Regarding a "clunky" transmission...

[sickopsycho]

Well I have the bike running fairly well now. I still have to fine tune the jetting, but I'm going to wait until I get my jet kit in and make sure I have the proper jets in the first place. This question is about how the bike feels moving slow in traffic.
This could be completely normal, IDK. This is my first bike so I'm just learning here. When I'm riding slow in traffic- say 10-20mph... I might be in 2nd or 3rd gear. RPMs are around 4k maybe, I don't pay too much attention to the dash (too much other stuff going on to worry about nonsense such as how fast I'm going ). Anyway, as I roll on the throttle, I feel a very distinct "thunk" when I roll on and off. It isn't a sound so much as it feels like someone bumped into the back of me (or I bumped into someone as I'm letting off). The closest thing I can equate it to is if your automotive transmission is really old and there is waaay too much play in it. It is almost impossible to give the bike an even amount of power and I'm constantly either accelerating or decelerating. I feel like this would happen regardless of gear or RPM range, except at a higher RPM it would be more distinct and maybe even scary?
Does this sound like a symptom of a worn out part or is this just normal behavior for the bike?
When I'm running from stop to, say 60mph- there is no problem. A smooth clutch application yields a smooth acceleration, I just noticed it when I was moving slowly in traffic. As I was trying to maintain a constant, slow pace I was literally rocked back and forth as it felt like it either REALLY wanted to go, or like I has hitting the brakes. I hope that makes sense...
If it helps, if I were to work the clutch to maintain a constant speed (clutch in, slow down a tad, let it out and speed up a tad over and over) I wouldn't feel this jerking. This is definitely a result of the transmission...

[csmith12]

Sounds completely normal to me but let's explore a few things that may help you smooth things out a bit.

Hardware (bike parts)
Chain - Make sure it's tightened within spec, or it will slap the swingarm making a sound. Also check for frozen links.
Sprockets - Google up sharkfin sprockets and make sure your sprockets don't look like that, the service manual will have measures for the operating spec
Cush drive - Some riders like to shim it to remove slop and enable a more crisp throttle response
Clean carbs - Dirty carbs make the bike act funny
Synced Carbs - Make sure they are in sync with one another
Carb butterflies - Make sure they are not sticking and snap open
Wheel bearings - Get the wheels in the air and ensure there is no wobble side to side, only rolling rotation
Swing arm pivot bolt - Ensure this bolt is tight and everything else looks in good service order.
Engine mount bolts - These are known to come loose on these little bikes and the sound you are hearing could be the engine moving around under you. Check these ASAP!!!
Throttle and clutch cable adjustments - Again the service manual will help you here to make sure they are within operating spec. Check for kinks and lube as needed.
Brake caliper bolts - Make sure they are tight!!!
Brake drag - While you may hear the pads touching the discs while spinning them, they shouldn't be stopping the wheel from spinning.
Oil need to be changed?
Clutch/gear where - Does it do it in all gears? What I am really asking is... is it relative to speed? I believe that answer is yes.

Software (human skills)
Throttle control skills - Since this is your first bike, do you have a friend that can ride it to get a second diagnosis of your issue? I could be something as simple as a technique change.
Clutch skills - Throughout your riding career, you will encounter many bikes with different personalities. This is where clutch skills come in to "calm" the beast. For example, my dad's old HD was a torque monster in low rps and gutless in the upper. Use the the clutch can smooth all that out.
Tight on the bars/stiff arms - Loosen up!!!! The tighter you are, then the more the bike puts inputs into you and you feel it more. To put it bluntly, the bike allows you to move around on it right?... so let the bike move under you. Flow with the bike vs fighting it.
Engine braking - Assuming your bike is mostly stock, these bikes have significant engine braking. This is even more pronounced at higher rpms while in the lower gears. This will be a consideration when selecting a gear for your given speed and a input and timing skill to smooth out. ie... it gets easier to manage with practice.

