HoughMade

I crossed the border ages ago.

My '79 XS 400F seemed to be idling very lean. After conversing with other ancient XS 400 owners, they confirmed what I should have known- the factory idle mixture setting are very, very lean. This led to occasional popping at idle and as revs increased. Also, it did not return to idle speed as quickly as it should. I richened the idle mixture and those problems went away. the factory setting was 2.25 turns out. At 3.5, it runs like a charm. Also, I suspected that the carbs were out of sync. I made a simple manometer- clear tubing and auto transmission fluid. Get 20 feet of tubing (whatever fits the vaccum nipple on your bike) and find the exact center. Place the center at the bottom of a 4 foot piece of wood, then attach the tubing up the length of the board (exact length is not important, but longer give you more time to shou down if you have to). I used zip ties, but I had the thicker wall tubing- whatever you do, make sure the tubing is not collapsed. The most time consuming part of this was getting the fluid to settle in the center. To get the fluid in, I put one end in the ATF bottle and sucked the other end like a straw. I drew up about 2 feet worth of fluid, the exact amount is not important. I then hung the apparatus with the tubes in the air and waited for the fluid to settle- took 15-20 minutes. I hung mine from a ladder to use it, but I was also using that to hold the gas tank (has to come off to get to the sync screw). After warming the bike up, hooked the tubing to the vacuum nipples on the carb holders, I started it up.....and the ATF nearly got sucked into the engine because the left cylinder was drawing much harder- way out of sync. Word to the wise, keep your thumb on the kill switch until you get it close to synced. Shut it down if one side starts to rise too fast. Longer tubing would also give more time to react...thicker fluid too. I adjusted it a couple times after having to shut it down, then it was close enough that the movement was very slow. I adjusted back and forth and got both sides of the fluid as even as possible. Perfect is near impossible, but I got it within about 1/2-3/4 inch. According to what I read, that's pretty good. Do not use a thin fluid as it will foam and be hard to read. I used ATF because it is easy to see and a bit (if only a bit) sucked into the engine will not hurt it. Anyhoo, here's a pic of my setup. This works great for twins with separate carbs. I have even seen these built for 4 cyls., so I imagine a 3 could be done as well. Bike runs smoother that I thought it was supposed to. It will idles easily where it is supposed to (1200rpm) and will even hold a good idle below 1000 rpm.

From what you say, sounds like the cable is too tight and needs adjustment. It could also be that the cable is bent too tightly at some point and is binding. I don't know youe bike, so I can not get too specific about what to do about it....beyond checking those items.

I got brand new ones on eBay with intake gaskets for under $40. Like these: http://cgi.ebay.com/ebaymotors/YAMAHA-XS400-CARBURETOR-HOLDERS-INTAKE-MANIFOLD-BOOTS-_W0QQcmdZViewItemQQhashZitem53e1217e98QQitemZ360259354264QQptZMotorcyclesQ5fPartsQ5fAccessories

As for the key issue, there are locks you can buy to lock the wheel or the brakes. If it were me and the ignition switch otherwise worked well, I would see if it was cheaper to get a decent lock or replace the switch and then go with the cheaper option...at least for the time being. As for the starter issue. How's the battery? That is the first thing I would check. Second would be to make sure the battery cables all have clean connections and there isa good, solid ground (earth?). Also make sure the wires to the starter are clean and in good condition. Only after elimination those would I look to the starter motor itself. Good luck! These are great bikes to learn to work on and to ride on. I love mine.

Here is my "restification". Not a single visible part replaced. Just resurected from sitting in a barn about 10 years.

A deep well socket- yep, that should work.

You have voltage and a ground...what about the lamp itself? [edit] Sorry, just saw that both filaments light up. Is yours one of those (like mine) that only lights up when the bike is running?

You didn't cap off or otherwise block the crankcase breather, did you? This will cause a buildup of pressure in the crankcase and can force oil into the combustion chamber...and this is a personal thing, but if I had the piston out, I would put new rings on no matter how they lookes...unless i knew with certainty that they were perfect. Rings are not that expensive.

I'd take a close look at the rings before I'd worry too much about the liner.

If it's carbon fouling, not oil fouling, you're running rich. First easy thing to check- how are your air filters? Does the bike run well otherwise? Did this come on all of a sudden or not?

