exhaust header air box question

im about to take my exhaust off and replace the 4 gaskets that go from the headers to the collector. and replace two worn rubber bumpers that hold the collector up.

i have already replaced the ones from the collector to the exhaust pipes last year.

i don't recall how hey exactly went on. so... i cant really compare.


on the headers to collector, do the gaskets slip inside the headers and also inside the collector or over the headers and into the collector?

any help greatly appreciated.

 

ps. im doing this in hopes to fix a rattle at around 4k rpms. saw a leak on one of the pipes. so might as well do it and hope it fixes my rattle.

 

I had a similar rattle, and it was a head pipe loose in the collector.

Where the head pipes meet the collector, the gaskets go on the head pipes and slip inside the flanges on the collector.

It's important to get the old gaskets out of the collector flange, and clean the flanges up so the pipe with the new gasket on it can fully seat into the collector flange.

Take note of the "splits" (slots) cut into the collector flanges; the pipe/new gasket has to go in far enough to ensure the slots are fully covered from the inside. If the inside of the flanges aren't cleaned out, it's hard to get the new gaskets to go in far enough.

I use a wire brush on my Dremel to clean out the inside of the collector flanges.

Also; here's a tip: the collector box was originally chromed before the heat shields were welded on, and then Yamaha slathered some sort of silver/metallic coating over the welds. When I clean up/refurb a collector box, I not only re-coat those areas, I also paint any de-rusted/recovered (Naval Jelly or Rust Converter) areas with the same thing--- high temp aluminum exhaust header paint. The 2000 degree stuff, not the 1200 degree stuff. I decant some into whatever's handy and slather it on with an old artist's brush. And do a second coat about 10 minutes after the first.

Lasts a good long time.

Another tip: after the exhaust system is all mounted up and everything's been torqued to spec, etc; check the clearances between the heat shields and the passenger peg/muffler mount plates. Be sure there's at least 3mm ~ 4mm space there; the motor shifts around in the frame more than you think and if the heat shields are too close they can "sing" if they make contact.

The heat shields can be gently "adjusted" with a wooden wedge without damaging them, if need be.

 

After you win the fight getting the Header Pipes OFF, ... do some Prep before trying to reinstall them with New Gaskets.

Wire Wheel the Bottom-ends of the Head Pipes.
Remove all rust and flake.
Shoe-shine a smooth end on each one with 320 Sand paper.

Prep the Collector Necks with a Dremel using a Medium Sanding Drum.
Or, wrap some 320 around a short length of Broom Stick.
Lube the Necks and ID's of the Gasket Sleeves.
Lube the ID's on the Collector
Replace the 4 Clamp fasteners with New ones.

Start the Gasket Sleeve on the Down Pipe as snug as you can get it.
Prep the Collector Neck to receive the Head Pipe.
Start the Head Pipe back on keeping BOTH Top and Bottom lined-up while fitting the Pipe to BOTH the Head and Collector.
Use a Rubber Mallet or Rubber Hammer.
Tape the Collar or otherwise prevent it from falling-down making the job less
aggravating.

 

thanks to you both again. i overhauled it all. looked for cracks. wheeled. sanded. and painted with header paint and ran it through the curing process. the rattle still exists.

went around with a mechanics stethoscope and its hard to located it. it is definitely from the exhaust (as thats the loudest the stethoscope sounds)

near the end i was just grabbing shit with a towel as to not burn myself. the last thing i did was grab one of the heat shields and im half sure it was the problem. i left in aggravation and am looking for a second set of ears.

its not hitting the kickstand and the weld looks fine. maybe its just vibrating on the collector?

i'll let everyone know what the update is.

 

Get a stiff piece of cardboard (stiff cardstock like a shoebox, not corrugated) about 2" wide and a foot long and make sure you can slide it between the collector box/heat shields and the rear peg mounts, the frame rails, etc. Even with new rubbers it's possible that the collector could be vibrating against the frame somewhere. If that's the case you can throw an extra plate washer on top of the "damper stack" between the collector and its rear frame mount.

The heat shields are both welded and clamped on (not quite sure why) it's possible one of the clamps has loosened.

Did you happen to give the collector box a good SHAKE when it was off? It may have a baffle inside broken free.

All three of these suggestions are from my own personal "fun fighting with collector boxes" experience.

 

If you have "Beauty Pieces" attached to the outboard sides of the Collector, ... the Welds attaching the Chromed Shield might have separated.

Sometimes they make no noise at all and the piece falls-off.

Other annoying clunking sounds:

• Weak Center Stand Spring
• Worn-down Side Stand Pivot Bolt.

 

when i hold that "beauty piece" on the kickstand side the rattle stops. so i shoved some cardboard in between and im going to ride it to work tomorrow and see if that helps and investigate a more permanent solution.

thanks guys.

 

Cardboard?

That would NOT be my first choice!!!

Wear fireproof socks.

 

i put in some industrial felt used to dampen cars from road noise. it is self extinguishing. that is an inherent property of wool felt.

no cardboard.

 

You coulda used cardboard and there wouldn't have been a fire. Doubt it would even scorch.

I feel your pain here. I've had a real fun time chasing a collector box "touch point" myself.

 

I had a rattle on my first 650 maxim.....it was the left side heat shield. The welded ring LOOKED good but the break was on the back side where it couldn't be seen. I wedged it til it didn't buzz anymore than made a small tack-weld. No more buzz.

On another bike, it is the inside of the muffer that is loose.....I can move the center pipe a bit at the end of the muffler. I just live with that one.

Dave F

 

good news

think i fixed the noise, but now that the bike is quiet after 4k im driving a lot faster.

so it seems the bottom edge of that beauty plate was too close to the collector. bent it out of the way and it rides quiet again.

thanks everyone for your help