Need owners imput: how fast does 3900 rpm...

[motocephalic]

3900 rpm in 6th gear is ~126km/h (~78mph) indicated

thanks , that is close the calculation, so that must be it.

 

[RMac]

thanks , that is close the calculation, so that must be it.

+ or - . I was going of the fact that rpm is "around" 3500 at 110 km/h.

 

[Jakeboy]

Dude. That is incredible! Since you've obviously done this before, how close does true speed relate to actual real world road speed? Yeah, it kind of seems obvious to me that it does, but my pea brain usually has to hear the same thing two different ways before it sticks. ???

If it is as accurate as it seems to be, we should all be able to use this informaton to determine our individual speedometer error? (I noticed that you have to know the error in order to use the speedo healer.) If it is not too much trouble, can you post a few numbers that fall right on one or two of the big numbers on the tach? Like right at 4K or 5K?

Thanks,
Paul

The most accurate way to determine true speed is using a stopwatch and a set, straight line, known distance, like the mile posts on expressways. Maintain an indicated 60 mph and time your travel over exactly 1 mile. If your stopwatch says 1:05 (or 65 seconds), for example, your speedo error (at 60 mph indicated), would be: -8.33%. If your stopwatch says :58 seconds, your error would be: +3.333%


There are some variables that affect the accuracy of the engine rpm and speed calculation:

1) The exact circumference of the tire will vary from tire brand to tire brand and amount of existing tire wear. More wear-smaller circumference-lower speed at a given RPM. Manufacturing tolerances within the same make and type of tire exist, too!

2) The air pressure in the tire affects the amount of tire compression at the contact patch, thereby affecting circumference. Higher pressure-bigger circumference. Higher temperature of the tire itself increases tire pressure and results in a bigger circumference.

3) Load on the tire-see above.
.
4) The faster a tire is spun, the larger its circumference becomes-centrifical force. This could vary depending on tire construction i.e.; sidewall stiffness (radial vs. conventional bias ply vs. steel belted vs. ad nauseum).

5) This stuff will give you a headache if you think about it too much! I'm no expert, for sure, but tires have always fascinated me for some odd reason. :question:

Having said all that, at 4000 rpm (in 6th gear), your speed would be 79.566 mph.
At 5000 rpm, 99.458 mph.
At 6000 rpm, 119.349 mph
At 3000 rpm, 59.675 mph

All other conditions being equal, as your drive tire wears, your engine rpm's increase at any given speed because a smaller wheel is being driven.

You could tune a Speed O Healer using a GPS, but I'm not sure if that would be the best way as the built in GPS offset may cause some error. Maybe not enough to make a practical difference, I don't know.

Unfortunately, due to temperature, pressure, load and speed, the circumference of the tire will vary, so you really can't 100% get rid of your speedo's error across its entire range. You end up having to average your error over a few different speed readings and typical loading and tire pressures and adjust the Speed O Healer somewhere "in between". If you're going to get one, wear your tires down halfway, then do the setting of the device. That'll give you an "average", tire circumference. If you can get within + or - 2 mph across the speed range you run, I'd call it good.

Damn, I can get long winded! It drives my wife crazy sometimes.

Sure wish the bike would get here.

 

[fredz43]

3Having said all that, at 4000 rpm (in 6th gear), your speed would be 79.566 mph.

Gee, I missed that by 0.434 MPH in my reply #5 in this thread. ;D

 

[ptfjjj]

Duh...... ??? Thanks for the ultra complete answer Jakeboy. That was above and beyond my wildest expectations. I guess that by using your calculations, I will get pretty close results within 1-2% with any tire similar to the stock tire. That's good enough for me, cuz I will probably always use a similar tire.

 

[Jakeboy]

Gee, I missed that by 0.434 MPH in my reply #5 in this thread. ;D

You have to be careful, that kind of error could get you a speeding ticket! Ha ha!

I'm one sick, long winded puppy, I know.

I need that bike!!! Now!!! Help!!!!

 

[fredz43]

You have to be careful, that kind of error could get you a speeding ticket! Ha ha!

I'm one sick, long winded puppy, I know.

I need that bike!!! Now!!! Help!!!!

Well, I can verify that your calculations are accurate, as I checked them at 3,000, 4,000 and 5,000 RPM in 6th gear. I'm too lazy to do all those calculations, but had a good time doing the field testing. ;D

 

[Mellow]

Mellow this is directly out of the US owners manual should be the same for everyone.

Engine break-in There is never a more important period in the life of your engine than the period between 0 and 1600 km (1000 mi). For this reason, you should read the following material carefully. Since the engine is brand new, do not put an excessive load on it for the first 1600 km (1000 mi). The various parts in the engine wear and polish themselves to the correct operating clearances. During this period, prolonged full-throttle operation or any condition that might result in engine overheating must be avoided.

0–1000 km (0–600 mi)

Avoid prolonged operation above 3900

r/min. NOTICE: After 1000 km (600

mi) of operation, the engine oil and final gear oil must be changed, and the oil filter cartridge or element replaced.

