joe4g63

Thanks Harv, I looked on the site and found the part I need, but they do not show the item number below the picture. Every where else I have looked has said the part is discontinued. Thanks again though.

Hello me again, well after a engine rebuild over the winter due to a stretched timing chain and a broken piston ring, I am back at playing with the bike. Well the thing runs pretty good but still has a little bit of an issue with the fuel I believe. I took the carbs apart before installing them back on the bike and found that one of the pilot jets was kind a plugged so I cleaned it out good. After riding the bike around I noticed that it likes to stumble a little bit off of a stop. It idles great, it pulls hard at WOT, but it just has a stumble between the two. So when the bike was idling I played with the L carb pilot screw and it changed how the bike was idling, but when I messed with the R one the bike did not respond. I do know that the pilot screw on the R carb is bent up some at the tip, but I can not find new screws. So I am wondering if I could get a xs 400 carb and throw that on there, maybe changing the jets between the two carbs. If not, where could I get some new screws at? I have been watching ebay religiously and really never see 360 carbs on there, and when I do they are usually missing these screws. By the way the bike is a 77 xs360

Harv did you ever check and see if the dimensions of the xs400 carb were the same as the 360?

By the way thanks Drewpy, Yoda, Ferg, and Stevar for all the input.

I have a 1977 xs360 w/ drum fronts and rears which kind a suck. I also have the spoke wheels, and am willing to swap over to the spokes if I have to. I have found some master cyl units, brake lines, calipers, and disks on ebay off of a 80 xs400. I am wondering if anyone knows if this year would swap over or if they know of any other years. If I could get a list of bike years that you know would swap over would be perfect. Thanks in advance.

So I got good news I finally got the right tools and a friend experienced with the points systems to check the static timing. My left and right cyl timing were both at the "LT and RT" marks. So after adjusting it to the LF and RF marks like the manual says the bike runs great, we think that somebody might have installed a new timing chain and didn't know where to time it at so they timed it to tdc. I still have a little back fire out the L exh pipe still. So my friend held a dollar bill up to the exhaust and said watch this, you would see the dollar move out most of the time but everyonce in awile you would see it get sucked tight onto the pipe meaning the exh valve was to tight, sticking or just leaking to much. I started a new forum about if anyone knew if a 79 xs400 cyl head would fit my 77 xs360, since I found one on ebay for dirt cheap that is in good shape.

I have a 1977 xs360 with a leaky exhaust valve on the left cylinder and I found a good used 1979 xs 400 cylinder head on ebay for $30. I am just wondering if anyone knows if this swap would work for me. If this can't work does anyone know where I could find new valve seals, I am hoping I could pull mine apart and just clean up the valves and seats.

the only way the bike would run is on the pri on the petcock. Also another thing that is kind a fishy is, the manual says to put the petcock to res when removing the tank, well my petcock still leaks when doing that. I put it on the on position and that seems to stop the fuel. I took the petcock apart awhile ago, and am pretty sure I put it back together, but is there a chance that it is not put together correctly?

So I let the carbs sit in cleaner overnight and reassembled them, and put them back onto the bike. I also bought new plug boots, so I know those are good now. Then I went out riding and same thing happened as usual, riding down the highway at about 60mph/mid throttle, whenever I craked the throttle wide open it would bog out, once i let off and went back to mid throttle it would come out of it and run decent again. When I got back to the house the bike would idle by itself good. I pulled off the left plug wire and no change in the engine, the right wire would kill the engine-so still the left cylinder is getting me. Then I switched the coils and started it up, and pulled the same wires again, and the left cyl would still not change anything-so the coil are good I would say. When it was idling i noticed the right carb had some fuel coming out of the rear of it, and the left carb didn't have much at all coming out (this is after i took off the filters so I could see in there). When I revved the engine both of the diaphrams would lift equally, so I figure the diaphram sliders are good then. When idling I would put my finger in the right carb and lift the slider up and the engine would die when I did this, but the left did not change the way the engine was running. I do have the vacuum line coming off of the petcock hooked up to the left cylinder, and the right port plugged. I figure that shouldn't matter though. I found some 1978 xs400 carbs on ebay pretty cheap and am wondering if I would be able to put these on the bike without any problems.

