1984 Yamaha XJ650 (YICS) float height?

[Stalk]

Hello everyone!
Sorry that this is a bit long but trying to give as much info as possible.
Got myself an 1984 Yamaha XJ650 (YICS) that had been standing for about 8 years, so I thought a carb clean was in order as it would not idle. Reset the float height to 3mm as detailed in the Haynes manual as it appeared to be quite a long way out. (There is evidence of previous work on the carbs, rounded screws ect) Problem is that the bike now runs very rich unless the pilot screws are almost fully closed, then it stalls. The pilot screw setting for the slightly earlier bike is 2 ½ turns out so as that detail is unavailable for mine, I used that as a starting point. I am thinking that maybe the 3mm float height specification may be incorrect, but as I is stupid I failed to measure the float heights before adjustment. I have made a tool for blanking off the YICS passages so that I can final tune & balance the carbs but have not yet tried that. The heights where checked with the carbs at the correct attitude on a bench (made a little jig to hold them in the right place) and used a clear tube from the float drain point to the underside of the flange to measure.
So the question is: Does anyone know if the 3mm float height setting is correct, or do you know different?

Thanks in advance.
Cheers,
Stalk

[temeluchus]

Its more like 17mm

That will explain why it runs a bit rich if you have it at 3mm

Never trust the " haynes book of lies. "
____________________
Some shite cruiser. Now with guns and FREEDOM!

[Stalk]

Will give that a go. It seems that it will leave the bowls only half full but
at this stage I have nothing to loose.

Cheers
Stalk

[temeluchus]

oh i quited the measurement by adjusting it against the carb body, with the carb upside down
____________________
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[Ichy]

I was going to mention that there are two ways to measure. One is float to body and the other is fuel height to flange.

Not 100% sure on these because I had a 750 but I never checked float to body, just used the clear tube method. I thought it was 3mm from the flange but its comes down to which carbs you have fitted.

The best place to find out for sure is xjbikes.com.


Are you sure the needle valves are shutting off the fuel supply to the bowls?
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[temeluchus]

aye does sound like the float valves are worn, almost certain with a bike that age
____________________
Some shite cruiser. Now with guns and FREEDOM!