81 xj650 has diaphram issues

I have this bike. It runs like the throttle is stuck but it is not. Iam pretty sure it is the slide diaphram because i dont think they seal properly.

 

Did you rebuild the carbs lately?
Broke rack?
You had the broken needle tip in a different post. Did you replace it?
Did you use silicone grease to hold the diaphragm in the groove during reassembly?

Any more information on what is happening?
Starts good?
How is it once the bike is warm?

 

the diaphragm lifts the slide up from vacuum, that big spring helps push it down.
did you do a running sync ?

 

The diaphram actually shrunk and will not go fully in the groove. I did purchase brand new needle jets. I think this is how the diaphram shrunk i put the whole slide in parts cleaner solvent and let it soak and when it dried it did the shrinking

 

If you did that you also ruined all the other rubber parts. Throttle shaft seals, fuel O-rings and diaphrams will have to be replaced. The warning on the cleaner usually says not to immerse rubber parts, lesson learned.

 

there's been good reviews on this guy
http://jbmindustries.com/
you might not have needed diaphragms but the seals and o-rings, your better off having anyhow

 

When u say the seals and o rings are them all in the slide and do you think their junk now.and are the throttle shaft seals in the slide. I also soak the whole carbs do you think any think in their is junk

 

All the rubber parts will have been ruined by the carb dip.

 

All the rubber parts will have been ruined by the carb dip. Take sloace in the fact that they would have needed replacing eventually anyway.

 

Like what are some of the parts in the carb and slide and where are they

 

Throttle (butterfly valve) shaft seals are rubber.
Fuel pipe connector o-rings are rubber.
Some original float valve needle tips are rubber coated.
Air/fuel mixture adjustment assy has a rubber o-ring.
Dust cover on enrichment needle is rubber.

My diaphragms shrunk a little during a recent rebuild. I did NOT soak them, they just got dry from sitting out.
Fortunately I got some RnR Fluid with my Deluxe Rebuild kit from Len (there he is again!). The RnR helped soften the diaphragms and restore their flexibility. I also (as recommended on this site) used some silicone grease in the groove to help hold the diaphragm in position.

If I understand you correctly, you said your diaphragms shrunk and would not go fully in the groove? If that is an accurate statement you will need to reassess what your definition of rebuilding is.

You must go through the process and be meticulous. That means you have small conversations with yourself. Like:
"That diaphragm IS fully seated in the groove and WILL stay in position when I attach the carb hat. In fact I will disassemble and reassemble this first one just to make sure that I am using the proper technique and can move forward with cautious confidence with the next three."

What you don't want to hear is:
"That is kind of in the groove but not quite; oh well that should be good enough."

 

If you put just the slide into the dip, then only the diaphragm is the issue. There are no other rubber parts on the slide other than that.

If you dipped the whole carb the there Are other parts to worry about.

If the diaphragm shrank but is still flexible, you can carefully stretch it by slow tedious stretching in a radial fashion til it fit the groove again. Once it fits the groove, go just a hair larger so it settles back into the groove. Have the big spring, cap and a couple screws right handy so that once it's in the groove you get the spring and cap on before the diaphragm can shrink back out. The cap will lock it into the groove, the diaphragm will stay put And relax back to its original size.

 

The diaphragm is the large rubber flange attached to the top of the slide; you already know about these.

The throttle shaft seals are located on both sides of each carb, trapped in place by the butterfly/shaft and linkage. To get at them, the rack needs to be broken down, and the butterflies and linkages removed from each carb to access the seals.

Those are every bit as important as the diaphragms and have probably been compromised. They are the main reason we do not recommend submerging still-assembled carbs. Every thing else is relatively easily accessible.

 

Hopefully i can take them apart and try to stretch them

 

Hopefully today or tommorow