• Welcome to the Yamaha FZ6 Forums. Member registration disables ads and allows you to post and share. Register Here.

Need Help New Member + 2008 questions: key, wheel lockup

Ben Franklin

Member
Joined
Sep 11, 2025
Messages
31
Reaction score
58
Points
18
Location
Arizona
Visit site
Hello all. New FZ6 owner, 2008 vintage.

It is a friend's problem bike that got gifted to me.

1000231806.webp

There are layers of problems to solve, but first and foremost, I don't have a key.

Is this a chip key bike, or can I just have a locksmith cut a standard key that fits the seat lock?

Prior owner claims engine runs fine, but parked it 5 or 6 years ago after the rear wheel locked up on the freeway at 70+ mph.

Bike didn't go down, but he had it towed and never touched it again.

Says engine was running when he skidded to a stop, with clutch in.

Sat and waited for a cop to block traffic, and was able to push it across 5 lanes to meet wrecker on other side of freeway.

He thought transmission blew up.

I have done a little exploration:

1. Rear brake caliper is not stuck. Piston in and out fine, caliper floats on pins, still had some grease on pins.

2. Chain wasn't awful. No kinks, no signs of carnage around front sprocket.

3. Wheel bearings feel decent, no slop, smooth.

4. Swingarm pivot bearings feel ok.

5. No key, so can't start the bike at the moment, but transmission appears to go up and down through the gears, while rotating the rear wheel on the center stand (clutch pulled in.)

Given the above story, anyone that knows these bikes got any theories? I couldn't find much on search.

My current hypothesis is that the prior owner might have have a toe resting on the rear brake, and heated it up to the point of locking, then it cooled down and released while waiting for the cop/wrecker. Pads dont look bad, but who knows?

Any brilliance will be most appreciated. I am an experienced mechanic, but this has me pondering what the alternative scenarios might have been.

I dont want to put a ton of money into it, but I think it has the potential to be a sweet commuter if I can get confident that the rear wheel won't suddenly decide to lock up again.20250910_223351.webp20250910_230452.webp20250910_225857.webp20250910_230411.webp
 
Last edited:
Welcome to the forum. Regarding the key you can get a new key set (ignition & tank) from Amazon for less than you’d spend to have the key & tumblers re-cut.

The lock-up is a strange one. The fact that he was able to push it to a wrecker indicates that the rear wheel wasn’t locked up. I can’t think of anything that could lock up, and then unstick itself.
 
Welcome to the forum. Regarding the key you can get a new key set (ignition & tank) from Amazon for less than you’d spend to have the key & tumblers re-cut.

The lock-up is a strange one. The fact that he was able to push it to a wrecker indicates that the rear wheel wasn’t locked up. I can’t think of anything that could lock up, and then unstick itself.
Thanks!

Yeah, it is a puzzler. Really, about the only thing that I can think of that would lock it up, then release when cooled down, would be a rear brake caliper either sticking, or a guy riding with his toe on it, until it got real hot and self applied the brakes from boiled brake fluid.

We will see.

Guess I answered my chip key question; I picked the lock, hooked up a battery, and it lit right up. Rev'd and idled fine.

Maybe will put it back together and see how it runs around the block.
 
If the bike doesn't have an immobiliser, you can just replace the lock barrel.

First thing I'd do, though, is find the timing chain cover on the right hand side (just in front of the clutch) and look for a circular cover with a slot in that.

Remove the cover and you'll see a bolt head. Use a socket to try turning the engine over (clockwise, no matter what the Yamaha manual says, they got it wrong!) and see if it will turn freely.

The original engine in my FZ6-SA died when a bottom bearing failed, although the engine didn't seize at the time :(

ADDENDUM: Ah, just seen you got it running OK, but so was mine when the bearing went, it wasn't until I tried to do an overtake that I found I had no power because only 3 cylinders were actually giving power...
 
I think a full lockup at 70mph would be pretty serious and give you a pretty good flat spot on the tire, is there one? If not, maybe not a full lockup?
A foreign object in the chain would damage either the front or rear sprocket, is the rear all good?
Maybe wheel bearing bad when hot?
 
I think a full lockup at 70mph would be pretty serious and give you a pretty good flat spot on the tire, is there one? If not, maybe not a full lockup?
A foreign object in the chain would damage either the front or rear sprocket, is the rear all good?
Maybe wheel bearing bad when hot?
Interesting thought about flat spot on tire. Just went out and looked. I could not see any sign of a skid on the rear tire. Rotated it slowly with a light on it, and nothing.

Now I am wondering about the story.

Guy has years of riding experience, and had owned bike since new. Currently showing just under 44k miles.

