Chokes sticking

[OldGold]

I have an 80 CBX that I have rebuilt the carbs on. Chokes were working perfectly on the bench. The bike was alittle hard to start when back together but then I balanced the carbs and all was well for a short time. The bike sits alot without use. At some point shortly after the carbs were balanced, the bike became very hard to start. With much appreciated help from Bikeymikey748, I discovered that the right bank of carbs were not choking unless I push them closed. I am assuming that all three carbs are not choking because of the difficulty in starting. I removed the tank today to see if I could see the problem. I remove dthe tops of both the outside carbs to observe choke function. The left side works perfectly and again I am assuming that the three left side chokes are all working. The right out side choke is stiff and will not close unless I put my finger on it. Where the choke mechanism is actuated at the center of the two banks, both rotate the same. I sprayed carb cleaner in this area but nothing changed. I moved the choke from closed to open many times, each time closing the right bank with my finger to try to free it up. Nothing has worked so far. Does anyone have an idea what to try next short of tilting the engine and removing the carbs? Tapping on the side of the carb with a hammer did nothing to help close the chokes.

Thanks for any help you can give,
Howard

[bikeymikey748]

Hiya,again, Howard.
As you move the lever to close ( activate ) the chokes, the cable moves part of the choke linkages. Between this and the actual plates being closed are, light, springs. In fact the plates can move independently of the lever, as mentioned before. Seems you have some binding between these two parts. You might have built up deposits, where the choke shafts pass, between the individual carbs, or there is some sort of restriction between the spring and the linkage.
As the carb tops are off and you have access to the plates, you might try activating the choke, leaving it in that position, and then use a light duty lube (WD40 or some such) in the area where the plate shafts pass & the spring is located. Try to manipulate the plates to work the lube into the areas mentioned.My money's on the shaft being the culprit. There's a good chance to free it up with the carbs in place. The fact that you can manipulate them to snap closed is a great sign. It shows the spring is in place and its being moved by the linkage. The rubber boots between carbs #4-5 & 5-6 will impede ( but not,totally prevent ) any lube from making its way into place. Access to the RH side of the #6 pivot is blocked by an ,outer, cap. The LH of #4 ,under the linkage/spring, shouldn't be too much of an issue. Chances are good you can return operation to normal, if you're careful & persistent. Avoid the impulse to over-lube.
Go get 'em, Cadet. Keep us up to date. I sure hope those puppies won't have to come out

[OldGold]

Mike, again thanks for chipping in on my issues. Since I submitted my question, I got the bike back together (I was torquing the head to see if I might stop an oil leak that I think is coming from the head gasket) and with all chokes closed, I could hardly tell any difference in the ease of starting. It still took forever. Between starting attempts I removed the right side carb top to make sure the choke was activated. It was. Now I am really perplexed. With the engine in place, I can only remove the top on #6 carb and #1 if the tank is off. I can't get to carbs 4 & 5. My plan is to drill a hole in the right side of the air box that will enable me to use a screw driver to activate the right side chokes and spray either lubricate into the area for the choke plates or spray starter fuid to accelerate the starting process. I have to admit that I am not willing to tilt the engine again to access the carbs. I will either live with the situation or make modifications to circumvent the problem. I am elderly and do not have the flexibility to do things that seem like nothing to younger folks. Once past the starting procedure, this bike runs great and makes it difficult to remove my smile after every ride.

Again, thanks so much for your input and help. I live in Wisconsin so if you are anywhere close, PM me and we can do a ride next spring.
Howard

[bikeymikey748]

No worries, Howard.
If you can move .#1&6 choke plates, the others are moving too. You can try fabbing a longer 'straw' to spray lube into the (likely) affected areas. Having the tank off will help out too.No need to start taking,more,things apart....hopefully.
I wouldn't go drilling about in the air box. Half measures are just that.

I could hardly tell any difference in the ease of starting. It still took forever

Likely, the plates are still not setting as they should. Until you can see them closing ( as you discovered with the #1& 6 tops off ) every time you engage the choke, I would have little confidence in them.

(I was torquing the head to see if I might stop an oil leak that I think is coming from the head gasket)

Did you verify that the copper washers, under the head bolts, weren't galled? I didn't catch it on mine, at first, & thought my gasket was leaking too. Galled washers will, eventually, allow oil past and then run down the cylinder studs to the cylinder fins. Retorquing a, failed, head gasket won't correct much however. The fluid path has already been established, there's nothing for it but to replace it. Though, a failed head gasket would contribute to your cold-start woes too. Any,abnormal, smoke on cold-starts?
Thanks for letting me try to help you out, and thanks for the kind ride offer. Trouble is, I'm in Montreal Canada. A bit on the far side of things. Still.....you just never know.

[OldGold]

Mike, I did not loosen any of the head nuts or bolts and did not know that the washers were copper. I used to be a Corvair nut and removed the heads on several engines. When removing the Cyl. Head nuts, one was always concerned that a stud would pull out. Is that an issue with the CBX nuts? I do not want to create more issues than I already have. However, if I can either remove one nut at a time and replace the washers without creating additional problems, I would be willing to do so. I can live with the oil leak if I have to. I would sell the bike (which I really don't want to do) before I would remove the head to replace a stud or two.

