Some more R18C thoughts:

[Adrian R]

So as of today I have got nearly 600mi on the bike's odometer. It will be going to have it's first service performed soon. Went out for a nice long ride yesterday with my woman on the back. This would be my second longer ride with a passenger. I tweaked the bike's rear suspension for the second time and now I seem to have it right with the passenger. I had to tighten it some from what the factory recommended. Three turns tighter did the trick. I no longer experienced any peg dragging with respectable lean angles. However, it didn't get this without a price. The seat once thought to be decent enough, got harder! I might buy a new seat in the future, but in the mean time I will see if it softens some with more use.

Some things really stand out with this bike. First of all I absolutely LOVE the way it sounds. Very unique. Perfect blend of audio frequency and volume. You can really hear both pipes as you roll the throttle..very deep and throaty sounding... It kind of sounds like and old airplane engine! I am totally leaving the stock exhaust alone. It's perfect. Good looking too.

The bike likes regular octane fuel, period. Regular here in the U.S. meaning 87-89 octane and without ethanol. With regular octane fuel it idles better, produces a bit more power, runs smoother, and DOES NOT sputter in closed throttle positions.... As soon as I started running premium, ethanol free fuel the rougher idle and off throttle sputtering began. Before I bought this bike, I spent many, many hours watching you tube videos and this one thing I noticed, that is the sputtering sound it made when coming off on throttle positions.

This thing is DEFINITELY a cruiser. BMW appears to have put quite a bit of engineering thought into producing this machine. The engine design and it's gearing is all about cruising. The gearing is tall period. I am sort of surprised at how tall the gearing is. It is most noticeable in first. This thing has got the tallest first gear I've ever encountered. The bike just likes going fast....cruising wise. 90mph in 6th is hard to avoid....it just loves it..... It's a combination of the engine's torque curve with respect to it's gearing that is so unique. I was so mesmerized by how smooth it was on a interstate at nearly 105mph.. I blew right by my exit without noticing it...

It would be cool if the bike had a second set of shorter gears... I can imagine how quick it would be! But it's perfect the way it is... truly a wonderful bike to ride.

Enjoy!

 

[WaydeG]

Glad to hear you've got the pillion suspension dialed in. It took several rides to get my C comfortable enough for longer rides. The seat isn't really that great and it will probably be the first major upgrade (like most of us). I agree that the R18 is correctly named a cruiser as it ploughs it's way down interstates and winds easily through more rural back roads. Im curious about the fuel though. Im wondering why BMW recommends premium fuel. Is it a difference in EU vs US product?

 

[Dmechanic34]

Glad to hear you've got the pillion suspension dialed in. It took several rides to get my C comfortable enough for longer rides. The seat isn't really that great and it will probably be the first major upgrade (like most of us). I agree that the R18 is correctly named a cruiser as it ploughs it's way down interstates and winds easily through more rural back roads. Im curious about the fuel though. Im wondering why BMW recommends premium fuel. Is it a difference in EU vs US product?

I run premium fuel in mine as I do in everything I own. My r18 runs beautifully at 60mph in 6th gear and I would suspect as I’ve founding riding mine it’s ideal rpm is 2,000-3,400. Below that it shakes and struggles and above that it vibrates you right off the bike. Quick interstates entries are easily obtained getting up above posted limits very smoothly in those ranges especially in rock mode. I pulled a 12% grade two up around 2,300 rpm following a victory and Indian with zero issues, I prefer the high octane fuel for instances like that. Engine hot, full load, zero knock and ping.

 

[Adrian R]

I run premium fuel in mine as I do in everything I own. My r18 runs beautifully at 60mph in 6th gear and I would suspect as I’ve founding riding mine it’s ideal rpm is 2,000-3,400. Below that it shakes and struggles and above that it vibrates you right off the bike. Quick interstates entries are easily obtained getting up above posted limits very smoothly in those ranges especially in rock mode. I pulled a 12% grade two up around 2,300 rpm following a victory and Indian with zero issues, I prefer the high octane fuel for instances like that. Engine hot, full load, zero knock and ping.

I've never experienced pinging or knocking yet...running regular fuel. My bike LOVES 90mph in 6th gear ..lol

 

[Dmechanic34]

I've never experienced pinging or knocking yet...running regular fuel. My bike LOVES 90mph in 6th gear ..lol

These engines are so advanced nowadays I’m sure the timing and power output will be adjusted/reduced regardless of what fuel you put it in it. I trust the manufacturers and engineers that make a lot more money than I do to make the important questions. If I wanted to save money I would have bought a used Honda lol or just kept the one I had.

 

[nielsm]

Glad to hear you've got the pillion suspension dialed in. It took several rides to get my C comfortable enough for longer rides. The seat isn't really that great and it will probably be the first major upgrade (like most of us). I agree that the R18 is correctly named a cruiser as it ploughs it's way down interstates and winds easily through more rural back roads. Im curious about the fuel though. Im wondering why BMW recommends premium fuel. Is it a difference in EU vs US product?