Additional piece of probably unrelated info. Front forks seals are shot, puking fork oil profusely. Can't imagine that contributing to a rear wheel lockup, though. (If that is really what happened.)
 
Dane,

Before I forget, one of the two wires by the sprocket cover, one appears to have been pinched
between the cover and block (not your issue but ..).

Your diag process sounds good. I'm wondering if excess fork oil made it
to the underneath of the bike, eventually to the rear tire. (Probably not, but something to explore).

For the most part, rear wheel lock up /issues are rare for the S2 bikes(which yours is).
The S1's had a re-call on front sprockets coming loose, not the S2's but your
aftermarket front sprocket looks fine.

The rear sprocket assembly does have rubber grommits between it and the
wheel. Never heard of those failing but worth a peek.

Lastly, the chain adjustment is MUCH LOOSER than most bikes. If he had it adjusted tight,
that may / could cause issues. If mines 1/16" tighter than 2", I can feel it...

If the chains operating smoothly and adjusted correctly, with all you've checked, I don't
think you'd have a problem for a test ride..

 
Dane,

Before I forget, one of the two wires by the sprocket cover, one appears to have been pinched
between the cover and block (not your issue but ..).

Your diag process sounds good. I'm wondering if excess fork oil made it
to the underneath of the bike, eventually to the rear tire. (Probably not, but something to explore).

For the most part, rear wheel lock up /issues are rare for the S2 bikes(which yours is).
The S1's had a re-call on front sprockets coming loose, not the S2's but your
aftermarket front sprocket looks fine.

The rear sprocket assembly does have rubber grommits between it and the
wheel. Never heard of those failing but worth a peek.

Lastly, the chain adjustment is MUCH LOOSER than most bikes. If he had it adjusted tight,
that may / could cause issues. If mines 1/16" tighter than 2", I can feel it...

If the chains operating smoothly and adjusted correctly, with all you've checked, I don't
think you'd have a problem for a test ride..



Hmmm... I suppose an oiled up tire might seem like a locked up rear to someone in kind of a panic in the left lane 6 lanes expressway traffic.

Will investigate further!
 
I'm doubting the story. If you're going 70mph and jam on the rear brake, you're not stopping in a straight line—you're gonna fishtail wildly until you wipe out.
 
I'm doubting the story. If you're going 70mph and jam on the rear brake, you're not stopping in a straight line—you're gonna fishtail wildly until you wipe out.
I have to respectfully disagree ^^^.

Keep the bike straight and you can indeed lock it up(rear wheel) W/O fish tailing.

How do I know? When I took the ADVANCED Police Motorcycle class, we did just that.
On full dress Harleys.. However, we were in the boonies and locked the rear wheel up
in the grassy median.... (No ABS back then either) . It was very controlled.

This maneuver, IMO, by anyone riding a motorcycle IS very beneficial, (using due care and starting slowly un-til comfy with it).
It's an excellent skill to have under your belt and just to KNOW, if in an emergency situation, it CAN be done safely...


I do agree with you that the story itself is BS.. Time and inspection will tell...


.
.
 
I have to respectfully disagree ^^^.

Keep the bike straight and you can indeed lock it up(rear wheel) W/O fish tailing.

How do I know? When I took the ADVANCED Police Motorcycle class, we did just that.
On full dress Harleys.. However, we were in the boonies and locked the rear wheel up
in the grassy median.... (No ABS back then either) . It was very controlled.

This maneuver, IMO, by anyone riding a motorcycle IS very beneficial, (using due care and starting slowly un-til comfy with it).
It's an excellent skill to have under your belt and just to KNOW, if in an emergency situation, it CAN be done safely...


I do agree with you that the story itself is BS.. Time and inspection will tell...


.
.
For sure, I don’t doubt it’s possible… like you said, with proper training. For the average rider cruising down the highway, this would be an absolute brown pants full-blown panic situation.
 
For sure, I don’t doubt it’s possible… like you said, with proper training. For the average rider cruising down the highway, this would be an absolute brown pants full-blown panic situation.
An average rider, for one trying to keep alive, would be practicing quick safety stops, maybe a finger or two ALWAYS over the front brake lever as well as the brake petal... I could go on but point made..

Did I ever practice this before the course, nope... Never did an "iron cross" either.

.
 
Update:

Rekeyed seat, tank and ignition (had an old Yamaha key, so I just remapped the tumblers to that key.) That ignition wire harness was a real treat to fish back through. Fortunately I thought to pull a piece of string through when I pulled it out, so it helped with fishing it back through.

Cleaned up brakes.

Cleaned and lubed chain.

Overall wipe down with WD40 to remove yuk from sitting.

