XS750 / XS850 FAQ
What’s the difference between a “Special” and a “Standard”?
The Special was produced starting in '78 and had an “S” in the model designation, i.e. XS750-SE. In 1979 it would have been XS750-SF, with the last letter changing for each year. A '78 Standard would be XS750-E, etc…
The differences are mainly cosmetic. The Special has a teardrop shaped tank, pull-back handle bars and a stepped seat. It was a “factory custom” as they used to call it. Mechanically, the Special has a leading axle fork whereas the Standard has the axle going through the centerline of the fork tubes. Also, the front brake calipers are different on the Special and the Special has dual megaphone exhausts that stop at the rear axle while the Standard has dual reverse cones that extend past the rear axle.
The Special in this picture has replaced the stock exhaust with a 3 into 1 and it has an aftermarket king/queen seat. And, now that I look at it, the Standard has a 3 into 1 also.
What is the “Headlight” Light on the dashboard
On the instrument cluster, between the speedo and the tach, are the turn signal indicators. Just below this is a display that is marked “headlight”. What is this for?
The triples came with a reserve lighting unit that acts as a fail safe device. If you are riding with the low beam on and the bulb burns out or there is a faulty connection, the reserve lighting unit automatically switches to the high beam and illuminates the indicator light that is marked “headlight”. The same thing will happen if the high beam goes out, it automaticly switches to the low beam. The “headlight” indicator light is there to tell you that there is a problem somewhere in the lighting system.
How Do I Know If My Cam Chain Needs Adjusting?
The cam chain should be adjusted every five thousand miles. To adjust the chain follow the procedure below.
- Remove the left engine cover(points cover)
- Remove the cap on the end of the cam chain tensioner assy.
- Loosen the lock nut and adjuster screw on the inboard side of the tensioner assy.
- Rotate the engine anti-clockwise several turns, watching the plunger on the end of the tensioner assy.
- When the plunger travels the deepest into the tensioner assy stop rotating the engine and tighten the lock screw and lock nut.
The tensioner is spring loaded. The lock screw simply holds the tensioner in place. When you loosen the lock screw the spring will take up any slack in the chain. Adjust the chain with the engine cold.
My Tach Drive Is Leaking All Over My Exhaust. How Do I Fix It?
Buy the O ring and seal from Yamaha. Disassemble the cable from the drive paying attention to the way the loose parts are placed and oriented–especially the little Y-shaped retaining yoke; it must be placed so that as its screw is tightened it presses tighter against the flange of the drive. Make a sketch for the next time you DON’T pay attention.(Now is a good time to check the tach-drive cable. Pull it out and look at it. If it’s nicked, replace it. The drive seal and O ring MAY come with a new cable.) Clean the parts of the cable assembly you’re keeping down to bare metal, i.e., connector threads, cable end, etc. Get some FormAGasket or any good gasket cement. Coat the threads on the cable connector, the OUTSIDE of the seal, and location for the O ring and the O ring itself. A thin skin of the cement is all that’s needed; try to avoid getting any on the cable itself. After lightly greasing the cable, reassemble the connection. (You may have to hand turn the cable end to align it with the square hole in the cable drive shaft.) Tighten it all down. Use mechanics pliers on the knurled cap and the Allen head wrench on the Y-yoke. (BTW, this method assumes the knurled cap has not been deformed by overtightening in the attempt to seal the leak. If it has, it’s probably new cable time.) Final step: Start and ride the bike 'til the engine is up to temp then quit for the day. This procedure should solve your leak. BTW the shop mechanics won’t bother. Oh yeah–if this doesn’t fix it–try a heavier O ring.
How Do I Set The Idle Mixture?
There is an increasing number of questions regarding the setting of the idle jets (on Mikunis specifically I believe, or both Miks and Hibachis in general). Follow the links in the Triples homeboy page to the XS1100 pages. From there, you will find a tech tips section which goes into a very good explanation of the proper ways to set them (and carb sync procedures, too if I’m not mistaken). What it boils down to is, working on 1 carb at a time, you turn the idle jet in until the engine stumbles, then turn it out, counting the number of turns until it stumbles again. Then set it halfway between the two stumble points. Repeat for carbs 2 & 3. Afterwards, resync your carbs, cuz this procedure affects the synching.
