Any Recomendations to Seal Aftermarket Exhaust?

I recently added a Yoshimura 4 to 1 exhaust on my 86 VFR700 and it is a slip fit onto the stock down pipes. I just slipped them together and so far I can't detect any leaks (by sound, carbon deposits or puffs of air), but I do have noticable popping under engine braking. I can't tell if I need to enlarge the pilot jets or if air is just seeping in around the joints so I want to seal them up nice and air tight.

Here is a general idea of the sizes I'm working with.



I can't use sealant as I remove the pipes often. I thought about black silicone tubing and fancy stainless T-clamps, but I'm not sure they could handle the heat. The silicone hose is rated to 500*F.



I found a honda muffler joint that is pretty close in size, but may not handle the heat.



I also found a suzuki exhaust joint that I know will hande the heat, but the ebay seller said the inner diameters are 32mm and 46mm, but it sure doesn't look like that to me.


If anyone has any more ideas, please post them up.

 

I doubt that those clams will stand up long to the heat. I think they look tacky too. Why not just go out and get a muffler gasket. They are cheap.

 

That's what I'm looking for. Have you seen any?

 

https://www.google.com/search?sourc...0i22i30l4.0.0.0.14639...........0.oumZcsDvp90

 

I'm still not understanding. Do you guys have a picture or description of the seals your referring to? I've looked extensively on google and eBay for something that would work and I've found mediocre solutions at best.

 

In your initial pic, I am seeing two measurements. One an OD and the other an ID. Wall thickness has to be cranked in to be accurate.

Muffler shops with the exception of the "National" brands have been doing custom work on cars for a very long time. Even they probably started oot doing "regular" work.

Let's draw an analogy.. I am an avid photographer. One of the local librarians knows me and recently asked if I wanted to have a lighting catalog from a NYC photo supply that have been buying from for years. I said, "sure", thinking I had probably seen most of the stuff in the catalog. Not so..The catalog was the commercial/pro catalog and is 530 pages of photo farkles. Kind of like SouthWestern Camera that was downtown for years in a four story building.

 

It's just 2 pipes slipped together. The smaller pipes OD is 35mm and the larger pipes OD is 38mm. I guess you could say the wall diameter is 1.5mm or a bit less. I figure a 35mm ID coupler of rubber or silicone could be stretched over the bigger pipe and the clamps would create an air tight seal.

I'm pretty sure a muffler shop would typically want to seal the pipes with putty which I don't want to do, weld them together which I don't want to do or crimp them together which I don't want to do. I don't think they have any acceptable solutions.

Band clamps are not an option either as they are not made in such small sizes.

If a stepped band clamp were made in the proper size that would be a good solution, but the smallest I've seen is 2.25" (car sizes).

(I don't understand your analogy at all)

 

I can see you don't. I'm exhausted.

 

OK you want to slip a tube OVER the joint I guess. It doesnt look like there is enough room between the yosh pipes to get anything in there and then add a clamp. I guess you know that reducing back pressure pretty much always results in burbling deceleration if you dont rejet.
I think more important measurements are the OD of the header and the ID of the yosh pipe. If there is about NO difference then that is the best you can do.

 

There is plenty of room. I think the gap is about 10mm. The silicone tubing wall thickness is 5mm and the clamp will squeeze it, so that's not a problem.

I've got this exhaust, plus an open air box plus K&N filter with Dynojet stage 1 kit with the bigger 118 main jets. The plugs look good and it runs great, but I'm not sure about the popping. I'm trying to figure out if more jetting changes need to be made or if it's fine as is. It sounds cool as hell.

It's a slip fit. There's no wiggle room. They fit together snuggly, but these are old bikes and the tubing is not 100% round, so there may be tiny air gaps. I guess I could use a smoke machine to blow in the muffler and look for leaks, but I don't have anything like that.

 

I have the same issue with the Yoshimura 4-2-1 on my '86. I can feel exhaust coming out of the area where the system joins to the headers. I'm also not too jazzed up about the idea of welding them together or using a sealant. Please post up if you find an acceptable solution.

 

https://www.google.com/search?q=mot...kHI3loATbl4GoAg&ved=0CFwQsAQ&biw=1440&bih=744

 

On my 84 the Yoshi system is a full system for exhaust ports back to the can,
the can has 2 1in. slits in the sides where it goes over the header pipe and I
use a good quality clamp to tighten things up. I have had no problems with this

 

Exhaust place should be able to expand the smaller pipe up so they are a snug fit in the muffler

 

Just another approach you might consider. Pick up some copper pipe from a hardware store. Cut a length of it and split. Hammer out flat, then curve the pc. around the ex. pipe. Copper is soft & malleable. You're only looking at 3mm thickness. If one pc. of copper formed this way is not thick enough, double up. The copper pc. fitted between the 2 items in your photo should make a good 'gasket' that is heat tolerant. I've done this, worked for me. Play with the length until you get it right. Doesn't cost much ...

ACE

 

My old 86 sounded like popcorn too. I think it was always there, just not really noticeable with stock cans. Honestly though, unless the popping turns into loud bangs, I wouldn't worry about it. I don't think sealing those joints up further is going to solve the issue. I had the old Kerker 4 into 1. I don't think any non baffle style muffler is going to remove that sound completely.

 

I'm not sure what you mean, but I'm guessing you mean to hammer the copper into a thin strip and then force it into the gap between the pipes? There really isn't a gap in the pipes that is uniform in shape, so that wouldn't work, but it does give me an idea.

Since no one makes stepped band clamps this small, what about building up the smaller pipe diameter and then using a regular flat clamp over the gap? Here is a diagram.



I could even add a thin piece of exhaust wrap or similar material under the clamp to further seal things. I know it would handle the heat, not distort the pipe ends making the exhaust hard to seperate and not cause any messy sealant problems. The copper should be soft enough to give a good seal and the whole thing (4 clamps and copper pipe coupler) should be well under $20 total.

What do you guys think?

 

You may be right. I may get it sealed up and it would sound exactly the same.

I've heard that enlarging the pilot jet a size or two should fix the problem, but I don't think the "transition" ports of that circuit really come into play when the throttle is closed, so I'm a bit confused how it would help.

I've heard it's due to a lean condition and that fresh air being sucked into the exhaust cause the popping. I know some carbs have decelleration enrichment circuits (including our Keihin VD series) to help cure the issue. I know my decelleration enrichment circuits under the slide covers are not stopped up, yet it still pops/burbles.

 

Dab, on another forum, suggested muffler tape and clamps. Now that's not a pretty or permanent solution, but it should work for only $5.

I'm gonna try Dab's idea and if it reduces the popping/burbling under deceleration then I'll buy the thick copper pieces and stainless T bar clamps and fab those up because that's a much nicer looking and permanent solution.

So I guess we can stop posting ideas on this thread until I can try them out and post back the results.

Thanks everybody.

 

Okay, I just read of an even cheaper and easier way to check if the pipe joints are leaking. Warm up the engine and just generate a little bit of smoke (like from incense or a cigar, etc...) and put it around the joints while the engine is running. Even the tiniest leak should be visable. I dont kow why I didnt think of it sooner.