What did you do to your Yamaha today?

What I did was zip tie a shure stereo microphone just above the cam cover under the tank for the sound and fed it raw into the AFM 3&4 of the recorder. I'm using a Sony BVW-50 BetacamSP which was the defacto broadcast format until the switch to digital.

The camera itself is stuck to an angle bracket that's mounted on the sheetmetal of the air filter inside the airbox looking at the #3 carb.

Reason for this was to maintain roughly the same environment and get a good picture of what's going on inside. The lighting is subdued to keep from glaring and crushing the details, going to make a longer run tomorrow afternoon and I will push the video up slightly.

 

The right hand muffler on the 650 had a huge rust hole. While it did emit a charming exhaust note somewhere between a Roadglide and a Briggs & Stratton, I figured it should be patched. My first inclination was actually to get a $75 pair of "universal" e-bay mufflers, but if I was starting with junk, why not make junque?

Here's the offending aperture. The internal baffle construction leaves a double wall in this spot, perfect for trapping moisture.





So first, mark out the area of surgery and cut away with the zip disc.



Then make a cardboard template and transfer to some donor metal, which in this case was a rotted away muffler from a 750. But hey, pre-chromed!



Then after some half assed fitting and grinding and blowing and filling holes in high winds to make sure all the shield gas rapidly returns to its home, the patch is more or less secured.



Then hit the whole thing with the wire wheel to rebuild the remaining chrome, and voila, this perforated pipe is remuffled. It's on the bottom, so it's ugliness shouldn't offend too badly. A reasonable result, and less effort than I would have spent welding on a couple of even uglier aftermarket baffle boxes.

 

Professional as it gets.........

 

Did another video run today only this time really got into it several times taking the motor to 10K. Clutch still breaks away despite the el-cheapo oil so that is next on the to-do list. I was able to replicate the 6000 flat spot and it seems to correlate with the position of the needle transition point so I might swap them to a set of police spec needles and see how that goes. The motor otherwise sang really good above 7000 and I goosed it several times going for the century mark. Will post a better quality cut in the next day or two for your entertainment.

 

Now you've got the problem that the chrome on the patch is shinier than the chrome on the rest of the muffler!

Both of the mufflers on my '80 Maxim are rotting out, I believe at the next baffle back from the one you patched. Not as bad as yours, just a lot of crunchy rust on the inside and bottom, but they're going. They were that way when I got the bike, so I don't know if they're making any particular noise. I don't think I'm going to try patching them, though, as I despise the misbegotten suckup-t0-the-EPA welded-together exhaust system that makes minor maintenance like pulling a shock bolt into a gold-plated pain in the rear. I notice from your third pic (the one where you've got the muffler open in preparation for the patch) that there is a nice internal pipe in there. Bet that if I sliced the outer shell off someplace closer to the front of the muffler, I'd be able to trim that internal pipe and clamp an aftermarket muffler to it.

Eventually. For now there are higher-priority projects.

 

That would work for sure. It might be a bit messy at the end where the internal pipe and the outer chrome shell come together. One thing to consider on the 650, they don't have a hanger bolt in the crossover area like other models, so your clamps would be structural in a sense. Probably not a huge issue since exhaust clamps seem to bond at the atomic level after the slightest corrosion. If I had gone the route of aftermarket mufflers, I was going to trim it shorter to get past the double wall section and weld it all rather than clamp, but then there is also a little angle kick in that spot to deal with.

 

Two steps forward, one step back, repeat...

Last week I decided to do something about my pulsating (warped) front rotor. Stopped at the local multi-brand shop, and the best he could find was an EBC rotor for about $240. Ugh. This "free" bike has already cost me enough that I wonder whether I'd be able to sell it for what I paid. I started looking around for cheaper options. There are many Chinese-made replicas of the stock rotor available on eBay and Amazon for about sixty bucks, but I am not that impressed with the design of the stock rotor. And it was damnably hard to get information about what actually replaces what. Eventually I found the OEM part number on Partzilla, and from there I found a NICHE Industries rotor (Chinese made as well, but I at least have some experience with that company and everything I've bought from them so far has fit and functioned) that looked like a copy of the EBC item. Drilled, floating, explicitly said to replace Yamaha Part Number 1J3-25831-00-00, $80 with three-day free shipping. All right, let's go with that.

