Topic: Preserving original 4-4 exhaust cb500

[kurtkarram]

I understand that the original 4-4 exhausts are rare because they "easily rust out". My cb500 looks to have a very good set, so I'm wondering if there are any special tips methods or precautions that would prevent my exhaust from rusting out over the years?

[fizzlebottom]

Pipes rust for a multitude of reasons that all stem from water being trapped inside. If the bike has been on more longer rides than short rides, it gives every bit of the pipes a chance to fully warm up and expel all water. If the bike has lived in a low-humidity area, or stored in a well sealed space then water didn't have as much chance to collect and condensate in the pipes during cooldown and in the off-seasons.

[Stev-o]

Some guys put an ounce or so of two stroke oil when filling the tank.

It must work, I have 5 two stroke bikes, all have original exhaust in good cond!

[TwoTired]

There is a drain hole at the low point of each pipe assembly.  Make sure each of these holes is clear to drain out condensate.    The pipes need a run of enough duration to vaporize all the condensate, like a boil off over the entire internal aera of the pipe. In other words, reach high temp and maintain it for 10-20 minutes depending on the amount of water trapped inside.  Same is true for the engine oil, btw.  Of course the humidity and dew point has a bearing on how fast the internal condensate accumulates.

FYI: the engine doesn't burn water.  It only vaporizes what it sucks in from atmosphere and chucks it into the exhaust.  If you ride in rain or high humidity, it places more water inside the exhaust when it is not at vaporizing temp.

Cheers,

[Tracksnblades1]

Do the Medyo Bastos and keep the originals under your bed…😁
And run some aftermarket and ride…😇

[Shtonecb500]

Do the Medyo Bastos and keep the originals under your bed…😁
And run some aftermarket and ride…😇

I second this, i have a set of pipes that only needed repair on one of them, im considering tossing them in storage for another 20 years if the bike doesnt pull a good price when i list it.

[Deltarider]

I have learned these exhausts can live very long indeed. Just avoid short rides. The headers and pipes down to where the mufflers begin (more or less where the drain holes* are) are dead easy to keep nice. It doesn't take much to keep them new and any rust there is a shame, indicating neglect by the owner.
My first set did more than 70.000 km and were still reasonably OK and I have even sold them. The set that has been on my bike for the last 30 years and 65.000km, still looks marvelous, with only one repair spot. The internal dampers are somewhat loose though. When I tap the pipes you hear sounds from inside.
Here an important tip for who will either mount or take the pipes of. By all means, have pillows or matrasses on the floor right under them! Believe me, no matter how concentrated you are, one or more WILL drop. Happened with my old set back then and - although warned by the first time - also some years ago with the actual set. The impact is not so much a problem for the outside, but there's a good chance the internal - by then no doubt partly rusted - dampers will come loose.
The original K3 mufflers lack drain holes, which is a shame. I know an owner of a K3 who uses a vacuum cleaner in his garage after returning from a ride.
* Check every now and then these drain holes are still open.

[kurtkarram]

Thanks for all the responses. Would it be okay to do a couple short rides throughout the week followed by maybe a once a week long ride? I was planning on bringing my bike to college for the first and last 2 months of the semesters. My ride to campus is only about 5-10 minutes, but my roommate will also have his bike and we’ll go for long rides when possible.

[Stev-o]

Would it be okay to do a couple short rides throughout the week followed by maybe a once a week long ride?

Of course!  The more the better, these bikes run better when ridden regularly.  Take the long way home...

[Deltarider]

These bikes are coldblooded and need quite some time to get real warm. Where I live, it is common practice for distances under 5 miles to ride a bicycle. Saves time too, as you don't have to dress up, put a helmet and gloves on, etc. By the time I would be out of the garage, I have already arrived on a bicycle. I won't start my bike unless it wil be a 30 min ride at least.