1982 maxim400 not starting


XS400 New Member
Reaction score
Kelowna, B.C, Canada
Hey guys! New member here, nice to find a forum for our bikes. Anyhow mine doesn't want to start this year. First ill describe the problem as best as I can, then I'll give some history.

So my bike won't start like I said. However it WILL start and run on starter fluid and will continue to run. Once she's warm it'll start up no starter fluid needed.

Now some history. My bike before would only start with the choke on and then once it ran for a bit I could turn it off and go on with my day. I figured since the previous owner and myself have both left gas in the tank and presumably in the carb bowls that she needed a clean. So I brought it to a yamaha dealership and they cleaned it for me in a subsonic tank (I think thats what its called) I put it back together and it wouldn't start still. So, under direction of a friend I started messing with what I thought was the mixture screw but however it was the synchronization screw. So after messing that up I peeled the carb out and bench synced it with a 3/8 drill bit. Threw her back in and she still wouldn't start. Figured maybe it was too lean so I thought if I could get starter fluid and she starts then that would tell me it needs more fuel, right? Anyway I haven't messed with the mixture screw since its been installed but when I did bench synch it I backed it out 3 1/2 turns. I also noticed yesterday that only my left spark plug was wet. However when I tried starting it this morning none of the spark plugs were wet. But they were giving a dull yellow spark so I have picked up new spark plugs that I'll be throwing in once I get home. The airbox is currently open as well if thats useful information. Umm what else can I think of. Once I started messing with my bike about two weeks ago I put in fresh gas. Prior to that the tank was completely empty. Turn the petcock to PRI and gas is flowing. There is gas in the bowls as well when I undo the drain screw. I've also sprayed starter fluid on my boots and anywhere else I suspected a leak while she was running and no rise in rpms.

So in short. Without starter fluid all it does is turn and backfires sometimes. The starter sounds strong and not clunky and slow. Although I have killed the battery while trying to get it going. And when she does run its only with the assistance of starter fluid and runs like a top after that. (At idle however. Haven't taken it for a test run) once she's warm off starter fluid the bike can start up within 1-2 turns of the starter whereas before the clean it would take a bit and turns of the accelerator. I have a receipt of what they've done at the yamah service place which isn't much put ill edit it in this post when I get home shortly.


  • FB_IMG_1615226241417.jpg
    108.1 KB · Views: 128
Last edited:
Compression check and set the valves. Everybody acts like the engines last forever, and older engine in bad shape starts up exactly like here. Because people don't set the valves and then they leak.