GaSo

I'd check ebay for the wheels and brake bits...I have no idea how complicated it is to change it over but it can't be that bad if you're a little handy with mechanical bits. Instead of cables and linkage, you'd just have hydraulic hosing. Actually, thinking about it, it sounds like quite a project. Maybe PM duaneage to this thread to answer some questions? I'm wondering where he picked up those handlebars from, I'm not looking forward to trying to make sure all my wires and cables fit a new set correctly, but really want to ditch my stock bars...

I ride pretty conservatively, never noticed the drum brakes being crappy. How hard was it finding a complete set to change over to the disc brakes? I'm in Williamsport, PA (middle of nowhere, PA). Might have to check out those painters if I ever decide to redo my tank, they did a mighty fine job!

Your bike looks like my bike's more beautiful sister: I was too cheap to buy new tank badges, so I just glued and painted over the old flaked chrome Also, you put a lot more effort into making the bike look brand new, holy moly nicely done!!! How do you like those handlebars? They look a little high to me, but that may just be the angle. I hate the stock swept back bars, I find them hard to use and uncomfortable.

If it does turn out to be this seal, I had the same issue and documented the process here: http://www.yamahaclub.com/forums/topic/14526-1981-yamaha-xs400-special-ii-xs400h/page__view__findpost__p__79825

I had a bad gasket under a nylon washer, under a circlip for the butterfly valve rod. Found it by dropping oil onto each of the exposed sections against the carb body, and when the RPMs dropped every time I hit that spot with oil, I knew I found my leak. I strongly agree with Runningdog, WD40 is a good choice for when you're searching all over hells half acre.

Worked a treat. Started about 6" from the top, was rock hard. took one drain screw out, put a tiny bit of weight on it and it shot some oil out, put screw back in, took other screw out, little bit of weight, shot oil, screw back in...now its got a couple inches of soft movement before firming up quickly, feels great. Thanks!

So to control dive when using the front brakes (which I have come to despise) all you have to do is fill it with 20w fork oil to about 6" from the top without following through with the other modifications listed (cause most of that was over my head).

My 81 XS400 had electronics: http://cgi.ebay.com/ebaymotors/1981-Yamaha-XS400-special-rectifier_W0QQcmdZViewItemQQhashZitem3ef97eb32cQQitemZ270473802540QQptZMotorcyclesQ5fPartsQ5fAccessories#ht_500wt_956 Mounts around/under the battery. I replaced that and my battery and I have no charging issues any longer. The holes in the diaphragm will certainly screw things up. The new diaphragms are expensive, so is gambling on whether an ebay special is going to contain a decent set. I'd go by the condition of your carbs in general whether that's a good idea or not. I haven't seen aftermarket carbs for the XS400, just her larger sisters. MikesXS has a lot of parts that will fit in our carbs without issue: http://www.mikesxs.net/products-35.html#products < was vital while I was rebuilding my carbs. EXCELLENT overview of the BS34 carbs on our bikes (while some of the specific jet sizing info may be off, in general this guide is amazing): http://drop.io/jn5sqkc

I'd say the idle screw needs adjusted on the right side. Sounds like it's too rich, so try turning it in a hair. Just my uneducated guess tho

Go to imgur.com, hit browse, select image, hit continue. Right click in the "Message Boards" box and select copy. Right click here and hit paste. Tada!

I got everything from http://www.mikesxs.net/ myself, but I have an 81 with BS34 carbs, so they had a lot of stuff that I could easily verify would work on my bike. The only thing that they didn't have a direct cross for is the needle jet and jet needle, those are slightly larger versions off the XS600. Looking at older years, it seems that they didn't have anything listed for BS34 carbs from before 1980? Maybe just because the XS600 did not use this smaller carb till after 1980? And further wild guesses, the parts listed for the 1980+ BS34 carbs would work on earlier BS34 carbs? (haha, good luck!!!!)

if you just want to get one image on the internet with a minimum of fuss, I highly recommend imgur.com. No registration necessary, free, and crazy simple/easy.

Tom, for reference (at least with my particular machine heh) it runs around 1500 RPM when cold with half-choke, around 900 RPM when cold with no choke. Once it is warmed up, with no choke it runs around 1250 RPM. Very cold (as in, needing full choke for a few seconds) it runs even higher, perhaps 2500 RPM if I remember correctly? Been a few months!

That's amazing! Both versions!!

heh...it could be so many things who knows where to start! how long ago was it last run regularly? I would first guess that you dislodged some junk and it wedged into some bit of the carbs which is essential to starting. Any difference between trying to start it with full, half and no choke? Does the engine at least try to catch on full? It wouldn't hurt to take the carbs off and give them a quick cleaning. Good excuse to begin becoming familiar with them. Also, while you have the seat off, might as well check for blown fuses and loose connections around the fusebox.