Booster Plug - The cure for surging?

[PAS]

This is why my airhead has 170 K plus and my oil head has 25k. Have fun...!

 

[nrpetersen]

Think of the throttle position sensor as the rough setting and the BBS as the fine tuning. You can turn the BBS screws a bit to compensate (increase or decrease) the vacuum to get a balanced reading in the area of 3000 rpm without moving the cables. This may give you a slight different vacuum reading at idle between the two sides, but that is less important than a equal vacuum higher up in the rpm range. The BBS and the throttle plate work together as both are affecting the amount of air getting into the intake tract to mix with the fuel. This method works well for very small differences in vacuum as the small cable adjusts are a pain.

Think of the left side as the reference point and you match the right to this reference point. in the stock exhaust the 02 sensor is located at the point where both headers intersect, so yes it might be a slightly different AFR for one side or the other, but the difference is not measureable and is balanced out by the throttle body sync.

No doubt would be better with 2 throttle body sensors and 2 02 sensors, but that came later. We work with what we got.

The cure for surging had lots written about it, could be allusive and certainly was more of a problem for some than others.

The Fuel injector delivery pulse is determined by the some hooky computer algorithm getting only rpm and TPS info. There is no measurement of intake manifold vacuum, and the whole system is a lo;w cost approach that makes the assumption that the two throttle bodies are identical enough to make that calculation without exceeding the combustible A/F mixture limits (which are about a 2:1 ratio of A/F ratios). I don't think that is feasible given the other variables.

The BBS by themselves do affect surging, but I suspect that the combination of offsetting BBS with throttle stop tweeking may be the golden screw approach for this problem.

What's really needed is a flow bench to test a real throttle body to establish its long term repeatability, and determine just how much throttle stop rotation corresponds to an amount of BBS rotation.

 

[roger 04 rt]

Niel, You're making this problem far more complicated than it is. These oilheads can be made surge free by simply richening the mixture. The reasons are as I gave a couple posts back. Equalize the air, shift the fueling toward Best Power Mixture and the problem is solved.

Thousands of bikes now have lambda-shifters installed and it removes the surging.

 

[beemerphile]

I'm with Roger. Overthinking it and a bunch of unproven hypotheses. Basic tune, proper sync, AF-XIED and fuggetaboutit.

It helped my 2004 1150R and my 2013 camhead. Next up is my K11RS. I have a 40 year old engineering degree and an inquisitive nature, but at this point in my life unnecessary figuring just ain't fun any more. Now riding motorcycles, that's fun.

 

[nrpetersen]

I'm with Roger. Overthinking it and a bunch of unproven hypotheses. Basic tune, proper sync, AF-XIED and fuggetaboutit.

It helped my 2004 1150R and my 2013 camhead. Next up is my K11RS. I have a 40 year old engineering degree and an inquisitive nature, but at this point in my life unnecessary figuring just ain't fun any more. Now riding motorcycles, that's fun.

Yes I have to agree also, but I have wanted to understand why the system worked only when new & most slowly deteriorates as the miles accumulates. I found the offsetting of throttle backstop and BBS on the right side to work on my R1100RT. No other fiddling or perverting with the OEM system.

Now onto the next assignment - identifying and fixing the Oilhead transmission input alignment and spline stripout problems.

My ME engineering degree is 54 years old, and not ready to retire from engineering problem diagnoses yet.

 

[gsaddict]

Now onto the next assignment - identifying and fixing the Oilhead transmission input alignment and spline stripout problems.

My ME engineering degree is 54 years old, and not ready to retire from engineering problem diagnoses yet.

Post #12, http://advrider.com/index.php?threads/1150-spline-lube.1167185/

Anton & Terry are onto something.

 

[PGlaves]

Post #12, http://advrider.com/index.php?threads/1150-spline-lube.1167185/

Anton & Terry are onto something.

That was also precisely my experience with Voni's R1100RS. But I know how it all happened. After about 150,000 or so miles with no problems I got ham handed with a stuck dowel. And soon thereafter it ate a spline. I had bent the clutch housing (flywheel) assembly. Replaced the bent clutch housing and it now has another about 200,000 trouble free miles.

 

[nrpetersen]

That was also precisely my experience with Voni's R1100RS. But I know how it all happened. After about 150,000 or so miles with no problems I got ham handed with a stuck dowel. And soon thereafter it ate a spline. I had bent the clutch housing (flywheel) assembly. Replaced the bent clutch housing and it now has another about 200,000 trouble free miles.

What dowel? One of the two engine-to-transmission alignment dowels? If so why/how was it stuck?

What clutch housing? The stamped assembly that is bolted to and rotates with the flywheel, or the aluminum housing that houses the clutch assembly and connects the engine block to the transmission housing..

 

[roger 04 rt]

Okay, this thread is officially hi-jacked! Here a link to its own thread: http://forums.bmwmoa.org/showthread...ear-The-Next-Assignment&p=1061180#post1061180.