My BMW R1150 conversions

[RickH]

A largish capacity flat twin in a light airframe will tend to have a few shaking problems. The light flywheeled R100RS wasn't pleasant at idling and just above. All motors where the pistons stop at the same time have a problem of losing and reversing rotational inertia. (varying flywheel effect) They balance well enough otherwise except for cylinder offset which leaves a rocking couple hard to eliminate the effects of. The way it's mounted in a motorbikeTHAT doesn't matter much. Nev

So why is it that the four cyl Jab, Continental and Lycoming engines have all four pistons "reversing rotational inertia" at the same time. look them up There are some very good photos of their crankshafts online. oh and guess what I just googled images of the Rotax 912 crank

and it looks awfully like they do the same. Funny that. Should really check your facts before making "expert comments" As for cylinder offset causing a rocking couple that is just a load of bollocks.the only reason for Cylinder offset is because you can't stick two pistons exactly opposite each other and all engines that are four or two or six cyl horizontally opposed have it.

 

 

[RickH]

I need to clarify above statement about not being able to stick two cylinders exactly opposite each other . You can if you use fork and blade arrangement as in some V twins. but none of the engines I mentioned above use this arrangement.

 

 

[fly_tornado]

R1200 with the take off gearbox and clutch

 

 

 

[cscotthendry]

I've seen a 701 with a converted Harley motor - I thought they were asking for trouble, Harleys convert 90% of their power into vibration...

And the other 10% into noise.

 

 

[mishulescu]

Hi,

 

i have an Bmw r1150 engine and i'd like to convert it for an aircraft.Anyone has some plans or some pictures according with this?

 

Thank you

 

 

[Litespeed]

Here is a link I just found

 

SonexBuilders.net View topic - BMW R1200: 115HP, 176 lbs. Are any in a Sonex?

 

Market leader for this is German naturally

 

Take Off

 

But there are others such as Silent Hektik in Germany

 

PSRU with BMW 1100 - 1200 engine assembly - short instruction in Poland

 

and some others as well.

 

this one is good

 

BMW - Engine

 

And a pdf on installing a engine and all mods for 1100-1150 model

 

It is not a huge deal converting one and they are excellent engines.

 

Basically add PSRU and remove all BMW electronics and add a standalone ECU to run the existing ignition and injection system. On the 100 and 1150 you can use the original electronics with a modded loom .They run best with a airbox- BMW really did a great job and can only be bettered by the 1200 version which has more power. Depending on which version of the r1150 you have as the different versions have different power settings from memory.

 

Welcome to the forum.

 

What do you intend to put it in?

 

 

[mishulescu]

Hi,

 

thank's for your answer.I know about these webpages,but i have to build it myself,that's why i need some plans or some pictures.I like Silent Hektik ,but they don't want to sell only if you buy five complete system,so i have to find another aproach.

 

I will build myself an light aircraft probably will look like Nynja..But first i try to make bmw engine conversion because i have it.In the meantime hope to find some building materials to start it.

 

 

[onetrack]

Good God, you might as well use a farm stationary engine, as use a HD V-twin. What were they thinking?

 

Nothing creates problems like vibration does - it will crack frames and mountings, shake accessory mounting fasteners loose, and cause whip in shafts.

 

Manufacturers spent decades trying to smooth out torsional and longitudinal vibrations in crankshafts, because they created such a host of problems.

 

 

[Yenn]

Years ago someone in the USA used a BMW motorbike engine to power I think a Nieuport. He didn't use a PSRU, but just used 2ng gear and it worked well. I can't recall whatBMW motor it was but it was in the nineties, if not earlier.

 

 

[Methusala]

G'day Yenn, as I recall, that was a Yamaha Virago motor. Read the story in Kitplanes

 

 

[cooperplace]

I used to read every instalment of Phil's "Rich Mixture" column in Rev Motorcycle news. Kept the lot for decades until the white ants found them...

Aprilia use 60 degrees on their twins. I loved the smoothness (and sound) of my 90 degree Ducati but it had a down side; compared to my old parallel twins it was too smooth. Lady passenger had to yell at me to change into top gear.

ah, those were the days: lady passengers on the back of a 900SS!! You had to fit the twin seat. You're taking me back now, almost 40 years. There's nothing like a Ducati v-twin.

