Ideas on engine status

I bought a 1981 xj650 some time ago.
Before I start pouring any money in to her I want to assert myself that the critical components are in decent shape.
She runs allright but since i adjusted the main idle screw so that she no longer stops on idle it seems like the revs does not want to go down after i rev it up. see the film in my photobucket album.
http://s1080.photobucket.com/albums/j339/IvarNelson/
I guess this is a carb problem? the cables are all fine and not stuck anywhere.
What do you think this slow drop in revs might depend on?


Furthermore i did a compression test with the throttle fully opened and normal working temp on the engine. It came out like this: L to R: 147, 143, 140, 150 psi.
Would you consider this OK? good? normal?
It seems to me that the spark plugs look fine.
Can you tell me anything about the status of the engine? what more tests can I do to assert myself that the main components are worth spending time on?

thanks


Ivar Nelson
/sweden

 

Sounds and looks pretty good.

Those compression numbers are right on, above 120 and within 15 of each other.

I don't think those carbs would pass the "clunk test". Read this:
Clunk test

I think if you do the "normal" maintenance that we have to do on these bikes when we buy them -
Front and rear brakes
plugs/oil/filter
valve shim clearance
clean carbs
etc.

- you'll have a bike that you can put a lot of km's on.

Welcome to the site!

 

Havin the same problem on my XS.
Usually means a Vac Leak, or carb related.
But yeah sounds like you got a good start on your bike! Keep it up! And we'll be here when you need us
-Chris

 

Right on!

Thanks for taking your time!

l´ll be going for my motorcycle-liscence tomorrow morning and after that I will be riding the bike a lot more.
Looking forward to overhauling the bike!

Ivar Nelson
/Sweden

 

REAR BRAKE before any riding: http://xjbikes.com/Forums/viewtopic/t=15874.html

 

Good tip regarding rear brakes. I will definetly check them out.

 

First of all: I got my motorcycle liscense today!
Took my xj650 out for a bit of a joyride! Only bad thing is that my idle sometimes goes really low and sometimes up to 4000revs. Im guessing this is due to the Carbs and I will look them over.
I am planning to order some stuff for this from XJ4ever. Since I live in Sweden I want to order all the stuff I need right away so I can complete the overhaul once I start.
I understand thats its difficult to say what parts are needed before examining the carbs but do you guys think that a "carb rebuild kit" is all i need? Is it common that the diaphragms are bad for instance?

I will replace the rear brake shoes like bigfitz recommended as well. Again; should I order any new seals or whatnot and replace them while im at it?

My intention with this is just to make it run a little smoother and be safer for the summer season. In winter I am planning to check valve shims and stuff like that. Although with the compression readings above there shouldnt be any problems with my valve shims right?