While I had the wheel off, I pulled the right fork leg to replace a weeping seal. As I had done on the left side (when the bolt absolutely refused to come out of the damper rod), I worked the seal out using small screwdrivers, with the fork leg otherwise still assembled (as I had changed fork oil less than 1000 miles ago). New one went in without incident, or so I thought.

Rotor came on Friday. A quick comparison showed it was the right size and shape, so on it went. Looks pretty cool, eh?



Put everything together and went for a little ride to scuff-in the new disc...

What's that clatter-clatter-clatter sound? Uh-oh. Came home after a mile and had a look at things. The pads told a story:



It's more visible on the outboard pad (the one with thicker friction material), but it's clear that on both of them the inner edge of the friction material's hitting something and being chunked off. So let's take some measurements on this "guaranteed to fit" (by both NICHE and Amazon) rotor...

On the original Yamaha rotor, the pads visibly sweep in some 42mm from the edge:



However, on the NICHE rotor, the swept area ends at 37mm:



...and the edge of the rivets on which the disc floats is about 40mm from the edge. In other words, there's about a 2mm overlap, in which pads and rivets are trying to occupy the same space. Ouch. You can see where their leading edges got a little scuffed.

What to do...? On the one hand, I could probably battle Amazon and get a refund, as the rotor is clearly not a "perfect fit." On the other hand, I'd then be back to Square One. And in all fairness, even with the clattery collisions, it was clear this rotor had better stopping power than the original. 35mm of swept area is more than enough. And so, the obvious, if brutal, solution:



A few minutes with the bench grinder removed the last couple mm of the friction material from the pads. On the outboard pad (the one with the thinnest friction material), I also cut away the backing plate lest it graze the rotor rivets when the pads are near the end of their service life. This is a messy job, and I was grateful I have already replaced the original stock pads with asbestos-free EBC semi-sintered pads. Even so, a Shop-Vac at the grinder and a particle mask are something of a necessity for this job.

Took the bike for an 80-mile ride, no problems with the brakes. The EBC pads do indeed bite the NICHE rotor better than the stock one. Absolutely no pulsation. Ah, relief! I suppose I could worry about whether my surgery in some way weakened the bond between the friction material and the backing plate, but my experience with modern brake pads is that they are stuck together really, really well... as in, I have had pads where the backing plate bent enough to crack the friction material in half (I still don't know how this happened on my Himalayan), but the material itself remained firmly bonded to the backing.

I'd go looking for skinnier pads, but the Maxim's front brake is such an odd duck I suspect there are no options other than stock size and shape. I don't think any other bike uses pads with that odd taper. So, case closed, at least for the next few years.

However... upon arriving home, I found green fluid all over the right fork slider. My new seal was leaking a lot worse than the one it replaced. Aw (deleted)! I rode home, cleaned up the mess, and discovered the leak was not between the tube and the sealing lips, but between the seal body and the fork slider. Huh? Popping the seal out (getting to be a fairly easy job with a proper small screwdriver) showed why:



WTF? Did I do that working the seal out with a couple small screwdrivers? Doubt it; these were some serious gouges. One actually looked more like a bubble in the casting. And they went most of the way around the perimeter of the slider, while my removal tools had stayed in a small area. Previous owner did a hack job replacing seals? Manufacturing defect? Gremlins in the dark of night? No idea. I cleaned things up as best as I could, and then installed a new seal, putting a thin layer of silicone around its perimeter and on the bottom of the outer ring. Keeping the stuff away from the sealing lips and tube was tricky; I finally found the best thing to do was (with the fork slider in a vise) slide the seal onto the tube and only then apply the silicone. Drive the seal into place, install the retaining clip, and say appropriate prayers. I let the silicone cure for 48 hours before putting any weight on the front wheel, as I did not want to push any oil up against the seal until it had fully cured.

Yesterday afternoon I took the bike out for a sixty mile ride, hitting every bumpy road I could find (including about ten miles pavement-free and rough enough I had to stand on the pegs while bouncing over potholes and washboards). The seal is holding; the fork tube is antiperspirant-ad dry. So, for now, I consider this problem dealt with. In the long term, both fork sides have issues--the mating surface for the seal on the right, the damper-rod bolt kept from leaking by a load of red Loctite on the left. On Friday night I noticed somebody on the site was offering a set of forks from an '82 Maxim (which my Haynes manual says will fit a 1980 model) for the price of shipping. PM'd him; still waiting to hear back. Serendipitous timing if he's still got them. If not, I guess it's eBay time... eventually...