 

 

[Litespeed]

Ah ?

 

Yes there is nothing like a old Duck motor, they were lovely sounding and looked great. But .................they were terribly short lived if run hard or poorly tuned.

 

A lot of mates had them and I always manged to show em on my R100cs ( mine had 40mm Delorto's and trick forks and flywheel from the factory) on anything but a billiard table smooth road. They rarely lasted beyond 40,000 km without a expensive trip to Ian Gowanloch, My R had 200,000 km and only cost a rotor for the alternator and valve guides at 120,000km.

 

All that complicated Desmo gear in the head and it revved no harder but made Ian a rich man. Later I got a Guzzi Lemans Mk3 which revved higher, had more power and was as bulletproof as the BMW.

 

I made the near fatal mistake once of riding my mates Ducati Pantah 600 to Philip Island. Thinking it would be okay as a newer generation motor and having been rebuilt only 3,000km earlier by Ian. The bastard machine had a conrod let go mid corner near Braidwood, which naturally stopped the motor dead and spewed chunks into the box and locked everything up. No clutch pull was going to help. And my sin was riding at a mere 130kmh. I somehow managed to stay upright and slide to a stop.

 

I laid in a paddock, watched the stars, smoked several special ciggies. And slowly thanked the stars for not letting a F..kin Ducati Kill me.

 

I am sure glad they don't make aircraft engines.

 

 

[onetrack]

Nothing like the Jap bike missiles. I've ridden a VF1000R at 280-290kmh for an extended period, and they reach that speed with staggering ease and rapidity.

 

Don't do that kind of thing any more, I'm getting too old for that kind of death-chancing stuff.

 

 

[IBob]

I used to read every instalment of Phil's "Rich Mixture" column in Rev Motorcycle news. Kept the lot for decades until the white ants found them...

Aprilia use 60 degrees on their twins. I loved the smoothness (and sound) of my 90 degree Ducati but it had a down side; compared to my old parallel twins it was too smooth. Lady passenger had to yell at me to change into top gear.

Speaking of lady passengers: sometime back towards the dawn of time, a mate of mine bought one of those little 250cc BMWs...to discover that it had a most peculiar, and apparently rather...um... pleasing vibration around the rear seat.

 

Nowadays, you could probably patent that???

 

 

[Old Koreelah]

My rear passenger of the day was greatly disappointed when I replaced my parallel twin with the Ducati 860.

 

Too smooth. She referred to the XS as her 87 inch personal vibrator.

 

 

[Marty_d]

Speaking of lady passengers: sometime back towards the dawn of time, a mate of mine bought one of those little 250cc BMWs...to discover that it had a most peculiar, and apparently rather...um... pleasing vibration around the rear seat.Nowadays, you could probably patent that???

I think Harley Davidson have cornered the market on turning horsepower into noise and vibration.

 

 

[Marty_d]

It's been written about before but I really think the Honda VFR motor would make a great aircraft engine. Water cooled V-4, smooth, bugger-all vibration and pretty much bulletproof.

 

 

[cooperplace]

My rear passenger of the day was greatly disappointed when I replaced my parallel twin with the Ducati 860.Too smooth. She referred to the XS as her 87 inch personal vibrator.

I could reminisce at length about the comments made by lady passengers on my 900SS; it had a certain throbbing character that they liked. Also, by going faster I could make them cling on to me harder.

 

 

[cooperplace]

Ah ?Yes there is nothing like a old Duck motor, they were lovely sounding and looked great. But .................they were terribly short lived if run hard or poorly tuned.

 

A lot of mates had them and I always manged to show em on my R100cs ( mine had 40mm Delorto's and trick forks and flywheel from the factory) on anything but a billiard table smooth road. They rarely lasted beyond 40,000 km without a expensive trip to Ian Gowanloch, My R had 200,000 km and only cost a rotor for the alternator and valve guides at 120,000km.

