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35 MPh in 6th Gear on a Ninja 250
Posted: Wed Sep 12, 2007 12:53 pm
by Brackstone
Hi Everyone,
Incase you haven't read my previous post I've been told by the dealer to keep my RPMs under 4k for the first 400 miles.
The problem is a lot of the roads near my area are 40 MpH roads.
The only way I can get up to 35MPH on my bike AND keep it around 4k RPMs is to be in 6th gear.
My question is which way am I doing more damage to this bike? Do I do more damage by keeping it around 4k RPMs at 35mPH? Or by letting it go over 4k RPMs in a lower gear?
Posted: Wed Sep 12, 2007 2:40 pm
by Flesher
Posted: Wed Sep 12, 2007 3:59 pm
by Septimus
IANAM (I am not a mechanic) but most people seem to fall into the "monotune" camp or the "by the book" camp and swear by it. I've heard plenty of anecdotal evidence on both sides.
From my own limited understanding, you aren't going to seriously damage your bike by going a little bit over 4k, but frankly, I'd rather follow the manual's advice unless I really read and digested and felt comfortable with the monotune alternative.
Just another reason to buy used. Let somebody else break it in for you.
Re: 35 MPh in 6th Gear on a Ninja 250
Posted: Wed Sep 12, 2007 4:23 pm
by olebiker
Brackstone wrote:Hi Everyone,
Incase you haven't read my previous post I've been told by the dealer to keep my RPMs under 4k for the first 400 miles.
The problem is a lot of the roads near my area are 40 MpH roads.
The only way I can get up to 35MPH on my bike AND keep it around 4k RPMs is to be in 6th gear.
My question is which way am I doing more damage to this bike? Do I do more damage by keeping it around 4k RPMs at 35mPH? Or by letting it go over 4k RPMs in a lower gear?
He said keep it under not over. also don't stay at the same RPM very big no no in the breakin.
Re: 35 MPh in 6th Gear on a Ninja 250
Posted: Wed Sep 12, 2007 4:30 pm
by Brackstone
olebiker wrote:Brackstone wrote:Hi Everyone,
Incase you haven't read my previous post I've been told by the dealer to keep my RPMs under 4k for the first 400 miles.
The problem is a lot of the roads near my area are 40 MpH roads.
The only way I can get up to 35MPH on my bike AND keep it around 4k RPMs is to be in 6th gear.
My question is which way am I doing more damage to this bike? Do I do more damage by keeping it around 4k RPMs at 35mPH? Or by letting it go over 4k RPMs in a lower gear?
He said keep it under not over. also don't stay at the same RPM very big no no in the breakin.
Sorry I'm not sure what you mean by keep it under not over. Did I say I should keep it over? I got confused :
Also why is staying at the same RPM bad?
Posted: Wed Sep 12, 2007 4:30 pm
by zed
There are two schools of thought:
1- Go by the manual
2- Ride it like you stole it
Pay your money and take your chances!
I had a look at this site and IMHO, another "expert" opinion.
Posted: Wed Sep 12, 2007 4:41 pm
by Ninja Geoff
I thrashed it fairly well during the first 600 miles. Just keep the revs changing constant. It may require doing a little jig with your left foot to keep your speed legal.
Re: 35 MPh in 6th Gear on a Ninja 250
Posted: Wed Sep 12, 2007 5:56 pm
by olebiker
Brackstone wrote:olebiker wrote:Brackstone wrote:Hi Everyone,
Incase you haven't read my previous post I've been told by the dealer to keep my RPMs under 4k for the first 400 miles.
The problem is a lot of the roads near my area are 40 MpH roads.
The only way I can get up to 35MPH on my bike AND keep it around 4k RPMs is to be in 6th gear.
My question is which way am I doing more damage to this bike? Do I do more damage by keeping it around 4k RPMs at 35mPH? Or by letting it go over 4k RPMs in a lower gear?
He said keep it under not over. also don't stay at the same RPM very big no no in the breakin.
Sorry I'm not sure what you mean by keep it under not over. Did I say I should keep it over? I got confused :
Also why is staying at the same RPM bad?
I got the impression that you thought it needed to be over even though you said under. The reason that you vary the RPM is a theory that you will have a ridge in the cylinder wall from a very constant RPM. I don't know if thats true but I have always thought that a varied speed and RPM just felt right. My personal feeling is that lugging the thing is not very good either. After the first hundred miles or so I have always starting beating it a little as I do tend ride fairly hard.
Posted: Thu Sep 13, 2007 9:11 am
by Brackstone
Thanks For all the tips everyone!
I'll remember not to keep the RPMs constant and try to keep it fluctuating!
Posted: Thu Sep 13, 2007 10:54 am
by jrdudas
I know that there are two schools of thought on the break-in period. Some folks at the Ninja 250 forum stand by their opinion that you should ignore the maker's recommendation and ride it the way you normally plan to ride. For me I try to buy used and don't worry about break-in.
As for varying the RPM; that may be a valid practice for a number of reasons, but I don't think that the forming of a ridge in the cylinder wall is one of them. A ridge will always form in the cylinder wall and the placement of that ridge is determined by the point at which the piston stops its upward movement. The ridge will be found where the top-most piston ring reaches its maximum height. Theoretically the piston rises to the same point on every revolution without regard to the RPM. The physical distance from the crankshaft journal (where the push-rod attaches) to the top of the highest piston ring does not vary.
What does vary with RPM is the wear on crankshaft bearings, valve seats, camshaft lobes, valve lifters, timing chain, and piston rings.
For more detailed break-in information on the Ninja 250 specifically a lot of data can be found on the Ninja 250 forum.
JR