BMW has knock sensors in their bikes, so it will retard timing if it senses knocks. Premium fuel is less likely to knock, so you can get the full power of the motor in those cases. It will run on regular, albeit with less power.

Ethanol adds another stick in the mud and is a distinctly American issue as I don't believe other countries use it. Ethanol fuel has less energy per unit of volume than real gas, so the bike won't make as much power as it would with real gas. It may be that regular gas without ethanol that has the timing retarded still generates similar power to premium with ethanol. Be interesting to see if anyone did dyno comparisons to confirm the tradeoffs.

 

[Adrian R]

BMW has knock sensors in their bikes, so it will retard timing if it senses knocks. Premium fuel is less likely to knock, so you can get the full power of the motor in those cases. It will run on regular, albeit with less power.

Ethanol adds another stick in the mud and is a distinctly American issue as I don't believe other countries use it. Ethanol fuel has less energy per unit of volume than real gas, so the bike won't make as much power as it would with real gas. It may be that regular gas without ethanol that has the timing retarded still generates similar power to premium with ethanol. Be interesting to see if anyone did dyno comparisons to confirm the tradeoffs.

All I can say is based on my experience thus far is that my bike seems to run it's best burning regular octane fuel with an ethanol treating additive added. The only fuel that I think would be better is regular octane ethanol free fuel, but that's next to impossible to get now nearly anywhere.

 

[nielsm]

All I can say is based on my experience thus far is that my bike seems to run it's best burning regular octane fuel with an ethanol treating additive added. The only fuel that I think would be better is regular octane ethanol free fuel, but that's next to impossible to get now nearly anywhere.

The best resource I've found for real gas is https://www.pure-gas.org. The downside is there might not be one near you. The closest station to me is >50 miles away, which makes it impractical.

Which additive are you using? I've only seen those that try to clean the fuel system. Would love an alternative that gives premium power without the ethanol impact.

 

[Adrian R]

The best resource I've found for real gas is https://www.pure-gas.org. The downside is there might not be one near you. The closest station to me is >50 miles away, which makes it impractical.

Which additive are you using? I've only seen those that try to clean the fuel system. Would love an alternative that gives premium power without the ethanol impact.

 

[Deleted member 939]

Speaking about fuel.....

Most gas pumps use a single hose for all the different grades of gas. My research says the first 1/3 to 1/2 gallon of gas is the grade bought by the previous customer at that pump. My fill ups usually takes just over 3 gallons so my premium fuel is diluted with regular by about 15%. Should we be...

www.r18forums.com

 

[Adrian R]

Speaking about fuel.....

Most gas pumps use a single hose for all the different grades of gas. My research says the first 1/3 to 1/2 gallon of gas is the grade bought by the previous customer at that pump. My fill ups usually takes just over 3 gallons so my premium fuel is diluted with regular by about 15%. Should we be...

www.r18forums.com

Yep ..I noticed that last weekend. I would have to guess on average...that most people use the cheaper, less octane gas. That's why I use it!

 

[Deleted member 939]

I hope 15% never gets into the mix.

 

[Vyk]

I don't see why these bike actually need higher octane fuel. It has super low compression.

That being said... I still use 93... lol!! *Mumble*Additives clean... cheap insurance... [insert more gooder excuses here ]*/Mumble*

I do wonder why they recommend 90...

 

[Adrian R]

I don't see why these bike actually need higher octane fuel. It has super low compression.

That being said... I still use 93... lol!! *Mumble*Additives clean... cheap insurance... [insert more gooder excuses here ]*/Mumble*

I do wonder why they recommend 90...

View attachment 5115

Exactly. People always think higher octane means higher power..which is far from the truth in many scenarios. Many times due to emission standards, at least with other bikes I've owned in the past... higher octane fuel made them run slighty cooler thus producing less HP... Typically higher octane fuel is for engines with high compression... of which is not the case with the R18. I'll stick with the cheaper, lower octane fuel thank you!

 

[Roadliner]

What you think that the bike runs smoother or better with lower quality fuel is actually a retarded lower performing engine not performing at its best. Engines can feel smoother when the knock sensors pull back performance

 

[BobW]

Octane basically stabilizes petrol so at high compression it doesn't ignite like a diesel rather when the proper timing of a spark(plug) ignites it. Otherwise these uncontrolled explosions are randomly occurring and are working against the power stroke which results in pinging/knocking. As others shared, most OEMs have knock sensors that will adjust timing and/or fuel to a point to help minimize or eliminate the knocking and this does result in less power, but to the degree it is felt depends on the engine and parameters it is being run. There is more energy in a gallon of "regular" lower octane gas than "premium" or higher octane gas and you only need the octane rating that an engine will run on without pinging, any more is just a waste of money. While the R18 is relatively low compression it does have pistons with huge real estate to control the burn across so the higher octane may not be needed in all riding circumstances, but I'm guessing it helps in extreme operating conditions as well as helping consistency/rate of burn to allow emissions to be met without requiring the L/C complications.