 

All that complicated Desmo gear in the head and it revved no harder but made Ian a rich man. Later I got a Guzzi Lemans Mk3 which revved higher, had more power and was as bulletproof as the BMW.

 

I made the near fatal mistake once of riding my mates Ducati Pantah 600 to Philip Island. Thinking it would be okay as a newer generation motor and having been rebuilt only 3,000km earlier by Ian. The bastard machine had a conrod let go mid corner near Braidwood, which naturally stopped the motor dead and spewed chunks into the box and locked everything up. No clutch pull was going to help. And my sin was riding at a mere 130kmh. I somehow managed to stay upright and slide to a stop.

 

I laid in a paddock, watched the stars, smoked several special ciggies. And slowly thanked the stars for not letting a F..kin Ducati Kill me.

 

I am sure glad they don't make aircraft engines.

a friend of mine had a 750GT and almost at the end of the main straight of Adelaide International Raceway, it went clunk and stopped producing power. She coasted to a stop, and then another bike stopped next to her. She looked at the rider, who was covered in oil and metalflake, and said, what happened to you? He said, look down, what's happened to your engine? Of the the front cylinder, there was little sign: just some bolts holding the head, and a bent con-rod poking out of a now-ruined case.

They sounded fantastic but were hand grenades. When I switched to Kawasakis, I was very grateful for their bulletproof motors.

 

 

[Old Koreelah]

I could reminisce at length about the comments made by lady passengers on my 900SS; it had a certain throbbing character that they liked. Also, by going faster I could make them cling on to me harder.

Cooper place, you devious bugger!

 

 

[Oscar]

The bevel-head Ducs were, ahem, 'personalities'. I used to ride a Darmah a bit, and lusted to ride a mate's 900SS - but his test was, if you could start it, and even though I had plenty of practice with my XL350, I jumped on the starter crank on the 900 and it elevated me... His point was: if you take it and stop and can't start it, it's going to be a bastard situation (no mobile phones in those days..) The 900 SS with Conti cans was such a delicious noise (only bettered, in my opinion, to a Vincent Rapide or Black Shadow).

 

The Sydney Duc brigade used to love the run through the National Park up from Scotland Island - and they would trigger every BMW car alarm along the way..

 

The bevel-head Ducs were extremely critical on oil quality; about the only reliable oil was BP Corse+ I used to use that in my XW Falcom GT and it was good for 15 lbs extra pressure when hot and, er, 'pressing on' in twisties (which you COULD do in one with almost full-spec HO suspension, though it took a fair amount of throttle-steering to keep it pointed. It had an ex Paul Gulson racing Windsor engine so was pretty much a Phase 1 HO but without the Shaker; a magnificent PTP vehicle if you worked at it a bit).

 

My '86 Viffer 750 - just brilliant. The 'two Ducs flying in formation' burble below about 5k revs, was tonic to the soul, and then it changed to a howl if you got into 'fun' mode. Choose your entertainment. But, as a basis for an aero engine, I think just a bit too heavy and not really good packaging; realistically, you'd need a PSRU to move the prop up sufficiently to be viable, and that adds weight and potentially unreliability to what is a brilliant, delightful engine.

 

 

[cooperplace]

Cooper place, you devious bugger!

the sad thing is that this is nearly 40 years ago: the late 70s. In some ways I don't feel any older but my knees, hip, joints, eyes, etc all tell me that I am. As do my kids.

 

 

[Oscar]

Ah, kids: love 'em or loathe 'em, you aren't allowed to hit 'em with a shovel.. they keep telling me.

 

 

[Litespeed]

Contis did sound nice but the best was always a good open reverse cone pipe. On the Guzzi it was explosive fire farts for starting and volcanic when riding.

 

Pure heaven

 

But the neighbours really bloody hated it. Such sweet music

 

 

[Old Koreelah]

A Ducati with Contis decelerating into a corner is the most stirring sound in motorcycling. At Bathurst one year there was a 900 SS and a LeMans in the same race. Both 90 degree twins, similar capacity.

 

(Edited) they were both fitted with Contis. Very different sounds, however. Must be down to cam profile.