certainly prefers 95 octane.  I don't think it has pinked on that; however, it never gets asked to accelerate from low down.

Dusty, (thread drift) saw what I think was a win from a few days ago; is that the one or have they pulled off another as well?

 Yep , NBA teams average close to 4 games a week . Stephen is playing again after his injury and really beginning to understand the NBA game  ;-T

  Dusty

[Moto Fugazzi]

My 2009 V7 Classic pinged since new (same engine as yours). I did use Guzzidiag, and turned the Lambda sensor off, and all pinging has disappeared. On the downside, my MPG dropped from upper 40's to the lower 40's. On the plus side, the bike feels "peppier", and my pipes haven't turned blue since I cleaned them after turning off the sensor.

I am a little concerned that there might be too much fuel going into the engine, and I haven't had the extra time or money to install an AFR gauge so that I can monitor the results.
Ken

[Penderic]

I had a rubber vacuum cap, that I had placed over the left manifold vacuum port, develop cracks after a year and leak air into the left manifold.

Ping it did, indeed!

Replaced with a short piece of fuel hose and a brass plug, secured with clamps.

[jackson]

I had a rubber vacuum cap, that I had placed over the left manifold vacuum port, develop cracks after a year and leak air into the left manifold.

Ping it did, indeed!

Replaced with a short piece of fuel hose and a brass plug, secured with clamps.

+1
What he said.  Check the vacuum ports on both sides and make sure that they're not leaking.

[Chuck in Indiana]

Duh duh duh.  ;D

Ok, so itsa 750. :D  I know mine will pink on our 91 octane if it gets loaded up a bit.  Certainly prefers 95 octane.  I don't think it has pinked on that; however, it never gets asked to accelerate from low down.

Dusty, (thread drift) saw what I think was a win from a few days ago; is that the one or have they pulled off another as well?

Your 91 and our 91 aren't the same octane, I think.

[Hugh Straub]

Many thanks for all the helpful suggestions and the generous offer of an ECU loan.

Attacking the simple first - the intake manifold vacuum ports - my 750 Breva has a brass nipple fitting in both right and left intake ports with a rubber fuel line connecting the two.  No obvious cracks. (I recall adding similar connections to the intake manifolds of my C10 Concours...the thinking there was to better balance the four carbs.)

Is the thinking with this bike that I should just cap off the right and left nipples rather than having the two intake manifolds freely communicating with each other through a rubber hose?

I appreciate the good ideas.

[Kev m]

Cap the ports.

There's no vacuum balancing between the throttle bodies of any significance. The ports are only there so you can measure the vacuum and use the linkage and balance screed screws to synchronize the throttle bodies to the same vacuum readings.

So they are used to measure when balancing, but connecting them doesn't really balance anything.

[Muzz]

Your 91 and our 91 aren't the same octane, I think.

If it is "octane" rating it should be the same.  However, how it is presented is another matter.  There are "RON"s, cetane ratings and others that I forget. That is why I used the term "our" octane rating Chuck.  May well be comparing apples with pears.

Actually, my book that came with the bike recommended a rating 3 higher than what we can get out here ::) so who would know. :-\

[Tom]

Stock exhaust?  If not.  You'll need to change the mapping.

[sign216]

How long has it been doing it?  Is this a recent issue that just started?  Just thinking about plugged injectors, fuel filter obstructions, spark plug gaps etc...starting with the easy stuff you know. To answer your question, yes,  it could be a mapping issue, or too low octane gas. I have a spare ECU if you want to borrow it and plug it in.  It has a the stock map loaded for an 07 Breva 750.

I removed my injectors and had them cleaned by RC Engineering.  They tested them, and found some clogging, and this is after only a few yrs and few K miles. 

Also, I've had an air leak into the manifold.  It could be leaning your cylinder out.  Look at the joint between the cyl and the metal intake "collar." 

Keep the board posted.

[Hugh Straub]

Many thanks for all the thoughtful replies

I traced the hoses from the right and left intake manifold vacuum ports to a T fitting and to a single hose to the bike's pollution carbon canister under the front end of the fuel tank.  Two other hoses, one from the air box and the other from the fuel tank vent line also go to the canister.

I realized that the vapor coming to the intake manifold vacuum ports from the canister are un-metered by the ECU.  I have no idea how much if any are combustible vapors or how much is just plain air.  Of course the latter leans out the air fuel mixture.  I noted while the 2006 Owners Manual for US bikes has this pollution system diagram, 750 Brevas for other countries are not so fitted.

So as suggested here, I have capped the manifold vacuum ports but am in a quandary regarding what to do about the canister.  My inclination is to cap the canister nipple to which the now purposeless hose is connected, leaving only the fuel tank vent line and the air box line attached to the canister.  I assume the air box generally has negative pressure which should draw vented fuel tank vapors through the canister and into the air box.  Those fumes ultimately will be drawn into the engine through the ECU monitored air intake. 

Any reason not to cap off the canister nipple for the now disconnected vacuum hose?  I look forward to your views.

Kind regards

[mwrenn]

That should work.  Be interesting to see if the pinging stops.

[Kev m]

I'm sorry, my post assumed you had no EVAP system or had eliminated it.

Personally I keep the systems installed more often than not.

But when I have removed them, I've kept the vent line from the tank open to atmosphere in some fashion.