Alright after the bike cooled down I checked everything again. Left coil primary 3.7 ohms, secondary 8.91k ohms----right coil primary 3.7 ohms, secondary 9.73k ohms and the manual says 9.5kohms it should be close to. So ,maybe the left coil is on its way out. I am also wondering if the xs400 coils will work on the xs360, I am looking at a pair on ebay that are off of a 81 xs400. With the caps I still get 4.48k ohms on the left plug cap, and 8.73k ohms on the right. The book says that if the ohms value exceeds 9k then then caps are bad, so I guess my caps are good then. I also ohmed out the condenser and that checked out with the manual. Since I had the coils off I figured I would take a look at the carbs once again. While pulling them apart I found a little fuel on top of both of the diaphragms for the sliders-i am not to sure it there is that was suppose to be there. Just to double check with the position with the needle and the clip, I have it at the middle position which is the 3rd from the top and the bottom.

So tonight I rode her for a good hour or so, and finally it started to act up. I brought it home and pulled the plugs and did a compression test quick while it was hot to make sure neither of the valves were sticking partly open making it lose compression-they both checked out. The bad part was that both of the plugs were nasty sooty black, not just the left plug anymore. Then I did a resistance check on both coils while still hot,-first I checked with the plug boots on, and I got 14.4k on the right, and 18.6k on the left, so I took the boots off, and the the resistance of both coils were between 9.6k and 10.3k. When I checked the boots themselves the right was about 4k and the left was around 8k which I don't think check out. I am going to search the manual tonght and see if I can find some specs. Also I am going to check the resistance later when both have cooled off.

Well hello again, I am still working on this dang thing. Well I checked the valves cold, and all four needed a little fine tuning. Then to the float height, they were really close but a little off, so I corrected them also. Went riding tonight and rode it pretty hard for about 25 minutes and it wasn't running to bad, still a little boggy mid throttle. Then i parked it at a store, and when I came out I had to kick about 15 times to get it to fire, and then once it did it was back to its old tricks-full throttle on the hand grip but was barely idling. I also noticed that the engine felt extremely hot. After about ten seconds of that it finally came out of it, and I could rev it up some, then off I went back home. While going home it was really boggy midrange again, and didn't really want to idle at stops or else it was revving really high. I pulled it into the garage and it wouldn't stay idling for me again. So I am pretty sure that it has something to do with ignition when it gets hot. Until the bike get really warmed up it runs great.

Well here is the latest and greatest. Tore the carbs all down, and let soak in carb cleaner-inspected pilot screws and both were bent a little bit at the tips. Found that the pilot screws were about 2 or so turns out, instead of 1.5. I did not check the float height yet though. So I reassembled the carbs and installed them. Also I figured I would make sure I even had the correct plugs in, the guy I got it from said they were. Well they weren't I had br9es in it, when it calls for bp6es so that's 3 stages hotter plug. Well I put the bike back together and so far it has been running pretty good, still a little bit of a bog coming from a stop through midrange which I think might be the pilot screws being bent. Also at idle it still back fires some out of the left pipe. I checked the plugs and the left plug is black, and the right plug looks great. I also did a compression tests with engine hot and got 125 on left, and 140 on right. The wet test was 140 on left, and a little over 150 on the right. So the compression isn't quite up to par (140-170 the manual says) but it is a 1977. here's the recap -pilot screws bent----causes bog? -float height no checked-- causes? -compression left 125/140wet, right 140/150wet------not igniting everything causing plug to turn black? -point gap not checked yet--Might cause the spark issue w/ the left plug? Where can I get new pilot screws at? I have looked on the internet and haven't really found anything.

Thanks for the replies. I went through both carbs and made sure the pilot and main jets were clean, the only thing I haven't actually done is put a carb kit in it yet. I also checked the compression with the engine cold-the left was 125 with about 10 kicks, and the right was 140 same amount of kicks. Then I got it all put back to together and she ran great, a little hesitation between idle and mid but wide open it ran great. About 20 minutes later though there went the left cylinder again. Could carb sync cause this, cause I have not done that, also how about those plastic adjustment screws( I believe they are for air fuel) I have tried them all the C.W., and CCW no change between idle and mid range. The tank was off this last summer and I threw some rocks in there and rattled the heck out of it hopefully to get some of the rust out. Today I am going to take off the pet cock and ensure the screen is clean, and also buy a cheap paper filter and throw in the fuel line. Any help would be appreciated.

I have a 1977 Yamaha xs 360. If it sits in the garage for about a week I can hop on it and go like crazy with it for about 20 minutes or so, then it will start backfiring on the left cylinder and start to run like crap. When I get back to the house it will only idle with full throttle, so I pulled off the left spark plug wire and the engine did not change at all but the plug is sparking. Just wondering if anyone else have had this same problem? Maybe when the engine gets that hot the valves are out of whack and will not create enough compression on that side, or might be a carb issue on that side.