Floats, book setting 32mm, youtube setting 20mm, started setting 22.7mm cannot go above 27mm

[Revvy Kevvy]

Setting the floats, where is right. I find quite a lot of different information even in our own forum....

In the haynes book its 32mm, I cannot get 32mm as it hits its own stoppers at 27mm

In the genuine yamaha xs400 H/SH service manual book it says 26.5mm +/1 2.5mm but to do a measurement using a clear tube 3mm below the line +/-1mm

In our own forum its 32mm, but I cannot get to this as it stops at 27mm
https://www.xs400.com/threads/setting-float-level.4774/

In the you tube the guy sets his to 20mm for a xs400

In the end I have set the floats to 27mm, its about as high as they will go and this leaves the level of the fuel about 10mm below the carburetta body edge, picture called final setting shows this. Hopefully it will work.

Today I will check the tappet clearances and then put the sparking plugs back in and reattach the carburetta back in its slot. Might even try starting it if not too late.

 

[Revvy Kevvy]

Well, she fired up for roughly 20 seconds today and went into a nice idle....I was so happy, until she stopped and no amout of trying got it going again.

I guess I have the floats set somehow wrong....tomorrow will try to open the bowls up agin and think this one out.

 

[CaptChrome]

You are getting close! Hang in there.... I think you are on the right track as I would look at fuel supply as the first issue.

 

[Revvy Kevvy]

Now she fires and can run albiet very badly and at high choke but it will run. What was the problem?
I discovered I could kick start her but never start her by electric motor? made me wonder why, if I kicked her then she would run for a while and stop.
I got suspicious of the spark as the motor would just die, and I could see there was lots of fuel. Fuel death is not as sudden as spark death I figured.

I turned off the lights in the garage and started her on electric, like usual no firing but looking at the contacts I also see no spark here? why? I shoudl see a spark when the contacts open.
Putting a multimeter on it I find only 3volts when the motor is turning, thats not right. so I start going back. Plenty at the battery but lots less on the fuse (2 volts drop) I checked the fuse its ok then I find a contact between battery and fuse and its in terrible shape. Cut and reconnect using new crimps and volia she will now start on the starter motor, albiet badly as you can see from the video she goes into some kinda runaway.

I guess there is still something wrong with the carburetta s she will not run at all except on max choke, and will just die if I turn the choke off even if I leave it to get warm. Thats the next problem to solve...why so high idle and why she only wants lots of choke.

 

[Revvy Kevvy]

Looks that the boots need replacing to cure the high revs, ordered new carbi boots.

See how its better to close a discussion so we all know the answer.


https://www.xs400.com/threads/rev-high-idle-sticks-1982-xs400.9932/