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Discussion Starter · #1 · (Edited)
This is a new thread inspired by a digression into engine rev.s within a discussion about after-market exhausts.
Since this forum is about providing information, and dispelling myths, I thought it appropriate to instigate it as a separate thread.
Please note that it is NOT meant to be contentious.
I fully endorse every rider's choice to ride in their own style, and no-one should be pushed to use more rev.s than they are comfortable with.

Here are the posts that inspired the new thread, 'Bold' highlights are mine:

Hi There,
I am on my 2nd 310r. I installed an Akropovic pipe on my 1st bike. It cost around $1,150NZ then, ie about 7 years ago. I couldn't say I noticed an increase in power or torque really. In any case the bike needs to be peak revving to get top performance & who does 10,000RPM anyway. However the sound was great compared to the older stock exhaust that came on the bike. The new bike has a better exhaust note. Nevertheless I'm wondering whether to install another Akropovic,,,,,wait for it.....at a cost now of $1,450NZ, ouch! I believe the sound will again be better, though somewhat of a lesser improvement on the new 2022 bike. Comments please???
Cheers, Mike.
Who does 10,000 RPM ? Me, for one....
Re RPM: Totally agree with Imperiton1. I have around 700,000 miles of riding experience. For a long, long, time, I kept my RPMs at that nice easy sounding ~4,000 rpm point most of the time (6-7,000 for the 310). Most riders with just street training and experience tend to avoid angry sounding higher RPMs. It took me many track days on my S1000RR to learn that every motorcycle is designed for the rider to use the entire RPM range.
Spending any money to upgrade performance is a complete waste if you are not using your bike's entire RPM range. It's really that simple.
End of quotes.

Background: My initiation into the world of motorcycles was in the era of 'sports mopeds'. Almost all of these were multi-geared, 50cc, 2 stroke single motors. With some legitimacy, they were referred to as 'lawn mowers' by 'real bikers'. The best of these engines would push out a maximum of around 4-5 BHP, and 50 MPH was an average top speed. Even the road surface would affect the performance ( there is a reason that racers go to Bonneville Salt Flats to make record-breaking speed runs ). It was a simple matter of fact that you HAD to use all the power available just to deal with regular road traffic. The best top speed on level black-top that I ever saw on my Suzuki AP50 was 57 MPH, lying flat on the tank, feet on the rear pegs, left hand around the indicator stalk ( no, I'm not joking ! ).
So, it became second nature to me to use all the available rev.s, in order to squeeze every last ounce of power from any engine. ( Including my old Kawasaki GPZ600R, on which I would regularly show clean heels to many a 1200 cc bike ).
Now, I see never ending threads on this forum about swapping power chips, 'performance' exhausts, front drive sprockets, etc., etc., all in the search of 'better' performance. ( Actually, a pretty subjective goal within itself. )
However, I must echo Jerry G above. In my opinion, it is a simple fact that unless you are already using the WHOLE rev. band right up to 10,000, that you are wasting your time and hard-earned money with ANY of the above. The available power increases as the motor's revolutions increase, until you reach 'Peak BHP', and/or 'Peak Torque' on the engine's power curve. This will be well up towards the 10,000 RPM red line on this bike. For the uninitiated, read Brake Horse Power as 'explosive drive', like a sprinter, and Torque as 'irresistable momentum', like a dray horse pulling a plough.
To anyone who is concerned about damaging the motor, rest assured: There is an automatic rev. limiter, built into the bike's computer, that simply cuts the engine until rev.s drop to an acceptable level. On this I speak from experience !

Now, please let me repeat:
The statement above is only my opinion. It is meant to help enlighten novices.
I cast no aspersion upon anybody else's riding style, or choices.
Please respond in kind.
 

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I’m not sure what you asking or stating. Myself I quite enjoy shifting at “snowflake” and staying close to that mark. That said, it’s a tad impractical off road and dangerous on tarmac to ride WFO constantly. Fun sure, where the 310 motor thrives but staying in the power band 100% of Your riding is really for racetrack and 18 year olds. Flip of that being, I suspect that, like most engines, lugging (too high a gear) is to be avoided.
 
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Discussion Starter · #3 ·
I’m not sure what you asking or stating. Myself I quite enjoy shifting at “snowflake” and staying close to that mark. That said, it’s a tad impractical off road and dangerous on tarmac to ride WFO constantly. Fun sure, where the 310 motor thrives but staying in the power band 100% of Your riding is really for racetrack and 18 year olds. Flip of that being, I suspect that, like most engines, lugging (too high a gear) is to be avoided.
Thanks, Arbolmano.
For other's ref. 'snowflake' refers to the dash light indicating that you are above the 10K red line, and that the rev limiter is in operation.
Neither am I 18 anymore, and I agree that riding WFO, always redlining, is not to be recommended. Nowhere above did I suggest that. But full disclosure: I specifically chose the 310 because it would help tame my twitchy right wrist.
That said, the points that I am making are simply that:
1) There is no risk to the engine to use the whole rev range right up to the red line.
2) That the peak power resides well above 6,000 RPM.
3) That if you are considering spending money on performance products, if you never use more than 6,000 RPM, you could probably find a better home for it elsewhere. But it's YOUR choice.
 