I have not noticed any smoke on start ups but I will do several cold starts in the next couple of days to verify. I quess by big question now is should I replace the copper washers or get used to cleaning the cylinder fins.

[bikeymikey748]

'Morning, Howard. You know, we have to stop meeting like this, people will talk
If you haven't loosened any head bolts,the copper washers are an unlikely source of your oil leak. Though if you had to move the head nuts too much while retorquing, that might contribute more to the leak. And, yes, sometimes the cylinder studs do turn out when the head nuts are removed. In some cases, they can be cleaned/reinstalled without taking the motor apart ( the 4 outer studs have 'blind' threading into the cases, the others are 'open').
How are the choke plates coming along?
Corvair nut? Man, you are a glutton for punishment

[OldGold]

You are right. I do seem to look for grief in my motorized preferences but the CBX does trump the Corvair in the grief department. I tried starting the CBX this morning, closing all chokes, to see if there was a difference if the bike had not set for weeks. I did two long tries on the starter without a single pop. I removed the air cleaner and shot in some starting fluid. The bike fired immediately but died within 10 seconds. Another shot of fluid and the bike stayed running. I have checked that the carbs had fuel in the past but I will do that again this evening before trying to start it. Since I am sure that the chokes are closed, the timing is on, there is fuel in the carbs, and I am assuming that I have good spark, although I will check it again, I do not understand why the thing won't start.

[FalldownPhil]

Forgive me for chiming in here but might you be having a problem with the vacuum fuel valve?
It sounds like it could be a fuel delivery problem. If the valve does not open correctly, there is no fuel delivery to the carbs.
Just for fun, you might try bypassing the vacuum valve and see what happens.
Just a thought.
Best,
Phil

[OldGold]

Phil, thanks for chiming in. More mind power certainly cann't hurt. Since I could not find the diaphram for the fuel valve, I had to remove it. There has been no fuel valve since I got the bike running this past spring. As far as I have been able to learn, there was no fuel valve on the 79's and as long as I remember to shut off the fuel when the bike is on the side stand, the lack of a fuel valve should not cause a running issue. I could be wrong if there were other mods to the system that I am not aware of. I did install an in line fuel filter so I will remove that to see if there is any difference. It might be good to know that I cleaned and sealed the tank with Por 15. The in tank fuel filter and petcock were in good condition and fuel flows freely through both. Any other ideas?

[bikeymikey748]

Forgive me for chiming in here but might you be having a problem with the vacuum fuel valve?

What? This isn't a private party.....chime! chime!
With all the info you posted,Howard, I'm still leaning towards the choke. The fact that you have no problems with hot starts or fuelling issues up through the revs/under different loads points out that you don't have problems with fuel flowing, or a host of other possibilities. The fact that if you spray quick-start into the intakes on a cold start, and the bike will then fire, and run (apparently until the quick-start is burnt off), leads me to believe that you just aren't getting the amount of fuel required for cold starts. With our carbs, the only way to,deliver that surplus of gas is to choke the carb, upstream, of the jets. The motor can't get much air, but it will draw more gas. Somehow, your bike isn't doing this.
Not to beat a dead horse, but are you certain that the plates are closing, fully, as they should? And if they are, are the springs I mentioned keeping adequate tension on them? They (the plates ) might be setting, but there could be an issue with the springs/linkage such that below normal vacuum will open them up, before adequate fuel is supplied.
There's a lot of volume in the air box, but what happens if you try a cold start while blocking the entry? You will, likely, have to crank a bit more than normal, but should see some improvement over what you presently experience. If that's the case, again the chokes are singled out.

[OldGold]

Mike, You were right. Even though the chokes are closed as far as they will go, they must not be "completely" closed. I read your comment and went immediately into the garage, removed the air cleaner and stuffed a towel in the inlet. The bike started within 5 seconds. The choke cable is pulling the clokes closed as far as they will go. I cannot force them more closed with my finger. I guess I will have to think of some work around until I have to tilt the engine forward for some other reason. Right now I have no desire or motivation to go through all of that work again. What is aggrivating is that the chokes closed completely when bench tested. I can now hardly get a fingernail between the choke plate and the carb body. I used red locktite on the choke screws so it is hard to believe that a plate moved, causing the rest not to close. Anyway, thanks so much for getting to the bottom of the problem. Guys like yourself make this forum great.

[daves79x]

It is not at all uncommon for the choke SHAFTS to move when installing the carbs - not just the plates. The choke system is a very complicated system that all has to work together for proper operation. I've fiddled with them on some sets for a long time to get them right. The 'work-around' for your problem is your best friend - the accelerator pump. If it is working properly you can 'pump' the throttle a dozen times or more, then turn on the key and start the bike. You cannot flood these things, so pump away at the accelerator pump and that will help a lot.

Dave