Octane rating

[Pokey]

Ok......lets throw in temp changes and elevation levels too, because I'm sure that Kawasaki took that into consideration.

[gPink]

Ok......lets throw in temp changes and elevation levels too, because I'm sure that Kawasaki took that into consideration.

If they were going to be that considerate they could have put a closed loop system on the bike.

[Pokey]

If they were going to be that considerate they could have put a closed loop system on the bike.

Yeah I have to agree with ya there.

[maxtog]

I had not seen that document before, good info, and it answers the question of why higher octane fuel when the compression is lower than a ZX-14 (top of page 12).

Jim, you should make it required reading for all newbies.    Although that might result in less arm chair engineering discussions.

That is a good read I have not seen before (although it is now not much new to me).  However, I LOVE this quote:

"Q: Are the front and rear brakes linked?

A: No. For sport touring bikes, brakes that can be used independently front and rear on winding roads are part of the fun. Our view is current Linked Brake Systems tend to remove this fun factor – the underlying principle of the C14."

Talk about back-pedaling    Of course, they would now say their linked system does not remove the fun because it is so much better designed than traditional linked systems, yada, yada, yada!

[Son of Pappy]

If they were going to be that considerate they could have put a closed loop system on the bike.

Mama Kaw must like Europe better

[maxtog]

Oh, since people were "blah blah blah" about the ZX being higher compression and the C-14 not needing higher octane.... straight from the PDF, above:

"Q: Why is the compression ratio lower?

A: The theoretical compression ratio of 10.7:1 is lower than the 12.0:1 of the ZX-14. However, the actual compression ratio increases when the camshaft timing is advanced higher. With intake camshaft timing becoming more advanced than the ZX-14’s via the C14’s Variable Valve Timing, it was necessary to start at a lower ratio so we could keep the actual compression ratio from becoming higher than the engine’s knocking limit."

My bold/emphasis.  When pushed, the VVT Concours engine is at the same compression ratio as the ZX.  And it is at high performance/compression levels when a higher octane is needed the most.  So, until they make a dynamically variable octane gas ( :O ) the higher octane is needed all the time.  Even the "new" ZX still does not have variable valve timing....

[jayke]

I have 35K on my '08. I've always used mid grade 89 octane.. 1 point below spec.

Runs fine and I run the snot out of it. As long as it doesn't knock you're good whatever you're running.

[texrider]

I use those little coffee filters to remove even more octane from wherever I buy regular unleaded...

[Son of Pappy]

I use those little coffee filters to remove even more octane from wherever I buy regular unleaded...

You must use one of those Braun gold plated reusable filters

On the VVT and probably a little condescending, if your bike has never seen redline in third or fourth gear mid grade is probably OK, if you like bouncing the rev limiter from second to third, premium is IMO required.  When I am out for a ride with SWMBO I wouldn't sneeze at midgrade as I never get above 4-5k on the tach.  As with anything that is grand, ride your own ride and never believe everything ya read on the internet

[Boomer]

If a modern, engine managed, fuel injected motor has knock sensors then it will run on just about anything you can get from a gas pump (no,... NOT Diesel!)  The knock sensor will change the ignition timing to prevent knocking which will have the effect of reducing the available power for lower octane fuels.

However, the C-14 does not have a knock sensor so you are better off staying within the manufacturers recommendations which are;

No less than 90 AKI
No more than 10% ethanol OR 5% methanol
No more than 15% MTBE

These are almost certainly over conservative so you may even get away with 87 AKI but buyer beware.
If the motor starts knocking then from there it's a short trip to blowing a hole in the piston. 

[ZedHed]

Alright OED riders -- how many of you have ever "holed" a piston from detonation?  EVER?  Right, just like I thought !! I owned a '68 Triumph Bonneville that has high compression pistons and it "knocked" like a can of BBs on hot days under any type of moderate acceleration even on high octane gas and I rode the wheels off that bike and it never holed a piston in all the years I owned it (misspent youth)  I wish I still had it today.  That engine was air-cooled, had points and condenser ignition, Amal carbs and certainly NO knock sensors.  Yeah, I tried to jet it "fat" (rich) and retarded the ignition as much as possible -- BUT no holed pistons.  I also owned two (2) Kawasaki Mach I 500s with high compression, expansion chambers, and lean jetting.  They also were notorious for detonation and holing pistons, and yet I rode the rims off my two and again NEVER holed a piston (did seize one twice in the same day though) from detonation.