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Engine power starts to build at 6K RPM and peaks at about 9,500 RPM.
For max acceleration, 9,500 is the time to shift.
There is no sense in trying to initiate a shift well up into the 10k range.
In the last 1,000 RPM up to the limiter (9,500 to10,500)... the hp drops about 4 hp. That is back to the 7K range.

If you were in a race... and run up to the limiter... you would lose.
Only time I've seen that is in a Motorcross/Supercross race, where they sometimes leave the throttle at 'max' during er... 'airtime'.
 

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I’ve found I see snowflake before experiencing any sort of rev limiter. I believe it flash’s at 10, 500 to say “tops” and ”shift now”. If you go further then you should hit the limiter, can’t say that I have ever felt any power reduction at all But do work hard at staying near snowflake if in that mode. Personally I’m not looking at anything but the surface far out in front of me when pushing the bike hard, snowflake gets attention as it flashes. The power generation of the 310 is kinda smoothed out quite a bit by the crazy ECU/slip assist thing I think. Sure seems easier to roll at low rpms than it should be. Many times I was convinced I was gonna stall out and didn’t, in fact able to roll on throttle. Just mind blowing for my wee brain.
 
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The power generation of the 310 is kinda smoothed out quite a bit by the crazy ECU/slip assist thing I think. Sure seems easier to roll at low rpms than it should be. Many times I was convinced I was gonna stall out and didn’t, in fact able to roll on throttle. Just mind blowing for my wee brain.
Give thanks to whoever designed the engine. Cams, combustion chamber design, intake/exhaust, ECU programming.

I have 390A and a 310 GS. 310 GS is far superior for trail and off road riding than the 390.
Smoother power, and somehow, with a twist of the throttle the engine generates more controllable oomph.

That said... on the top end though the 390 takes home the cake. (Yup, bigger displacement.)
 

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Discussion Starter · #7 · (Edited)
Give thanks to whoever designed the engine. Cams, combustion chamber design, intake/exhaust, ECU programming.

I have 390A and a 310 GS. 310 GS is far superior for trail and off road riding than the 390.
Smoother power, and somehow, with a twist of the throttle the engine generates more controllable oomph.

That said... on the top end though the 390 takes home the cake. (Yup, bigger displacement.)
Can't beat cubes.... :unsure:
Unless with bigger valves, higher lift cams, more rev.s, higher octane fuel, forced aspiration, and/or weight loss ! :)
 

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Can't beat cubes.... :unsure:
Unless with bigger valves, higher lift cams, more rev.s, higher octane fuel, forced aspiration, and/or weight loss ! :)
And loss of reliability.

About 1 hp (+-) per 10cc of engine displacement is pretty close to the 'standard' for reliability.
310 GS = 32 hp or so. 390 KTM = 41 hp or so. FJR 1300 = 140 hp or so. etc etc.
On the other hand... professional 250cc Motocross with 48 hp = rebuild every race for factory teams.
GP bikes... 1000 cc engines.... 300 hp. They have 7 engines to get through a racing season.
 

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I didn’t make that one up, credit to Kent Forrest, who’s vanished. But it BMW set it up….
 

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I didn’t make that one up, credit to Kent Forrest, who’s vanished. But it BMW set it up….
Was he referring to a G310GS? I ask because both my S1000XR and S1000RR have a bright light that strobes as you approach the "shiftpoint", but it's not snowflake shaped. It's a bar of white light at the top of the TFT on the 2021 S1000XR and a white circular light at the top of the instrument cluster on my 2017 non-TFT S1000RR. So, perhaps the more generic version of the saying should be "Shift on White!", but that doesn't have the panache of "Shift on Snowflake!" :unsure:
 

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My 1200RT had a yellow flash (triangle?) but it kicked in real quick it seemed with rev limiter. On that bike, like any 100hp+ unit things are getting serious at that point. Perhaps 34 hp a little less serious.
Interestingly enough the RT did have a snowflake symbol!! But it warned of “Potential Ice” and would come on when really cold, like 30 degrees (butt cold for a so cal person.)
I’d say duh! When it came on….and praise the fairing, heated seat and grips.
A little freak when I first saw “snowflake” on 310, thinking “ice”?? WTF….ha ha on me. Read the manual Tonto.
Some bikes you shift when you run outta go. Some don’t seem to run outta go, you shift to go faster. I love love love bikes of the latter scheme myself. The next thing for a 310 I think would be a small bottle of nitrous oxide.……..
 

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I think Jerry is exactly right here. A lot of riders, me included, are instinctively trying to avoid the angry noise that comes with higher RPMs. It's almost like you have to unlearn that instinct to really get the most out of the bike. The 310 GS is my first bike and I put 5,000 miles on it over the last five months, but it's only now that I'm deliberately making myself stay in gears longer before shifting up. Otherwise I'm intuitively trying to stay in the 4,000-5,000 RPM range. I think Kent Forrest put it well when he said that avoiding high RPMs has more to do with psychology than engineering.
 

