EMERGENCY! HOW FAR DO I HAVE TO TEAR INTO THE ENGINE???

Oh this is a doozy. I was on my way home last night about a block away, when I started hearing this really wicked rattling noise. There was no change in performance just the addition of the noise. Having seen a couple threads on it recently, I figured it was the timing chain adjuster out of whack. I pulled the valve cover off today to check the slack, and what did I find? One of the sprocket bolts on the exhaust cam is missing! JUST PERFECT!!

Before I start pulling the engine apart, would it have dropped straight down into the sump pan? Or is there anywhere it could've gotten stuck along the way? And a bigger question, can I take the sump pan off without taking the engine out of the bike? I know I'd have to take off the exhaust, but since this is my only mode of transport right now, I'm hoping I dont need to fully dismantle it.

Why does $#!t luck always happen in groups?

 

You might be able to get it out with a magnetic pick up tool from the top. The fact that it is rattling means it is hitting something so hopefully not fallen down too far. You probably will have to take the cams out if you can't get it at first, remove the top guide and pull the chain back to give more room, a helper could do this while you fish the bolt out with the magnet.

If you can't get it out this way, most likely you will have to remove the engine.

Torque wench and loctight when replacing, if any damage at all to the bolt replace it, remember it is a special part and yo will need a original, I would replace it anyway.

 

Down the camchain tunnel is the camchain, front guide and rear guide and at the bottom the crankshaft with the cam gear. There is still room for it to fall through to the oil pan. The pan is removable without removing the engine. Also in the cylinder head are several areas where oil pools for the camshafts. I would check for the bolt there also. But most likely it is rattling around between the guides and camchain, so a small telescoping magnetic tool will retrieve it. Kiwi is sooo right about using an original bolt. It is a special hardened one so a stock bolt will not work! Once you have the bolt torque all the cam sprocket bolts to 14 ftlbs.

 

Ok after I took the exhaust off I figured out how to take the pan off, and I found the bolt at the bottom (sucks, had it been 1" farther forward it probably would've stuck to the drain plug magnet and saved me a lot of trouble). I had already checked everywhere in the top end that it could've been flung. I think the rattling I was hearing was from the new slack between the sprocket and camshaft.

It is definitely wrecked so I will need a new one. The dealer by me is closed on Mondays so I will have to call tomorrow, since I need a new pan gasket anyway. In a worst case, if the dealer doesn't have one and has to special order it, can I get by with a Grade 8 for a week? Or is it a bastard thread or something that I won't be able to find anywhere?

 

Re the Cam Sprocket Bolts...

When doing a top end overhaul I ordered new ones but sure 'nuff the dealer only had 3 in stouck (need 4). One had to be ordered. It only took a few days but the dealer forgot it was in and didn't make the call to me until a week later!

My recommendation is that you got away scot free this time - that little bugger of a bolt could have ended anywhere and done a lot of damage. Get the right one.

It's not a special thread as far as I can make out but it's length, thread pitch and hardnes all combine to make a bolt that shouldn't come out or self destruct if torqued correctly.

Cheers.

 

I realize that red, (and I will offer a blood sacrifice to the bike gods for sparing me a wrecked engine), I'm not saying leave it in there, but the bike is my daily wheels. I can't be without it for 3 days to a week. I'm going to get new ones tomorrow, but what I'm asking is will I be ok for a week using Grade 8's if the dealer doesn't have them and has to order.

 

For a few days, Grade 8's set in place and torqued correctly, not ridden hard for a few days I think will easily get you by.

Like you, my XJ900 is my wheels to work, daily, if it's out of action then I have a problem.

Just playing it safe.

I reckon the bolts will either be in stock or have to come rom Head Office in another state - they could do it pretty easily within a few days.

 

I have a feeling that the Cam Sprocket to Camshaft Securing Bolt is specially "Shouldered" ... or, "Fitted" to the Sprocket in some fashion.

I won't know, for sure, until I can get a look at the parts of a 900 Engine I'm building ... but, I DO know you dodged a big bullet if that thing wound-up in the Pan without doing something nasty to the Cam Chain lower-end ... or, getting sent into a place where you couldn't retrieve it.

You're a lucky guy!
Don't push your luck and use a Non-perfectly fitting part that might not perform right and cause you more of a problem you won't be able to wave a magnet over to fix!

Be happy you didn't flip the Cam Chain off the lower sprocket and waste the Engine.

Chill.
Wait for the parts and do-it-up right!

 

Rick is right there the bolts have a positioning shoulder.



Only use the correct parts.

Shame you were not closer as I have spares.

So the sproket is loose and moving round?

Replace both bolts.

Check the thread on the cams for damage.

They should not come loose, make sure you use a torque wrench to reinstall.

 

You're also quite lucky it didn't get knocking around on top of the head and get behind a cam lobe. You'd need a camshaft, maybe shim and bucket and probably head.

 

The motorcycle Gods were smilin' on you, bro!

That hardened little bolt could have fallen or got knocked down and derailed the Cam Chain ...
The Engine would have been scraped in a heartbeat!
You'd have locked-up and might have been hurt when the bike came to a screeching halt.

Buy a lottery ticket!
You're having a run of good luck!

 

Just for piece of mind, check the torque on the intake cam as well. Might be that you have loosy-itis on the loose! Its fairly contagious I hear.

 

And remember to torque the cam bolts in the correct order - as shown in the Haynes or Yamaha shop manuals.
That may have contributed to the original problem if a PO didn't torque them down in the proper order.
Also, do buy a lottery ticket - you're one very lucky bugger!
thx,
baz

 

There's an order? There's only 2 bolts per cam...

I used Loctite and torqued them to 14ftlbs. The intake ones were tight, but I took them off and put the Loctite on and retorqued them anyway

And my lottery ticket was a dud