Author Topic: Sprocket bolts snapping off - Removing Bearing Retainer??? (Read 7372 times)

brycegp · « **on:** July 12, 2010, 08:42:03 AM »

So I was riding home yesterday....50 mile ride. And every sharp left turn i would hear a "tick tick tick"...then I would lean back to see/hear the issue and nothing. I pulled over and the chain looked a little dry so I thought maybe it was making noise cuz it needed oiled. Found an auto parts store around the block...oiled the chain.

But sure enough, the next sharp left turn I heard it again. And this time when I looked back at the rear tire (sprocket side) I see a piece of metal fly off. So I immediately pull over and inspect. but the wheel still was spinning smoothly. finally i realize that three of the four sprocket bolts are missing.

somehow the sprocket bolts were hitting the swing arm when I took a sharp left turn. And it was clipping them off. But since it was only in a sharp turn, when I inspected it upright it was fine.

I know how to fix it. And I need a new cush drive.

but anyone had this issue before??

CycleRanger · « **Reply #1 on:** July 12, 2010, 08:45:26 AM »

Allow me to be the first: What bike?

fire113 · « **Reply #2 on:** July 12, 2010, 09:21:58 AM »

Quote from: CycleRanger on July 12, 2010, 08:45:26 AM

Allow me to be the first: What bike?

1+ ^^

brycegp · « **Reply #3 on:** July 12, 2010, 01:12:44 PM »

Sorry...

1972 Honda CB500

brycegp · « **Reply #4 on:** July 13, 2010, 12:07:05 PM »

Nothing, guys? Thought you guys would have some input on this....

turboguzzi · « **Reply #5 on:** July 13, 2010, 12:13:56 PM »

the NUTS, not bolts in a stock 500 hub should have bendable long washers underneath, they are there exactly to prevent this very dangerous situation. could end in tears. if you omitted them while fitting your rear sprocket slap your own hands, if its the PO, then find him and kill him...

TG

CycleRanger · « **Reply #6 on:** July 13, 2010, 12:53:30 PM »

Quote from: turboguzzi on July 13, 2010, 12:13:56 PM

the NUTS, not bolts in a stock 500 hub should have bendable long washers underneath, they are there exactly to prevent this very dangerous situation. could end in tears. if you omitted them while fitting your rear sprocket slap your own hands, if its the PO, then find him and kill him...

TG

Example of what sprocket lock washers might look like.

brycegp · « **Reply #7 on:** July 13, 2010, 01:23:21 PM »

the nuts and studs (BOTH) were clipped off by hitting the swingarm...and them coming loose doesn't seem to be the problem. the lock washers WERE on there. the one NUT AND STUD that is still on there...still has the lock washer on there.

the problem is that they got clipped off by smacking the swingarm when I leaned into a LEFT TURN. So the wheel must be flexing when leaning into a turn. Can a bad rear wheel bearing allow the rear wheel to flex off center in a turn or something?

eurotrash · « **Reply #8 on:** July 13, 2010, 01:27:36 PM »

Guys, so to be clear here, the hub uses studs/nuts to retain the sprocket... aided by lock washers that Cycleranger was good enough to show.

I think what Bryce is trying to express is that it seems his hub is somehow leaning into the swing arm while turning left.. I don't think bad wheel bearings cause this?! Seems like they would have to be pretty toasty and generating serious noise before getting to that point. And knowing Bryce, he'd have noticed that weeks ago.

So where, aside from the attaching point, could the wheel/hub assembly possibly give enough to allow the sprocket to lean into the swing arm?!

lone*X · « **Reply #9 on:** July 13, 2010, 01:29:45 PM »

Axle nut properly torqued? Wheel properly aligned with the bike? Bad swing arm bushings?

brycegp · « **Reply #10 on:** July 13, 2010, 01:55:58 PM »

pic one of the missing nuts and studs...

xenoscr · « **Reply #11 on:** July 13, 2010, 02:02:57 PM »

Do you have a pic of the whole swing arm that shows the spacing between the swingarm and sprocket? If you lift the bike onto the center stand, how much play is in the wheel? If there is noticeable play, can you visually see where?

