Monday, March 26, 2012

Fixin' yer Subaru exhaust

This is just a quick one but I wanted to write it up somewhere before I forgot.

If you own a Subaru and know the undeserved feeling of superiority that comes with driving around a monster truck that looks like a dumb station wagon, you probably have had or will have your blissful driving experience ruined by a noisy exhaust. Most old cars in general are riddled with exhaust problems (it takes a beating down there piping out highly corrosive mixtures of acidic vapors).

It seems like every Subaru I've owned (3 now) has suffered from the same problem, the whole exhaust holds up pretty well but for some reason these stupid flanges rot out. It probably has something to do with how they are welded or the material of the flange or something like that but you go over a bump and your car gets louder, you smell exhaust and go underneath to find something like this:

So the other day I cut out a handful of flanges and made a couple of these:

Quick, easy, permanent. You cut off the tail pipe with a hack saw, angle grinder, sawzall, sharpened toothbrush whatever. This little guy bolts onto the other flange and clamps on around the tail pipe with a regular exhaust u-clamp thingy. Since every Subaru from the '86 brat i have up to the 2001 outback uses the same flange and same 2" exhaust plumbing, this little dingus is pretty universal.

If you want one send me an email. $35 shipped, cheap! I even shot some paint on the weld and unprotected flange so it wont rust so fast.

I put one on the 2001 outback and it worked great. Still a pain in the ass having to jack the muffler out of the rubber hangars, cut the pipe off, somehow everything moved.... 15 minute repair turns into 3 hours.. but its a hell of a lot easier than the alternative which involves going into the parts store, sifting through a catalog to get the right flange (ordering it and waiting 3 days while your car is up on jacks with no exhaust system), removing the whole exhaust, trying to weld the new flange to the rusty old pipe... blah! And the flanges aren't welded on exactly straight!

The slight bit of slop in the slip-fit coupler takes up enough of the wierdness to get it all together, and it makes a tight seal without needing a welder or having to weld an airtight seam on rusty pipe... tough.

Thursday, March 15, 2012

the Bridgestone lives!

Last nights ride was awesome. Yesterday we were in the mid-70's in Milwaukee, with the slightest hint of breeze and a cloudless sky. Basically a perfect day in all regards. I was watching Lyle, so he and I got a lot of work done on the Bridgestone. My goal was to have it running for the ride, Caitlin's folks agreed to babysit so we could go out with the Cranks and celebrate finishing up midterms.

I didn't take good pictures because I was rushing to finish the bike, but I'll snap some better photos and maybe get a ride vid tonight or tomorrow.

I've edited the Bridgestone page to have most of the info up to last weekend, and I'll add the final details as soon as I get some free time.

The ride itself last night was great. It was the first time Caitlin and I have ridden together in over a year, since before she got pregnant, so it was pretty special. The little Bridgestone is going to be a great bike, I can tell already. I got the lights working just as it was getting dark, we hopped on the bike and rolled to fuel. On the way, we had a minor hiccup, Carlos must have removed the bolts from the chain guard and left it sitting in place, I never noticed it wasn't bolted down. If you haven't experienced a chain guard/chain interaction on a motorcycle, you are lucky, its a completely terrifying sound and handling experience. Especially on a tentative first ride about half a mile from home! I pulled the chain guard off and stashed it in a bush to get on the way home.

The rest of the ride was really uneventful. The TMX has a dual rear sprocket, like many enduros of the time. With the amount of power this thing has (really surprising for a 1960's motorcycle- blows any comparable honda out of the water) the short gears are pretty silly. It is revving uncomfortably high at about 40 mph. I'm sure it could rev out higher, but I'm afraid that it is a little lean. The rotary valve induction has the carb sitting in a little box off the crankshaft. The air comes in from the air filter, through plumbing, into that box, and there are about 4 or 5 different plugs to cover up clutch, carb, and oil pump adjustment holes... the cables also come in through a wierd rubber snorkel dingus, and the fact that all this stuff is over 40 years old probably means that it is leaking somewhere. I dont mind the leaks because i'm not driving through mud, dust and water, but I will have to up-jet to compensate for them.

Pretty dissapointingly by the end of the night i could tell that the pressed-in kickstart cog bushing thing was slipping. Carlos, being trained as a machinist, informed me that it was obvious that it was going to slip, and he would have done it differently- thanks buddy hindsight is 20/20, right? I'm a little nervous because when that bushing slips out, the clutch basket pulls forward allows for some misalignment in the gears... not the best situation.

On friday, before frozen snot, i'm going to have to fix it again. I came up with the idea of drilling out a hole on the interface of the two surfaces and jamming a brass pin in there.. I'll probably also knurl the bushing a bit, and use some Loctite Retaining compound (aka bearing glue) in order to give everything a bit more hold.

All in all, i'm really happy with this little bike. Its very well designed in a lot of ways, the 4 down rotary shifter is an awesome idea that more bikes should have- you just keep stomping the gearshift until you get into the right gear. Going from 4th to neutral is accomplished by one click down, and if you do ever have to 'downshift' in a turn, its a lot easier to flick it up once than most bikes where you are constantly wearing out your boot going up and never go down.

I can tell already that the points need some atttention, i'll try to dress them but lately i've been of the opinion that points should just be replaced all the time. Its not worth the headaches they cause. (see Peugeot).

All in all, it was an awesome night.. nights like these remind me why I work so hard to get bikes running and keep them running. Sometimes after a long winter, especially one where you have 5 active projects, and no running bikes, you get lost in the shop time and forget why you're doing it. Being out with my girl, on a bike that I brought back from the dead, and riding with my best friends, is really the whole point isn't it?

That said, with 3 people on motorcycles at moped night, I did feel a bit like we were cheating. I cant wait to be back on a moped again. Motorcycles are cool, but mopeds are still more fun.

Thursday, March 8, 2012

Steady Bloggin'

Or not so much.

I just finished compiling the list of  Tech articles I've written. It was good to go back and look at some of that stuff from years ago. Its good for me to see how much I've improved in my understanding of mopeds and engines and such, how much better my shop practices are and see some of the comments I missed.

The only thing that hasn't improved apparently is my actual blog writing. I should be writing more and writing better, taking more pictures, and thinking about my work. Right now I'm working on my senior design project and my project notebook is a big weakness. The original reason I started this blog was to slow down and doccument what I do, hopefully to improve. In some ways I have, in some ways I haven't. Either way to be a good engineer it is critical and now is as good a time to make myself keep notes as any.

Now that I have an exciting new format and its getting to be spring again, I'll be trying harder to make good habits stick and continue to write and document everything I do.

Speaking of, there is a lot of new stuff that can go in the 'Bridgestone' build page from last weekend. I spent a whole day in the machine shop re-machining a little cog thingy that works with the kickstart mechanisim. I'll put up some more pics and try to write up the current state of progress on the 'Bridgestone' page soon.

Moving right along, the Sachs build is progressing incrementally and I'm hoping to have time to pull the Peugeot engine this weekend. Got a motorcycle skills class on Sunday that should be interesting.

Thanks for reading!