plain old dave

Here's where we're at: the left side of the ol' Green Machine has quit working. Swap coils, no joy. All mechanical adjustmens are in spec: carbs, point gap, valve clearance. Interesting discovery: On the left side, I have @12vdc on the positive side, and nothing on the ground side. On the right side, I have @12vdc on the hot side, and 12vdc on the ground side. When I unplug the left coil from the circuit on the negative side, I then have 12vdc out. Good continuity all the way from the out on the coil to the points, just no sauce when it's in circuit. Electercity: PFM.... Thoughts?

Checked with Z1 Enterprises and they have an XS750 kit for only $21. Same BS34 carbs on both bikes, but @1 size larger jets I believe on them than the XS400. The bike mechanically is not stock; I have Uni foam pod air filters and the EMGO knockoff of the old Dunstall Decibel mufflers. Plugs look good with what I had before the carbs went belly up, and I would think 1 size up on the jets would help all round. Thoughts?

Just as a reminder, here was the Before: Here's where we are now; almost back on the road.... New mufflers and a couple cycle parts are coming, and the color's the same BASF paint code the US Navy's Blue Angels use on their F/A-18 Hornets. New name for the bike is on order: Bonnie, the Blue Angel

1) A top end build shouldn't involve THAT much cash; that should solve your oil leakage. If it ain't bad, I would just run Shell Rotella T 15W40 Diesel oil. Lot cheaper than motorcycle oil, more zinc too. The 15W when cold will help with leakage as well. I have put several thousand miles on my 400 with that oil and honestly IMHO it protects better than the motorcycle oil I used to run. 2) Things to check for your transmission trouble: a) The clutch pushrod. Mine was in 2 pieces (is made of 2 metals apparently brazed together), and a good used one dramatically helped my trouble finding neutral. Til you tend to that, the old school method is to shift into Neutral while rolling. Clutch adjustment. Dragging clutch can cause those probs too. The way the 400 clutch is adjusted, it's very possible that in tighening the lock bolt, the clutch was inadvertently tightened up. c) Shift linkage adjustment, both inside the cover and with the lever on the shaft. Try the lever a spline down on the shaft, might be that where you have your shifter it doesn't positively engage the gears, thus false neutrals and 'popping out of gear'. Bottom line: I wouldn't retire this bike.

That's only about 9500 miles. With a decent oil, that's not too much. I have put 12K on mine in the year and a couple months I have had 'er and still starts fairly easy and still get 60mpg. How do you know this? Compression check? Define minor transmission troubles. If you mean false neutrals, you might just need to adjust the clutch and/or shift linkage. That's right around 30K miles, and that's where I am. The bike's in the shop right now for a top end rebuild, among other things. PLEASE leave it more or less stock. IMHO way too many nice old XS400s and XS650s have been bobbed and cafe-d. Only mod(s) I would consider w/your bike would be Ebay the luggage rack, get some saddlebags, different signals, either Daytona Touring or Superbike bars, and enjoy. I run Daytona Touring bars (3" rise, 3" pullback I think).

Just spent @45 minutes or so trying to kick the ol' XS through. Got completely out of energy, and all of a sudden I noticed the Neutral light was dim. Cut the headlight off and it got brighter. Took the thing down to Auto Zone and turned out to present 11.5 volts with no load, and I learned HERE that that means the plugs will not fire. Right now I am charging the new battery (the old one was a Wal-Mart EverStart, probably the worst battery made for any motor vehicle), and I should be able to go for a jaunt later this afternoon. Thanks again to the best source for vintage Yamaha info on the Web.

The old XS400 now has JUST over 30K showing and still running good... These here XS400s sure are reliable...

Sounds good. Did you have to change any of the bike's wiring or were they plug and play?

Mine has front and rear disc brakes, and 2 things I have done that completely transformed the bike are bronze swingarm bushings and properly sized tires, which are 3.00-18 on front and 3.50-18 on back. Oversized tires made mine handle like a Harley Sportster. Not really; I believe I will go with alloy fenders over the winter. Kinda goin' for a combo Triumph T100 Daytona/ Vincent look.

I see tons of bobbers and cafe racers, but few if any semi-original bikes. The XS400 is quite a competent roadster with only a few modifications, most of which can be done without compromising the historicity of the bike. Is anybody besides me riding a stock (or close to stock) XS400?

ALL plugs are threaded on the end under the screw on piece automotive plugs have on the end of them. Got mine at Advance, the bit that car plugs snap onto is a cap that screws right off, standard threading.

The Bike: 1978 XS400E. Tried to drop the strainer cover on the bottom of the crankcase today, came off fine, and even went back on fine. I used a new gasket as I always do on any old vehicle. Tightened the thing what I thought was good and tight, put the 2 1/4 quarts of oil in to account for the new filter and no matter how tight I tighten them little bolts it won't stop leaking. I thought they just weren't tight enough, so I tightened more. Then one of them snapped off AND IT'S STILL LEAKING. Now I only have 4 of the 6 bolts I can use, though I am going to see tomorrow if the empty hole that's been there since I got the bike has a potmetal Jap bolt half in it or if it's got good threads. What have I missed? I saw there was an arrow on the cover and can't remember for the life of me if it was pointing toward the front or the back of the bike, or does that even matter? I need help as this bike is how I get to work and I have to get back to work Thursday.

They have discontinued it, so it looks like I am down to Emgo or Mac (rust? quality?) or Sito.

1) How much louder are they? 2) Define "midrange". I have noticed that in normal riding I stay between 3000 and 5000 rpm. 3) How much more power?

I like lower rev punch and don't really care for 2 into 1 pipes... Do the motads boost power?