XeNoSCR

Frostyboy · « **Reply #12 on:** July 14, 2010, 03:55:04 AM »

Now I'm only guessing that the rear hub is the same as a 550, but what if the rear wheel bearing retainer nut has loosened or come off? It's hidden behind the plate over the sprocket & the final drive flange could move outwards, away from the hub & possibly allow the sprocket studs to strike the swing arm. If the bearing is still being held in the hub by the spacers & the axle nut is secure, the drive flange could still be on the loose. Why it only happens when turning left, I can't imagine. Maybe gravity?
See if the final drive flange can be moved away from the hub & that should hopefully reveal the problem.
Just my .02 cw.

turboguzzi · « **Reply #13 on:** July 14, 2010, 04:11:41 AM »

if everything is left stock, the left wheel spacer presses on the bearing and the bearing presses on the cush drive, so even without the spring clip, the cush part cant move sideways. the wheel would have to be impossibly miss-aligned for the studs/nuts to touch the swingarm.

something is wrong big time....

better pics will help us understand what

TG

lone*X · « **Reply #14 on:** July 14, 2010, 11:45:48 AM »

Could it be that the left wheel spacer was not installed?

brycegp · « **Reply #15 on:** July 14, 2010, 02:57:28 PM »

Thanks for all the suggestions for what to look for, guys!

I'm waiting on my new cush drive and wheel bearings to show up and then I disassemble it find out what is causing the problem.

I get picks up when I disassemble it....

brycegp · « **Reply #16 on:** July 17, 2010, 02:33:07 PM »

New, used cush drive showed up today.

Before:

Shortly after:

Just waiting on my new wheel bearings and I'll get it swapped out.

brycegp · « **Reply #17 on:** July 17, 2010, 02:50:06 PM »

Keep in mind fellas, I rode this bike EVERYDAY for the past 2 years...so this isn't an install issue. Unless the PO did it wrong and it just cause a problem 2 years later.

Here are pics of the rear before I take it apart...

1.

2.

3.

4.

5.

dave500 · « **Reply #18 on:** July 18, 2010, 04:27:44 AM »

is the chain one link too short and its all too far forward?

Frostyboy · « **Reply #19 on:** July 18, 2010, 05:24:13 AM »

What strikes me as odd is the amount of thread that is exposed on the studs compared to my rear wheel. There is 1½ threads max outside the nuts on my flange. There looks to be about 4 times that on your pic.

CB500_k2 · « **Reply #20 on:** July 18, 2010, 05:32:47 AM »

Here is a picture of my rear sprocket (CB500) You will notice that end of the securing bolts does not go beyond the rim of the chain retaining ring. On your pictures the remaining bolt extends way beyond the ring. This suggests that there may be a problem in the wheel hub, possibly the cush drive.

brycegp · « **Reply #21 on:** July 18, 2010, 12:33:35 PM »

Quote from: Frostyboy on July 18, 2010, 05:24:13 AM

What strikes me as odd is the amount of thread that is exposed on the studs compared to my rear wheel. There is 1½ threads max outside the nuts on my flange. There looks to be about 4 times that on your pic.

After inspecting a friends cb500, i noticed this as well... it is definitely at least part of the problem.

Like I said, I've been riding this for 2 years. And it only recently became an issue.

Is it possible that the stud has been vibrating/turning...and working its way out...while the nuts because it is locked stays where it is??

brycegp · « **Reply #22 on:** July 18, 2010, 12:46:52 PM »

Quote from: CB500_k2 on July 18, 2010, 05:32:47 AM

Here is a picture of my rear sprocket (CB500) You will notice that end of the securing bolts does not go beyond the rim of the chain retaining ring. On your pictures the remaining bolt extends way beyond the ring. This suggests that there may be a problem in the wheel hub, possibly the cush drive.

I've had to replace the cush drive...and I will make sure that the studs are not extending so far outward this time around. In addition, I am replacing the wheel bearing just in case there is an issue there.

andy750 · « **Reply #23 on:** July 18, 2010, 01:33:49 PM »

Curious question but shouldnt the axle nut be on the other side (right hand side)? I have no experience with 550s but on all the 750s I have seen its been on the right.

Andy

IndyFour · « **Reply #24 on:** July 18, 2010, 01:51:00 PM »

Quote from: andy750 on July 18, 2010, 01:33:49 PM

Curious question but shouldnt the axle nut be on the other side (right hand side)? I have no experience with 550s but on all the 750s I have seen its been on the right.

Andy

The axle nut is on the left (chain side) on the 500/550. I never realized that it was different for the 750 until you asked that.

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Author Topic: Sprocket bolts snapping off - Removing Bearing Retainer??? (Read 7372 times)

eurotrash