Goldfinger

Anyone you read my last post- She Lives!!, will know that after getting my XS400 running I had a problem with fuel leaking from the overflow of the right carb. I was advised the problem could be from the carb seals or float needle, or from the petcock. Looked on ebay at rebuild kits, and considered even another set of carbs, but decided to strip the carb one last time before I spent more money ( my budget for the project has already doubled!) On the float there is a small tab that, when the float rises, the tab pushes up a valve that controls the amount of fuel entering the float chamber. The tab in the leaking carb was almost flat, while the one in the other carb was sticking up about 1 - 2mm. A quick poke with a screwdriver so they both stick up the same amount, put it all back together, and back on the bike. She fired up first time, idled good, didn't cut out when revved up or after running for 10 mins. And most importantly, no leaks! It would seem the running issues was caused by to much fuel flooding the right carb. I hope this can help other bikes that have the same problem, before you go and spend your hard earned cash on unnecessary parts.

Hi, does that mean the seals in the petcock and/ or the carb are shot? Or does the float needle need replaced? When I removed the gas tank to drain it, with the petcock in the on position, there was a constant run of fuel. Does that indicate the seal is gone, or would it run as it is off the bike and there is no vacuum? This is all quite new to me, so please forgive any stupid questions!

On my wife complaints of gas feumes coming from the garage, I just went out to check, and half a tank of gas has just flowed out the right carb onto the garage floor. I thought that if the petcock was in the on position, the gas flowed only when the engine was running? Is this correct? Or should to be in the PRI position when it is sitting? Any ideas as to what is wrong with the right carb? Any advice would be greatly appreciated.

Tried her today when I got home, fired up on the button, without any choke. Ran for a good 10 mins, gave a few coughs and splutters when I reved her up, and also a couple of backfires, but on a whole, running much smoother than yesterday. Wasn't keen to start up a second time, but after I left it for 10 mins, started up again and ran for another 5 mins. The only problem now is fuel leaking from the right carb into the air filter box. I read on another post on here,(but I'm damed if I can find it now!) of someone else who had a similar problem, my question is- A. Why is it doing that, and B. How can I stop it. I know it needs some fine tuning regarding the mixture, I was wondering if that was something to do with flooded right carb?

After a few days of refusing to fire up, my XS400 slowly starts to show signs of life. After some confusion with wiring( thanks for your help, Drewpy!), I was still convinced the problem was electrical. Today I decided that it would run this week, as winter is fast approaching and there won't be many good riding days left. Checked a few posts on here to see where to start, and set about it. Thought I should start with the carb, left hand carb was fine, jets clean, opened up the right carb, the float was stuck and the rubber diaphragm ( is that what it's called?) was not seated correctly. Put it back together, checked the float was working smoothly, put it back on the bike. First turn of the starter, and she fired up. It ran for about 2 mins on full choke, then cut out. It fired up a few times more, but cuts out after 10 to 15 seconds, or as soon as I give it some revs. So it still needs some adjustment, but I'm well chuffed with the progress so far. Not to bad, considering it sat in the last owners back yard all winter, under a bush, at -30! I will now check the posts here for ideas on how to get it to run properly. I think a celebratory beer is called for!

I am just about finished my 77' XS400D cafe racer,( pics to follow soon) and it has the rounder cruiser style tank. The id plate on the frame dates it as October 1977, I just asumed that was the year they changed the shape of the tank. I did prefer the squarer shape tank, however, the shape of the dome seat I got mirrors the curve of the tank perfectly. I have seen old Honda CB750 cafe's which had a tank similar in shape to your's, and they look wicked with a Dunstall style seat, it really compliments the box shape of the tank. I'm not sure if the old and new tank are a straight swop, though. When I bought my bike, the previous owner had fitted a few non-original parts, (most of them badly), so mine may have had the tank swopped.

Just a quick update on my wiring dilemma.... I tried to wire it as suggested, however the wiring is as follows, the single gray and orange wires are male ends, the double gray and orange are female ends, both orange wires from the coils are female and finally the orange/gray wires from the contact breaker are male. The only possible way is contact wires to double wires, and single orange/gray to coils, or vice versa. Is there any possibility of damage if I get the order wrong, or should I just try the different combinations? My bike is Canadian although I cannot imagine the wiring being different from a European model?! Any advice would be appreciated. Either way, I won't be able to try and start it for few days as my next problem is a leak from the gas tank, it appears to be leaking from where the securing bracket on the underside of the tank is welded on. Hopefully I can seal it myself, or I will need to look for a replacement. Ah, the joys of old motor bikes!!!

Thanks for the reply, Drewpy. Your reply makes more scense than my question! I haven't had a chance to change the wiring and try fireing up the bike yet, but I will let you know how it works out. Thanks again, Goldfinger

Hi,This is my first post on here and really need some advice! I have just built a cafe racer from a 1977 XS400, and have some confusion with some of the wiring. I will try to describe the problem as best as I can! The condencer has two black wires with a white box end, which is connected to the other white box connector from the wiring harness. From the same point in the harness is one gray and one orange wire with male ends, and one red/white wire with a double female end. From the ignition coils there are one orange (female) and one red/white (male) wire from each one. Unless I am mistaken, the red/white wires connect to the r/w double end. With me so far? Further forward on the wiring harness is two orange wires with a single female end, and two gray wires also with a single female end. And last of all, there is the orange and gray wires coming from the engine head, which I think is from the contact breaker. If I could find out where the orange and gray wire from the engine connect to, and what connects to the orange and the gray double wires ( with the single female end). I have tried starting the bike, it will turn over on the electric start but won't fire up. I am getting a spark at both spark plugs, and the fuel is going into the carb, so I am guesing that I have a wire or two mixed up somewhere. Any advice would be greatly appreciated!