Soft seat...

What exactly does a soft seat mean in the context of the idle mixture screws? Right now I have them 2.5 turns out from the point I couldn't turn them by hand anymore. But since adjusting them like that, my XJ650 doesnt seem to want to hold an idle anymore. Do I have this right?

 

Soft seat or soft bottom means to turn them in until they bottom out without snugging them down (they should just touch bottom).

Gary H.

 

Now then, What lse has been done to the bike, and how many turns out were the screws when you seated them?

 

You should be able to turn them completely out the threaded holes. A drop of oil in each hole should help.

Gary H.

 

Thank you! I've been trying to search for a clear definition of that for some time!

 

I got it non running. I started by replacing the head after I snapped off a couple intake bolts. I've taken the carbs to church. The bike ran, but had a run away idle until I set the mixture screws at about 5-6 turns out.

 

Maxim or Seca? 5-6 turns out is way too much. A run away idle in this case suggests a vac leak.

Gary H.

 

Carbs bench synched? Float levels wet set? Running synch?
These should all be done after Church.

And then if your valve clearances aren't right everything is for naught.

 

I'm re-doing a bench sync now, I did wet set my floats, valves have been adjusted. When attempting to colortune and running sync with a carbtune is when it all went to crap. It seemed to be alright until I wanted to make it just a little better

 

Sounds like you are on the right path . . . .
Is that 5-6 full turns out?
What color does the colortune show at that point?

 

Yes, Full turns. The colortune shows a faint blue at that point, which I'm sure isn't quite right, with adjustment, I found I can lean it out, but I can't make it run rich

 

Well that sounds like what rocs82650 said - vacuum leak somewhere. Try using an unlit propane torch and wave it around, see if the idle rises.

 

If I actually manage to make it idle for a while, I'll get my hands on a torch and try that.

 

Ummm I think you read that wrong.

 

Some thoughts:

Throttle shaft seals were replaced?
Throttle shaft seals installd the right way-round?
Idle mixtuer screw o-rings replacd?
Vacuum caps inspected or replaced?
Vacuum line replaced with vacuum line?
Petcock rebuilt?

 

Probably did. Clarification?

Gary H.

 

He was explaining that he turned the screws in until they would not turn anymore, not that he could not remove them.

 

Oh, ok. Explains why his bike wouldn't idle. Thanks.

Gary H.

 

a soft seat is where it stops turning while holding the screwdriver between your thumb and ring finger.
maybe you should take them out and see if they still have a little point on them

 

Yes, new shaft seals, installed correctly
I have new springs and o-rings on all 4 mixture screws
new vacuum caps, but my intake and airbox boots are in pretty rough shape, I wouldn't be super shocked if one of those was the cause
New vacuum and fuel lines from the tank
I have not rebuilt the petcock though.

 

I'll do that, thank you.

 

Yep. you called it! #4 carb boot leaking.

 

Looks like I have a vacuum leak! #4 carb boot. I'll probably replace them all just for the hell of it. I'm sure the others aren't far behind. Thanks for the time and all the help guys!

 

If you want to ride sooner you can clean and degrease the existing boots and repair them with black oil-resistant RTV. Sincc its #4, you can do that without needing to remove the carbs. That way you can save the rest of the work for winter.

 

I'll probably do that. A full teardown and resto would be pretty cool once the rainy season starts