What is the lowest optimal rpm for the FZ07

[The Pioneer]

So when cruising around at 20-30mph my bike can get pretty hot, so I figure a higher gear like 3 or 4th would be best to keep rpms low to keep temps low, but too low luggs the engine and keeps it just as hot. Does anyone know the lowest optimal rpm? This question really came to me when I was on a gravel road for the first time and wanted to keep the bike in a higher gear to keep from washing out.

[geophb]

When you say "hot" what temps are you seeing?

Lugging can introduce some knock as well.  Also your water pump obviously spins faster at higher rpm, so that would aid in cooling if you're at higher rpm and low load.

[mjh937]

I am usually in third when the speed limit is 25 and fourth when it is 35 (and I typically ride about five mph above the limit).  I am not sure what the rpm is, I just go by engine sound and what feels comfortable.  The engine temperature is usually around 180°. 

[The Pioneer]

1 hour ago, geophb said:

When you say "hot" what temps are you seeing?

Lugging can introduce some knock as well.  Also your water pump obviously spins faster at higher rpm, so that would aid in cooling if you're at higher rpm and low load.

About 190f to 200f. The bike runs fine, but the slow speeds and hot weather make it hot and when I stop it'll go up to 210f and 220f at which point the fan kicks on if I don't shut it off prior, then it starts to cool down. I was just wondering if anyone knew a solid number like how the bike makes max torque at 6500rpm maybe there was a specific lowest rpm for proper coolant speed.

[Fugitive]

6 hours ago, The Pioneer said:

So when cruising around at 20-30mph my bike can get pretty hot, so I figure a higher gear like 3 or 4th would be best to keep rpms low to keep temps low, but too low luggs the engine and keeps it just as hot. Does anyone know the lowest optimal rpm? This question really came to me when I was on a gravel road for the first time and wanted to keep the bike in a higher gear to keep from washing out.

Based on those speeds, I'd be in third gear most of the time when cruising.

Have you had your ECU remapped?  You mentioned the heat factor. I think with some remaps, the temperature that the fan kicks in at is lowered - when I had mine remapped by 2WheelDynoWorks, I believe the fan was changed to come on at 205F, and off at 195F. Could be something to consider. 

[robbo10]

Where the lugging starts gives me the 'rpm too low' point, whatever the temperature may be. I have never felt the need to check engine temperature and so maybe temperature control is the issue for you.

[Beemer]

Just put it in the gear it feels best at and go with it, it's water cooled so don't worry about it. It's not going to get so hot you can't ride it. Besides, I don't know of any tests done to know what gear is best to control engine heat when riding in gravel. 

[klx678]

Personal opinion based on the Cycle World dyno run chart, working in a Honda dealerhip, and personal riding on a variety of bikes from 250 single to 1100cc four, air and liquid cooled.   The chart shows the torque peak to sort of plateau  from 3500 rpm to peak. 

My KLX650 pulled best working 3500-4500 and up.  For max mpg - most efficient range - for the GL1100-1200 was running 3500-4500 rpm, per Honda.  Riding the XSR700, and  some years back  a Nighthawk S 700, both will pull cleanly accelerating hard from around 3500 rpm up.    I think we're seeing a pattern here...

Seems in the general area of average bikes from 650 up to around 1100 are starting to hit stride with best performance  ranging above 3000 rpm and better at around 3500.   Lugging around, as we learned with Wing riders who seemed to think the bikes were diesel powered trying to run down below 3000 rpm, is inefficient, reducing gas mileage and if not burning efficiently then I kind of assume that will also mean generating more heat.    Remember, the water pump is driven by the engine.  So it just kind of makes sense to work the rpm and  stay up around 3000-3500 for efficient mpg and good coolant circulation.   The engines are built for that.    Not to try to lug around like a tractor.

Now going to the KLX250 I ride and other smaller bores, the range pushes up.  My 250 tends to work best if I'm around 4500 rpm.

