1. S

    '77 XS360 Backfiring above 5000 rpm + other issues

    EDIT: I think I found the issue, the new battery I installed is bad. For the life of me I cannot figure this out. Sorry for the long read but I feel like I should include everything I did, which is a lot. I recently replaced the coils on my Yamaha (1977 XS360) because the bike didn't really...
  2. M

    Can't Take It Off Choke

    So... This kinda feels like AA, "Hi My name is Mike and I have a problem." JK. But in all seriousness, I'm hoping a few kindhearted Journeymen XS-folk can lend me some knowledge. Experience level: Noob, like total, complete noob... Bike: 1981 Yamaha XS400HS BLUF: basically, bought diamond in...
  3. B

    Xs400 engine job

    Hi everyone! I've very recently bought an 83 XS400 Maxim, I did a compression test and have about 35 psi difference in between the two (sitting on the bike, left 130psi, right 95psi) proceeded to do a leak down test and concluded the compression is going into the crankcase. I haven't opened it...
  4. Jared salsano

    1978 xs400 motor issue

    Hey, new to the xs world and new to the forum. I just picked a 1978 xs400. It's been sitting for a long time and the motor was locked up so I started pulling it apart to see what I could find. I put some marvel in the cylinders and let it sit. Pulled the side cover and put a wrench on the crank...
  5. J

    Spark plug hole stripped/cylinder head removal

    Bought my first xs400 yesterday for my gf to learn to ride on and have been trying to get it run and was taking the spark plugs out and who ever worked on it last time decided that they need to be at 100ft/lbs and on the hole is stripped , I believe the best way would be to take the cylinder...
  6. L

    '81 Connecting rod big end bore diameter?

    I'm fixing up an '81 engine and there is scoring on the big end of the connecting rod. Does anybody know/have a source for the big end bore diameter for the conn rod? Since the Haynes manual only has the small end bore diameter and I have not been able to find this spec elsewhere.
  7. RockyRo217

    1978 Yamaha 400XS one cylinder won’t run!

    Hi guys/gals. I have been using all the treads religiously and have found great help from everyone’s conversations but I’m defeated with my ‘78. I bought the bike as a project for myself throughout the offseason and was able to get the bike running but only with the right cylinder. I have had...
  8. thekinggrim

    Gooseneck Chopper

    Gday peeps thought my current xs400 chop build might tickle some of your fancies its a 70s inspired gooseneck frame hardtailed one off just started work on it this week still gotta rebuild and polish the old xs lump but planning on running a 1/2 chain driven pma alternator as the old coil and...
  9. Zachat03

    Engine bolts broke

    So my 78 xs400 has a seized engine so I went to pull off the cylinder head to manually rotate the pistons but before I could get the engine apart almost all my bolts broke in half or completely stripped. The worst part is I have no idea where to get replacements. Anyone have suggestions?
  10. Bury Me In Smoke

    For Sale - Parting Out 1976 XS360 & XS 400 Engine

    Selling everything I'm not using for a build Side Covers - $40 each Rear Turn Signals - $30 each Both Front Turn Signals w/ Headlight Mount - $70 Chain Guard - $15 Tool Box (no tools) - $15 Front and Rear Fenders - $30 each Battery Box - $25 Rear Inner Fender - $25 Seat (no tears) & Seat Pan -...
  11. J

    '79 bouncing idle. I'VE TRIED EVERYTHING (kinda)

    So this has been a year and a half worth of trying to figure out what is wrong with my bike. I bought this fully running about 3 years ago I think, and rode it around with no problems for about a year and a half. Here's my problem now: My idle will bounce around a bit and "searches." After...
  12. B

    Stainless steel bolts for the engine

    Hi All, So I have stripped and cleaned my XS400 engine and am about to start the rebuild. I purchased a set of SS bolts for the engine off've eBay ( *Link*). This doesn't contain all the bolts for the engine assembly so I was going to measure the left overs and order individually. But then I...
  13. I

    Make Offer - XS400 Engine and Carbs

    I have an engine and carbs that I acquired long ago and would either like to sell the engine to someone who needs it, or buy a parts bike off someone who doesn't want it. I am not looking for a bike that is restoration worthy, but rather something that I could chop. I won't cut up a classic...
  14. E

    Crazy High RPM after revving the engine

    So pretty much my bike is running fine until i rev the engine, after that the rpm's seem to go crazy high and wont go back down unless I am to pull on the choke all the way, someone want to enlighten me as to what may be happening? I have a 80' XS400G if it helps Thanks,
  15. W

    Unknown Problem?

    Just got the bike a few weeks ago, was riding it yesterday and noticed as I coast to a stop the bike makes a high pitch noise. Any ideas? Thanks The bike is a Maxim 400 1983
  16. burr

    1981 XS400 Engine Build: A Story of Pictures, Videos, Beers & Tears

    Hey Everyone! After hijacking a few threads, I figured I'd start my own. I'm rebuilding my 1981 Yamaha XS400H (4R5 engine). It's my first bike. I'm pretty mechanically inclined but I've never worked on anything like this before. Here goes nothing… A Little Intro: Bought this guy for $600 CAD...
  17. M

    First time XS400 owner, first time replacing a camshaft. Anything I should know?

    A friend gave me his old bike (78-79 SOHC) that had been sitting a while with a broken camshaft (timing chain came apart and crunched the socket). I've tinkered with old bikes and cars before, but never to this extent. My plan is to remove the engine completely and then just following the...
  18. Kosan181

    Low speed, won't rev higher than 5k and won't do above 45

    I have a problem that my bike doesn't want to go any faster than 45 maybe even 50. I have stock jets still and I'm not sure if that means much. When I screw out my fuel mixture screws nothing happens. I already cleaned my carbs. It is also sometimes difficult to start.
  19. D

    Engine will NOT mount

    So, I picked up an '82 XS400RJ w/ DOHC, and as part of my tune up procedure checked the valve gap... Now I can't get the engine to mount to the bike, what started out as 2 bolts is now the entire engine... First question is do the top mounts need all 6 bolts? (2 to hold bracket on per side and...
  20. OopsAboutThat

    DOHC Seca/Maxim Engine Differences

    Hey all! I've recently started an engine rebuild here and I have a Seca engine as well as a Maxim engine. My plan is to use the best bits out of both engines. I've checked part numbers and it seems that the crankcase, head, cylinder, valves, camshafts and most other internals are all matching...