Cam Chain Guide Broken

[hop along]

Tinkering today has been fun.  Haven't even gotten to the lubing yet: lubing cables, fresh oil etc.

My last valve check was at 60,000 miles.  I'm at 120,000+ now so I figure it's time to take a gander. I've been curious to look in the front cylinder head anyways since I've gone through some front cam chain tensioners.  I've also had a nagging feeling that the left side of the bike has been feeling hot for along time; the local Powerhouse Honda solution was to change coolant without considering anything else.  Odd that the cooling fan comes on during a 5 mile ride in 20 degree weather still.  But I digress.

So while removing the Front Cylinder head cover, which is admittedly a tight fit with the radiator still hinged at its top mounts, a piece came flying off.  Naturally I had a brief moment of panic; after all there shouldn't be any loose parts.

What was it?  The Cam Chain Guide.  It was snapped straight off from all 4 (four) of its mounting points!  I can't believe I did that while removing the cylinder head cover-it wasn't that hard to take out, nor was any force required, just maneuvering in tight spaces. 

So.  I wonder if that is why I went through 2 cam chain tensioners in 13,000 miles?  FWIW the underside, which the cam chain will run against if slack, has some gouges with a few small nicks and one big nick in it.  I don't have a camera to share pics just yet though, I am not working where my camera is.  (Should be taking pictures as I disassemble I know... but I'm living on the edge this weekend!)

Now that it's Saturday, dollar bets on how long it will take to get a new Chain Guide?  I'm guessing here that I shouldn't ride without it.  Any more technically knowledged minds able to contribute on that thought?

Hop Along.   

[Smoked U]

If it was any other manufacturer but Honda, I wouldn't have the answer, however, if the Honda engineers designed this thing into the valve timing mechanism, you can bet it is there for a reason and needs to be replaced before you ride the bike around. The fact that it is a "guide" suggests that the cam chain in this assembly bounces around enough as it is traveling in that area between the timing gears that the guide was necessary for alignment to keep down excessive wear from unwanted cam chain movement. Based on where the guide broke (fractures), does it appear that the chain might have worn its way through those areas of the guide creating the failure?

In any event, carefully remove the remaining pieces of the guide from under the cam shaft holder bolts when you get ready to replace the guide with a new one. Don't drop any of those pieces down into the head to be lost in the engine. It would be a good idea to get those holder bolts properly torqued in place (12 N-m or 9 ft-lbs) and not guess at tightness with a regular ratchet and socket. Getting something warped in this mechanism is really not cool.

[hop along]

Thanks Dave, I do plan on the suggestions you've mentioned.  Especially the "do not drop into cylinder" parts
I don't think the Cam chain guide is worn on the sides, just the top.  When I get my camera and the part in the same place I'll post pics.
Hop Along

[hop along]

Two pics of the cam guard; you can see the broken bolt hole mount points on the side.

First pic shows a few long gouges on the underside of the guard, where the cam chain has run against;

Second pic is trying to show a larger 'divot' if you will - a large concentrated spot of wear. 

Hop Along

[Smoked U]

Snapped off right at the ears. Fascinating.

I am looking at the first photo and it appears that the metal is rolled a bit where the ear holes are located (whats left anyway).

Are the hold down bolts for this guide tight? It looks like the guide was whip sawing back and forth to roll the metal in this fashion.

The wear pattern under the top of the guide is normal I'm sure where the chain is slapping up and down a bit between the gears.

[hop along]

The bolts used to hold this down are the same bolts holding the camshaft mounting brackets (not sure their technical name...).

I do not look forward to removing said bolts with a magnet at the standby to catch the very small, semi circular pieces once they come loose...
Hop Along

[Smoked U]

Yeah, but ya gotz to do it.

[lragan]

Just from the pix, it would seem that there may already be bits of loose metal somewhere in this engine.  Hopefully they have been caught in the oil filter.  I imagine, but don't specifically recall, that the oil drain plug is magnetic.  Have you noticed any metal "grit" as you changed the oil?

[hop along]

Lawrence, oil change is planned once the rest of this service is done.  I do have a magnetic drain bolt and will examine it closely.  Last oil change a few thousand miles ago was the first time I had a magnetic bolt in there; there was some-minimal-dust-like shavings. 

The part is at least 5 days out according to shipping info... maybe it's coming from across the left pond! 
Hop Along

[lragan]

So, I take from your response that the stock drain bolt is not magnetic.  I would like to replace both mine with magnetic bolts at the next oil change.  Do you recall where you bought it?

[hop along]

Larry I'm not honestly sure if the stock bolt is magnetic, I didn't think so but I could be wrong.  I'd bought mine from my local independent shop-if I have info at home I'll post it back up here.

Not getting much work on the bike done, working at work too much 
Hop Along

[lragan]

We need another word for "work" when used in "work on the bike".  Not work to me, I love it!

[Smoked U]

You can up here and put the swing arm back on my green Valk. I'll teach you meaning of the word "work".

[TLRam1]

What are you doing to it?

[hootmon]

You can up here and put the swing arm back on my green Valk. I'll teach you meaning of the word "work".

Just put a "hover tire" on the back..
Hey we are up to where Marty McFly was in the future and there were hover boards.. Why are we so behind on this technology???