What is the model and year of your bike and what muffler are you using? I would be careful about make a change that cannot be reversed. The standard Honda exhaust is highly tuned. You may not like the result of your modification.

If you shorten the pipe, you will be moving the peak power up the RPM band. The intake side is also tuned. The intake, exhaust and cam profile are designed to match.

The intake and exhaust are timed to the four engine cycles. On the exhaust side: when the valve opens a pressure pulse shoots down the pipe, when it hits the muffler (usually referred to as the collector) a low pressure pulse shoots back up the pipe. If the low pressure pulse hits the exhaust valve at the same time as the next valve opening, a supercharging effect happens.

The same things happen on the intake side. The difference is the air/fuel travels down the intake tract it is interrupted by the valve closing. When airflow stops, it builds up pressure. If the peak pressure hits the same time as the next valve opening, a supercharging effect will happen.

The longer the pipes (intake tract and the exhaust pipe), the lower the peak power occurs on the RPM band. The shorter the pipe, the higher RPM the peak power happens.

The length of the power pulse determines how wide the the RPM band (low to high) is when the super charging effect happens. A smaller pipe has a longer pule. A larger pipe has a shorter pulse.

 

Thanks for the reply JamesPal. It is a 1971 cb175 k5, the muffler is an Emgo 26" long megaphone style w/reducer. I dont want to cut any length off of the pipes. Here is what I'm trying to find out.

Can I butt the muffler up to the ring and clamp it down: View attachment 53855

Or should I remove the ring on the header and thus being able to get a deeper grab on the header: View attachment 53856

This is how the muffler looks: View attachment 53857

And it reaches back to just past my rear axle darn close to stock length.

Sorry if my original post was not really clear enough! Thanks

 

IF you have adequate overlap to seal and provide a decent structural/mechanical joint, there is no need to remove the ring

 

Thanks for the reply JamesPal. It is a 1971 cb175 k5, the muffler is an Emgo 26" long megaphone style w/reducer. I dont want to cut any length off of the pipes. Here is what I'm trying to find out.

Can I butt the muffler up to the ring and clamp it down: View attachment 53855

Or should I remove the ring on the header and thus being able to get a deeper grab on the header: View attachment 53856

This is how the muffler looks: View attachment 53857

And it reaches back to just past my rear axle darn close to stock length.

Sorry if my original post was not really clear enough! Thanks

 

Had to repost so pics would show. What do you think 66sprint now that you can see the pics?

 

Sorry, you links are not working. Go to the Advanced Reply screen and use the picture upload icon.

 

One more try!

Thanks for the reply JamesPal. It is a 1971 cb175 k5, the muffler is an Emgo 26" long megaphone style w/reducer. I dont want to cut any length off of the pipes. Here is what I'm trying to find out.

Can I butt the muffler up to the ring and clamp it down:

Or should I remove the ring on the header and thus being able to get a deeper grab on the header:

This is how the muffler looks:

And it reaches back to just past my rear axle darn close to stock length.

Sorry if my original post was not really clear enough! Thanks

 

You will NOT get either a seal or mechanical strength unless you remove the offending protrusion ring.....Even at that, the muffler clamping area is too large a diameter to work well....
When I'm faced with this scenario, I grind all the ring off and weld on (spotwelds in through holes) an adapter tube/sleeve that is "unsliced" to prevent leaks.... Those provided adapters almost always leak.....

A T-bolt clamp (SS band) will work much better than the provided "pinch-ring clamp" as well.....

 

Thanks 66, I will look into getting someone to weld for me if I can, or I will just have to use the adapters that came with it. May I ask where you get those t-bolt clamps?

 

Hey Hobbsla,

I'm looking to get the same exact mufflers on my K5 as well. This look pretty close to OEM and I'm hoping the sound is similar too. Make sure to update this thread as I really want to know who everything turns out. I heard the kickstarter will hit the muffler so people have recommended bending the kickstarter. I also heard from a different post to use an aluminum can as aluminum flashing to make a good seal with the muffler and header.

As for T-Bolt Clamps, I've near heard of them before but I did a quick google search: http://www.amazon.com/Pro-Tie-33730...f=sr_1_1?s=industrial&ie=UTF8&qid=1424833178&sr=1-1&keywords=t-bolt+clamp+1-7/8 Here's one I found on Amazon, however, it's only 3/4" in diameter.

Please update as I really would like to know how this turns out and if you need to do a large amount of "tuning" afterward.

 

I used the 27 inch dunstall wide mouth mufflers on my 175. Took the baffles out and wrapped them with exhaust wrap nice and tight, making it more like a straight pipe. Loud as hell (personal preference) and still the power benefit of the longer exhaust.

 

I bought the Emgo 80-84034 Megaphone Muffler. Sounded pretty much like the stock exhaust. As others have mentioned before, the reducer set and clamp are insufficient at being able to tighten the header to the muffler. I'm currently in the process of having a 1 3/4" pipe, about 2" long, welded to the header. This will allow me to not have to use the reducer set, and should provide the tightest connection. As for T-bolt clamps, these are probably a little over-priced but I bought some off Amazon, I think the 44mm-51mm will fit best over Emgo muffler. Amazon.com: HPS (SSTC-44-51) 44mm - 51mm Stainless Steel T-Bolt Clamp for 1-1/2" Hose: Industrial & Scientific

I'll post picture once I get the pipe welded.

 

Recently received the pipes I mentioned before, see the picture below. Each pipe is 2" long, 1 3/4" OD and 1.5" ID. My header pipes are from a 1971 CB175 so they're a little different than yours. I plan on having the 2" pipe welded to the header, and the coupling the header to the Emgo mufflers which have a little bit wider than 1 3/4" ID. I'll update again once welded.