Topic: Baffles on stock four in fours (500) and how they've been modded(?)

[blacknapkins]

Hello folks, this is Alex from Bavaria, Germany. Been reading here for ages and think this is the no.1 resource on the planet. Finally got my bike running since it has been sitting for 20 years. I might be getting close to legal inspection and registering, soon. Bike used to be loud back then and seems damn loud hearing it now. Obviously, someone has been fiddling with the Pipes back in the day, but I can't figure out what it was about. I attached the pics where you can see the "shims" being riveted times 4 are removed. THis I've done to get closer to the secret. On all four ends the outer holes were covered by what I call shims, finished up with some kind of bondo stuff, probably to seal it up airtight. When I try to peak inside I guess it's all still pretty intact (tubes and chamber subdivisions and so forth).

What I wonder is
- if anyone can name resouces where I'd be able to see how the assembly's compartments look like when it was new.
- what was possibly done and why? apart from puming up the volume...
- was there any baffle filling packed in there at the time they were stock? I doubt it can get removed by any of the existing openings.
- how would I best close the ends once shims are riveted back into place? I'd go with some high temp sealing compound, as it was before. Any suggestions here?


Bike is a K2 USA by engine number and K1 GERMANY by FIN.

Thanks for your time!
Alex

[bryanj]

The only hole you should see at the end is the one in the middle

[blacknapkins]

sure, Bryan. It's how it looks opened for inspection. And sure it must be louder than with the plates / shims on.

[blacknapkins]

Or could so. kindly post a pic of the stock muffler's rear end?

[Kevnz]

Hope this helps.

[Stev-o]

Hey Alex...first off, welcome from Texas!   No, there was no packing originally in these exhaust pipes.  The only reason I can think of why anyone would remove it is for sound.  It actually may run worse with less back pressure.
Are you able to fabricate some plates that you could fit back on there?  I dont know what you mean by the shims, I think it is getting lost in translation.

[seanbarney41]

I had one pipe on a 550 that I had to replace.  The replacement had been drilled.  I just fabbed up a patch, basically just a big old washer, and used high temp exhaust sealant to glue it in place.

[Little_Phil]

There were some pics here. Not sure if this is the whole story.
http://forums.sohc4.net/index.php/topic,185126.msg2143709.html#msg2143709

[blacknapkins]

Thanks Steve and Sean and all, now we´re talkin. Plate, patch, whatever 
Mine was fixed up just like Sean shows it, the "washers" were riveted to the pipe ends. Exhaust sealant seems to be what I need, hadn´t heard of the stuff before. It´s good to know that there wasn´t any packing used on these.

I´ll go ahead and try to seal it up the best I can.

Are these pin sized holes where the small pipes grow into the big silencers (around the foot pegs) for draining water, condensation... ?

Cheers
Alex

[flatlander]

yes those little holes that open towards the bottom are for letting condensation drain out. they like to rust themselves closed. check them once in a while and keep them open.

[Stev-o]

Exhaust sealant seems to be what I need, hadn´t heard of the stuff before.

This is one product that should work, not sure if it is available in Deutschland?

https://www.amazon.com/J-B-Weld-8297-HighHeat-Degree/dp/B007PP26RI/ref=asc_df_B007PP26RI/?tag=hyprod-20&linkCode=df0&hvadid=312174034736&hvpos=&hvnetw=g&hvrand=3833389113567332787&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9028253&hvtargid=pla-486132852917&psc=1&tag=&ref=&adgrpid=62149253516&hvpone=&hvptwo=&hvadid=312174034736&hvpos=&hvnetw=g&hvrand=3833389113567332787&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9028253&hvtargid=pla-486132852917

[blacknapkins]

finally I have this finished up (after breaking my hand, holidays, work stuff...) and it runs like a charm, not too loud. I ended up using HOLT´S GUN GUM which I think has been around for ages. It´s a small tin jar and it comes very cheap. Containing lots of small fibers, it has done the job easily.

thanks to all the contributors!!

[Deltarider]

It's been around for ages absolutely. Used that stuff many times on mopeds exhausts and later for minor leaks in the exhausts of my cars.