[Rod Fryatt]

1979 CB400a
Drained oil and found this. There was none in the filter bowl so it must have all come through the drain plug. It is like a soft paste between my fingers and when smeared on paper I can see tiny fibers through strong magnification.

I am well aware of the balancer problem, is this what the disintegrating rubber looks and feels like?

 

[dtsmjr8dan]

Yup. That's what it looks like.

 

[Alan F.]

Sorry to hear it Rod, i wish there was a 'don't like' button i could press.

 

[Rod Fryatt]

Oh dear, better start clearing my bench!

 

[80cb400t]

LDR did a large amount of miles with decayed balancers, you could probably risk leaving it until winter if you don't have any cross country trips planned.

My cb400t has survived 500ish miles so far without blowing up

 

[Rod Fryatt]

Thanks for the encouraging words but I don't think I will use it until the problem is sorted for three very good reasons.
1, I am afraid of bits of that stuff blocking oil ways.
2, I have other bikes to ride.
3, If I keep him off road till his 40th birthday in April I will never have to pay road tax again

Engine has been running very well. Minimal oil consumption and good compression so I intend to do as little dismantling as possible. However I would like to renew all possible bits of disintegrating rubber. I have been going through all the informative posts on here but any further advice on what to look for would be appreciated.
The price of rigid 450 balancers is far too high to my way of thinking so I intend to keep the originals. My reasoning is.... rubber has proved unsuitable as it breaks up, so all I need to do is fit something that will not break up, such as blocks of brass.
Anyone else done this? If I learn anything of benefit to others I will post it on here.

I

 

[Bill H]

The rubber lasted 39 years so new set should last another 39 years but maybe not. Would be interested in seeing what you come up with.

If you stay with the rubber I have a new set you can have for postage. Let me know if your interested.

Bill

 

[Rod Fryatt]

Thank you for that kind offer Bill. My first instinct is to abandon the rubber but when I think about what you say, it is perfectly true. I am now of the age (nearly 70) when I look at the potential life of my toys in true perspective.

Will PM you

 

[CBSigmund]

Simple: Lower case off and replace with CB450 solid balancers or if you can weld then make them solid. Check my 400 to 450 thread and I think there are pics of what I did, it's working fine still....

 

[longdistancerider]

I first noticed the bits in the oil in San Diego during and oil change, I proceeded to Baja, Key West, up thru Maine and back to California, @15,000 more miles before I changed them out. They won't block any oil passages because first they have to get thru the sump strainer then thru the paper oil filter before they get into the passages. This is what my strainer looked like

 

[Rod Fryatt]

Finally opened up the engine last week.
Found balancer rubbers slightly compressed but not breaking up at all. New ones ordered from David Silver of course.
Project well worth while though as there was plenty of sludge in the sump after nearly 40 years. Also found cam chain was very loose as the spring tensioner seemed to be caught up and only sprang into life when I poked it.
Balance chain needed replacement as slack varied during rotation. Also intend to beef up the bal shaft tension spring as it was set too soft to operate.

Hoping for a much quieter engine after this.

 

[longdistancerider]

If you can find a 450 spring for the balance shaft it would be a good idea to use it. 450 spring on top vs. the 400 spring on the bottom

 

[Rod Fryatt]

Sound advice and I would certainly fit it if I had one. However an impecunious existence and a meagre pension means that I will just give the old spring an extra turn and set the chain up by feel.
Furthermore a simple equation involving the recommended checking interval, my age, and mileage covered, shows that I will never adjust that chain again.