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Riding a wee bike hard to limits (shift at snowflake) is far more rewarding than always reining in a monster to be legal, never seeing a snowflake. On my 1200RT 5th and 6th gears were useless if you wished to be legal and in power band.
I really dig “shift at snowflake” for a cool term myself. Thanks Kent.
 

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Question asked by @Mike Stockwell on the former thread where this discussion started:
"Ask yourself how long can the bike rev at the red line before .......what?......seizing or piston thru the side or a thrown con rod."

The general answer to this question is that manufacturers determine redline by testing. However, testing always has use-cases. This implies that the G310GS redline should be sustainable for those use cases. Let's hope BMW/TVS got those right.

That said...

I was recently informed, by a unimpeachable source with first hand knowledge and lots of experience, about three G310GS engines that failed in use.

The first two were when the G310GS engines "ate a valve", both at just under 30,000 miles. Knowing the source, I'm sure the engines were well exercised during those 30,000 miles. The source also told me that, despite being out of warranty, BMW replaced both engines. I queried for additional info on the circumstances, but nothing further has been offered.

The third G310GS engine failure was one of the above replacement engines; the crankshaft "became deranged" at about 3,500 miles, failing so badly that it cracked the engine case. BMW replaced this engine because it was still under the two year replacement parts warranty from the first replacement.

The source also told me that they now ride these G310GS "mostly locally...and not to tour on like we have".

Re the valve failures: Because of this, I'm not going to be skipping valve adjustments on my G310GS. I might even go the other way by increasing their frequency from once every 12,000 miles to once every 6,000 miles. Purely by coincidence, I have scheduled my 12,000 service for next week; this is early as I only have 10,577 miles. I'm doing this service early only because my dealer is moving to a new location (closer to me - yeah!) and might not be able to do the service when I expect to be at 12,000 miles. Depending on what they report about my valve clearances from that service, I might decide to increase the valve inspections/adjustments from every 12,000 miles to every 6,000 miles.

Re the crankshaft failure: I attribute this to a "bad part", i.e. a random failure for which nothing can be done to avoid or even watch out for.

Re their local/tour decision: I have 10,577 miles on my G310GS with no problems. Given the above information, my plan is to minimize straight flat boring long distance high RPM runs. Two examples: I will be trailering my G310GS from NC to California to do the CABDR and attend the Death Valley Noobs Rally in March this year, but I will ride my G310GS to and from NC when I do the Mid-Atlantic BDR, PA Wilds BDR-X, and BMW National Rally in Richmond VA in May/June, all in one trip.

Re my warranty: Given these three engine failures, I intend to max out use of my G310GS during it's three-year, 36,000 mile, warranty. After that, we'll see.
 

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The 310, like many of the newer generation engines makes use of new manufacturing methods. Specifically Diamond Like Coatings (DLC). These coating cause wear surfaces to be very very hard (like diamonds) thus they will not wear easily, they also have this property of being near self lubricating. Really has opened up performance and changed maintenance.
But it’s still really new and there are issues. One we know of, avoiding additives that can attack the coatings. There are reports of cam followers being so hard as to take out cam lobes, happening without warning unnoticed until valve clearance check. It’s still new enough that there’s no knowing what happens after a million heat cycles (few years of use).
My take is that if your unit holds together the first 1000 miles or so your good, follow the maintenance schedule. Don’t dally on valve clearance inspection as this is the time to “check your camshaft/follower assembly for wear. Sadly no way to check crankshaft journals.
Though I suspect that vigilant use of oil analysis could be an excellent window.

I think the best policy is to ride the unit. Try not to exceed the red line but going near it shouldn’t be an issue. Teams of engineers worked on that. That said, it’s a BMW performance unit with a motor from a track racer. It’s not a Honda. For myself, I’ll love mine until the warranty is runs up. By then there should be more data points but most likely the smart move would be sell the unit as most probably there will be something even better out. We are so close to an electric unit that works, not more than two years.
If I found myself “babying“ the bike because I was concerned it was weak, I would ride straight to dealer and trade it in on a Honda.
 
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Discussion Starter · #19 ·
[
I think Jerry is exactly right here. A lot of riders, me included, are instinctively trying to avoid the angry noise that comes with higher RPMs. It's almost like you have to unlearn that instinct to really get the most out of the bike. The 310 GS is my first bike and I put 5,000 miles on it over the last five months, but it's only now that I'm deliberately making myself stay in gears longer before shifting up. Otherwise I'm intuitively trying to stay in the 4,000-5,000 RPM range. I think Kent Forrest put it well when he said that avoiding high RPMs has more to do with psychology than engineering.
Thanks for picking up this thread, SKX. While many experienced riders are having fun with it ( :) ), my main purpose for launching it was for riders such as yourself. I hope that it provides some insight, and inspires the confidence to get much more fun out of your bike. (y)😁
 
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