BMW R1200R R1150R/T F800 K1200R R1100R/T R1250R RnineT Message Board

Ok got the 1150 motor on the stand to tinker with. Connected almost all the bells and whistles and, naturally, decided to start. Well not so lucky. Engine (without transmission) works as though it either fires too early or too rich. It idles at about 700rpm with instant stall as soon as I open throttle. Backfires into TB. When it runs it produces dull sounds as though exhausts have been plugged (I have no exhaust pipes at all as seen from the pic). Oil temp sensor and air temp sensors are not connected. I tried to wiggle with ignition timing plate but no luck. Since Motronic handles all the timing and mixture I quickly running out of ideas. I hear that when ECU gets powered off it needs to relearn TPS position or something like that? Any ideas on course of action? Thx.

zaebis

First let me say that I like what I see....however based on your post there are a lot of potential issues with the set-up.

1) The oil temp and the air temp sensors should be connected or if not, a suitable resistor representing a specific temperature should be in place of the sensor. Even though I have worked a lot with Motronic systems a lot, both on cars and bikes, I don't know how the ECU will respond to having one or more open inputs. I can give you a resistor value to simulate a specific air temperature since I mapped that one, but you will have to map the oil sensor.

2) Before starting the engine, with the ignition in the run position, you need to fully open and close the throttle a couple of times, this allows the ECU to range the TPS located on the left TB.

3) I saw the fuel lines but wonder what are you using to pressure up the fuel, the fuel pressure regulator is a 3 Bar unit, or ~ 43 psi, I hope the pump is putting at least 20 psi above that. The ID of the supply and return lines appear to be adequate.

4) I wouldn't worry about the ignition timing plate, as it isn't the source of your problems and can only be advanced by about 3 degrees.

5) You don't have the clutch and pressure plate on that will provide some rotational mass, that being said, I would imagine that the idle speed and the throttle on acceleration will be affected as the engine response would be faster than the time that the ECU can process the information, just a partial guess on my part.

The following is what I consider the main problem.. You have very little restriction on the intake and exhaust, IC engines do require a certain amount of restriction to operate. Allow me to bore you with the short version.....

On a typical engine there are sound waves in the exhaust that assist with the evacuation of the spent gases and the filling of the cylinder. Likewise, on the intake end there is a specific range of gas velocity that will promote filling of the cylinder. So with the cone filters, small restriction and the shortie exhausts I believe that you have disrupted the combustion process significantly. Under present conditions I would say the mixture is way too lean to sustain combustion further aided by low cylinder filling velocity. I'm sure that my good friend and colleague CycleRob will eventually catch a glimpse of this interesting post and chime in.

If you are intent on running the engine on the stand I would suggest masking at least 60% of the cone filter area (paper tape is OK) and find some pipe ID reducers that will decrease the existing exhaust pipe diameter to about 1/2 of what you have.

Please keep us informed since this is one of those dark side posts……and I love it.

This is great! What an opportunity for folks to see up close some of the basic systems of this bike engine.
I notice the TB throttle cables going up somewhere out of the picture. Are they attached to the junction box? If so, since they are longer than the OEM TB cables, how have you got them synched for throttle up?

Beautiful! Keep us posted.

boxermania wrote: 1) The oil temp and the air temp sensors should be connected or if not, a suitable resistor representing a specific temperature should be in place of the sensor. Even though I have worked a lot with Motronic systems a lot, both on cars and bikes, I don't know how the ECU will respond to having one or more open inputs. I can give you a resistor value to simulate a specific air temperature since I mapped that one, but you will have to map the oil sensor.

Pls enlighten me on the resistance fix. I will try to get my hands on the actual sensors in the meantime.

boxermania wrote: 2) Before starting the engine, with the ignition in the run position, you need to fully open and close the throttle a couple of times, this allows the ECU to range the TPS located on the left TB.

Cool will try that!

boxermania wrote: 3) I saw the fuel lines but wonder what are you using to pressure up the fuel, the fuel pressure regulator is a 3 Bar unit, or ~ 43 psi, I hope the pump is putting at least 20 psi above that. The ID of the supply and return lines appear to be adequate.

Oops. The pump is from the street car KIA something. I dont know if it delivers 70psi but what I do know is that my return line is quite busy streaming fuel back so I assume that pressure reg opens and therefore pressure is sufficient. But I will go ahead and measure the pressure.

boxermania wrote: The following is what I consider the main problem.. You have very little restriction on the intake and exhaust, IC engines do require a certain amount of restriction to operate. Allow me to bore you with the short version.....

