Topic: CB550 Cam chain tensioner screw slot broke !! Now what?

[eworth]

Well crap!!
First time I've ever cracked my engine open to change the camshaft.  Was trying to break the cam chain tensioner nut loose and snapped the slotted screw adjuster.   What do I do?   Do I know remove the cylinder head and have to replace the cam chain tensioner?    If so, anyone have a 1977 CB550F cam chain tensioner in nice useable condition?

PS.   What model and year cam tensioners are interchangeable?

       Mark

[Rgconner]

That might be hard to come by, and not cheap either.

Removing it and having a welder weld on a bit of metal to make a new slot would probably be a more reasonable choice.

But, I think you are going to have to pull that head to get to it. Maybe not, if the welder thinks he can do it place.

Somewhat fortunately, you can do all this without removing the engine from the frame. Little tight, but not impossible.

[eworth]

OK, so I cut the adjuster nut off and remove the head to get the tensioner out?


** Would a cam tensioner from a 1976 CB550 K or F fit my 77 CB550F ? ** Are they the same?

[Greggo]

** Would a cam tensioner from a 1976 CB550 K or F fit my 77 CB550F ? ** Are they the same?

All SOHC4 500/550's share that piece.

[Duanob]

Just curious exactly how did it break? The way you adjust these is loosen the nut let the adjuster settle itself and tighten the nut. You really don't need to monkey with the screw at all unless it's froze up, then you have bigger problems. If you just snapped an end piece off and the adjuster works freely I would leave it til you really need to remove the head, then replace it.

[eworth]

Duanob,

The nut and screw were froze together.  I had put the screwdriver in the slot and with my 10mm wrench, I was trying to loosen it.  That's when it snapped.

Well, the head it off.   While it's off, maybe I should have some headwork done!!     Not full out expensive but is there anyone on the list that does reputable work I can send it too?

And thanks GREGGO about the tensioner interchangeability.!!   One on ebay I am gonna go snag.

[bryanj]

Best head work going, send it to MReik, Also if the head is off pull the cylinder and replace the base gasket and ALL the "O" rings. DO NOT get bits of gasket in the dowel holes as they will block the oil restrictor jets wrecking the head and cam.

ALSO READ THE MANUAL carefully about replacing the valve cover or you will bend the valves

[eworth]

Thanks BryanJ for the tips.    Per your advice, I just went ahead and ordered a top end gasket set from Vesrah.   I also purchased some viton valve seals.

Gues I should go ahead and get a valve spring compressor and clean lap the valves while I'm at it.   

[Duanob]

Only problem is you have to pull the engine to pull the jugs and replace the bottom gasket. You can leave the engine in the frame if you just pull the head. Sometimes you get lucky and you won't disturb the base gasket (I count myself lucky!)

Having the head reworked while it's off is a great idea. You will be stunned and amazed at the power increase especially if you had bad or really gummed up valves causing low compression.

remember: When installing the head gasket make sure it fits perfect around the (new) little o-rings for the oil galleries. Mine didn't (crappy gasket) and now it leaks like a sieve. I thought once I torqued everything down it would be fine but naw, it leaks all over my boots. Now I'll have to pull the head again this winter to replace the head gasket with a better quality one and new o-rings. It's a loot of work for something as simple as that.

Remember: which way the camchain guide goes in. I think I put mine in upside down (one end is longer than the other) and causing more cam chain noise than usual. I don't think it's hurting anything just bit noisier.

Valve cover rubber band trick:
 

[eworth]

I was able to remove the jug with no trouble in the frame.  Surfaces are now clean.  I will make sure to check the gasket as you've mentioned.    Awesome trick with the rubber band!!   

Ya, it's the end of the riding season here in Wisconsin.   I have PM with Mike Reick pending.  Hope I can procure his services for valve lapping and porting.   Sounds like head work makes a great difference!!   That.. plus the brand new OEM CB650 cam (63hp) version will breathe new life into my CB550.

[Duanob]

I was able to remove the jug with no trouble in the frame. 

Wow that's awesome. I may have to try it again when I redo my gasket. I don't have any leaks at the bottom of my jugs but what the heck i have new gaskets I might as well use them.

[ABikeNamedTrouble]

I did pretty much the same thing on my cb650 custom.  Except I was just trying to tension the chain and ended up rebuilding the engine  .

Anyway I found a cam tensioner at a local salvage yard.  They're crazy folks but they have LOTS of old Honda parts and they'll ship anywhere I think.  http://www.williescycle.com/.

[eworth]

Got a tensioner from fleabay for less than $15.00 including shipping.   Now, the head is going off to the machinist with the intake tubes for porting and so forth.  That with the CB650 cam will add plenty of smiles per mile.   

[dave500]

yeah the 500/550 complete top end comes off in the frame unlike our 750 bigger brothers,,are you doing anything with the bores and rings etc?if its anything starting to show wear trying to garnish more power out of it with you mods may result in a smokey dissapointment,measure or have it done for you the bores etc.

[eworth]

Dave,  engine has about 16000 miles on it and the cylinders look good.  Was running very nicely before removing the top end.

No plans at the moment to do anything with the bore or different pistons.   Two reasons primarily.... funds and I have  no knowledge of what would be affordable options. 

If anyone knows of a simple and cost effective piston / bore performance upgrade.... I'm listening.