Repairing holes in exhaust

I would just cover the holes with a plate. JB Weld is worth a try. Ed

To clarify -
There are no screws in the ends of KZ650-C1 mufflers.
There are no removable baffles in KZ650-C1 mufflers.
The carbs on KZ650-C1 bikes are Mikuni VM24SS.

This is the rear view of stock KZ650-C1 mufflers:


This shows the muffler internals - there is no way to remove a baffle without destroying the muffler:

bemoore wrote:

StreetfighterKz wrote: I can't really think of an elegant solution but a plate that looks like a giant washer could be made then welded to cover all the holes at once. But you'll have exposed weld beads that should be coated to prevent rust.

Later, Doug

I thought of doing something like that. Would JB Weld be able to hold the "washer" in place without welds?

welding :ohmy: would be better but you could try epoxy .....the worst that will happen is the patch washer will blow off...still worth a try

My experience has been j/b weld will not hold up when there is pressure applied.
I 'over ported' a cast iron automotive head and hit water. Tried j/b weld multiple
times with no long term success.

.

Might consider drilling 4 more small holes through the repair plate and solid parts of the original baffle-end, then use pop-rivets or metal screws to hold the plate in position. Followed with flat black paint.

Good Fortune!

Nebr_Rex wrote: My experience has been j/b weld will not hold up when there is pressure applied.
I 'over ported' a cast iron automotive head and hit water. Tried j/b weld multiple
times with no long term success.

.

How much pressure is applied to the end of the exhaust? I'd think at that point that the pressure (and temperature) would be low. I'm pretty sure JB Weld wouldn't work at the engine end of the exhaust, but I thought it might work at the tail end.

Patton wrote: Might consider drilling 4 more small holes through the repair plate and solid parts of the original baffle-end, then use pop-rivets or metal screws to hold the plate in position. Followed with flat black paint.

Good Fortune!

Hmmm. Hadn't thought of that. For some reason, I was only thinking of some type of adhesive. Thanks for the idea.

If the exhaust area is cleaned, Permatex high temp copper sealant may be another adhesive option.



The product should be sufficiently heat resistant, because it's used satisfactorily to help seal the copper gaskets in exhaust ports.

Just before metal-screwing or pop-riveting, the sealant could be applied between the repair plate and muffler to better seal the holes and help avoid possible vibration.

Good Fortune!

bemoore wrote:

Nebr_Rex wrote: My experience has been j/b weld will not hold up when there is pressure applied.
I 'over ported' a cast iron automotive head and hit water. Tried j/b weld multiple
times with no long term success.

.

How much pressure is applied to the end of the exhaust? I'd think at that point that the pressure (and temperature) would be low. I'm pretty sure JB Weld wouldn't work at the engine end of the exhaust, but I thought it might work at the tail end.

Guess again. The temperature may drop some by the time it reaches the exit of the muffler.
But exhaust gases will still be expanding also. Then there is the expansion and contraction
rates of the muffler vs. the patch.


.

Patton wrote: If the exhaust area is cleaned, Permatex high temp copper sealant may be another adhesive option.

The product should be sufficiently heat resistant, because it's used satisfactorily to help seal the copper gaskets in exhaust ports.

Just before metal-screwing or pop-riveting, the sealant could be applied between the repair plate and muffler to better seal the holes and help avoid possible vibration.

Good Fortune!

I agree with this approach. By themselves, neither provides a quality seal. However, combined they just might do the trick.

You could attach a plate w screws in addition to the sealant. The screws will keep it in place & the goop will seal it.

As for the aftermarket exhaust mentioned, you'd probably only need to change the main jets a size or two, which should be no big deal.

Here's a photo to show how I plugged some holes that someone drilled. There was enough material to cut a couple of threads for some brass plugs, and I used a high temp thread locker to keep them in place, then painted w engine enamel. The repair has held up for over 10k miles, including the paint.