I doubt this is the issue, but you should not use automotive oil and it should probably be a bit thicker. The Yamaha service manual recommends 20-40 in most situations (I use 15-40). Motorcycle oil or diesel oil is the stuff to use. Automotive oil will not play friendly with your wet clutch. Like I said, I doubt this is the issue. I was thinking that if you used something real thin (10-30 in warm weather or thinner) it could be easier to get in the combustion chamber one way or the other. However, I'm thinking that with a recent assembly, it would not be too unusual to see blue smoke for quite some time- maybe the first 1/2 hour. How did it run before you tore it down? Any hint of smoke then?

What kind of oil are you using?

7/8ths only. Sounds like a fun project.

Do your carb holders look like this? http://www.z1enterprises.com/detail.aspx?ID=2635 That brass port is what provides the vacuum for the petcock. If the vacuum petcock goes bad, it does not matter what position you turn it to, the gas will keep flowing.

Wish I could help you, but I don't have the old style bike. What i do know- and obviously you do as well since you have the bike, is that even though the seat is stepped, the frame is flat under there. I can't imagine there is that much difference.

XS 400s in the late '70s to early '80s came with a vacuum petcock....which failed frequently. The inlet connects to a vacuum source which is usually a nipple on the rubber cab holder/carb boot. Mine ('79) was connected to the right carb holder, but it does not matter which one. It just matters that whatever one is not connected is blocked off. Because of the failure rate of the vacuum petcocks...mine refused to stem the fuel flow and overflowed the left carb, many people replace the vacuum petcocks with a manual one. I did. there are rebuild kits available for the vacuum petcock and used petcocks (not sure if new ones are out there0, but frankly, opening the fuel flow at the start and turning it off at the end is not that big a deal.

um.....wow....those insurance rates...all of them look pretty outrageous. Out of curiosity, what kind of coverage is that for? I know that the UK has different insurance requirements, so I am trying to figure out how to compare that to what we would pay in the U.S. I ran a quote for my XS 400 the other day- I realize that the collision and comprehensive will be more on a new bike...and I don't carry it anyway, but this is what I can get: -personal injury liability coverage of $100,000 per person and $300,000 per occurrance -property damage liability coverage of $50,000 -medical payments coverage of $5,000 (payment of any medical expenses caused regardless of fault) -no collision or comprehensive coverage $91.00 a year, which today equates to 59 GBP. In my state I can get away with liability coverage of 25,000/50,000/10,000 rather than the 100,000 /300,000/50,000...but I own stuff as in a home, other real estate and a portion of a business, so I like more insurance as i would like to keep all of those things. If I went with the state minumum I would be looking at about $65 a year (42 GBP). If I carried collision and comp. on a new motorcycle in the 125 class (only scooters and about 1 street bike available in the U.S. at that size), I would probably expect to pay $200-300 a year (130-194 GBP). ...as I said, however, I expect that there is a vast difference in the type and the nature of the insurance coverages.

There you go- during daylight hours, there should be no problem whatsoever.

In the short term...and on the cheap side, I initially thought that there was too much rust on my exhaust to save it, but I soaked the pipes and mufflers in a phosphoric acid rust remover, then polished with chrome cleaner- not perfect, but the flaws are pretty hard to see, especially at more than 5 feet. Keep them clean and hit them with chrome polish every so often and the rust will not recur for a long time.

Some time in my bike's past, someone installed a cutoff switch for thr headlight. As designed, my headlight would be on whenever the engine is running. I think in the U.S. we are not required to keep the light on all the time, so during the day, there's an easy and cheap way to create some extra capacity. I don't know if your bike has the constant on headlight, and I know at some point before '79 (my bike's year) they had a headlight switch. If yours has the cutoff switch or it does not, but you add one- daytime running with the GPS should be no problem withe headlight off. Think about it. If the bike runs reliably with the headlight on, cutting it off will free up 30-60 watts (depending on the headlight).

A map and a sense of direction draw 0 watts.

You should turn off the petcock when you are done riding, but the needle should keep the carb from overflowing over the course of several minutes. If the carb overflows over a few to 10 minutes, it is a float/needle issue that is the primary problem.

On my '79, if the floats are adjusted to 32mm like the manual says, it will leak fuel. At about 29-30mm, it's fine. However, it could be just stuck and not an adjustment issue. I would pull the carbs and check for free movement of the floats and check the float for leaks. If it moves freely and there is no leak, check the height. I test my carbs be blowing into the fuel inlet and rotating the carb so that gravity just closes them. If that blocks the air flow, the movement is OK and the needle is sealing.

I'm with you. I just like wandering the back roads and seeing the sights. I can do that sitting up without my feet behind me.