 

Put a new clutch in the 1100 tonight and hastily jumped on the road for it's maiden voyage. Hastily enough that I hadn't tightened the rear motor mount bolt or reinstalled the brake pedal...figured that out by the end of the driveway though. Then onto the road, and it's faaaast. At least until I blew two of the vacuum caps off the intake boots because I didn't put the clamps on...that haste thing...and limped home on two cylinders. A bit of sputtering in the mid range. The Supertrapp was wide open, so I need to figure out the whole disc tuning thing and if I need to tweak some jets along with that. But pretty good for a first trip.

 

I just ordered a friction & steel set for my SECA, it's burnt.

 

that it does, I'm looking for replacements for my Turbo, I'm using FZ600 rotors which are a very common fit, 2nd Gen Virago, YX600, RZ350, FJ600.
I see Niche has replacements but don't see floaters. This would avoid the problem you encountered but yours really looks great.
I passed on a mint (really mint) FJ600 front wheel w/rotors at a swap meet a year ago for $30, kicking myself now.
Does anyone know if any later model Yamahas have this same bolt pattern?

 

Have you posted videos to youtube?
I have a borescope that I shoved into the airbox of my XJ to look at slide activity when throttling up. It did not have sound though. It does record to SD card. showing CV carb slide movement when accelerating and running would be really good learning tool, especially if we could split screen it with the throttle position.
Too many people think a CV carb slide moves exactly with the throttle. It does not.

 

No, it goes up in response to the vacuum below it (between it and the main jet), which connects to the area above the diaphragm. Essentially to prevent the vacuum at the jet going up as a square of the airflow (ask Mr Bernouli). This is why they are (or should be in the US) called constant vacuum instruments.

 

Im interested to hear how the Niche brand rotor works out.

I ended up buying EBC rotors for my bike (two fronts on the yx600). I was able to find two NOS items at a reasonable price.

Chinesium rotors make me nervous. I’ve seen pictures of them falling apart on the road. Could be disastrous..

 

Oh my, suddenly I'm back in Physics 101 and thinking of Gaussian fields. About the only thing I really recall is that "F = Ma and you can't push on a rope"..........

 

Actually there are two videos posted now, just completed the longer one that includes a few runs to 9000+ and clutch slipping. Ordered a new set of steels & friction for some weekend work.

Longer Video is here:
Short Video:

 

Another test run on the 1100 today with similar results. Didn't lose any vacuum caps, so maybe blaming them was incorrect yesterday. But both days, it was cylinders 3 and 4 that quit. I'm waiting on fuel hose to rebuild the octopus and currently have both fuel lines teed from one petcock, so maybe I'm getting some weird air bubble and starving 3 & 4 carbs. Plugs were white and clean, so maybe fuel starved before they quit. Got it home and it fired right back up after sitting a bit.

Valves are all in spec, and I did consider something heating up and causing it, but felt like fuel. Not sure though.

Maybe I'll get my fuel lines all proper before another attempt.

On the plus side, I really like the setup of the 1100 for bars and seat and foot controls. Very comfortable.

 

After reading @Roast644's post about muffler repair, I decided I ought to see just how far gone mine are. Not an easy task when you're 70 years old and arthritic, until I figured I could use the selfie camera on my phone:



Notice the somber expression as I get my first glimpse of the carnage. These things are not pretty. Think they might be past the point of being patched.

 

Those are intimidating for sure! But my thought going into it was, I can't screw it up worse than it already is.

 

Some people fit Harley Sporter mufflers l believe.

 

Wouldn’t surprise me. Having owned a Sportster from around that period, I’m constantly noticing similarities to my Maxim. Same tire sizes, same seat height, about the same riding position, same ridiculous buckhorn bars… Of course, one big difference was that my late ‘82 Ironhead came with all of a 6-month/6,000-mile warranty!

I figure the regular Sportster shorty duals might be a bit restrictive; then again the Maxim is barely half the displacement of a late model XL. Might be worth a look, at least in the short term. There are plenty of them around, cheap. I could even weld them on without their getting in the way of shock bolts.

In the long term, the closest thing I’ve found to the look and size of the stock muffler is the EMGO “blunderbuss,” but they’re around $80 each, would need mounting hardware, and come without baffles.