Downshifted to 2nd @ 45ish; sounds funny now...

So, yesterday I came around a turn and to my surprise there was a vehicle stopped at a stop sign that I wasn't expecting.. I hit both my brakes and downshifted a couple of gears (into 2nd I think) and released the clutch and the bike jerked like hell and the back tired stuttered a bit, guessing 3rd might have been more appropriate. Anyhow, ever since then (20ish miles home and roughly 80 to and from work today) the bike seems .. odd.

(I'm at about 1300 miles, I've changed the oil at 200ish and 1100ish, tightened the chain at about 1200, which resolved the chain slapping issue.) During acceleration the motor has always seemed very smooth and even smoother (it purrrred) when getting into the higher RPMs (don't ask me what they are, there is no tach =) .. Since yesterday the motor doesn't seem as smooth getting into those higher RPMs and it sounds louder. The chain also has more slack in it than it did yesterday morning.

No issues starting, doesn't really sound any different at idle, oil level is correct and a pretty amber color, clutch doesn't really feel any different.

Anyone have any idea what I jacked up?

...v

You basically described the process for backing it in.

Should not of hurt anything.
Unless your clutch cable stretched a little bit and your clutch is slipping at higher rpm's.

f3joel wrote:

You basically described the process for backing it in.

Should not of hurt anything.
Unless your clutch cable stretched a little bit and your clutch is slipping at higher rpm's.

Backing what in?


I supposed I'm mostly concerned with the rapid change in the way the motor sounds; it also appears that I stretched the chain and just I'll need to adjust it again. I really haven't been that hard on it yet, I've only adjusted it 1 notch so far. I don't know how much stretch these stock chains have.

...v

I highly doubt that downshifting one gear too many and letting the clutch lever out will stretch the chain.
Make sure you're not adjusting the chain and leaving too little slack in it because it has to have some, and if you leave too little, it will never stop loosening.

Either way, if there was enough traction (usually unlikely to the standpoint that the wheel would not break traction - the "backing-it-in" description) seems it would terminate at the rev limit.

...or can you over drive the limiter during breaking ?

All other things being nominal, we tend to hear strange things after we do something unusual. Just a thought...

X-Racer wrote:

...or can you over drive the limiter during breaking ?

Yes, it's possible because the energy of the bike in motion is driving the engine RPM up, and not the energy from combustion.
This could happen if you hit the kill switch at this time.

This is one of the ways guys on modern 4-stroke motocross bikes can blow-up their valve trains:
Downshifting early just before landing from a jump, and once the wheel touches down, the RPM is driven to the moon, rev limiter or not.

The rev limiter cuts power when you're increasing RPM via the usual way - with the throttle.
Rev limiter won't guard against an increase in RPM coming in through the back door.

"Backing it in" means breaking rear wheel trackion when decelerating and allowing the skipping/sliding rear wheel to slew to the side.

viroid:
Unless the engine RPM went sky-high during this event, your bike is probably OK.

https://www.youtube.com/watch?v=GDbWSkTwJdk <-- clicky

at the 36 second mark ----that's backing it in....

Some call it drifting, but I think of drifting as stepping out the rear wheel under hard acceleration.

I think of backing it in as stepping the rear out under braking. Setting up for the apex.

Inspect your chain and sprockets. Pull the cover off the counter shaft sprocket and check the sprocket teeth. An improperly adjusted chain will sound and feel bad. There is no hope for a terminally stretched chain. If it all bothers you too much, replace the lot (chain and both sprockets). This may be an ideal time to consider dialing in your preferred final drive ratio.

YZEtc wrote:

X-Racer wrote:

...or can you over drive the limiter during breaking ?

Yes, it's possible because the energy of the bike in motion is driving the engine RPM up, and not the energy from combustion.
This could happen if you hit the kill switch at this time.

This is one of the ways guys on modern 4-stroke motocross bikes can blow-up their valve trains:
Downshifting early just before landing from a jump, and once the wheel touches down, the RPM is driven to the moon, rev limiter or not.

The rev limiter cuts power when you're increasing RPM via the usual way - with the throttle.
Rev limiter won't guard against an increase in RPM coming in through the back door.

"Backing it in" means breaking rear wheel trackion when decelerating and allowing the skipping/sliding rear wheel to slew to the side.

viroid:
Unless the engine RPM went sky-high during this event, your bike is probably OK.

YZEtc,

I'm guessing the RPMs flew to the moon as you put it; the motor just isn't as smooth, I'd say it's a noticeable difference in both power and sound at higher RPMs. Could I have screwed up the valve adjustment? Is it possible to bend a valve rod in these? I might hear a real light tapping or ticking sound if it were the valves right?

Coasting with the clutch in and no gas, or light revving while sitting still there is no abnormal noise.

...v

If I were worried, I'd measure the valve clearances.
If they were OK, I'd quit worrying. :)

The motors were designed to run in excess of 13000rpm so RPM should not have hurt anything
If it did it would float a valve and the valve would hit the piston, the result would be a distinct non running condition (blowed up)
Modern 4st motors basically have 2 conditions perfect and broken, there's not much in between with stuff in this state of tune
Make sure your chain doesn't have a severe tight and loose spot and go run the bag off it, that always set's my mind at ease after I have an event

v,

Keep us posted. Glad you avoided the rear-ender.

