Topic: 82 650SC carb help needed

[ak58lp]

I am opening my carbs up for the first time right down to the jet removal. I have had issues for a long time related to low power up in higher revs and have a post somewhere here about it. While trying the usual fixes for this bike (removing air cover, draining overflow tubes, etc) I decided to remove the carbs and soak them in Pinesol. It helped, but I think things got stirred up worse as the bike is running rough at low speed and high speed now. I also placed an inline fuel filter in and the tank looks very clean inside.

Long story short, I hope to replace those annoying rubber tees between carbs 1&2 and 3&4 but I am waiting on parts. In the meantime I soaked the carbs for 24 hours in Pinesol and just removed the jets this morning. Here's what I found so far:

-one long needle from the upper chamber was bent inside and needs to be replaced.
-luckily on this model the low speed jet is not pressed in and can be removed. High and low jet holes are not completely plugged with calcium, but need a lot of compressed air ran through.
-one pilot screw does not have a small O ring present
-almost sure the accelerator pump rod that goes into the short rubber tube does not have an O ring there either.

Question:

I can get 4 complete rebuild kits with new jets, O rings, needle jets, etc but for this bike they will cost $140 for all 4 carbs. Is it worth it to replace them as new (no idea if they ever were) or clean, clean, clean???

Thanks guys

[cb650]

Sounds like you might need a new set.  They are pretty easy to work on but with what your finding parts might cost more than you can get another set for.  I have the needle if you want to continue with this set.   81's will work to but the slow jet is pressed in.

[ak58lp]

Thanks CB, my gut feeling is to get a new set. The bike is coming up on 30 years old and I don't know if they are original or not. The parts I took out were the screw on the bottom and then gently tapped the main jet out that you can see from the upper carb throat (high speed?).

Next was the pilot screw and spring.
Then the low speed I believe which just unscrewed right out.
That's all I think will come out that needs to.

This is the set i was talking about. I looked with a magnifying glass and can tell the high speed is #118 and the low is #35.

http://www.siriusconinc.com/pro-detail.php?pid=&product_id=474

[cb650]

Jetting is stock for 82.  81 had 120 mains for essentially the same carbs.

[ak58lp]

The white blanking plug that goes into the top of the piece that hold the long needle in the vaccum piston, does it need to sit right down flush with the top? Mine were all sitting just at the O ring level (1/2 in /half out). Hard to explain and can't find a decent picture. If it does not go in all the way would would be the result?

[cb650]

Yes it only goes in about half way.   Just past the o ring.

[ak58lp]

Thanks CB, glad you are answering no one else seems too. 

I see now when I put it back in, it has a smaller end that can only go in one way to the hole.

Starting to put the carbs back together and I notice the choke plates do not close completely now. I have tightened the bolts on the mounting brackets up and thought that might help. I followed the choke spring replacement procedure to a tee on the Nighthawk forum but it just seems like they catch at the last bit. About a 1/4 inch from complete closing. I don't want to split these carb bodies again..what at PITA!!

[scunny]

re the lack of respondants, not many 650's out there.
for your choke plates hanging up, loosen the backing plate then start tightening it back up evenly across all the screws, operating the choke after each phase. you might find where it's hanging up or even better, get it sorted.

[ak58lp]

I had a buddy look at it. He just loosened all the choke plate screws and tightened one by one. That was it.

Next question:

On float bowl number 2 is where the accelerator pump rod is located, I understand an O ring should be place in the small hole where the rod goes through the carb body. The tube came right out when I pulled the bottom off but where does it go? The tube has a small hole in the very bottom side and looks like it should sit above the carb body and ride up on the rod?

If I put it on the rod and press it between the float bowl and the carb body it's too big. My book does not show a detailed enough picture.

[coldwave007]

I'm not really familiar with the CV carbs (my 650 has the PDs), but on mine the accelerator pump rod just pops through a hole in the housing and bumps against a little lever coming off the throttle assembly.  That way when you "blip" the throttle it'll give a little squirt into the carbs.

So if the CV carbs works the same way, it should probably run through a hole and up to the throttle linkage...The Rod itself should pass through into the carb bowl itself and to that little external "housing" where the accel.pump diafram is.

Hope that helps....

[ak58lp]

Yeah I understand how it works maybe I just didn't explain it right. I know the spring fits under the acc pump cover and the rod goes through a hole in the carb body. Right in this hole is where the O ring is supposed to fit.

But where does the black rubber tube on the far left go? This is closest thing I could find..one off an old Gold Wing.

[coldwave007]

Ohhh, gotcha!  Sorry, but I have NO CLUE!  My CB carbs don't have that.  :-/

[cb650]

As stated in the other thread its just a dust cover.

[ak58lp]

Thanks everyone..rebuild is complete.