Re: Cam Chain's Gone Wild

General Discussion

Cam Chain's Gone Wild

DaveNearAtlanta 12-08-2007, 7:16 PM
Several weeks ago I purchased an 81 GL500 and have been going through it from one end to the other, taking care of things that need attention. I rode the bike home about fifty miles and it seemed very solid. The engine sounded great and had lots of power.

Since I had the engine out already, I figured I'd crack it open for inspection and take a few photos. Before opening it up, I adjusted the cam chain tension using the procedure in the Honda shop manual. The intent was to check for cam chain wear by seeing where the adjuster bolt was on the tensioner.

The rear engine case came off without major incident, although one water pump bolt broke off in it and will have to be dealt with later.

So here's a close look at the cam chain tensioner bolt.

From looking at the photo, it appears there is plenty of adjustment range. Nice!

Then I saw this below the camshaft.

YIKES!!! The cam chain has been rubbing!

So it was time to pull the flywheel and cover plate for a closer look.

Things aren't looking so good now.

With the tensioners removed, it was easy to push the chain where it would get into trouble.

I had a new cam chain in the spare parts stash, so it was temporarily installed for comparison.

Notice the difference.

Even though the old cam chain appears to have plenty of adjustment range remaining (first photo), I'm going to replace it. The tensioners also had some noticeable wear so they are also being replaced.

The chewed up bolt is being replaced. And the jagged edges will be deburred to prevent any filings from breaking off.

Interestingly, there was no trace of metal particles in the oil, and I looked closely when it was drained. I'm pretty certain the engine had never been removed previously, so this should have been the original cam chain. The odometer shows a little over 30K miles.

It's likely the most recent previous owner had adjusted the cam chain tension and changed the oil. This is probably why I couldn't find any metal particles, and is a testament to the oil filtration design. I think I will pull the front crankcase cover to check the oil strainer, though.

This experience shows how important it is to keep the cam chain tension adjusted on a periodic basis.

It also shows how important it can be for the oil filter to work properly. Missing the oil filter washer? Not worried if a little oil just happens to get by around the filter? Better think twice.

May your cam chain never go wild.

My Home Page
1981 GL500I
1982 GL500I
1983 GL650I

This User ID is no longer used. DaveF is my new User ID.

Re: Cam Chain's Gone Wild

dean 12-08-2007, 8:37 PM
holy smokes. makes me want to check my cam chain now. good thing you opened her up.

83 Gl650I

Re: Cam Chain's Gone Wild

trev_h 12-08-2007, 11:46 PM
Hi, Those are good pictures of what happens when the chain is not adjusted on a regular basis. It is also quite clear how the rattling of a worn chain is made and why you should investigate this fault immediately before any aluminium particles go in the oil. I have only ever opened 1 cx motor up that didn't have any damage in that area. I bet you are glad you did this job and once you have it is really not a big problem to deal with. If your mech seal and stator are fine you have a motor that is good for 30,000mls with regular maintainence.

cx 650/500c special, 78 500z, 94 bmw k75rt

Re: Cam Chain's Gone Wild

beach3091 12-09-2007, 11:03 AM
hi how are you do you know if a 1983 cx-650 custom also needs adjustment im not sure but i think i read something that it has an automatic cam adjustment is this true thanks for your time.

Re: Cam Chain's Gone Wild

dozer1 12-09-2007, 2:31 PM
Cam chain adjustment? Huh?

1980 CX500 Ratbike "Stella"
1979 CX500 Deluxe(Parts)
Dozer1 AKA Snowplow

http://www.youtube.com/watch?v=6TK5VY90ILs&feature=related

Re: Cam Chain's Gone Wild

jr26400 12-09-2007, 4:09 PM
If you look at Daves first picture the bolt head (which has an o-ring on the shaft protrudes from the rear casin just below the right hand carb inlet tract, If you have no bolt you are auto adjuster

regards Joh

Regards John
ride safe

Re: Cam Chain's Gone Wild

DaveNearAtlanta 12-09-2007, 4:32 PM

dozer1 wrote:
Cam chain adjustment? Huh?

I see your bike is a 1980 CX500. This bike has a manual cam chain adjuster and it needs to be adjusted periodically. It's easy to do - just follow the procedure described in the service manual for your bike (either Honda or aftermarket).

The 1983 CX650 has an automatic adjuster.

As a general rule, at least for CX/GL bikes sold in the US, the 500's have manual adjusters and the 650's have automatic adjusters. The CX500TC is an exception as it has an automatic tensioner.

My Home Page
1981 GL500I
1982 GL500I
1983 GL650I

This User ID is no longer used. DaveF is my new User ID.

Re: Cam Chain's Gone Wild

dean 12-09-2007, 6:53 PM
i have a 650 and have never looked at the cam chain. should i look into it? and does the engine have to be pulled for this? and will i need to be planning on an oil change?

83 Gl650I

Re: Cam Chain's Gone Wild

TomC 12-10-2007, 1:43 PM

Thanks for the VERY interesting story and photos. I do know from experience one can get over 60,000 miles from the CX 500 without problems if you keep the required service up. Just have to watch buying a bike with unknown service history.

