Exhaust project begins - GS300

[Ric]

Since the factory header pipes on the bike are rusting away, it's time for new pipes. Only these will be WAY overkill - gonna run 1 5/8" headers down into 1 3/4" tubes along the frame rails and into the 17" shorties. Should give a deep rumble.

Pieces include a pair of 1 5/8" VW Bug exhaust port flanges(same bolt pattern as on GS bikes), pair of 1 5/8" combo bends, and a pair of 1 3/4" combo bends. I spent three hours filing the flanges for a snug slip fit around the 1 5/8" pipes. Now I just gotta cut/fit/weld them together, put them on and take an obligatory test ride to work and back, then put the current exhaust back on and send this set off for ceramic coating.

 

[Who Dat?]

... Should give a deep rumble.

A "rumble"?

From a 300?

You owe me a new keyboard and monitor. I just laughed so hard while taking a drink.

Seriously, though, it appears to be a decent project, please post updates.

 

[Ric]

Will do! I'd post pics of the pieces I cut and mocked up today, but I have like zero signal here - tomorrow for sure though when I get into town.

The one thing I'm gonna run into is bolting them in. The flanges are gonna be a tight squeeze, and the flange nuts on the aftermarket studs won't clear the pipe. So I'll either hafta use allen nuts on the studs, a spacer and a regular nut so I can get a wrench on it, or do away with studs and use allen bolts instead.

 

[Ric]

Yep. A rumble... LOL ROFLMAO!!!! I couldn't hold it much longer LOL!

But it actually sounds somewhat decent as it is, albeit obnoxiously brappy - hence the bigger pipes. I'll post a video of a friend taking off on it from his place when I can.

Sorry bout your keyboard and monitor, dude.

 

[hillsy]

Are you doing anything to the motor like head porting, bigger valves, big bore?

Just putting larger diameter pipes on a stock engine will make it run worse, not better.

 

[Ric]

Not gonna go as crazy on the engine as I am these pipes. Probably put 250 cams in it since they have 20? more duration than the 300's. If they even make a 10.5:1 or better piston for a 300 I'd do that for sure. I already have K&N pods on it, and I've almost got the jetting nailed down - the K&Ns made it inhale MUCH better, and the pipes will certainly make it exhale a thousand times better.

I'm kinda of a different school of thought on the exhaust. Of course bigger isn't always better, but better design is better. The 1 5/8" header pipe is a good deal bigger than stock, yes. The step up to 1 3/4" allows for the exhaust pulse to slow down with less reversion back into the cylinder... kinda like a 2-stroke expansion pipe, though not that wild.

 

[Ric]

Here's a comparison of old vs new.

 

[Ric]

First-time mockup. Little bit of tweaking and shaping and she'll be ready to weld.

 

[Ric]

Okay, since the initial mockup I've cut another inch off of the ends going into the head, as well as trimmed a half inch off the bottom of the downpipes. That should tuck things in a bit more snug against the frame. Did meet two hiccups - first one is that I'd hoped the pipes would be about three inches longer than they are. But I have plenty of straight 1 3/4" pipe left to weld onto the back end. Also gonna hafta do some grinding on the outer edges of the flanges to make them clear the cooling fins - nothing a bench grinder and a steady hand won't fix.

 

[Ric]

DONE. Still need to be ceramic'd, but I'm impressed with them so far if I do say so myself!

 

[Who Dat?]

Here's a comparison of old vs new.

You were mentioning that the 1 5/8 pipes were a little bigger than stock. In that picture, yes, they are a little bit bigger, but they are bigger than the OUTER pipe.
Stock pipes are double-walled, so your new pipes are not just a little bigger, they are a LOT bigger than the stock pipes.

Now that it is done, how is your "rumble"?

 

[Ric]

Well? Maybe rumble was a bit strong of a word LOL!

For real though, I am really happy with the tone. The other pipes have this crackle to them that honestly hurts over time, and these new ones knock that crackle out. Still brappy, but that's to be expected with shorty megaphone mufflers. I got a short video clip of a friend of mine flogging on it - he was on it in the other video clip that I have yet to post. Next time I'm near wifi I'll upload them both for yall.

 

[Ric]

Finally found enough signal to upload a couple of short clips. It's my buddy riding it - he had a Harley and nearly got killed in a T-bone collision, so I let him ride the piglet every now and then.

Here's the before - stock header pipes into 1 3/4" pipes into 17" shorty megaphone mufflers:
https://youtu.be/0WYkrwCD73Q

Here's the new exhaust pipes into the same mufflers and revved higher:
https://youtu.be/znvFOjxywjA

 

[sam000lee]

What type of welder did you use?

 

[Ric]

I used a MIG welder at the shop where I work. I'm way out of practice, but they're together at least.

I posted pics from a plug chop I did the other day in another thread in the Tuning forum. Then it hit me that I'm gonna be FOURTEEN jet sizes above stock once these come back from ceramic coating and go on for good. THAT'S if I don't put 250 cams in it.