dogodell

not sure if your already a member but try fzr archives... forum with only fzr owners those guys really know their stuff and have helped my out alot over the years with advice and cheap parts

Hey all, Currently in the middle of a complete (well sort of anyway) tear down and rebuild of a 75 mx400… motor is set to go once I get the rest of the parts in the mail and I figured while I was waiting I would do a little repaint (previous owners thought rattle can camo was a good color for a classic bike)… I have seen the examples of the restored white mx400 floating around online however I have also heard rumors that these bikes also came in the “competition yellow???? The original color of my tank (sanded down bottom to figure it out) and plastics appears to be yellow too??? (yes I’ve checked the vin its not a 76 yz) though for all I know the tank and plastics could be from a different bike but for what its worth they do look correct... So any ideas/ opinions on whether to stick with the known white or is yellow also a “correct” color to repaint Thanks in advance

first off I am new here and haven't worked on that particular bike however, as far as the key problem is concerned I have had good luck in the past with both a FZR and an old XS650 taking the tank lock apart and removing/ rearranging tumblers in order to make an ignition key work (hopefully someone with more experience can tell you which ones need to be removed for this particular bike) if not trial and error doesn't take as long as you might think (you should be able to see pretty well which ones are causing the problem once you have the lock about halfway apart) sorry I dont know more details and good luck on your project ps... there are probably better ways... but a long straight blade screwdriver and a plastic putty knife will usually remove the cap from the tank just take your time and dont pry too hard on the lip of the tank

hello all, looking for some input from shop manuals and/or personal opinion on optimum piston clearance for my 75 MX400... doing a complete rebuild of the motor and dont want to go crazy w/ boring it out just enough to get things back to "like new" thanks in advance

lol alright that's about what I was figuring thanks for the help

that explains a lot... instead of 1-2 mm play I have more like 1/4-1/2 inch (sorry dont know the equivalent and Im a carpenter in the US so its easier to estimate in what I know so I obviously need a connecting rod bearing which means splitting the case... ??? do I need to remove anything on the clutch side of things??? (pulled the cover off and noticed that there is no bolts from that side... or can I just remove everything from the flywheel side??? also is there anything that I should watch out for transmission wise when I break the cases open i.e. is anything gonna fly out at me that I am going to have to put back later or will it all stay in place so I can at least get a look at it and know how the thing works and fits together??? thanks again

oh yeah and if this is the wrong section for this sort of question than someone please tell me so I can put it in the right one thanks again

hey, let me start by saying that I have the skills to rebuild a car engine but have never been inside a bike engine before... with that in mind I am still working on my 75 mx400... found that it had very little compression even after I fixed the "decompression" valve cracked it open and discovered that sometime in its life it decided to eat what I think is part of one of the rings.... needless to say not a pretty sight with metal everywhere top of cylinder and piston both have more craters and pits than the moon... I pressed out the piston pin (luckily I found the little clips before I tried it) and the needle bearings in the rod just slid out and can be wiggled around easily??? Is this normal??? Second issue is that while the bearings in the cases for the crank appear to be tight (no play in the crank in any direction as far as I could tell) the rod bearing appear to be very loose... I can easily take the rod and move it around??? Once again is this normal and how much "play" should this have??? last question is... would it be possible to replace the rod bearings without breaking the cases and removing the crank??? well I lied one more question... how bad would it be to do a quick top end job and leave the rod bearings as is for a couple months of riding??? (its almost winter and I planned on a complete rebuild then anyway) thanks in advance

looks like the DT wiring diagram will work its definitely close enough for what I am trying to do anyway thanks again for the help

hello, picked up a 1975 MX400 the other day finally received the CDI in the mail... now I just need to figure out the simplest way of wiring things up... can anyone tell me what the essential wires are and how the kill switch on these is supposed to be wired up or send me a wiring diagram so I can figure it out email is [email protected] thanks in advance

Hello all, I am new to this forum and to this particular bike when replying consider me to be a decent mechanic but a complete moron when it comes to electronics and wiring I recently picked up a 1975 mx400 its in pretty rough shape and some idiot sprayed it camo but other than that it looks like it should be an easy one to get back on the road or well field/ trail just bought a new stator and cdi (both from 76-77 yz400's which I am told would work on my bike... babbits says so too but I wont know until I get some wiring done) now I just need to attempt to recreate some semblance of a wiring harness and go from there... only problem is like I said I am a complete moron w/ electricity can anyone point me in the right direction to wiring up a simple harness i.e. Stator-> CDI -> Coil with a simple ground out kill switch thrown in there somewhere??? also would love to get a hold of a wiring diagram for a 75 MX400 so far all I can find is the smaller DT schematics and I have no idea how close they are to my bike sorry for the rambling post and thanks in advance for any help