Jump to content


  • Posts

  • Joined

  • Last visited

About mdsims

  • Birthday 09/01/1986

Previous Fields

  • Current Bike(s)
    1977 Yamaha xs400

Profile Information

  • Gender
  • Location

mdsims's Achievements


Newbie (1/14)



  1. mdsims

    Fuel Petcock

    like i said before, with proper operating techniques such as turning the fuel valve to the off position when not riding the bike (just as all MSF instructors teach) there is no harm to having a manual petcock. I do agree, the danger is when people forget to turn that valve after riding the bike so it is much easier to just have the vac petcock and thus the peace of mind.
  2. mdsims

    Fuel Petcock

    harm? not at all. extra and perhaps unnecessary work? possibly. just remember to turn it to off when the bike sits for a period of time. my vac one hasn't bothered me at all. did take some getting used to when removing the tank because the stock vac line was very short. new carb boots and vac lines about 2 months ago solved that problem. what exactly is wrong with it?
  3. adjust your points, that may very well fix the hard to start issue. That's what was up with my 77 xs400. I also fully rebuilt my carbs and added an inline fuel filter between the tank and carbs. A little piece of mind, that way I'm sure what's going on in the carbs...nice and clean now. Post up a picture of your xs
  4. http://slo.craigslist.org/mcy/1268834864.html ran across this gem today. Looks like a steal to me
  5. Totally welcome! I'm pretty sure our bikes share the same wheels and thus require tubes. Hope the bike rides better after the swap!
  6. see one of drewps previous posts, he runs the same as you, 90/90-18. That size tire will be fine for the front. I'd suggest getting new tubes every time you change tires. They are too cheap and too important not to change ($6.00/each). As for not needing to run tubes, yes you SHOULD run tubes. The tire may say tubeless but unless the wheel itself says tubeless you need to run them. Tubeless rims are made with different lip shapes to help a tire bead hold on the wheel better.
  7. x2 on checking the bearings. Smaller tires alone won't cause a wobble but they do have an effect on performance, acceleration, rpm ranges (power band), top speed, etc. A 90/90-18 is even small as a front tire. 100/90-18 is where the front should be per spec. Running the smaller front tire is also going to cause your speedometer to be inaccurate.
  8. hahaha, there's your problem! spec for your bike's rear is closest to 110/90-18, If my memory serves me. That is roughly a 2" difference in overall diameter. Effectively, you've changed the final drive ratio of your bike. At 70mph, what do your rpm's look like? Seems like it could be an alignment or balancing issue as well. I'd also suggest using a very small amount of rear brake to help you get out of that wobble zone safely.
  9. Maybe you hurt the battery but I suspect everything is just fine. If the battery voltage is too low, the relays that work the turn signals won't break back and forth and thus the lights stay on full time. After you charge the battery that problem should go away.
  10. Is this true? Something you witnessed firsthand? I haven't purchased anything directly from Mikesxs.com but I have had a decent amount of contact with Michael "Mercury" Morse over at 650central.com and that guy is pretty awesome. He's a fountain of information and more than willing to help with any of my issues. He answered all my questions until I was satisfied and knew full well I was riding an xs 400. Best part is, he's only 100 miles away. Back on topic - This is what I just did for my front brake troubles: 11mm XS Performance master cylinder (~12.1:1 ratio), slimline and lightweight Vesrah sintered pads Caliper rebuild kit New caliper piston braided stainless line Eventually I may get a nice new drilled stainless rotor, but for now this should make a world of difference for the bike. Turns out the rear disk on a 650 is the same as the front on the 400. Maybe once I strip the bike down and start chopping into the frame, rebuilding the front end and powder coating the wheels, well...maybe then I'll buy that shiny new front disc. Either that or graft a modern superbike setup onto the right side and make a custom mount for a 4 piston caliper. Endless possibilities really.
  11. who does this bike belong to? and why all the drilled out material?
  12. The oil light will ALWAYS come on after you shut down the engine, least on my 77. It's a low oil pressure indicator and an off engine has no pressure. it's when that light turns on and the engine IS running that you start to have problems and risk seizing the engine. Either way, that sound doesn't sound very pleasant.
  13. oh wow, that stuff is cool. worth looking into.
  14. http://www.mikesxs.net/products-27.html#products 2nd one down, item #14-0901 Is there any reason why this wouldn't work on my 77 xs400? I sent MikesXS a couple emails and they said they have no way of knowing if it'd work. The next step would be to contact the manufacturer and ask you guys here. If the advance assemblies are the same, I think this kit should work fine. This is something I'm looking to do eventually, not immediately. matt
  • Create New...