Reading the comments on having the same model engine running best on "regular" or "premium" in my experience comes down to fuel blends in different regions, ambient temps, humidity and load/operating parameters. For me over the years on various motorcycles if running hard on our mountain roads on a nice relatively cool, springtime, ride I never hear anything, but a heathy engine and on those same bikes when out west running across the desert areas with temps in the 110+(f) range, low humidity, fully loaded and fighting the winds, etc., occasionally I would have to adjust speed to keep pinging/knocking in check even though I was "in tourist mode" while running premium gas. With all things YRMV, YMMV. Be safe, have fun, repeat often....

 

[Deleted member 939]

What you think that the bike runs smoother or better with lower quality fuel is actually a retarded lower performing engine not performing at its best. Engines can feel smoother when the knock sensors pull back performance

That is a definite possibility.

When I did the Bren Tune my handlebars really smoothed out and started better.Before the tune,My bike almost never started on the first try.I also added the K&N filter and the DNA open cover.The tune made the bike a little deeper sounding and the air filter added a bit more.
The bike is breaking in and close to 15,000 miles.I have been using 91 exclusively.
The other day I started to notice a little more bump in idle at the handlebars.Not like previously when it was new.I would say it seems to have a little more power.
For anyone that wants to try 87 I would suggest using 2-3 tanks before comparing to other grade.
As stated the bike may adjust to fuel better than all of the motorcycles out there with narrow band sensors.
Lastly,I rode my bike to Hannigan without the sidecar and back home with side car.Arizona,NM,Texas,Arkansas and Kentucky.Some stations had only ethanol free 87.Some had 91 and even 93.I could not tell the difference.Except mileage went down with the car attached,LOL!

 

[Deleted member 939]

Octane basically stabilizes petrol so at high compression it doesn't ignite like a diesel rather when the proper timing of a spark(plug) ignites it. Otherwise these uncontrolled explosions are randomly occurring and are working against the power stroke which results in pinging/knocking. As others shared, most OEMs have knock sensors that will adjust timing and/or fuel to a point to help minimize or eliminate the knocking and this does result in less power, but to the degree it is felt depends on the engine and parameters it is being run. There is more energy in a gallon of "regular" lower octane gas than "premium" or higher octane gas and you only need the octane rating that an engine will run on without pinging, any more is just a waste of money. While the R18 is relatively low compression it does have pistons with huge real estate to control the burn across so the higher octane may not be needed in all riding circumstances, but I'm guessing it helps in extreme operating conditions as well as helping consistency/rate of burn to allow emissions to be met without requiring the L/C complications.

Reading the comments on having the same model engine running best on "regular" or "premium" in my experience comes down to fuel blends in different regions, ambient temps, humidity and load/operating parameters. For me over the years on various motorcycles if running hard on our mountain roads on a nice relatively cool, springtime, ride I never hear anything, but a heathy engine and on those same bikes when out west running across the desert areas with temps in the 110+(f) range, low humidity, fully loaded and fighting the winds, etc., occasionally I would have to adjust speed to keep pinging/knocking in check even though I was "in tourist mode" while running premium gas. With all things YRMV, YMMV. Be safe, have fun, repeat often....

It may be good to run 91/93 every other fill and alternate with 87 as your comment is spot on:There is more energy in a gallon of "regular"

 

[TodkaVonic]

A bit of a thought exercise

Three gallon tank. Fill up with 93 with the assumption that the prior customer used 87. So 2.5 @93 and 0.5 @87. Effective octane is 92. This is, by the way, the highest octane you can absolutely count on. But I digress. Run it to almost empty, say half a gallon. now refill. You've now got 0.5 gallons at 92 (left-over in the tank), 0.5 at 87 (left-over in the line), and 2.0 gallons at 93 (new gas.)
K. Now blow through that and refill when there's half a tank left. You've diluted half a gallon from 93 to 92 and will continue to dilute that half gallon portion of the mixture with each successive tank. In other words, because there's a very slightly less octaneous (my word) mixture with each successive tank, the leftover part with each tank continues to drop every time you need to refill.. 92 to 91.83 and 91.76 and 91.72, etc. It gradually sinks down, less and less though with each tank,
Until the numbers plateau just above 91. The decimal goes out to the 100,000th and then the millionths. It just keeps moving right. But the number never drops below 91.

 

[tommymck]

My bike doesn't seem to care, either from a performance perspective or a mileage perspective.