Nylon Tube from Left Side Crankcase

[CatatonicBug]

If you look at the VIN, it has the Serial number in it. You're looking for the prefix (i.e., 3H3, or something like that) with a few numbers after that.

You can download a manual from the link in my signature. Don't cut yourself short on doing repairs yourself! There is nothing you can't do to these bikes yourself! These are simple machines, and do not take any crazy tools to fix them. Brakes are super simple, and are nothing to be afraid of. Personally, I agree with having someone else do the tires, but only because I don't have the tools, and it's not too expensive to have someone else mount them. Generally, you will spend a fortune with any other kind of repairs if you tke it to a mechanic, and most mechanics are not familiar with bikes as old as these, and there are MANY horror stories because of that.

Take your time, ask questions here, and you can fix anything on your bike - all by yourself! You'll feel a much higher sense of accomplishment when you're done too.

[CatatonicBug]

So does the vacuum advance line just push in there or does it connect onto some port in there?

It connects to a pipe on the back of that little shiny dome thingy at the top.

[fredintoon]

Okay, what am I missing? Did you mean check my VIN to the list or a serial number that I don't have access to here at work?

Hi DJ and welcome,
you got your registration in your billfold or can at least remember the letter prefix?
Go back to Catatonic Bug's post where it sez
"You may want to compare your Serial Number to this list, and put your model designation in your signature file. "
In that post (but not here) the words this list are underlined and are a link to click on that'll take you to a bike colour and serial number designation chart.
From that chart you can work out which bike you actually have.
The perished tube is a vacuum line from #2 carb body to the pneumatic advance mechanism behind the left side cover casting. As has been posted, you can buy the tubing at most auto stores.
A final thing; in it's own unique fashion, the XS11 engine runs backwards

[DGXSER]

That tube as stated runs down that bushing and then into the back side of the mushroom looking device in that last picture. That is the vacuum advance. It has a nipple on the back side to connect it to.

As to the VIN, they sometimes have some numbers and letters at the beginning to get them up to the 17 digit std here in the US. I have/had two 81 models and one starts off with 1JAY7 or something like that before the 4RO, the other starts off 4RO.... Made for an interesting discussion with the insurance agent.

Unfortunately, it is VERY common for folks selling these bikes to list them as a midnight special because they are the rarest and most valuable even by NADA. And most folks would never know the difference. Until I found this site and learned what I have over the last year and a half or so, I could never have told you the differences either.

[DJ48170]

Okay, guys, what my insurance cert has for a VIN starts with 383 and ends with 063. Is there another list that includes VINs such as these?

Also, I do not know what has been done to this bike from previous owners. The one I bought it from painted it and took off all of the Yamaha decals from the tank and side covers. He kept them and gave them to me, but I have not put them back on yet. He also painted the tank black with "ghost" flames. For an amatuer, he did a nice job.

[DGXSER]

I'm willing to bet that 8 is actually an H. Very common for even the title folks to transpose or misinterpret a number or letter like that. Which would make it a 1980 Midnight Special. Are the wheels a gold color in the inside? is the front fender and the bottom fork legs black? Entire engine black?

[DJ48170]

And by the way, DG, my VIN is not 17 digits, but only 9.

[DGXSER]

Yeah, I am thinking the 17 digits started in 81, since my earlier 81 did not have it and the later numbered one did.

[DJ48170]

No, there isn't any gold on it, the forks are all chrome/aluminum and the registration says it is a 1979. Where do I find the VIN on the bike itself? When I get home I will check it then and compare to Catatonic's list.

By the way, does anyone know where to get a seat or seat pan? Mine is quite rusted on the left underside of the seat pan. Are there any that are compatible with the bolting style of these?

[DGXSER]

Well it appears you may have a 79 special then. I was mistaken, happens once a year tried to go from memory on the vins. 3H5 = 80 Midnight Special. 3H3 = 79 Special.

The VIN is on the neck of the frame. It is stamped into the metal in the right side and written on a tag on the left side.

As to the seat, well, the 79 special had a unique seat pan from what I understand. I have a couple seats I am going to be selling soon, one is a king/queen type, but their pans are for an 80-81 special frame.

[DJ48170]

Another question (and I don't want any ROFLMAO) - What the heck does "vacuum advance" really mean to a lay person. I mean, what is it's purpose and if I never connected that hose to the little bell thingy (now that's my kind of language) what would happen?

[DGXSER]

As the engine speed increases the timing of when the spark is ignited in the cylinder needs to be adjusted or advanced. Basically, the faster the engine turns the sooner the signal to send spark needs to be given for it to spark at the optimum time in the combustion chamber of the cylinder. As engine speed increases, so does the vacuum it creates at the carb where the tube connects. The vacuum line applies that vacuum to one side of the diaphram in that mushroom bell thingy and it causes the rod looking gizmo to pull up on the rotating whatchamacallit which makes nub on the spinning shaft beneath that plate contact the pickup coil assembly ( what we use to call points essentially) sooner in the rotation of the pistons. So the signal to spark is given sooner, or advanced based upon the vacuum created at the carb. So it is called the "vacuum advance" for short.

Hope That Helps (you will see abreviated as HTH) And i did not even LOL..let alone ROTFLMFAO

[Montreux_Blue]

It connects onto the canister looking thing, in the upper right portion of the picture. You will see the tube sticking out.

[CatatonicBug]

No, there isn't any gold on it, the forks are all chrome/aluminum and the registration says it is a 1979. Where do I find the VIN on the bike itself? When I get home I will check it then and compare to Catatonic's list.

By the way, does anyone know where to get a seat or seat pan? Mine is quite rusted on the left underside of the seat pan. Are there any that are compatible with the bolting style of these?

The VIN/Serial is in 2 places: On the left side of the steering neck, and on the right side of the engine, just below the airbox on an angled flat panel.

There are no aftermarket seat pans for these bikes, but the covers are available for about $70-$100. If you take the seat pan to an upholstery shop, they can custom-make one for you, with new foam and everything. If you pan is not usable, you might look for people parting out bikes, but be careful because they are not all the same. '79's have a rather unique seat setup.

[jwhughes3]

You might update your insurance

Or registration for that matter. Having an 8 instead of an H can turn into a claims nightmare later.

John in San Antonio