[Huskey]

Hello! I'm new to these forums as well as with riding. I've been riding around on a 150cc scooter for a year or so now, and I've been looking to move to a bike. After looking at all the entry level bikes Like the Gt250 Hyosung and Honda Rebel, I decided the Ninja250r is best fit for me. I completed the Mass motorcycle safety course and learning clutch was easy. FRICTION ZONE!!! However, that class can't teach like actual road experience can. So here are my questions.

When your riding down a hill... Is it best to engine brake by down shifting.. or is it just easier to hold the clutch down the whole thing?

Another question I have is specifically about the 250r... What RPM's are you at when you get out of neutral into 1st?

And last of all. What type of gas do you all use? I heard some bikes run better off 87 or 89 octane rather than premium (93 octane). It seems like such a small tank that you might as well fill it with the best there is.

 

[Systematic]

To question number one, personally I like to let the bike to most of the work. To slow at anytime I like to down shift and then easily let the cluch out and get into the FRICTION ZONE. While i do this i am breaking. My logic is, its easier on the breaks and it helps the engine. Again you down shift AND break.

To question number two, I would have to go check again but I believe that i am around 3 or 4. No higher ( unless you wanna pop a wheelie! )

To question number three, I personally like to use the higher octane gas. The gas tank is so small it isn't that much of a change in price. It is also better for the engine.


HAPPY RIDING!

 

[StockWall]

Well, first welcome to the club. 250r is a great choice. When you ride down hill, are you refering to down a hill to a stop sign or just down a hill in general? If you are going down a hill to a stop sign I usually engine brake till about 2nd or 3rd gear then hold the clutch in until I stop. If you are just cruising down a hill, then just cruise and you will naturally feel what to do.
I get the bike up to about 3000 rpm to get going in first. If you hold the clutch in while shifting out of neutral then the rpms shouldnt change untill you give it some throttle.
Just because the octane is 92 or 93 or even 101, that doesnt mean its better gas. Just a higher octane. I am doing an octane test right now so I will let you know next week if high octane is worth it or not. Our bikes are made to run with 87 octane.

 

[StockWall]

Quit saying that "its better for the engine" crap. Unless some one can show me that it is better, its all in your head.

 

[Felix]

Welcome, I think you will have a blast going from a scooter to a ninja!

Quit saying that "its better for the engine" crap. Unless some one can show me that it is better, its all in your head.

Haha, you are a real no believer! Go to the BP site and check out their Ultimate product, Also shell, and clatex here in Aus do a simliar product with the same great results. At the end of the day, like i said in the other thread, it made a MASSIVE difference when tuning my ute... if it does or not with the bike is another matter.

Felix

 

[redrider]

There is a HUGE misconception about what the difference in Octane is.

Octane rating is based on a 100% scale. The percentage of iso-octane/n-heptane is the octane rating. for Example 91% iso-octane/9% n-heptane is 91 Octane.

This however, is not how it is ACTUALLY measured at the pumps. Other fuels and additives (Like ethanol) can change the octane rating, so 91 octane means that is has the knock-resistance of pure 91% iso-octane fuel. There are also different ways that octane is measured. RON, MON, AKI, or (R+M)/2. (R+M)/2 is the most common in the US. Not all measurements are equal to each other. For example a 95 RON rating is only a 91 (R+M)/2 rating.

Ok...so now that you got that useless information...what does a different octane rating mean to an engine?

Higher Octane = Harder to ignite (by the spark plug, or detonation).

The spark plug igniting the fuel is what you want, detonation or pre-ignition is not what you want. Pre-ignition is when the air/fuel mixture is set off before it should in the engines timing cycle. This can cause severe engine damage/failure. This is usually caused by extremely high air temps, timing that is off, or LOW OCTANE fuel.

The engineers who have designed the 250 engine put HOURS and HOURS into research to figure out what kind of pre-ignition resistance (octane) fuel it needs. The only reason to use higher octane is if you have modified the engine for higher compression, are running forced induction (effectively making the compression higher), or drive the bike under extreme hot conditions (where air temps would be really high). I run 91 octane because it is hotter than satan's ass crack here in the summer and I would rather not chance damaging the engine.

Higher octane fuel DOES NOT mean more power, infact the opposite. When fuel is harder to burn....less of it gets burned, meaning less power. The amount of difference between 87 and 91 (R+M)/2 isn't much so my small loss in HP is worth the safety I gain from it.