TomC

1978 CX500 x2
1998 Ural Tourist
1974 CT90
1961 Cushman Eagle...just in case

Re: Cam Chain's Gone Wild

Randall-in-Mpls 12-10-2007, 3:53 PM
I found the same thing when I had mine torn down this summer:

I, too, had adjusted it prior to pulling the rear cover, and found that the adjuster took up enough slack that there's no current wear on that area. With 33k on the clock, I have about the same remaining adjustment range, as well.

R

'78 CX500 - The Black Maggot

CX500 Factory Service Manual
1978 CX500 Parts Manual

Re: Cam Chain's Gone Wild

DaveNearAtlanta 12-10-2007, 6:04 PM
That photo could have been taken of my engine, it's so close.

This evening I pulled the front engine cover to inspect the oil strainer screen.

There was no sign of any metal particles, just nice clean engine oil. No sludge build-up, either.

The oil pump chain was a little loose, so I was able to take advantage of this chance to snug it up.

With the front engine cover off, I'm also going to change the clutch lever seal because it's been leaking slightly.

My Home Page
1981 GL500I
1982 GL500I
1983 GL650I

This User ID is no longer used. DaveF is my new User ID.

Re: Cam Chain's Gone Wild

DaveNearAtlanta 12-10-2007, 6:22 PM

dean wrote:
i have a 650 and have never looked at the cam chain. should i look into it? and does the engine have to be pulled for this? and will i need to be planning on an oil change?

Whether to inspect the cam chain in your 650 or not is a judgement call on your part. The automatic tensioner should keep it from wreaking havoc like a manual tensioner that is not adjusted periodically. That said, automatic tensioners have been known to break.

If it were my bike, I'd probably swap the cam chain out about every 30K miles or so just as a preventive measure. But I can do this sort of thing myself and don't have to pay someone else to do it.

For this job the engine has to be pulled and the rear engine case removed. Doing this requires the coolant and oil to be drained, so an oil change and coolant change are part of the task.

My Home Page
1981 GL500I
1982 GL500I
1983 GL650I

This User ID is no longer used. DaveF is my new User ID.

Re: Cam Chain's Gone Wild

dean 12-10-2007, 6:27 PM
ok dave,
is there a way to check it without pulling the engine or even to check it i'll have to pull the engine and drain all the fluids?

83 Gl650I

Re: Cam Chain's Gone Wild

N1265 12-10-2007, 10:05 PM

Somewhere, there is a post that explains how to remove an inspection plug, and by using a small light and dental mirror you can somewhat see in there.....

I have done this and even with its limited view it did give me some piece of mind.... I can not explain how to do it, but I will look for the post and post a link to it here.

1982 SilverState
" no mater where you go, there you are "

Re: Cam Chain's Gone Wild

N1265 12-10-2007, 10:59 PM

Here is the link I was talking about, It is further down this page in the discussion forum under " cam chain "

It is very difficult to see in there but if you look at it long enough you can figure it out.

http://choppercharles.com/cs/forums/11450/ShowPost.aspx

1982 SilverState
" no mater where you go, there you are "

Re: Cam Chain's Gone Wild

Sture (in Sweden) 12-10-2007, 11:22 PM

The tech "guru" of the Swedish CX-Club (Honda Pro mech) has shown us how he regularly checks tensioner condition on CX / GL bikes with automatic tensioners.

He´s using a thin screwdriver/rod or whatever to press against the tensioner "body", just where it presses against the chain. The tricky bit is to know where to press, exactly...It´s "behind" / i. e. immediately in front of the flywheel.

With engine running (you´ll have to accept some oil mist) it´s possible to hear if engine noise/rattle is reduced as you press on the tensioner "body". As said it has to be done with running engine, which takes some nerves... I tried once, when I had my GL:s but never had the guts to try hard enough. Unfortunately the only alternative is to drop the engine to check, as far as I know. My chain was worn so the tensioner was at the end of its adjustment travel. (Seems the manual tensioners have somewhat longer adjustment travel and therefore allow more chain wear). .

Regards

Sture

Honda CX 500 (B) -81 x 4
Yamaha SRX 600 -86

Re: Cam Chain's Gone Wild

trev_h 12-11-2007, 7:16 AM
Hi Sture, Not sure if I would want to try the screwdriver test ! but I agree with you on the adjustment travel, I much prefer the manual type. When I overhauled my 650 engine I put in a new chain, guides and auto tensioner and there seems very little travel on it.

cx 650/500c special, 78 500z, 94 bmw k75rt

Re: Cam Chain's Gone Wild

R80Dave 12-12-2007, 8:03 AM
Trev the rear covers are different ...

David in Wisconsin

Re: Cam Chain's Gone Wild

trev_h 12-12-2007, 9:10 AM
Hi Dave, rear covers?..... No I'm not swopping them but over here we have 3types of 500 engine. Cdi type with manual adjuster, Transister ign. with manual adjuster and a Ti with the auto tensioner. I prefer the Ti type with the manual adjuster as these have more travel on the adjuster than the auto type. As far as I know the 650 engines only had the auto adjuster.

cx 650/500c special, 78 500z, 94 bmw k75rt