And your other question about will it get worse at higher rpms? It shouldn't, because these bikes love to be ridden in their high-mid rpm ranges. Will it be as smooth as your cage from the start, of course not. But it CAN be assuming your bike is well maintained and ridden with skill.

Good luck and hope it's something easy for you to fix.

[sickopsycho]

Originally Posted by csmith12

Sounds completely normal to me but let's explore a few things that may help you smooth things out a bit.

Hardware (bike parts)
Chain - Make sure it's tightened within spec, or it will slap the swingarm making a sound. Also check for frozen links.
Chain is good, I tightened it when I got the bike (30-40mm methinks was the spec, I followed Kawasakis spec)
Sprockets - Google up sharkfin sprockets and make sure your sprockets don't look like that, the service manual will have measures for the operating spec
I got a bunch of results, none of which were helpful. Are you referring to a sprocket that is heavily worn on the drive side or just heavily worn in general? I think they're ok but I'll certainly double check
Cush drive - Some riders like to shim it to remove slop and enable a more crisp throttle response
"If there is too much slack, you'll feel excessive drive lash when applying and releasing throttle." Thats it EXACTLY. Thanks for the info, pretty sure this is exactly what I'm feeling. Excess lash. What I meant when I was saying an old transmission whas when the rear diff is going out or poorly adjusted in a rwd vehicle. Excess pinion lash makes it drive funny at a constant rate of speed. I'm pretty sure this is exactly what I'm feeling, thanks for the info.
Clean carbs - Dirty carbs make the bike act funny
Not perfect, but darn clean- I did it myself =)
Synced Carbs - Make sure they are in sync with one another
Still gotta check this
Carb butterflies - Make sure they are not sticking and snap open
Nope- they're spotless and smooth =)
Wheel bearings - Get the wheels in the air and ensure there is no wobble side to side, only rolling rotation
Never checked this- derp. Bike is going in the air when I get home from work.
Swing arm pivot bolt - Ensure this bolt is tight and everything else looks in good service order.
Torqued this down when I tightened the chain.
Engine mount bolts - These are known to come loose on these little bikes and the sound you are hearing could be the engine moving around under you. Check these ASAP!!!
Never checked these either, but I did a fair amount of tugging on the motor when reinstalling the carbs and would think I would have felt it. I will check regardless when I get home. Having a motor fall out at 60mph would be pretty embarrassing
Throttle and clutch cable adjustments - Again the service manual will help you here to make sure they are within operating spec. Check for kinks and lube as needed.
These are good
Brake caliper bolts - Make sure they are tight!!!
Will check
Brake drag - While you may hear the pads touching the discs while spinning them, they shouldn't be stopping the wheel from spinning.
These are good, checked when I checked the pads
Software (human skills)
Throttle control skills - Since this is your first bike, do you have a friend that can ride it to get a second diagnosis of your issue? I could be something as simple as a technique change.
Clutch skills - Throughout your riding career, you will encounter many bikes with different personalities. This is where clutch skills come in to "calm" the beast. For example, my dad's old HD was a torque monster in low rps and gutless in the upper. Use the the clutch can smooth all that out.
Tight on the bars/stiff arms - Loosen up!!!! The tighter you are, then the more the bike puts inputs into you and you feel it more. To put it bluntly, the bike allows you to move around on it right?... so let the bike move under you. Flow with the bike vs fighting it.
Engine braking - Assuming your bike is mostly stock, these bikes have significant engine braking. This is even more pronounced at higher rpms while in the lower gears. This will be a consideration when selecting a gear for your given speed and a input and timing skill to smooth out. ie... it gets easier to manage with practice.

And your other question about will it get worse at higher rpms? It shouldn't, because these bikes love to be ridden in their high-mid rpm ranges. Will it be as smooth as your cage from the start, of course not. But it CAN be assuming your bike is well maintained and ridden with skill.