I guarantee that none of you will ever "hole" a piston on the modern, water-cooled, fuel-injected, computer-engine-managed C14 from using 87 octane gas -- EVER. 

Now if some of you just feel the need to appease your OCDness that is your business, but quit trying to scare everyone else about this issue even if you still jump when you see your shadow and can't sleep without your nightlight on.

We can all read the manual -- there is no need to continually recite it to the literate

[B.D.F.]

To no one in particular:

It is all fine and well to read the manual and follow the guidelines (rules if you prefer). That said, I think it is always desirable to try to understand a situation and understand the reasons for specific requirements. Further, as this is a forum specifically dedicated to discussing [our favorite] motorcycle, I think the science behind the need for octane is perfectly acceptable to discuss. Perhaps we can even learn something- I shoot for that very thing everyday.

Just my opinion but I think it is a good and valuable thing to have knowledgeable folks render their opinions and thoughts on subjects like this. My point is that any / all of us can disagree with anyone but there is no need to try to stifle the posting of information, even if we are not interested in it.

Of course if all of that fails, we could always resort to just being reasonable and polite.... 

Brian

[ZedHed]

Brian:

I agree with you completely, but every time a topic is discussed that differs with the "manual" even the slightest -- you get the obligatory, "but the manual says this..."  or "the manual says that...."  "You can't do that because the manual says you shouldn't..."

It just gets old like none of us is literate enough to read the manual or make inferences on our own.  You would think the darn thing was the US Constitution for crying out loud !!

One of the reasons I bought a C10 originally was because the COG guys were WAY more knowledgeable than the dealers or the factory as far as I could tell.  I knew I could get maximum utility and enjoyment for my C10 and myself from the discussions and tech articles in the forum.

Something has changed with the advent of the C14 -- the owners as a whole seem much more resistant to modification of maintenance procedures and factory recommendations than the C10 riders and I'm not sure why.  It's as if many of the C14 riders are "afraid" to do anything not written in stone in the MANUAL.  You would think with guys like Fred Harmon running interference for us that we could be free to discuss things like replacement batteries for the TPMS, different octane ratings, tire pressures/ sizes/types, improved replacement parts, etc.

Maybe too many switch-over, follow-the-herd riders from other brands and types of motorcycles to the C14?  Not familiar with the innovative environment of the COG-o-sphere?

[gPink]

Many too many switch-over, follow-the-herd riders from other brands and types of motorcycles to the C14?  Not familiar with the innovative environment of the COG-o-sphere?

Must..Not...Respond....

[Pokey]

Seems pretty clear to me that comparing the C10 to the C14 is apples to oranges. Fred left us all high and dry here, so now we are just a buncha lost dumbasses......right?

[VirginiaJim]

Brian:

You would think with guys like Fred Harmon running interference for us that we could be free to discuss things like replacement batteries for the TPMS, different octane ratings, tire pressures/ sizes/types, improved replacement parts, etc.

Fred Harmon?  Who's he?  I don't think I've seen him respond lately to any of those subjects here.  However, those subjects have been discussed quite a bit without his input on this forum.  Heck, we even talk about car tires here...  You forgot that one.  I haven't heard any of us discuss deleting or locking posts on those subjects.  You can talk just about anything in this forum.  All you got to do is bring it up.  Course if you ain't got a sense of humor in getting some of the responses or get riled up easily then there's other places to go as well.

[Flathead]

WOW... Four pages and still going.  This is getting as good as an oil thread!

[VirginiaJim]

It's only getting warmed up....

[VirginiaJim]

Must..Not...Respond....

Sure you can.  I'm not near locking this thread yet.

[ZG]

However, those subjects have been discussed quite a bit without his input on this forum.  Heck, we even talk about car tires here...  You forgot that one.  I haven't heard any of us discuss deleting or locking posts on those subjects.  You can talk just about anything in this forum.  All you got to do is bring it up.  Course if you ain't got a sense of humor in getting some of the responses or get riled up easily then there's other places to go as well.