On a typical engine there are sound waves in the exhaust that assist with the evacuation of the spent gases and the filling of the cylinder. Likewise, on the intake end there is a specific range of gas velocity that will promote filling of the cylinder. So with the cone filters, small restriction and the shortie exhausts I believe that you have disrupted the combustion process significantly. Under present conditions I would say the mixture is way too lean to sustain combustion further aided by low cylinder filling velocity. I'm sure that my good friend and colleague CycleRob will eventually catch a glimpse of this interesting post and chime in.

If you are intent on running the engine on the stand I would suggest masking at least 60% of the cone filter area (paper tape is OK) and find some pipe ID reducers that will decrease the existing exhaust pipe diameter to about 1/2 of what you have.

Ok will try masking intakes. However I have seen many beemers with cones to aid performance.

boxer wrote: I notice the TB throttle cables going up somewhere out of the picture. Are they attached to the junction box? If so, since they are longer than the OEM TB cables, how have you got them synched for throttle up?

Ya on the second pic you can see red barrell which couples 2-to-1. No I didnt do the sync just eye job but I would expect much better engine performane even with slightly out of sync TBs.


My plan is to try different things on the motor and see how they affect the performance.

1/ aftermarket injection contraptions
2/ fuel regulators 3bars+
3/ aftermarket pistons and cams
4/ exhaust pipes
5/ compressor assisted aspiration to see if turbo will do any good on the motor.
6/ aftermarket motronic 2.4 chips

all that will be measured off the crankshaft directly into the dyno. I will machine a snout that clips right on the 5 collar bolts to the crank.

1--You're not using the main coils! I see no wires hooked up!
2--Put the throttle bodies (TB) on their correct cylinders. Yours are swapped left/right.
3--There's too many things missing for it to accept any throttle. The oil and air temp sensors are needed for the Motronic to do it's job correctly.
4--The main thing is the normal rotational mass of the pressure plate assembly is missing. Also missing is the additional rotational mass of the missing alternator. Both are more than substantial and required for the engine to run properly!
5--Missing sensors, shorty exhausts, missing intake tubes, missing air filter and no airbox all conspire to stall the engine.
6--Resetting (actually relearning) the Motronic memory is necessary.

I have experienced the erratic running you described when I intentionally started a vertical shaft walk behind lawnmower without the cutting blade attached. Besides being very hard to start, the absence of the "flywheel" (the blade) made it stall instantly if the throttle was opened too quickly. Drastically reducing flywheel mass by removing the pressure plate puts severe dynamic loads on the starter reduction gears and the motor's armature . . . . an expensive risk, especially if the ignition timing is a little too far advanced. The popping thru the intake and/or exhaust tells me the starter assembly IS being hammered by unabsorbed power strokes that will occur with a drastic reduction in flywheel mass.

.

zaebis

It has been proven that a stock R1150R motor will see ~ 10% power increase with a full exhaust, advance timing and a fuel nanny such as the Techlusion, for about $70 per hp at current pricing. The gains are crispier acceleration, improved throttle response and it is noticeable.

Internal engine mods are expensive and basically shift the torque curve up the rpm range reducing the drivability of the bike. Turbo charging takes it a step beyond, in complexity and cost.

I think your plans for the tests are well thought, obviously you enjoy tinkering and I applaud you for that, but you are not going to get much from a 60 year old design whose changes have been evolutionary rather than revolutionary.

In closing, I'm sure that if you read the posts in this forum you'll notice the significant amount of "idiosyncrasies" that the R259 model has been plagued with.

Best of luck to you, BTW, where is home?

after seeing the aircraft prop in the background ,if this engine is to be used in an aircraft at least it wont have spline issues!

ok thanks guys. I will add on sensors, some weight to the flywheel and take care of the intakes/exhausts shortly. Yes I am aware of some but probably not all of the peculiar traits of the beast, I guess others I will learn as I go. I ripped this motor of the toast bike that is why I dont have all the pieces on hands. Anyways good feedback and I shell proceed with my adventure. Here in BC, Canada as rainy season begins I will have plenty of time until the spring to brush up my skills. I will post some 1150 motor relevant info as I discover it.

ffafp wrote:after seeing the aircraft prop in the background ,if this engine is to be used in an aircraft at least it wont have spline issues!

actually I am connecting it to the redrive (planetary) via spline shaft. Gotta do that to incorporate the rubber dampener.

If th engine is planned for aircraft use, I would imagine a dry sump system might be in order, or a Porsche 3.0L six as they have a dry sump system already and 2.5X the hp. Ooops....just getting ahead of the game......

boxermania wrote:If th engine is planned for aircraft use, I would imagine a dry sump system might be in order, or a Porsche 3.0L six as they have a dry sump system already and 2.5X the hp. Ooops....just getting ahead of the game......

nope you are not... dry sump and a whole new crankcase are already in Solid Edge CAD! External 3 stage oil pump as well.