Good luck and hope it's something easy for you to fix.

This last part is certainly a factor. This IS my first bike so I'm still learning. I have been getting a little looser, my first few rides were so white knuckle I was afraid I was gonna pull off the grip handles. I have to straighten them up every time I came to a stop, lol. Thanks for the info- most of this is stuff that I didnt do or check because it wasnt in the maintenance schedule. I appreciate the help!

[csmith12]

My pleasure to help you out.

Sharkfin sprockets = worn sprockets, here is an example.



The same applies to the rear.

[Triple Jim]

csmith12 gives great information. I'll add that I know a woman who recently bought a brand new Sym Wolf 150, rode it away from the dealer, and while turning in a parking lot with the clutch lever completely released, applied a little throttle. The driveline lash, which is what you're asking about, caused a lurch big enough to make her lose her balance, and she fell and hurt herself enough to scare her into selling the motorcycle.

Most motorcycles have very noticeable driveline lash, and we get used to keeping it under control, as csmith said, by slipping the clutch a little, or by shifting to a higher gear, or by being careful with the throttle, etc.. A lot of the lash comes from the dog clutches in the transmission that have a lot of lash by design, so you can get them into engagement easily with things spinning fast. Some racing transmissions have half the dogs cut off to make engagement easier. You think you have lash with all the dogs, you should try half the normal number!

You can see one of a transmission's dog clutches in this photo. There are several types, but this is one type used in the Ninja 250. A pair of dogs is circled. You can visualize how much lash there is if you rotate a gear the other way, making the dogs separate and then rotate until they contact the next one, and this is what happens when you let off the throttle or re-apply it.

[Triple Jim]

I've seen sprockets on a motorcycle that make the one in csmith12's photo look brand new. A friend rode to my house years ago, and I couldn't believe what I was seeing when I looked at his rear sprocket. All the teeth had broken off, and the chain was driving little round nubs. Google "worn sprockets" if you want to see some extreme examples.

[csmith12]

Originally Posted by Triple Jim

I've seen sprockets on a motorcycle that make the one in csmith12's photo look brand new.

Here is my last rear sprocket. Count em up! 13 broken teeth. Yes!!! This sprocket made noises and created lash when rolling on/off the throttle.



ps... don't follow my lead here and ride on sprockets like this.

[Ghostt]

@csmith12 aluminum sprocket I assume? From your track bike?

[csmith12]

Originally Posted by Ghostt

@csmith12 aluminum sprocket I assume? From your track bike?

Yes sir

[greg737]

It's unlikely you have a transmission problem, but the feeling is being transmitted up to you through it.

I agree with the other posters that the sprockets could account for part of the problem, but you should shim your bike's cush-drive. The pre-gen EX-250 is known for having sloppy, loose, undersized cush-drive rubbers.

Unfortunately, ordering a new set of cush-drive rubbers from Kawasaki just doesn't solve the problem. The replacements are just as loose-fitting as the originals.

That's why you have to shim the EX-250's cush-drive.

Getting rid of the EX-250's drivetrain lash is a great feeling, it makes the bike feel like new again. Shim the cush-drive, install new sprockets and chain, properly adjust the chain slack.

http://faq.ninja250.org/wiki/How_to_shim_the_cush_drive

[VaFish]

As I read the original post my first thought was shim the cush drive and check the chain slack.

Looks like several others beat me to the suggestion.

[Triple Jim]

Originally Posted by Ghostt

@csmith12 aluminum sprocket I assume? From your track bike?

For the record, the one I saw with round nubs was a steel sprocket.

