The CBR250R Gas Mileage Thread - Page 69 - Honda CBR250R Forum : Honda CBR 250 Forums
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post #681 of 689 Old 11-14-2018, 03:54 PM
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You recommended that stuff so often you should become a sales person for them.
Ha! That's funny! I guess I do.

Techron Concentrate (now renamed "Complete Fuel System Cleaner" - not the regular Injector Cleaner) was recommended to me by friend that's an Engineer in the auto emissions research industry. They did some tests with it and were impressed at how well it removed deposits.

It's not easy to impress this guy - so that's good enough for me.

Another friend that was a professional mechanic said the GM recommended running Techron every 3000 mi. That seems excessive though.

I can't recall the exact threads, but it sure sounded like the CBR could have issues with carbon build-up that caused some serious problems.

Running it once per season should remove any deposits that may eventually become a problem.
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post #682 of 689 Old 11-14-2018, 07:36 PM
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Thanks,

Will buy the 10 oz Chevron Techron next time im at Wally World. Im usually lucky enough to get a cash register with a fat girls a.s.s in spandex to stare at for 20 minutes. So I will put 3 oz in the motorcycle and the rest in my car (which has an 8 gallon gas tank)

Just to make sure I am understanding, are you guys saying to upshift at 5000 rpm or 7000 rpm? I have been coasting with clutch in as much as possible (when it is safe to do so and no car riding my tail)

Last edited by Radha21; 11-14-2018 at 07:44 PM.
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post #683 of 689 Old 11-15-2018, 09:04 AM
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Thanks,

Will buy the 10 oz Chevron Techron next time im at Wally World. Im usually lucky enough to get a cash register with a fat girls a.s.s in spandex to stare at for 20 minutes. So I will put 3 oz in the motorcycle and the rest in my car (which has an 8 gallon gas tank)

Just to make sure I am understanding, are you guys saying to upshift at 5000 rpm or 7000 rpm? I have been coasting with clutch in as much as possible (when it is safe to do so and no car riding my tail)
That's fine, but an occasional run up to redline (like when merging into traffic) is fine too as long as everything is good and the engine is fully warm.

I never coast with the clutch in, but sendler does all the time. It doesn't present any problems.
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post #684 of 689 Old 12-05-2018, 01:49 PM
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Has anybody else noticed that if coasting with the clutch pulled in that when you reach 1st gear on the click down the motorcycle makes a high pitched whine style of sound (very soft noise)? I wonder if its just my bike that does this?

Thats how I know I am finally in first gear while the clutch is pulled in. I clutch-in coast almost exclusively when approaching red lights
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post #685 of 689 Old 12-05-2018, 10:50 PM
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Originally Posted by Radha21 View Post
Has anybody else noticed that if coasting with the clutch pulled in that when you reach 1st gear on the click down the motorcycle makes a high pitched whine style of sound (very soft noise)? I wonder if its just my bike that does this?

Thats how I know I am finally in first gear while the clutch is pulled in. I clutch-in coast almost exclusively when approaching red lights
Motorcycles use straight cut gears in their transmissions so they will make a whining sound. It is most noticeable in first gear.
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post #686 of 689 Old 12-06-2018, 09:58 AM
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Originally Posted by Radha21 View Post
Has anybody else noticed that if coasting with the clutch pulled in that when you reach 1st gear on the click down the motorcycle makes a high pitched whine style of sound (very soft noise)? I wonder if its just my bike that does this?

Thats how I know I am finally in first gear while the clutch is pulled in. I clutch-in coast almost exclusively when approaching red lights
I don't normally coast with the clutch in, but I would suggest waiting until you are almost completely stopped to drop into 1st gear.

If you have coasted for a while with the clutch in, parts of the trans have stopped moving and getting into 1st may take extra force. If you were coasting at a reasonable pace with the clutch in, and in 1st gear, and let the clutch out abruptly you could lock the wheel and cause control issues.

Downshifting one gear at a time, and letting the clutch out in between, keeps the trans spinning and keeps your gearing matched to your speed so if you need to accelerate you are in an appropriate gear for your speed.
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post #687 of 689 Old 12-06-2018, 07:48 PM
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I don't normally coast with the clutch in, but I would suggest waiting until you are almost completely stopped to drop into 1st gear.