When My Petcocks Are Set To “ON”, Gas Still Flows. What’s The Problem?
Even after hours in two different chemical carb cleaner baths, the flat surface that turns against rubber peice with four holes in it was not flat. Some slight deposits or pitting, could feel it when I ran my finger over it. (CBMMA microscopic surface inspection). I resurced this to return it to truly flat. Used a piece of 800 wet or dry papaer, oil with wd40, placed on a piece of 1" thickplate glass. I learned years ago that if you need a cheap truly flat surface, that a piece of scrap plate glass works. I took off only a tiny bit and it was flat and smooth again, which I think will give a better seal. On the other side, where the o ring on the plunger seats, as I started to reassemble, on close inspection, I found some slight corrosion on the tapered metal seat in the petcock body. This could have prevented proper seating of the o-ring and allowed the o-ring to weep. It took a small tapered hand reamer (though anything will probably do) wrapped some 000 steel wool around it and twisted it against the tapered seat to polish it. Just a few turns and it polish right up. Put them all together and so far have tried to blow through them and they seem tight. Will know for sure when I reassemble and try the tank.
Herb Bell wrote an article on installing in-line shutoffs after the petcocks valves. (LINK CURRENTLY UNAVAILABLE)
- Fitting new o-rings in the petcocks seems to stem the flow. The dimensions of the o-rings are: 4mm inside diameter, 2mm cross section and an 8mm outside diameter.
My Manual Mentions A Middle & Final Drive Dipstick. I Don’t Have One, What Are The Dimensions Of It?
The middle drive high marking is 65 mm, the low marking is 68 mm. The rear drive high marking is 19 mm, and the low is 23 mm.
Here is a picture (thanks to Bob Gray)
My Oil light is on, but the crankcase is full and pressure is good. What’s going on?
In their infinite wisdom, Yamaha decided to use the oil light as an indicator for a burned out tail light bulb. So the light has a double meaning. If you are absolutely sure there’s not a problem with your oiling system, check your tail light bulb. Here’s a JPG of the circuit:
My Bike Doesn’t Have The Stock Toolkit. What Was Originally In It?
Should I Buy One From Yamaha?
I still have the original Yamaha tool kit that came with the bike. It is even still in the original cheap plastic pouch.
Take my advice. Don’t buy one from Yamaha. They are cheap tools that I won’t even use. There are a selection of open ended spanners (wrenches for our American readers) in 10mm, 12mm, 14mm and 17mm. There is a badly made Philips double ended screwdriver and handle. Point sizes 1 and 2. Stupid thing here is all the cross head screws on the bike have PosiDriv heads. These are a different shape slot to the Philips ones. A pair of slip jaw pliers and a spark plug spanner live in there too. And a 5mm and 6mm Hex key. There is a 24mm and a 27mm box spanner (very thin) and extension handle for removing axle nuts and the middle and final drive gear case dipstick.
Go to your local tool supplier. Buy good quality tools. I use either Aigo or Sidchrome spanners. I use Stanley screwdrivers. I have a set of Facom hex keys. And a good socket set.
Real money spent on good tools is money you only spend once. A lot of mine are getting on for 20 years old. And yet they still feel like my new tools. Well, they are. I haven’t bought things to replace them as they still work well.
And if this sounds like I have broken out of the CBMMA philosophy, some of the cheapest bastards I know have the best tools. Reason? They only buy once, and with good tools, they can make the most amazing things. Without spending any more money.
Sorry this turned into a bit of a rant, but I feel strongly about this. I have seen too many jobs turned to shit by using shoddy tools that broke, or broke the workpiece, or by using the wrong tool.
I’ve read somewhere that it was the 77’ XS750C (of which only a few models were produced) had a 3 into 1 exhaust, starting the following release XS750D or 2D they implemented the 3 into 2 exhaust