[sickopsycho]

Thanks guys, yeah I read the wiki on the cush drive mod and that described exactly what I'm feeling. I will definitely do that in the near future. Regarding Triple Jims explanation of the well-spaced dogs in the gears... that makes a lot of sense, too. It could partially be that, and since there is nothing I can do about that then I'll have to move on and get used to it. The cush drive mod will be done this weekend though I'm sure ;-) Thanks for the input- once again you guys are spot on. I'm glad you could understand my explanation of the problem... reading back through it I realize it was a little disjointed.
I just wne out and checked- my rear sprocket looks near new. There is no noticeable wear on it. I am in dress clothes, so I couldn't really dig in to take a look at the front one, but I will later when I get home. The chain, also, looks good. No tight links or kinks or anything. I just tightened it, like I mentioned, and when I did I completely cleaned it off and applied a liberal amount of chain lube.

[Triple Jim]

Originally Posted by sickopsycho

Regarding Triple Jims explanation of the well-spaced dogs in the gears... that makes a lot of sense, too. It could partially be that, and since there is nothing I can do about that then I'll have to move on and get used to it.

I'd bet that most of the driveline lash is from the transmission, but reducing excess lash in the cush drive will obviously help. Next time you have your chain off, put the bike in gear and rotate the front sprocket back and forth by hand, and you'll see why I'm saying this.

[sickopsycho]

Originally Posted by Triple Jim

I'd bet that most of the driveline lash is from the transmission, but reducing excess lash in the cush drive will obviously help. Next time you have your chain off, put the bike in gear and rotate the front sprocket back and forth by hand, and you'll see why I'm saying this.

Actually I've done that and I know exactly what you mean now. Regarding this, though, and tightening the chain (sorry to jump topic)- when I was tightening my chain, the wiki I read said to rotate the wheel until the chain is tight then measure the slack at this point. The only way I could get the chain tight was to put the bike in gear, but later in the wiki it said to always check the tension of the chain in neutral. How am I supposed to get the chain tight in neutral? The tire just spins and spins, the chain never gets tight.

[greg737]

The cush-drive shimming pictures on the ninja250.org website aren't the best example of how to do it, the guy in the pictures has chosen to shim the drive by inserting material into the gaps where the flanges of the sprocket-carrier fit into the cush-drive rubbers.

There's a better, easier, cleaner way to insert material into the cush-drive. You're just trying to take up some of the extra/excess space within the confines of the cush-drive.

I thought I would include a few photos of cush-drive shimming on my Suzuki GSF400. These pictures demonstrate shimming a cush-drive by inserting material from the outside of the rubbers rather than trying to jam the material into the same space that you'll also have to fit the sprocket-carrier flanges into.

You can use a couple of layers of insert material to get a nice tight fit for the sprocket carrier when engaged. Don't leave any space, go ahead and make it fit snug.

[sickopsycho]

Originally Posted by greg737

There's a better, easier, cleaner way to insert material into the cush-drive. You're just trying to take up some of the extra/excess space within the confines of the cush-drive.

I thought I would include a few photos of cush-drive shimming on my Suzuki GSF400. These pictures demonstrate shimming a cush-drive by inserting material from the outside of the rubbers rather than trying to jam the material into the same space that you'll also have to fit the sprocket-carrier flanges into.

You can use a couple of layers of insert material to get a nice tight fit for the sprocket carrier when engaged. Don't leave any space, go ahead and make it fit snug.

Good deal- I like pretty pictures. This is definately something I will be doing this weekend.

[Triple Jim]

Originally Posted by sickopsycho

Actually I've done that and I know exactly what you mean now. Regarding this, though, and tightening the chain (sorry to jump topic)- when I was tightening my chain, the wiki I read said to rotate the wheel until the chain is tight then measure the slack at this point. The only way I could get the chain tight was to put the bike in gear, but later in the wiki it said to always check the tension of the chain in neutral. How am I supposed to get the chain tight in neutral? The tire just spins and spins, the chain never gets tight.