Sarah

If the bike starts fine it's all good. This is a low comp motor and if you tapped a valve and bent it you would know it. You would be on your ass before you got the rpms up that high dropping gears at speed.. Go adj your chain and take it for a ride and do it with ear plugs in.. Ear plugs will help cut out all the others sounds that you don't need to care about...


If your not feeling right about it get it hot and do a comp, test..


Nicky Hayden is a big dick for making it look so God dam easy... Got to love him tho

Please correct me if I am wrong, but isn't it possible to float a valve when you downshift too far and exceed the limiter from engine braking rather than combustion? At least that's what I've always heard about these little 4strokes

clint wrote:

Please correct me if I am wrong, but isn't it possible to float a valve when you downshift too far and exceed the limiter from engine braking rather than combustion? At least that's what I've always heard about these little 4strokes

you can, but 45 in 2nd is right around rev limit and not in the danger zone.

And keep in mind the motor you have under you. Your not going to float a valve as easy as you may on a full race bike like a KTM, WRf KX.....
+ in the street your ass would be down long before, sorry your tires are not that good to not let go at speeds you need to get that motor up that high..

clint wrote:

Please correct me if I am wrong, but isn't it possible to float a valve when you downshift too far and exceed the limiter from engine braking rather than combustion? At least that's what I've always heard about these little 4strokes

Yes it's possible to float a valve on any engine but unless it hit's the piston you won't hurt it

Yes you can but it's not going to be so easy on this motor...
I love the internet..Something happens to ONE person and everyone runs..

With the earplugs in you can hear the vibration (or rattle) when cruising. Definitely noticeable when up-shifting, you can hear it as the motor winds down. Hard to hear it over the motor/exhaust/wind at higher speeds though, but I can still make it out depending on how my helmet is turned.

I stopped by the dealership on Wednesday, one of the mechanics took it for a ride but said without having another WRR to compare it to he didn't really notice anything odd. He said it seemed like it was running fine. I'm scheduled to drop off the WRR on Tuesday the 29th; dealer is going to take a more thorough look at it and perform a compression check.

...v

seems somewhat familiar to mine when my crankshaft bearing went bad. had slightly more vibration and a slight odd noise, nothing big, just didn't seem normal but no loss of power what so ever. checked over many things and never could figure it out, I think I had 150 miles on it before I finally determined it was an internal motor issue. I hope yours is not. when the mechanic tore the motor apart and showed me the damage I could not believe the thing was still running.
have the dealer check it out just to be sure.

sorry if I missed it but what year bike is it?

mattf wrote:

seems somewhat familiar to mine when my crankshaft bearing went bad. had slightly more vibration and a slight odd noise, nothing big, just didn't seem normal but no loss of power what so ever. checked over many things and never could figure it out, I think I had 150 miles on it before I finally determined it was an internal motor issue. I hope yours is not. when the mechanic tore the motor apart and showed me the damage I could not believe the thing was still running.
have the dealer check it out just to be sure.

sorry if I missed it but what year bike is it?

It's an 08. It could be a bearing, I'll have to remember to mention it. Thanks.

viroid wrote:

mattf wrote:

seems somewhat familiar to mine when my crankshaft bearing went bad. had slightly more vibration and a slight odd noise, nothing big, just didn't seem normal but no loss of power what so ever. checked over many things and never could figure it out, I think I had 150 miles on it before I finally determined it was an internal motor issue. I hope yours is not. when the mechanic tore the motor apart and showed me the damage I could not believe the thing was still running.
have the dealer check it out just to be sure.

sorry if I missed it but what year bike is it?

It's an 08. It could be a bearing, I'll have to remember to mention it. Thanks.

mine's an '08 also. does it sound like it's on the right side, almost like it's coming from near the exhaust header pipe? I could hear it clearly standing on the right side (mainly standing even with the motor or slightly ahead of it) while it idled and could hear nothing abnormal while standing on the left side.

mattf wrote:

mine's an '08 also. does it sound like it's on the right side, almost like it's coming from near the exhaust header pipe? I could hear it clearly standing on the right side (mainly standing even with the motor or slightly ahead of it) while it idled and could hear nothing abnormal while standing on the left side.

Yes, it does sound like its coming from the right side. I don't usually hear anything during idle, but I'm usually on the bike or on the left side of it. I'll have to check that later.

Well, general rule is mechanical problems never get better, they always get worse especially in the case of a rod bearing as when it spins it plugs the oil delivery hole, this get's much worse in minutes and will not even survive hours or full load for more than a few seconds
If you have a truck shop around they can analyze the motor oil and tell you if there is bearing material in it
Doing what you did by overspeeding the engine would not cause a rod brg so skid, that is exclusively an oil starvation issue
My WR has cam chain noise that I don't hear in other WR's, a tech can tell you if that's what you are hearing
I call this cosmetic noise as it is just there but does not affect anything but my ear

Viroid,

Did you ever find anything wrong or is it still running ok?

Thanks,

BigFeet