Point of all this rhetoric?   Let it rev a bit.  Circulates coolant.  magic number is probably around 3500.  Seems to be where I'm at without looking at the tach.   (If you saw the sorry excuse for a tach on the XSR you'd definitely understand.)

 

[FZ07R WaNaB]

On 5/27/2020 at 4:13 PM, The Pioneer said:

So when cruising around at 20-30mph my bike can get pretty hot

I just happen to be a temp watcher (OCD) on my FZ as in that it is my default on my display. I got worried at one point too which is why I always have the temp displayed

I have just over 13,000 miles on my bike, plus a 2WDW flash. My flash has my fan kicking on at 201 degrees. When I'm riding around at speed my temp varies from 174-178 with it being cooler based on  the outside temp. What freaked me out was when I was going slower the temp would go into the 190-200 range sometimes pretty quickly, and then the fan went on. What I realized that this was normal for slow, in-town riding especially in hot weather, and was actually just the way the bike is. The fan always brought the temp back down to acceptable levels, as well as just cruising at higher speeds. Basically, it is not hurting the bike.

FWIW, ride for a couple of hundred miles with the temp displayed, and you will soon realize that is the way your bike operates. I would highly recommend a 2WDW flash for many reasons one of which is their lowering the temp when your fan comes on. I also wouldn't worry about gearing and rpm with respect to the temp, that will just take some of the fun out of your riding experience.

 

Edited May 28, 2020 by FZ07R WaNaB

[geophb]

For all worrying about temps just remember Harleys are air cooled and easily hit oil temps of 300f+ when in hot weather and slow traffic.

Obviously thats the oil and not coolant.  In the fz/mt you wont see less than about 178 or so, as that is the thermostat temperature. In my 2019 mt07 the factory fan engagement temp is 221 degrees.  I would not worry about anything under 230f.

To OP question, anything over 2000 rpm should be high enough rpm for riding you mentioned. Like what klx678 was saying, around the 3500-5000 rpm is probably the sweet spot.  Engines like rpm, low lugging is not good.

[klx678]

3500 rpm is where when you hit the throttle there is very little bog or hesitation, it gets moving quick.  Good thing in traffic to squirt away.   Under 3000 is an invitation to hesitation and bogging in acceleration possibly at a time when it is critical.   

I will say riding around like that I'm running around 57 mpg  or about 24 kpl.   I don't think that's too shabby.  I'm not thrashing hard, but riding a decent pace and not really trying for any hypermileage record.

[FZ07R WaNaB]

18 minutes ago, klx678 said:

3500 rpm is where when you hit the throttle there is very little bog or hesitation, it gets moving quick.  Good thing in traffic to squirt away.   Under 3000 is an invitation to hesitation and bogging in acceleration possibly at a time when it is critical.

With the exception of being in a gear way too high for the speed, I've experienced zero bog or hesitation at any rpm with my FZ-07. Thank you very much 2WDW for that, and that has been for the 10,000 miles after my flash

[klx678]

You just hit the nail on the head.   Put your bike in 5th gear and wind it open at 2000 rpm.   Odds are it won't be wheelieing off into the sunset.  Right gear right rpm.

We had a Gold Wing rider complaining about mpg and that his bike shuddered under acceleration...  he was in 4th gear riding across a parking lot at 2700 rpm!     That is the problem,.not coming off idle from a stop or rolling in first or second gear and accelerating, but trying to run along at some ridiculous low rpm in too high a gear.   It is rolling in traffic in 5th at 20 mph or 6th at 30 mph.   Plus the slow circulation of coolant with the water pump.

[rfmueller]

The owner's manual lists the best minimum revs for each gear.  It's been a while, but 38mph is the minimum for 6th gear, which puts the revs at about 2800rpms.  Personally, unless moving down hill, I keep the revs higher as a rule of thumb for quick actions if needed.  The motor is most efficient, so best bang for buck MPG, when the revs are above 3500 RPMs, and of course, best torque at about 6500RPMs.  I love to hit it at about 75mph because the engine just comes alive and screams ahead.  So much fun at 90mph!

