All of a sudden I am getting a slight wheel wobble that only happens when I brake with the front. Now, I'm a big car nut, and so the first thing I thought of was possibly a warped rotor.

1. Are there any other possibilities that would cause this?
1. Where can i get a cheap replacement rotor?

Thanks.

If it is a wobble and not a surging then it shouldn't be the brake.  Check the tire pressure, if you tire is really squared/might have become unballanced.

How about at speed with one hand.. any vibes then? Could be your forks. Check for leaks and the Fork oil level 

It's more like a heavy vibration/wobble that only happens when applying the front brake. The seals on the forks are a little cracked, but there isn't oil visible anywhere.
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haha no one said anything about wheelies!

The first thing I would check is the rotor as well.  Easy check is rolling the bike and listening real closely and listening for a periodic scrubbing sound.  You may have to lift the front of the bike and get right up next to the rotor to get a good listen, though.

Other options would be bad bearings or a loose axle.  Instability under braking in the front can only have so many options.

oh and I hadn't realized you signed up here man!  welcome and all that jazz.

Well I was out riding today and all of a sudden I hear this awful rattling noise, so I started to head home. It got progessively worse, and now there is a very clear knocking/rattling noise that is consistant with the rpm's. 

Yesterday, after I got back from my ride, I adjusted the the fuel mixture (knob that changes idle) to make my bike idle around 1500rpm. I did this because it was starting to idle so low that the oil light would come on (like it was going to stall). You guys don't think boosting the idle up is what cause it, do you? Also, the oil is very clean, and not low at all.


Now, what are my options as far as getting this thing back on the road?

If ya been doing wheelies,look for a slightly bent fork and possibly damaged steering bearings.Cneck ya fork brace over the fender for bends and loose bolts.

drain the oil and run a magnet through it...sese if you get much residue on the lodestone. If you've spun a bearing then it'll have a lot of debris...filter couldn't catch it all.

Also, are you sure the knocking is RPM consistent?  If you park the bike and rev it in neutral it's still there?

At worse you'll be looking for another motor...which can be accomplished for less that $500 pretty easily.

idling at 1500 rpms wont do anything, thats how my bike has been set up since i got it.

Definately is consistant, it does it at idle and in any gear including neutral. Would someone pretty knowledgeable about bikes be able to call my cell and listen to it over the phone? PM me if you can.

Also, are there rebuild kits available? If so, about how much do they run?

it's too hard to really tell anything over the phone.  If it's a crank bearing it'll sound just like someone hitting a chunk of cast iron with a hammer.

To add, anything that sounds like a loud knocking noise coming from inside the motor is bad bad.

i'm sure kits can be found for rebuilding but it's easier to just get another motor...or that's what I would do...or actually I'd buy a temp motor and rebuild the current one with a 600c setup.

Dude ... sudden rattling and low idle = ready for this ... really ... OK ...
Intake manifold leak. WD40 test baby.
Crank bearing will be a banging noise, rod bearing will be quiet on acceleration and rattle on decceleration, counter balancer will be scraping and they all are bad news.
You should be able to wd40 check it.
Cool.
Srinath.

Makenzie, I'll keep an eye out for replacement engines, just in case my worst fears are true. Any places I should look besides here and ebay? I would love to have a project like a 600, but I have my mind set on another bike real soon, so it would kind of be a waste.

Srinath, what is this wd40 test and how is it done? What's involved with replacing the intake manifold?

I will do my best to record a video and post it up tomorrow.

ebay's the best bet...then craigslist...most of the free bikes i end up with I find on craigslist.

he means to spray WD40 on the manifold boots while the bike is idling and check for leaks...but that would just cause issues at low RPM, not across the board.

i've recently noticed a rattle/groan on deceleration. sounds like it's coming from the top left part of the engine ---- bad news?!

Any links for an engine rebuild kit?

I realize it will be easier, mechanically speaking, to just get another engine but the odds of finding one within reasonable driving distance are slim. Shipping is out of the question, as it would rape me dry. Plus, I've got a Clymer's manual, and a fair amount of wrenching know-how, so I'm not TOO afraid .

There is no engine rebuild kit that I'm aware of.  You can buy a kit that has all the gaskets you'll need (check e-bay) but you won't know what needs to be replaced until you tear into it. 

The gasket kit is basically all you'd need...and new crank bearings.

http://s94.photobucket.com/albums/l89/JBR8387/?action=view&current=MOV00938.flv


^^^ Video 1



http://s94.photobucket.com/albums/l89/JBR8387/?action=view&current=MOV00939.flv

^^^ Video 2

Doesnt Sound Healthy