Drained 6 year old gas, refilled with fresh. Threw 3 ounces of Stabil in for good measure.

New battery, cleaned cable end terminals

Lubed cables

Put some fork diapers on to go for a test ride:

1757925095497.webp

Ride:

Bogs a little off idle, but revs freely. Assuming the old gas needs to flush through the lines. Doesn't like to start hot. Plugs? TPS calibration? Looked down through the throttle bodies while I had the airbox out. Intakes were clean, at least.

Basically runs like a little banshee, though. Pulls real strong up to redline.

Rowed up and down through the gears a few times, no surprises.

I am starting to think the "fork oil on the rear tire" hypothesis might be what happened to prior owner to cause his unfortunate brown pants dilemma. The forks were leaking badly, just rolling it around in my shop.

I think I will go ahead and title, register, insure, replace fork seals, and ride it for a bit. Seems like I may have lucked out here.

1757925451156.webp

I'm sure it would like some new tires, as these have sat for quite a while, but they do not seem to be weather checked and will do for a bit.

A little less than 44k miles on the clock, so likely some life left in her.

Anything I should look out for? Cam chain tensioner? Other stuff?
 
Last edited:
Most excellent! Great progress.


Brake fluid.

Check that the front wheel calipers are releasing fully.
The four piston calipers like to stick.

Yamaha notes every 2 years to replace them. (not needed that often IME).

Lastly, do you think you can save the fork legs with the rust?


With new seals, very little drag:

.
 
The cam chain tensioner shouldn't be a problem with the low mileage.

A few suggestions:

I'd drain the coolant and see what state it's in. If it's brown and murky, flush the radiator and put new in. Also I'd suggest checking the rear shock and see if the sag and rebound are ok.

Put the bike on the stand and get someone to push down on the back (or put some weight on it) and use fingertip pressure to turn the handlebars each way to see if there's any notching or roughness. While you're there, try to pull the forks back and forwards or wiggle them from side to side that could indicate rusted or loose headset bearings.

Try to wiggle the swingarm from side to side as well to check those bearings and check the rear wheel is properly aligned.

Do you know if the 24k mile valve clearance check was done? The next one would be at 48k, but if you're not sure, it may be worth having a look (although it's a bit of PITA to do!)

Balancing the throttle bodies might also be a good idea.

Hope these help :)
 
I recently purchased an 08' FZ6 S2 and ran-into some brown & lumpy coolant in my radiator/cooling system;it seems to have been original. :mad:
I drained and flushed Many times using distilled water until it drained-out mostly clear,although I will do a few more flushes.
I'm glad to see you have your FZ6 just about ready to return to service.
I was curious about the PO's words about the back wheel.. and I'm pleased to see that isn't an issue. 🤔
 
The cam chain tensioner shouldn't be a problem with the low mileage.

A few suggestions:

I'd drain the coolant and see what state it's in. If it's brown and murky, flush the radiator and put new in. Also I'd suggest checking the rear shock and see if the sag and rebound are ok.

Put the bike on the stand and get someone to push down on the back (or put some weight on it) and use fingertip pressure to turn the handlebars each way to see if there's any notching or roughness. While you're there, try to pull the forks back and forwards or wiggle them from side to side that could indicate rusted or loose headset bearings.

Try to wiggle the swingarm from side to side as well to check those bearings and check the rear wheel is properly aligned.

Do you know if the 24k mile valve clearance check was done? The next one would be at 48k, but if you're not sure, it may be worth having a look (although it's a bit of PITA to do!)

Balancing the throttle bodies might also be a good idea.

Hope these help :)
Swing arm feels good. Bet it would like to have throttle bodies balanced

Cooling system looks OK, but will flush soon. Stuff in there has to be old. Oil looked fresh, and full.
.
 
Well, went for a little longer zip around the neighborhood and solved the main mystery, I think.

Hit and held 60 mph on a flat stretch of low traffic road.

After about 5 miles, FRONT brakes self applied hard.

Managed to stop straight with a lot of smoke coming off front tire, didn't dump it.

Nice guy in a pickup truck pulled up behind me and helped me huff it up over the curb to get out of the road. Front brake was still applied hard.

Dug around under the seat and found a 12mm wrench in the OEM toolkit. Cracked front brake line at the mc to relieve pressure and rode gently home.

Right caliper was way hotter than left, so guessing that is the culprit.

Will disassemble and service when I get a seal kit, but think that was the real problem that prior owner had on the expressway. He must have thought rear wheel locked, when it was really the front; go figure...

Slight update: ordered kits for all 3 calipers, along with a fork seal set.
 
Last edited:
Back
Top