Hmmm. After adjusting it, I just sit on the bike with the engine off and the trans in neutral and check the slack by reaching down, grabbing the chain, and wiggling it up and down. You'll force the slack to be on the side you're wiggling (top or bottom run) if it's in neutral. Most bikes tighten the chain a little when the suspension compresses, hence sitting on it to check it. Having someone else do the chain wiggling makes it easier, but there's seldom anyone around when I want to do it.

[sickopsycho]

Originally Posted by Triple Jim

Hmmm. After adjusting it, I just sit on the bike with the engine off and the trans in neutral and check the slack by reaching down, grabbing the chain, and wiggling it up and down. You'll force the slack to be on the side you're wiggling (top or bottom run) if it's in neutral. Most bikes tighten the chain a little when the suspension compresses, hence sitting on it to check it. Having someone else do the chain wiggling makes it easier, but there's seldom anyone around when I want to do it.

THERE'S an idea. Put the bike on the ground instead of the centerstand (where the rear wheel can spin freely). DERP. Thank you Jim, you are a big part of the reason why I come here. =)

[Ghostt]

What is the condition of the chain/sprockets? Mileage? Care? Etc....

IMHO when buying a used bike, assume your going to need new chain/sprockets, along with other consumable parts, tires, brakes, fluids, etc....

When in doubt, throw it out! It's a matter of safety, and reliability. Nothing suxs more than having an unsafe/unreliable vehicle. Spend the money right the first time, don't buy cheap quality, in the end you'll be happier spending more time in the wind, than in the garage.

Sidenote: I'll be in N.C. at the end of this month, I've been known to make house calls.

[sickopsycho]

Originally Posted by Ghostt

What is the condition of the chain/sprockets? Mileage? Care? Etc....

IMHO when buying a used bike, assume your going to need new chain/sprockets, along with other consumable parts, tires, brakes, fluids, etc....

When in doubt, throw it out! It's a matter of safety, and reliability. Nothing suxs more than having an unsafe/unreliable vehicle. Spend the money right the first time, don't buy cheap quality, in the end you'll be happier spending more time in the wind, than in the garage.

Sidenote: I'll be in N.C. at the end of this month, I've been known to make house calls.

Where are you coming in NC? I'm in Raleigh, right in the middle of the state. I have definitely seen you post some good info here- I'd love to sit down and talk to someone who knows this bike inside and out.
Regarding the condition of the bike- I actually went to trade school for automotive service. Had a few of my ASE certs at one point, but went into a different employment field and let them lapse. The reason I mention this is because I know my way around a wrench as well as some. The first thing I did when I got the bike was go over it with a fine tooth comb. Replaced any missing bolts, torqued everything down and performed every bit of maintenance that should have been done by 17k miles as if nothing was ever done.
Chain and sprockets are in good shape- that was one thing I didn't change (although chain did need tightening, which I did). I replaced all fluids, plugs and adjusted valves. Removed and cleaned carb. The "problem" I posted about here is most likely a combination of what I'm feeling in the cush drive along with what Jim was talking about where the space between the dogs in the gears allows for a lot of lash. Since I can mod the cush drive to remove a little of this "looseness" I will, but other than that I guess I just need to get used to riding a bike vs. driving a car. On the way home yesterday, I tried to replicate the issue then adjust my riding to compensate- that actually seemed to help quite a bit. Being looser on the bike (riding it vs holding onto it for dear life) made a difference as well as working the clutch a little more rather than leaving it in gear the whole time. A shift up to a higher gear helped some too.

[InvisiBill]

Originally Posted by greg737

The cush-drive shimming pictures on the ninja250.org website aren't the best example of how to do it, the guy in the pictures has chosen to shim the drive by inserting material into the gaps where the flanges of the sprocket-carrier fit into the cush-drive rubbers.

There's a better, easier, cleaner way to insert material into the cush-drive. You're just trying to take up some of the extra/excess space within the confines of the cush-drive.

I thought I would include a few photos of cush-drive shimming on my Suzuki GSF400. These pictures demonstrate shimming a cush-drive by inserting material from the outside of the rubbers rather than trying to jam the material into the same space that you'll also have to fit the sprocket-carrier flanges into.

