Author Topic: Cam Shaft Bolts Came Loose (Read 2377 times)

Mo · « **on:** March 13, 2013, 10:18:35 AM »

I went to start my bike up today and the engine had mysteriously frozen over the course of a week. Weird. So I proceeded to remove the rocker cover and discovered the cam shaft bolts had come loose and off. Luckily the didn't fall into the lower end and I was able to remove them.

I'm wondering why this happened and what I can do to prevent this in the future. As far as I can remember, I had installed them pretty tightly when I did the top end over the summer.

Elan · « **Reply #1 on:** March 13, 2013, 10:32:59 AM »

"pretty tightly" - did you torque them to spec? any liquids like antisieze or loctite or anything?

Mo · « **Reply #2 on:** March 13, 2013, 10:34:37 AM »

Hmm my manual doesn't list any spec for torquing. Would you by chance know the value? Also would loctite be a good idea?

Elan · « **Reply #3 on:** March 13, 2013, 10:36:25 AM »

Also do you mean the bolts that hold the rockers or the cam sprocket bolts? and what bike?

Mo · « **Reply #4 on:** March 13, 2013, 10:39:06 AM »

The two bolts that hold the sprocket. It's a CB500. Thanks

Elan · « **Reply #5 on:** March 13, 2013, 10:48:26 AM »

ya some use loctite, I probably would. I believe torque is 13-15ft lbs. search that to double check. When mike did my top end, he used a bolt with a larger head/more surface area too.

Mo · « **Reply #6 on:** March 13, 2013, 10:50:01 AM »

Hmm okay. I'll head to the store now and report back. Thanks for the quick replies

raymond10078 · « **Reply #7 on:** March 13, 2013, 10:58:55 AM »

Manual shows 10.1 - 10.8 ft-lb for a CB500.

http://manuals.sohc4.net/CB500/HSM500550_1.pdf

Mo · « **Reply #8 on:** March 13, 2013, 02:19:50 PM »

Man this bike loves to mess with my head. Anyway, I was able to reattach new bolts, and torqued them to spec. Bike won't start now, but I probably messed up the timing. Regardless, I didn't have time to pull the cover again (I know, I should have checked first) so I'll figure that out later.

Thanks guys! Hopefully, they wont come loose again.

tool14 · « **Reply #9 on:** March 14, 2013, 05:01:47 AM »

can you spin motor or is it frozen,you might have bent some valves.

Mo · « **Reply #10 on:** March 14, 2013, 12:07:31 PM »

Quote from: tool14 on March 14, 2013, 05:01:47 AM

can you spin motor or is it frozen,you might have bent some valves.

Motor now spins fine, after I pulled the cover and replaced the bolts. I'm pretty sure the problem is my ignition timing. I messed with the plate when I was trying to diagnose why the engine stuck. Once I fixed the issue, I had forgotten I even touched the plate, and now I'm fairly certain its off by ~20 degrees.

bluesoverlord · « **Reply #11 on:** March 15, 2013, 11:38:32 AM »

I'm pretty sure I read in hondamans book that those bolts are specially hardened and placed in a specified order (at least on the 750 one has a rounded shoulder) although placement in order like the factory is not a big deal. Anyway, the hardness apparently is, or why would it be specified?

KRONUS0100 · « **Reply #12 on:** March 15, 2013, 06:11:34 PM »

consider yourself lucky. that same thing cost me a cam, cam towers, cam sprocket and 2 new bolts, and another set of gaskets and oil change. i coulda swore an oath that i had put red loctite on em the first time and then staked em as well.......guess what i didnt. made dang sure i did the 2ccd time

Mo · « **Reply #13 on:** March 15, 2013, 09:25:07 PM »

Hmm well I just replaced them with machine bolts I picked up at lowes. I doubt they're anything crazy? I was hesitant to use the loctite. I figured since they didn't have loctite back then, why would I need it now? I bought it and all and then just had second thoughts. Bad idea?

I did make sure to torque them to factory specs this time around.