Other than octane, there are companies that apply additives to their "ultimate" or "premium" fuel, that they don't add to the lower octane fuels. The main thing is detergents to help keep the fuel system clean.

I hope this helps clear up the debate a bit.

 

[subiedriver07]

redrider, nice post, its good to clear this kind of stuff up for us "newbies"

So, here's a question... If you mix 91 and 87, what kind of damage can that do, or does it do any damage at all?

 

[redrider]

There would be no damage, it would just be something in the middle like.. 89 octane.

 

[Huskey]

Thank you for the great posts everyone. But I have one more question!...

If you want to speed up down a hill, can you just hold the clutch in, all the way down? Is that bad for the clutch/engine/gearbox? It seems like that method would save gas and time.

 

[redrider]

I assume you mean slow down going down a hill? You can hold in the clutch, or put it in neutral and let out the clutch and coast down the hill, but the better way would be to let the engine help you decelerate. Not only does this save your brakes a bit, but decel actually uses less fuel than idling as it is under "negative load", whereas idling is under a tiny bit of load.

 

[Huskey]

Thank you Redrider, that's exactly the answer I was looking for.

 

[Captain Scruffy]

I assume you mean slow down going down a hill? You can hold in the clutch, or put it in neutral and let out the clutch and coast down the hill, but the better way would be to let the engine help you decelerate. Not only does this save your brakes a bit, but decel actually uses less fuel than idling as it is under "negative load", whereas idling is under a tiny bit of load.

Question for ya 'rider. I can see feul consumption being equal but I have a hard time seeing it as less. Certainly you are under negative load but you rs will be higher creating a flow through the engine and your throttle plates will still be open,air/fuel still going through the engine but at a rate metered as it would be at idle. How can this add up to lower consumption than idle? :-\

 

[Felix]

Ok, Octane rating does not increase burn rates, it decreases the chance of the fuel auto igniting before the optimun point. So Redrider is spot on in the case of the Ninja. In my case, it makes a MASSIVE difference... I can control charge voltages and timing so I can make the most out of the fuel. I have a tune just for crap fuel, if I am stuck somewhere.

So it sounds like the best thing to do is run 'regular' and once in a while stick a tank of Bp ultimate through or something simliar, give it a flush. Sure would be nice to stick regular in, it was only 1.48/lt today! Filled my tank with 98 at $108

Wise one Redrider, all bow down! How about doing a 'how to' on installing a knock sensor on a ninja

Felix

 

[redrider]

Question for ya 'rider. I can see feul consumption being equal but I have a hard time seeing it as less. Certainly you are under negative load but you rs will be higher creating a flow through the engine and your throttle plates will still be open,air/fuel still going through the engine but at a rate metered as it would be at idle. How can this add up to lower consumption than idle? :-\

You are right, It would still be pulling fuel through as the engine is under vaccum. I completely forgot (DUH) its carbed! Most EFI cuts fuel completely under decel until it reaches lower rpm's, and this is what I was thinking of. There is an anti-afterburn valve that opens on most carbs that allows lots of air to bypass the venturi, stopping fuel from flowing. I am not sure if these carbs have one though. I need to do some research!

 

[Captain Scruffy]

Aaaah. Anti afterburn valve? You teach me something sensei, this is news to me . I thank you.

 

[StockWall]

Ok, Octane rating does not increase burn rates, it decreases the chance of the fuel auto igniting before the optimun point. So Redrider is spot on in the case of the Ninja. In my case, it makes a MASSIVE difference... I can control charge voltages and timing so I can make the most out of the fuel. I have a tune just for crap fuel, if I am stuck somewhere.

So it sounds like the best thing to do is run 'regular' and once in a while stick a tank of Bp ultimate through or something simliar, give it a flush. Sure would be nice to stick regular in, it was only 1.48/lt today! Filled my tank with 98 at $108

Wise one Redrider, all bow down! How about doing a 'how to' on installing a knock sensor on a ninja

Felix

Thats exactly what Ive been trying to say. I just didnt know how to say it so I paid Nick to say it for me. HAhah, no. But that is what I was trying to say.

 

[R6S_2NR]

welcome!

 

[Delta107]

Welcome!!