Topic: CB550 Primary Chain tension

[betterthanurs916]

So I have torn down my 9,000 original mile CB550 to replace a badly leaking crank seal, and of course I have found a couple other things that need attention.

The cam chain tensioner was pretty much toast, and the primary chain apparently is starting to make contact with the case.

The trouble is that I can't exactly find any sort of tension spec in either my Clymer or Honda service manual...but I imagine that if it is loose enough to contact the case...there is something wrong.

I have seen that people shoehorn 650 tensioners into the 550 case, but I haven't come across any decent looking ones on ebay, and I don't quite have the patience to wait around for one seeing as we're getting really great riding weather down here in the southeast now.

***so I guess my real question here is***

For those of you who have simply dropped the $120 on a new primary chain, how tight do they actually get? If I do go ahead and get one, am I going to be disappointed to find that it isn't actually any tighter than my (relatively) fresh 9,000 mile one?? Meaning, is the slop an inherent design flaw that I will just have to sacrifice my peace of mind for?

[classic bike tuner]

i think you mean 90000 mile

primairy schain do not wear after 9000 mile  or is it a ex race bike 

a new one is pretty tight   now clearance at all

gerrit

[betterthanurs916]

I'm pretty confident that this bike really only has 9,000 miles on it.

It had 2 owners before me and they knew each other.  Cylinder bores look good and spec out nicely, valvegear is all in spec, original paint and chrome shines well. I guess the bike could have been ridden hard at one point, but it has all the original parts and seems so well maintained that I doubt it. Maybe my specific chain is just an anomaly.

Either way, I guess I will go ahead and order a new one if it will be sure to take all the slack out of it.  Mine has nearly 3/8" of slop in it.

[bwaller]

If it's wearing the case change it. A new chain wil still have some slack. It is also possible that if the bikes carbs were never in synch and the chain rattled away for years it would be hard on it. Seems goofy but stranger things have happened.

[bryanj]

Carbs out of sync or hard riding(on/off the throttle continuously) will wreck a primary chain and i have seen a totaled one in 23,000 miles.

550 is less of a problem than 500 as the 550 hits the case first whilst the 500 hits the oil galleries first.

As you already have the engine in bits and don't want to pay for all the gaskets again i would change it but check out Dave Silver for parts costs, he does a pattern chain cheaper

[That 70s Bike]

I know this is an old post but it popped up while I was "googling" for the name of the type of chain used for the CB's primary drive chain. I believe it was called Hyvo or Hyvol.

January 1975, I spent my entire savings of $1,100 on a used '74 CB 550 with 11,000 miles. It had a 4 into 1 Jardine Header & increased jets (#105?).
It ran very strong but after a needed carb balancing, there was still an unknown rattle in the bottom. I tore it down mainly to address a cyl. o-ring oil weep but soon discovered the stretched primary drive chain and after splitting the cases saw it had cut halfway through a main oil channel cast into the lower case. Once installed, the new (Honda $30) chain had little play compare to the worn one. A lesson that a few thousandths inch wear on the many pins in the chain = s t r e t c h!
After this repair I had to replace the alum. valve cover ($40) as the "rocking" steel shafts oblonged the aluminum holes.
I admit this bike was rode hard  by its 1st owner but Honda's engineering made me swear off motorcycles & the Honda brand for many decades.
However that ended in 2003!

[bryanj]

As an addition to my previous post (long forgotten) if you are changing the primary chain on a 500/550 you really need to replace the 8 rubber cushions in the primary cush drive (same piece has starter clutch) as these are all worn now after many years in hot oil

[jonda500]

Where on earth do you find a honda 500/550 primary chain for only $30?
John

[FunJimmy]

As an addition to my previous post (long forgotten) if you are changing the primary chain on a 500/550 you really need to replace the 8 rubber cushions in the primary cush drive (same piece has starter clutch) as these are all worn now after many years in hot oil

Good point. Thanks

[That 70s Bike]

Where on earth do you find a honda 500/550 primary chain for only $30?
John

My post was about my experience in 1975, with my first motorcycle: a used '74 CB-550 that I sold in 1978.
Tom's inflation calculator at halfhill.com puts that $30 in 1975 at $135 this year.