RH Clark

I recently purchased a 1983 Miyata 610 about 62cm. I took it to a local bike shop and had bearing checked and packed throughout. The mechanic says he checked the bearings and repacked both upper and lower on the fork. I still have a rattle in the fork that I can feel and hear badly when I bounce the front tire any. It rattles on bumps and if I am breaking hard. Mechanic tells me some of these just rattle and it's a mystery. I don't feel like he is trying to cheat me but he may not know what to do. Any ideas?

Piff 

Rattle? Do you mean you can feel the fork knocking/shuddering when applying the brakes?

Could mean a few different things. I would find a better mechanic as your first priority...

Near as I can tell your headset is too loose. That may be because it simply is poorly adjusted, or it could mean that your frame is damaged.

RH Clark

If you stand over the bike and lock the front brake and try to move the bike front to rear you can't feel any looseness. If I hold the handlebars or top tube and bump the front tire on the ground and hold it in the air,you can hear vibration in the fork. I can also feel and hear that vibration-chatter when braking hard on the front brake like down a step hill. I'm doing the best I can on bike mechanics. They are few and far between around here and way over worked.

noobinsf 

Quick google search, a different forum suggested maybe front hub cones are loose with this type of symptom (not specific to Miyata). That would be worth checking, and would take a few seconds to fix with the right cone wrenches.

dedhed

Could also be a piece of loose braze rattling around in a fork tube.

SurferRosa

Isn't there a non venomous snake that mimics the rattlesnake?

Salamandrine 

If you bounce the front wheel on the ground and it rattles, it usually (75%) indicates that the headset is loose. Or, the headset bearings could be shot, in which case they can be loose even when they are tight enough to start binding. If the headset isn't loose, then the front hub is loose.

It may have been adjusted properly after the mechanic repacked it, but then settled in slightly.

Adjusting loose bearings is something of an acquired skill. I imagine that younger mechanics are not going to have tons of experience with it.

Yeah, it could be a loose bit of brazing material or something inside the frame, but I doubt it. I've probably put together thousands of Miyata built bikes and haven't run into that ever. Sometimes rattles are something totally dumb, like a loose water bottle cage bolt, or a cable end rattling against the frame. Can't tell you what it is remotely, but I can say that rattles are not a normal part of a properly set up bike.

stardognine

It could easily be a ball bearing that got dropped into the steer tube somehow. 🤔 Or something.

Piff 

Don't forget to make sure the quick release is properly tightened.

MetinUz

Is there any side to side play in the front wheel? Could you try it with another front wheel?

Chuckk

Check the head bearing adjustment.
A quick check for looseness is to drop the front of the bike an inch or two and listen for a clink.

madpogue 

Describe in more detail how you "feel" it? Can you feel two parts of the bike moving relative to one another? Can you narrow it down to which parts?

79pmooney

Do you have a full frame pump on the top tube? Several of my Zephal HPX pumps rattle sounding just like a loose headset. I can put my hand on it riding and silence it. I've heard of loose quick releases being the guilty party.

Edit: Engage brain - Oh yeah, I had a 610 for years. Like most of 30 and a lap around this planet (mileage-wise). No, it didn't rattle. Mine didn't put the grin on my face because it fit poorly but it was a rock solid, very well made bike and would have gone on much longer had I not reduced the wheelbase several inches.

Wharf Rat

I’ve also got an 83 610. It definitely does not rattle. It does however put a silly grin on my face every time I ride it. In my opinion these are just fantastic bikes. I hope you get yours sorted. A rattle would definitely keep me from enjoying the ride.

RH Clark

I'm going to take the fork off and check everything myself,which is what I should have done to start with. It's definitely in the fork. It's a dull vibration,not a light rattling sound like something small rattling around. The fork is definitely causing the vibration. I'll let you guys know what I find. It's definitely a great bike and would be a favorite if I can sort it out.

SJX426 

I would remove the wheel and try to create the sound. If it is still there, then I would remove the brake calipers and do it again. All accessories should be removed too. Note that a vibration can propagate through metal easily allowing for the sound to present itself at a different location. I would even remove the cockpit as a last resort just to isolate the source.

mrv 

What about the quill stem? Do you have it all the way down, where the wedge would be at the bottom of the steer tube (or nearly so, where ever it would bottom out)?
My thinking is that this could maybe - possibly - allow the stem to "knock" at the top of the steerer tube where it exits the fork.

I am thinking this because of have this crappy old NISHKI I have a NITTO Tecnomic stem in. I installed some riser pars and lowered the stem as far as it would go. I'm getting a bit of a rattle, but the headset is not loose. I check it often because it does come loose. I am suspicious that the quill stem is so low it's kind of - sort of - acting like a pivot point and the stem is knocking at the top of the steerer tube.

Just a thought.