Retro Rocket · « **Reply #14 on:** March 16, 2013, 12:54:19 AM »

Quote from: malkaysi on March 15, 2013, 09:25:07 PM

Hmm well I just replaced them with machine bolts I picked up at lowes. I doubt they're anything crazy? I was hesitant to use the loctite. I figured since they didn't have loctite back then, why would I need it now? I bought it and all and then just had second thoughts. Bad idea?

I did make sure to torque them to factory specs this time around.

You are going to completely screw your bike up unless you start asking {and listening} to someone that knows what they are doing about engine work on these bikes, very amateur mistakes.. Use the RIGHT PARTS, nothing on your bike should come from Lowes.....WOW

bwaller · « **Reply #15 on:** March 16, 2013, 04:34:04 AM »

+1 RR.

Whatever you do install proper cam bolts or suffer the consequences.

Mo · « **Reply #16 on:** March 16, 2013, 05:54:53 AM »

Lol I'm not opposed to listening. No one says anything about the types of bolts required for this. Where does one obtain the proper bolts?

Man, there's a reason I'm asking here first...

Mo · « **Reply #17 on:** March 16, 2013, 06:16:59 AM »

Looked up the PN: 90081-246-000

Pretty available from HONDA, so I'll just go buy it since its a dollar...

Out of curiosity, why are these different than normal bolts?

RR: I truly do appreciate the help. I know it may seem frustrating to someone who knows a lot about these bikes to hear about some of these mistakes, but I would very much like to learn and that's why I turn to all of you guys.

bwaller · « **Reply #18 on:** March 16, 2013, 09:58:06 AM »

First they're 7mm and a higher grade fastener. They also incorporate a shoulder that fits snugly in the sprocket.

Part # 90082-HA0-000

Fritz · « **Reply #19 on:** March 16, 2013, 01:08:53 PM »

And loctite surely does not hurt on those bolts

I don't hesitate to use it on any rotating parts just for peace of mind.

Mo · « **Reply #20 on:** March 17, 2013, 10:07:43 AM »

Quote from: bwaller on March 16, 2013, 09:58:06 AM

First they're 7mm and a higher grade fastener. They also incorporate a shoulder that fits snugly in the sprocket.

Part # 90082-HA0-000

Thanks for the help guys. Bwaller, are you sure that's the correct PN? I have it listed as 90081-246-000 and is a 7x12 bolt. The 90082-HA0-000 is a 7 x 10.5. When I look it up, it says the 90082 replaces the 90081, but I'm just concerned about the dimensions.

I have the old bolts at home so I can measure them accordingly, but I'm not 100% sure as to what the numbers correspond to. I assume its dia x length in mm?

Jerry Rxman Griffin aka MuthaF'er · « **Reply #21 on:** March 17, 2013, 12:12:16 PM »

Here's a nice tool to use for your parts numbers

http://www.motogrid.com/pages/OemParts?aribrand=HOM

Mo · « **Reply #22 on:** March 17, 2013, 01:23:15 PM »

Yeah makes sense, and I have checked out the parts fiche. My question now is in regards to the labeling (and potentially sizing) for the bolts. The old PN (and the manual) lists it as a 7x12. The fiche lists the new PN (which replaced the old) as a 7x10.5. Wouldn't this be off?

bwaller · « **Reply #23 on:** March 17, 2013, 05:59:10 PM »

I just checked some original cam bolts and they all seem to be +-10.7mm long. The new HA0 bolts are 10.5 and have a flange style head but honestly the bolt shoulder is puny, I have some. Mike Rieck suggests and I have used the Yamaha FJ cam bolts. (#90105-07004) This is the best bolt of the bunch, +-10.6mm long, flange head and a good machined shoulder.

I have a bunch of cam bolts and none are 12mm long. At that length there will be at least one thread though the camshaft, longer than need be. If you can still get the "246" bolt it's probably better than the "HA0", but may not be available.

Mo · « **Reply #24 on:** March 17, 2013, 07:53:17 PM »

Hmm okay. I'll take the bolts with me tomorrow to work and see what they measure to. I seem to be able to find both, so I may just order both and see which is closer to the stock bolts.

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Author Topic: Cam Shaft Bolts Came Loose (Read 2377 times)