What would cause straight line instability and scraping/grinding noises turning?

[inreb]

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^ Zip tie on sacrificial pinecone. 1 per side.

 

[CafeRay]

I wish you had told me about the steering head bearings 4 years ago. The first bike I had, had bad steering head bearings but I didn't know any better cause I didn't know what a bike in good condition was supposed to feel like. It wasn't until I brought my bike over to Fawaz at Speedworx and he explained the situation.

That should have been checked on a safety. There was a period of time when some brands were not properly greasing the steering head bearings from the factory. With the loss of centre stands, it's harder to check for notchiness in the head bearings or slop back and forth.

 

[GreyGhost]

Is your rear axle loose? Wheel wobbling around and chain scraping on things?

 

[油井緋色]

Update from Fawaz, it was the rear bearings. Both are being replaced now.

 

[-JERICHO-]

Update from Fawaz, it was the rear bearings. Both are being replaced now.

Glad you didn't get hurt when it was failing.. that is something I wouldn't want to happen to me at any speed.

 

[CafeRay]

A good spring check is to get the bike up on stands and spin the wheels and give them a shake for any play, check the steering head while you are at it. Also check the swingarm for any side-to-side play. Do this with another person to help secure the bike.

I would consider changing the front wheel bearings.

 

[ZX600]

Rear Wheel bearing.

You are probably going to notice your chain adjusters are not even causing the problem. Stop riding and get it fixed.

Edit: Next time you install your rear wheel ensure your chain adjusters are properly setup and even or it will happen everytime.

Went for a rip yesterday. I noticed a few weeks ago, when the weather was cold, taking 30km/h highway ramps at 60km/h caused a lot of instability. I figured it was the weather so took it easy.

Yesterday, same thing happened but I ended up hearing random scraping noises that started occurring more frequently as the ride went on; the rear started kicking out every so slightly too. This never happened on left turns (though I only turned left at intersections and Bayview -> DVP). Eventually the front started becoming very unstable in a straight line above 60km/h (wobbling back and forth).

Google says wheel bearings, bike is at Speedworx right now...just wanted to discuss cause this sucks =(

Bike is a 2008 GSX-R750 regularly serviced at Speedworx.

 

[油井緋色]

Rear Wheel bearing.

You are probably going to notice your chain adjusters are not even causing the problem. Stop riding and get it fixed.

Edit: Next time you install your rear wheel ensure your chain adjusters are properly setup and even or it will happen everytime.

It wwas the rear wheel bearings.

I always check the chain adjusters and tension every other week.

This was something that happened gradually after winter (and after my crash at mosport). I wasn't quite sure if my instincts were in PTSD mode or if the bike was unstable until I started hearing noises and felt wobbliness at low straight line speeds.

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