Repairing holes in exhaust

A while ago, I bought a stock exhaust system for my 650C1 off ebay. I failed to notice that it had holes in the end of one side. So now I need to find some way to repair this. Any ideas?

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

Possible internet searches: motorcycle end caps, muffler tips, exhaust caps, exhaust baffles, tips

Replacement mufflers.
EMGO UNIVERSAL DUNSTALL STYLE MEGAPHONE MUFFLER

HELIX RACING UNIVERSAL DUNSTALL TYPE EXHAUST MUFFLER

Verner-650's bike w Dunstall Replicas

Are you sure it's not used as a drain hole?

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?

martin_csr wrote: Possible internet searches: motorcycle end caps, muffler tips, exhaust caps, exhaust baffles, tips

Replacement mufflers.
EMGO UNIVERSAL DUNSTALL STYLE MEGAPHONE MUFFLER

HELIX RACING UNIVERSAL DUNSTALL TYPE EXHAUST MUFFLER

Verner-650's bike w Dunstall Replicas

Verner-650's exhausts look nice, but I'm interested in an actual stock exhaust. I would have no confidence with an aftermarket system that it would run as well as stock. It may flow better, but it will not flow exactly the same as stock, so stock jetting won't work. I have a Kerker now. If I decide to not go stock, I'm going to stick with the Kerker.

Thanks.

As long as you don't make a crazy changes to the exhaust, most mufflers will react similarly to stock. The holes in your exhaust were probably added by the previous owner to get the to sound 'better' and to reduce back pressure.

As long as you haven't removed the airbox from your bike, this simple change should be fine, performance wise. The slight reduction in back pressure shouldn't require you to rejet, but you may need to tune the carbs slightly.

While some carbs sets (Keihin BS carbs, for example) do not react well to any changes in the performance envelope, others (like the Mikunis) are more tolerant of changes.

We're kind of 'rule of thumbing' the advice. Since your bike is a '77 and probably has Mikuni 26mm or 28mm carbs, you can make some pretty radical changes to EITHER the exhaust or the intake and not have to do a thing. My '77 KZ1000 ran without a single change to the tuning when I pulled the original exhaust and replaced it with a 4-into-1 high performance rig. Put on pod filters and a high performance exhaust and you might have to rejet.

Because of the way the Constant Velocity (Keihin) carbs actually operate, even slight changes translate to huge changes in carb performance.

Good luck.

nickleo373 wrote: Are you sure it's not used as a drain hole?

Yes, I'm sure. The other side doesn't have these holes.

I noticed that there are screws in the ends of the mufflers. Have you tried removing those to see if the baffles are removable?

Cynjut wrote: I noticed that there are screws in the ends of the mufflers. Have you tried removing those to see if the baffles are removable?

No, I haven't tried that. I'll give that a try.

Cynjut wrote: As long a

While some carbs sets (Keihin BS carbs, for example) do not react well to any changes in the performance envelope, others (like the Mikunis) are more tolerant of changes.

Good luck.

Keihin??? :whistle:

bemoore wrote:

Cynjut wrote: I noticed that there are screws in the ends of the mufflers. Have you tried removing those to see if the baffles are removable?

No, I haven't tried that. I'll give that a try.

Good luck removing them screws.