XS400 New Member
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Hamilton, ON, Canada
Hello everyone!

I've got a 1977 XS400D with 19000 km on it (or so my speedometer says) the bike and engine is in great condition visually, carbs are in great condition as well. Im the first one to register this bike in Canada so theres literally no record of it prior to May 2021.

When I bought the bike it wasn't starting - had no oil due to a leak in the crankcase. I filled it with oil and managed to get it started after kicking it for an hour although it was idling rough, making a weird clack once in a while almost like a backfire but higher pitch. I suspected the timing might be off.

I fixed the crack in the casing, filled the oil - cleaned the carbs THOUROGHLY (3 times) replaced a stripped pilot jet, cracked diaphragm and sprayed carb cleaner in every hole along with compressed air. I also installed an electronic ignition system from MikesXS and replaced the points system. I followed the steps on the site to install that.

It started up cold and first shot with the electric start which ive never been able to do before (felt amazing). Started it yesterday and today no problems. (i also replaced the plugs and boots fyi) great spark and coils all check out with my multimeter.

The issue im having now is that the bike doesnt really wanna idle when i push the choke in all the way. It will idle with it in the middle position between 2-3k rpm when cold then it starts to kick up to 5-6 once it got warm. As soon as i push the choke in it falls down to 1.5 for a couple seconds then dies. keep in mind that when its idling in the middle position its kinda choppy and it still makes that strange clacking noise once in a while (mostly when it gets to like 5k rpm).

A) I'm thinking the float height might be off because when i checked it it was looking around 20-23mm or so if i was checking it properly (spec says 32mm)

B) could the timing be off still? i have a xenon light gun which i tried to use and i couldn't see the LF on the alternator window?? again, ive never used a light gun prior to this so im not even confident i was using it right. I borrowed the gun from a friend and its very high tech.

THANKS SO MUCH for reading if you made it this far and i appreciate your help!!!