If you have coasted for a while with the clutch in, parts of the trans have stopped moving and getting into 1st may take extra force. If you were coasting at a reasonable pace with the clutch in, and in 1st gear, and let the clutch out abruptly you could lock the wheel and cause control issues.

Downshifting one gear at a time, and letting the clutch out in between, keeps the trans spinning and keeps your gearing matched to your speed so if you need to accelerate you are in an appropriate gear for your speed.
Thank you for this advice. I will follow this advice and I will not click down to the very 1st gear until I am almost completely stopped (under 5 mph). When I heard that "1st gear noise" while coasting with clutch in at lets say 15 mph I had a "feeling" that this may not be good for the motorcycle.

If you or anybody else would care to elaborate a little more on what is going on internally with the transmission and engine while this is happening I would be very grateful to hear about it and learn.

I actually drive a CB300F but the bikes are very similar. I had a bad habit of upshifting at around 4k rpm and did not realize I was lugging the engine or that it was bad for the motorcycle to do this. In fact I was thinking that I am "saving gasoline" by upshifting early and often and was even driving at 35 mph in 6th gear (I did not know there was anything wrong with this) ......Basically I was in the habit to get up to 6th gear as quickly as I could.

I tell you that it is just this week that I started waiting until 5 or 5500rpm to upshift. It still sounds to my ears that I am straining the poor little engine too much by upshifting at 5000 rpm, the engine sounds VERY LOUD if I wait until then. It is probably because I am accustomed to driving a manual transmission car that I upshift at 3000 rpm on the car and have carried over this bad habit to the motorcycle now.

But no way could I wait until 6000 rpm to upshift, that just sounds like the motor is going to blow up, you guys would have a hard time convincing me that 6000 or above rpm in 5th gear is not unhealthy
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post #688 of 689 Old 12-07-2018, 06:38 AM
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But no way could I wait until 6000 rpm to upshift, that just sounds like the motor is going to blow up, you guys would have a hard time convincing me that 6000 or above rpm in 5th gear is not unhealthy
Honda did not put the red line at 10500 without serious consideration. If it wasn't safe to rev the bike up that high this forum would be full of stories of blown engines.

Regarding fuel mileage, I find changing up at 5-7000rpm gives me adequate acceleration and fuel consumption in the range of 85 to 95mpg (UK measures) which is a bit better than the average on Fuelly.com of 80-84mpg. After 7500rpm the torque produced by the motor is fading so the bike actually feels faster in a higher gear.
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post #689 of 689 Old 12-07-2018, 08:18 AM
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Originally Posted by Radha21 View Post
I actually drive a CB300F but the bikes are very similar. I had a bad habit of upshifting at around 4k rpm and did not realize I was lugging the engine or that it was bad for the motorcycle to do this. In fact I was thinking that I am "saving gasoline" by upshifting early and often and was even driving at 35 mph in 6th gear (I did not know there was anything wrong with this) ......Basically I was in the habit to get up to 6th gear as quickly as I could.

I tell you that it is just this week that I started waiting until 5 or 5500rpm to upshift. It still sounds to my ears that I am straining the poor little engine too much by upshifting at 5000 rpm, the engine sounds VERY LOUD if I wait until then. It is probably because I am accustomed to driving a manual transmission car that I upshift at 3000 rpm on the car and have carried over this bad habit to the motorcycle now.

But no way could I wait until 6000 rpm to upshift, that just sounds like the motor is going to blow up, you guys would have a hard time convincing me that 6000 or above rpm in 5th gear is not unhealthy
Generally you are "saving gas" by keeping the revs down and getting into top gear as soon as possible. One thing that also helps though, even though it sounds counter-productive, is accelerating briskly in the range of peak torque (where an engine is most efficient) to get to top gear quickly. That reduces the time accelerating and gets you to top gear quicker.

It's not going to blow! Don't worry about revving as long as you are under the red or even rev limiter. These bikes do get to the track, where they are in the red all day long - and they don't blow.

I'm just concerned that keeping the rev low consistently may lead to excessive carbon build-up. This may be due to poor fuel additives in some countries and not a widespread problem. Good idea to run a fuel system cleaner once per season and rev 'er up now and then!

sendler might chime-in with some mileage tips - he's the Mileage Man!
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