Kerker 4-1 Repack (Also a Pilot Air Jet Question)

[sztandanga]

I figured it would probably be a good idea to repack my Kerker 4-1 exhaust. Shining a flashlight in there, the baffle looks empty.

It's definitely rusted in place, and the head of the retaining screw sheared off, but I'll just need to drill out a bit to clear the megaphone.

My real question is, the megaphone is stuck pretty hard to the header. I loosened the clamp and removed the support bracket bolt, but could not for the life of me separate the header and the megaphone. Is it typical to use some sort of gasket material here that would keep it in place, or is it just rusted in place like the baffle? Would it be easier to get the complete exhaust off the bike and try pulling or twisting that way? OR maybe heat the megaphone with a torch and put an ice pack on the header?

My other question is the size of the pilot air jet. My bike has a Mikuni 190 in there right now. I was looking at stock specs and it these bikes came with either 180s or 200s. Would there be a reason for the 190? The other jets are a stock Mikuni 40 pilot jet, but a Dynojet 128 main jet. I have the stock airbox with a H&N insert.

 

[rphillips]

???, I've re-packed a bunch of baffles, but never needed to separate the megaphone from the header to do it???

 

[sztandanga]

The baffle is pretty well rusted in place and there's not much of a lip for a slide hammer or anything to grab onto.

The baffle is actually quite long and sticks out past the clamp end of the megaphone as seen here: https://www.denniskirk.com/kerker/chrome-megaphone-exhaust-system-128-61001.p4339.prd/4339.sku

My plan was to try to hammer it out from that end.

 

[rphillips]

Sorry, that's new to me. I've never seen a baffle anywhere near that long. Many times penetrating oil, soaking for a couple of days, will work wonders. Good luck.

 

[Guest]

My real question is, the megaphone is stuck pretty hard to the header. I loosened the clamp and removed the support bracket bolt, but could not for the life of me separate the header and the megaphone.

If you still decide to take the canister off the header I would suggest using a propane torch on the canister portion of the overlap and then twisting it loose. You may have to heat it a couple times and use some penetrating oil as well, depending on how badly they are corroded together.

You can often wiggle the baffle loose from the canister with just the end cap off, it shouldn't be tight into the header tube and doesn't look like it would be based on the pictures you linked to.


Mark

 

[sztandanga]

Well, now I'm confused. I looked here: http://www.dynoman.net/exhaust/baffles.html#kerker and saw this image: http://www.dynoman.net/images/exhaust/kerker/baffles/kerker-dbae2.jpg . I don't have the solid pipe inside of the perforated pipe, but I still think that I have the longer baffle, not the shorter competition.

Maybe I'll try to rent a slide hammer tonight and see if I can knock the end cap loose somehow. If that fails I'll try to heat and twist.

 

[Grimly]

If that one you link to in post #3 is the same as yours I would remove the system before getting brutal with it. If you don't you'll crack off the header flanges in the exhaust ports and that's a bstd to fix.
Once off, just resort to normal exhaust seperation measures - plenty of penetrant, heat, chisels under the joint to lift up the metal and let more penetrant into the overlap.

Also for re-packing, I recommend Acousti-fil. Depends on what you have locally and it's not all that cheap, but one length (they only sell it by the metre) will last two re-packs normally on pipes on bikes.

 

[rphillips]

A useful tip to make the packing last longer. Find a piece of metal screen wire (like from a screen door) available at hardware stores, cut it to fit & wrap it around the tube of the baffle a couple of times & secure it with tape, or small wire to keep it tight. Then wrap the fiberglass, tight, around the screen. Wrapping the fiberglass with some masking tape will help hold the fiberglass tight while installing the re-packed baffle.

 

[salty_monk]

It’ll be rusted too...heat is probably your friend!