The FAQ example has the shims inserted along the dividers between the sections, not in the middle where the sprocket carrier inserts. Also, Kawasaki uses one big piece of rubber (there are little rubber bridges going over the wheel's dividers near the center), as opposed to your Suzuki's individual U-shaped pieces. It would be more work to get your longer strips underneath the monolithic cush drive on the Ninja. If you wanted, it might be an option to cut those bridges and convert it into 6 individual U pieces though.




Your method is super clean though. Like you said, the goal is to simply take up some of the empty space in there so things are held snugly, instead of slapping around.

[jkv45]

I just shimmed our Ninja's drive last week. Cut 12 pieces of 1/16" ABS into 5/8" x 1 1/2" strips and inserted them next to the spoke in the hub (as shown in Bill's picture of the Ninja wheel).

The sprocket carried dropped in snugly, but wasn't difficult to install. Removed every bit of the slop. Sprockets and chain are good, so any slop left now is from the transmission.

[sickopsycho]

Originally Posted by jkv45

I just shimmed our Ninja's drive last week. Cut 12 pieces of 1/16" ABS into 5/8" x 1 1/2" strips and inserted them next to the spoke in the hub (as shown in Bill's picture of the Ninja wheel).

The sprocket carried dropped in snugly, but wasn't difficult to install. Removed every bit of the slop. Sprockets and chain are good, so any slop left now is from the transmission.

How long did it take start to finish? Looks like maybe a 2-3 hour job, quicker even if you've taken the wheel off a few times and know the procedure...

[jkv45]

Originally Posted by sickopsycho

How long did it take start to finish? Looks like maybe a 2-3 hour job, quicker even if you've taken the wheel off a few times and know the procedure...

Not bad. Removal of the wheel is the most time-consuming part.

There's nothing to installing the shims once you have your pieces cut.

[csmith12]

Originally Posted by sickopsycho

How long did it take start to finish? Looks like maybe a 2-3 hour job, quicker even if you've taken the wheel off a few times and know the procedure...

To someone who hasn't gotten proficient at taking off the rear wheel and reinstalling it, cutting the shims (I used old 1 gallon plastic milk jug pieces), fiddling with the rear brake and get the chain back to proper spec, I could see the job taking about an hourish.

To those who have been around the block more than a time or two, it's a 10 min job at most. So many of the jobs we do, we spend more time finding & getting the tools ready than doing the work. lol

[Ghostt]

@sickopsycho I'll be heading to the coast, Bath Co. to visit family there.

[Triple Jim]

If you're ever riding up in the direction of Kerr Lake, let me know. If I can get away, I'll show you some really nice riding roads.

[Ghostt]

Unfortunately for this trip I will be taking the cage, due to transporting items, a bit too much for SERENITY to haul. I do plan next season taking SERENITY again.

[Triple Jim]

Oh, you too Scott, but I was thinking of Andrew. He's about an hour and a half from me if you take back roads. I could meet somewhere between, too.

[sickopsycho]

Originally Posted by Ghostt

@sickopsycho I'll be heading to the coast, Bath Co. to visit family there.

Bath is beautiful- my dads side of the family is from there. We spent a lot of time in Oriental, which is close-ish IIR.

Originally Posted by Triple Jim

If you're ever riding up in the direction of Kerr Lake, let me know. If I can get away, I'll show you some really nice riding roads.

I'm sure I can find my way up there. We also had a lakehouse in Ponderosa, just on the other side of the NC/VA line. Spent more than one 4th of july taking the party barge over to the little historic town on the lake where they do a lot of fireworks- Clarksville, I think it was?

[Triple Jim]

I ride past Ponderosa often. Yes, Clarksville is the little town at the bridges. I ride though there often too. One 80 mile loop I like to take around the lake goes past both.