Damn Crappy Roads

Saturday, I'm cruising along on the 405 freeway. I take the transition to the 118E. On the overpass, I hit the expansion joint from hell. Its a stiff jolt, the bike didn't lose composure. However, as I transition onto the 118, the bike feels like shit. The whole bike is vibrating badly. The pegs are vibrating so badly, my feet are going numb. I was in BT communication with a friend, so I had him circle the bike at speed and check for anything wobbling. He didn't see anything. Indeed, a later physical inspection of the wheels, just spinning them on the stands and eyeballing them for imperfections, showed nothing. It seems like all the weights are still on the wheels. Except for the shaking, the bike seemed fine. It has plenty of power, but is popping more on decel than it used to. The bike has a little less than 5000 miles and just had its second service.

I was talking to a mechanic today that said with the whole bike shaking sounded more like a motor problem than a wheel problem. He said that dirt bikes have been known to throw a cam chain off one tooth after a hard impact. If that happens, the bike still runs, but it runs like shit.

So what say you, knowledgeable ones? Has this happened to anyone else? I'm really hoping the fooking 405 did not claim my new forged Marchesinis.

How does the motor feel/sound when you give it a rev while standing in neutral ?

I've had a car throw the chain over 2 teeth before, I don't know how it happens because they're so tight, but it does happen.

With your wheels, the only way to check properly is to mount a magnetic dial gauge onto the forks to see if they're "true". Although I suspect it may be as your mechanic says, as I've seen some seriously damaged rims that still feel fine to ride on because the tyre takes up the shortcoming of the wheel.

Just as an after thought, maybe check your wheel bearings.

Is the vibration road speed or RPM dependant?

You might have a bent axle. Also check for cracks around spokes on your rims.

There was another possibility. I have a tender and heated grips attached to the positive terminal along with the main lead. I might not be getting the best contact. I'm going to check that out tomorrow and do a reset as well to potentially rule out an ecu issue.

Ok, so yesterday I visually inspected the wheels again. It doesn't look like any weights are missing and the wheels have no cracks. I do not have a runout gauge to attach to the wheels to check TIR, but I can't see or feel anything significant.

I fired it up and the bike seems to be running rougher than usual. I performed a reset, but haven't had time to take it out for a test ride to see if it made a difference.

Sorry to hear about your problem. Just wanted to say that I know that transition very well and it is terrible, those 2 steel beams feel like they are going to break the wheels into pieces when you hit them. I don't even like hitting that overpass in the car, just jolts the hell out of you. Good luck on getting your ride figured out.

Try getting the bike up to freeway speed and cluch in to an idle. If the vibes stop it's the motor, if not, it's the chassis.

Has nothing to do with your fueling Crotch, unless one of you coils is not firing and you're running on only one cylinder (but this would be noticable at all RPM). 15 min reset is useless at best IMHO.

Keep us apprised, John

Bummer.
A shot in the dark, but try checking the coil sticks. I have seen one pop out on a BMW R1200, which in turn caused the motor to run like shit. clicked it back in and all was good.

Well, it did it again today. I rode the bike all day Saturday w/o incident. I fired it up today to take it to the dealer (I was debating whether to drop the rough running issue and just have them look at my bumpy tank) when it did it again. Checking the gauges, the low fuel indicator came on and the mileage indicator displayed an F. I've noticed the fuel light coming on recently, but never put 2 and 2 together with the rough ride. When the light went off a couple of miles later, the odometer displayed miles, and the bike ran fine again. Great, an intermittent electrical fault. Stay tuned.

May not be electrical but possibly crap in your tank? If it was me I would drain the tank completely and replace the fuel filter on the beast making sure that the interior of the tank is crystal clean...

Just a thought..

I just remembered that the dealership replaced the R/R a couple of months ago. I'm having them check that as well as the fuel filter while its in the shop.