I think I lost a gear?

[Old Lemon]

so i bought my ninja with 7k miles and shes at 19k now. the chain was starting to kink and decided to change it along with the sprockets. (i assumed it was the stock chain / sprockets) which should be 14 / 45 right?

Well thats what i got for my new sprockets and i didnt really notice until i got onto the highway. But in 6th gear doing 80 mph i was at like 10k rpms. I use to be around 8. 65 at 8 now when it should be at 6. 3rd gear at 30 is at 6k where it should have been in 2nd gear.

And 45 in 4th is like 8k so now my chilled back road speed 45 - 50 i have to do in 5th cause i dont want to waste all the gas going a steady speed at low speeds.

The guy who put it on says he did tighten the chain more than he normally would because over time as i break the new chain in it will loosen on its own. Am i getting these higher rpms from the chain or were the sprockets i bought the bike with not stock?

[xSean13]

I put a 15t front sprocket on mine and get about 9k rpms in 6th at 80mph, and was around 10k with the stock 14, 8k sounds low for stock, based on my experience

[Vampyre]

Sounds like it may have had 15/42 or similar. A lot of people do that to lower the revs at highway speed.

[Motofool]

Originally Posted by Old Lemon

.........Am i getting these higher rpms from the chain or were the sprockets i bought the bike with not stock?

The difference you see is not caused by the tension of the chain.

Buy a 15 front sprocket for $15 and replace the 14.

Nothing bad will happen to your bike for leaving everything as it is: the engine will happily work at 10 K all day long.

[Old Lemon]

thanks for the input guys

[Motofool]

You are welcome, Michael

Your bike has better pick-up now.

[subxero]

my bike is stock and 10k at 80mph in 6th sounds about right to me. i think my 5th is at red line at close to 80mph and i shift to 6th and it drops to 9k-10k ish.

[Old Lemon]

Originally Posted by Motofool

You are welcome, Michael

Your bike has better pick-up now.

indeed it does. WOT in 2nd i was very surprised that i actually accelled that quickly. But probably gonna lose some mpg from the constant higher rpms now which makes me a sad panda

[alex.s]

note, "losing tension over time" is actually the chain stretching and is caused by things like over tensioned chains, poorly lubricated chains, damaged sprockets, improperly aligned rear wheel. a properly maintained chain will not stretch for about 20k miles.

you should never "tighten the chain more than he normally would because over time as i break the new chain in it will loosen on its own".

[csmith12]

[Motofool]

Originally Posted by Old Lemon

........But probably gonna lose some mpg from the constant higher rpms now which makes me a sad panda

There are many opinions about it, but mine is that there is no change.

The engine must deliver the torque that the rear wheel demands, based on the speed of the bike and the friction of the air.

That torque comes from burning fuel; same torque equals same amount of fuel.

It is hard to quantify, but at higher rpms, you open the throttle just a little less than at lower rpms, being the mileage about the same.

This whole thing of the sprockets and transmission ratios works like a regular lever, what you gain in force, you loose in distance.

As usual, I very much agree with Alex's post above.

[Old Lemon]

@alex.s maybe he did that cause he saw that maybe my chain maintenance wasnt what it should be. But i can always go back and ask him to loosen it. he also said that there should be like an inch and a half of play either way? when he was showing me the chain it looked looser than my old one did when he was showing me how far it should be able to go.


@Motofool i see i see. that is good to hear cause i like my 50 mpg

[alex.s]

please don't take it back to that guy. he clearly doesn't know what he is talking about. 1 inch of play, total. the top of the chain pushed in one direction to the top of the chian pushed the other direction.

[Old Lemon]

maybe this is a good time to learn how to adjust my chain

[alex.s]

its very easy. there are two adjusters on the back of the swing arm, the adjuster nut, then a lock nut. it is very important that you hold the adjuster nut and tighten the lock nut into the adjuster nut, otherwise it loosens, falls back, the plate falls back turns and hits the sprocket, bending the bolt... after that you get to spend $40 to replace the entire aluminium insert. its good to silicone the lock nut as well its tightened. im paranoid.

make sure the wheel is aligned properly or you'll eat through rear tires and chains.

[Old Lemon]

does messing with the chain have possibilities of dis aligning the wheel?

[Motofool]

Originally Posted by Old Lemon

.......he also said that there should be like an inch and a half of play either way?.......

Did he charge you????

Originally Posted by Old Lemon

maybe this is a good time to learn how to adjust my chain

[alex.s]

from the factory they should have a properly aligned rear wheel. if you change where the adjusters are screwed into (you pretty much have to in order to change sprockets/chain) then its possible that its not set back correctly. you can use two very long straight edges lined up with the rear wheel to check, some people use string. i just kinda look down the back wheel and the chain and make sure the chain is straight. if the wheel is straight but the chain is totally crooked, the horizontal spacing of your rear sprocket/wheel might be off. one time i rebuilt the 250 bottom end but accidentally spaced the output shaft incorrectly so the offset between the small drive pinion and the large back sprocket was totally out of alignment.

[Old Lemon]

@Motofool so according to that picture, say 1 inch of slack is what im going for, that means i should have half an inch of play going up, and another half an inch going down right?

@alex.s kinda went vroom straight over my head

[Motofool]

Originally Posted by Old Lemon

@Motofool so according to that picture, say 1 inch of slack is what im going for, that means i should have half an inch of play going up, and another half an inch going down right?

@alex.s kinda went vroom straight over my head

Yes, but the practical way to do it is measuring one point on the chain from max top position to max bottom position (forced with your hand) for several sections of the chain (rotate wheel backwards - watch for fingers pinched between rear sprocket and chain).

http://www.horizonsunlimited.com/tech/chain-adjustment

In order to keep the wheels and chain alignment (assuming it is correct), just adjust the tensioners on both sides the same number of turns, pushing the wheel forward while torquing the shaft up (a helper at front will avoid the bike rolling froward and falling over).

[Old Lemon]

so i checked out my chain and it looks like i can push it up about like 3/4ths of an inch but it barely moves down at all. So what does that mean?

[Motofool]

3/4 is within the recommended range.

It doesn't matter if up or down, the important is the total free movement.

[Old Lemon]

alright sweet, ty

[nickjpass]

My dirt bike can have 1.5 inch slack