1000–1600 km (600–1000 mi)

Avoid prolonged operation above 4700 r/min.

1600 km (1000 mi) and beyond The vehicle can now be operated normally.

NOTICE

_ Keep the engine speed out of the tachometer red zone.

_ If any engine trouble should occur during the engine break-in period, immediately have a Yamaha dealer check the vehicle.

Thanks, that's easy enough.

 

[jajpko]

I think there are two things, that have not been discussed, about engine break in, that are important.
The first is, never hold the same rpm for long extended periods of time.
And the second is a heat cycle. I believe the engine needs to be shut down and let cool off during the
break in. I may put 4 or 5 heat cycles in a 100 mile run.

 

[motocephalic]

I think there are two things, that have not been discussed, about engine break in, that are important.
The first is, never hold the same rpm for long extended periods of time.
And the second is a heat cycle. I believe the engine needs to be shut down and let cool off during the
break in. I may put 4 or 5 heat cycles in a 100 mile run.

I don't think I have that much patience. I am lucky if I can stop 2X in 100 miles. I will try and vary the speed though.

 

[eemsreno]

I think there are two things, that have not been discussed, about engine break in, that are important.
The first is, never hold the same rpm for long extended periods of time.
And the second is a heat cycle. I believe the engine needs to be shut down and let cool off during the
break in. I may put 4 or 5 heat cycles in a 100 mile run.

That would take a lot of will power to do the heat cycle thing in the first 100 miles Even to stop and let it cool in first 500 miles would be tough. I might even go for a 1000 the first day.

 

[Mellow]

The way I see it, it's in Yamaha's best interest to state the break in period. Their engineers are a heck of a lot smarter than I am so I assume if it's good enough for them, it's good enough for me... and I like to keep things simple.

 

[20valves]

Keeping it under 3900 RPM's for the first 600 miles.

I have owned several Yamahas and I do not believe Yamaha has hard RPM limits during break in. Having read so many of their owner's manuals over the years I'm pretty sure it states "avoid prolonged operation over x rpm..." I have never read a Yam manual that says "do not exceed x rpm..."

I like to ride feeder roads to the interstate near my house to break 'em in. You can vary the rpm getting on and off the highway, going through all the gears, then return to base to let it cool, repeat. You get your miles, rpm variance, brake usage and heat cycles. 8)

 

[markjenn]

And the second is a heat cycle. I believe the engine needs to be shut down and let cool off during the
break in. I may put 4 or 5 heat cycles in a 100 mile run.

Various "experts" on the net stress heat-cycling, but I've never seen an OM, factory source, or any authoritative source say it matters. Personally, I don't think it matters. I've never read a sound technical rationale why an engine would break in differently when run through many heat cycles vs. fewer. In fact, I would think it better not to subject the engine to startup wear over and over during break in.

But believe what you like. Nobody has any good data. I mostly think it doesn't matter.

- Mark

 

[motocephalic]

I have owned several Yamahas and I do not believe Yamaha has hard RPM limits during break in. Having read so many of their owner's manuals over the years I'm pretty sure it states "avoid prolonged operation over x rpm..." I have never read a Yam manual that says "do not exceed x rpm..."

I like to ride feeder roads to the interstate near my house to break 'em in. You can vary the rpm getting on and off the highway, going through all the gears, then return to base to let it cool, repeat. You get your miles, rpm variance, brake usage and heat cycles. 8)

I found this information in the service manual:
"0–1000 km (0–600 mi)
Avoid prolonged operation above 3900
r/min. NOTICE: After 1000 km (600
mi) of operation, the engine oil and
final gear oil must be changed, and
the oil filter cartridge or element replaced"

that is where I got the numbers. I agree the feeder roads is the way to travel. It's a time thing for me. I am figuring how many days to take off from work, and I need little provocation for that... )

 

[gazxt1200z]

Hi, yes 3900rpm is 78mph and 4700rpm is 92mph then you start getting real buffeting from the wind so hopefully somebody will make a more angled back screen soon,gazxt1200z

 

[motocephalic]

Hi, yes 3900rpm is 78mph and 4700rpm is 92mph then you start getting real buffeting from the wind so hopefully somebody will make a more angled back screen soon,gazxt1200z

Thanks for the confirmation. After yesterdays ride, I have confirmed it for myself as well. The gearing is tall allowing for ample speed keeping the rpms low.

 

[colorider]

Hi, yes 3900rpm is 78mph and 4700rpm is 92mph then you start getting real buffeting from the wind so hopefully somebody will make a more angled back screen soon,gazxt1200z

Check out Greg's windscreen adjuster:

http://www.motorradgarage.com.au/catalog/product_info.php?cPath=106_247&products_id=1191

 

[motocephalic]

Check out Greg's windscreen adjuster:

http://www.motorradgarage.com.au/catalog/product_info.php?cPath=106_247&products_id=1191

I like it . I have it on my to buy list.

 

[colorider]

I like it . I have it on my to buy list.

I have one in my "bin of farkles", waiting for my SuperT to arrive!!