Regarding cooling?  It doesn't matter to me; it's controlled temp water cooling so it's always in a good place regardless of revs.  geophb makes the obvious point that air cooled engines run much hotter, and they don't last as long as a result.  The FZ engines take a real beating and just keep right on going without a hitch.

[Beemer]

I think this is being over thought, it isn't a big deal to begin with. I grew up riding gravel roads and dirt and all you need to do is feel the bike. What I mean by that is if a gear is too low (and you'll know if it is) then go up one gear and it should be fine. Go up one gear too high and yes, it tends to bog in gravel so don't do that, it's that simple. As far as the cooling goes bikes tend to overheat going slower speeds for long periods of time, especially in lower gears but not to worry, your cooling system is doing it's job, your fan kicks on and your bike is just fine. You're over thinking it and worrying over nothing, just ride it and enjoy it. It's a Yamaha, give it a little credit for not breaking so easily. 

[klx678]

I would agree, but those who are overthinking need some answer.  I ride an XSR with the really cheesy thin perimeter LCD excuse for a tachometer, it's kind of necessary to ride by the seat of the pants as if on an off road bike.  Wish it had a real analog display tachometer, but really the way the engine works it's not much of a problem.

One other comment - just because the temp goes over 200 °F/93°C does not mean it is "overheating" .  Part of the reason for a pressurized system and coolant is to raise boiling point to maintain the liquid state of the coolant.  Then there is the fan that operates to increase the rate of cooling by drawing more air through the radiator.   Fact is unless the temperature light comes on it isn't "overheating", it is just warmer than at a normal cruise speed.    Half the problem with some people new to it (having instrumentation) is that they don't learn what is and what isn't a problem.   The owner's manual doesn't seem to have any problem with temperature until it actually hits the limit then reads HI or if the coolant temperature light comes on.

I wouldn't really be very concerned until the temp went over around 230°F/110°C at which point I would want to get moving a bit to get more air circulation through the radiator.   Fact is the the XSR will read up to 242°F /116°C at which point it reads HI and should be shut down.    I'm guessing the FZ and MT will be similar.  I figure if Yamaha was concerned, If they felt it should be at a lower temperature it would come on at a lower temperature.  With my KLX250 I've learned what I needed to know about the temperature levels including when the thermostat opens and closes as well as when the fan turns on and off.  I'm thinking the fan comes on around 211°F/99°C and goes off a few degrees lower than that, so no concern if the fan comes on.  Even when it has, it's only been for a couple minutes.  

Good related story.  In the early days of the Ninja 600 Kawasaki got complaints about the engine temperature being high on the gauge, which has no actual temp markings, just the red zone up high and a couple markers on the face.   The cure to the high temperature reading - adding a resistor to drop the reading.   Yep, the solution wasn't to have the engine run cooler, it was to have the gauge read cooler.  They knew it wasn't a problem with the engine overheating, it was that the gauge just read higher than what some were comfortable with seeing.  Word was they figured peak safe engine temp was around 260°F/126°C  at which it should be shut down to cool.  Obviously they didn't set the gauge at that limit though.

Edited May 29, 2020 by klx678

[Beemer]

Good answer. "Half the problem with some people new to it (having instrumentation) is that they don't learn what is and what isn't a problem." ........... I couldn't have been said better.

So Kawasaki did what doctors have done for ages, they basically gave the Ninja 600 people a placebo to make them feel all better.   

Yamaha could use a few people from Kawasaki on their team. 

[klx678]

As long as they aren't the cam chain tensioner engineers.   I sell Kaw 250 at about 15:1 Yamaha 250!

[botticelli]

Over 50k on 2WDW tune on the bike after the tune, and did 30k+ before the tune, the tune will keep the temps cooler but this is for the rider, not the bike, I mean sure it helps, but its a naked water cooled bike, if its under ~240 indicated, just send it, in whatever gear makes you smile the most, and the bike not lug.

On my long commute in the summer, I would have the bike at or around ~200-210 for over an hour, 2x a day, day in day out, lane splitting, its fine, again in those days It was me that needed a bath after the ride from getting toasty.