Immaculate 1981 Surprise

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Airborne
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Re: Immaculate 1981 Surprise

Post by Airborne »

Hello Dave,

Yes, this is a valid concern. I have checked most of them and they seemed to have movement without any issues, but that said, I will closely verify it yet again and as you recommended I will polish the seats to make sure everything is spot on before I attempt the second leak test. From the initial assessment though it seems that those floats were set wrong, since the needles move freely and simply fall in deeper than the set height. I will verify everything you said, polish seats, set them right and send pics to you guys for verification.

Once again, thank you for helping me on this!

Kind regards,
Airborne

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Re: Immaculate 1981 Surprise

Post by Airborne »

Gentlemen,
I have made a startling discovery!
Firstly, I polished the seats exactly like you recommended (please find pics attached). They looked all nice and shiny, as you indicated they should, so I started getting ready to adjusting the floats. Just to be safe, as Dave recommended, I made sure none of the needles stick in the seats and that's when I've realized what was the major problem... I looked very closely how the floats operate and how the tongue sits on the needle in order to adjust it properly, when I realized, comparing with the only properly adjusted float, that the top spring on all but one needle are seized. Please find the pic that shows a comparison of needle tops, where the float tongue rests. Only on of those has free movement, all the other ones are collapsed and seized. I don't have any experience with this bike, but from logical standpoint, this is the source of the problem, not incorrectly adjusted tongues, correct? Looking closely at those needles, it seems that nothing can be done other than replacing them...?

Please kindly let me know what are your recommendations.

Kind regards,
Airborne
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daves79x
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Re: Immaculate 1981 Surprise

Post by daves79x »

Now you get it! You need to re-read what I said very carefully. That's exactly what I was referring to as the spring plunger at the end of the float valve. Not the needle sticking in the seat. I was pretty sure that's what you'd find. Some may be revived, but I wouldn't trust them. New ones from (look up the website I've referenced a bunch of times here - I can't remember the URL and I'm tired of constantly copying and pasting it - sorry). They are OEM Keihin needles only - you have to reuse your stock seats. Don't use any other aftermarket ones. Get all 6 while you're at it.

BTW - Those needles still look pretty cruddy - spend some time cleaning the seats up better whilst you are waiting for the new needles. Totally clean is good. Sorry, the end of a long week and I can't muster any more patience just now.

Dave

Airborne
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Re: Immaculate 1981 Surprise

Post by Airborne »

Hello Dave,

Certainly, thank you kindly for the advise. No need to reference the website, I know the URL you're referring, I have it bookmarked :) I will get the needles promptly and in the meantime, I will keep polishing the seats to perfection. I've got a bit of international traveling ahead in August, so not sure how soon I can finish this, but I will certainly keep you posted and will refer in case I stumble across the problem. Maybe this feed will help someone in the future to know what to look for :)

Once again, thank you and I will keep you updated as new needles arrive!

Kind regards,
Airborne

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Re: Immaculate 1981 Surprise

Post by Airborne »

Hello Gentlemen,

It's been quite a while since I posted here. This forum has been instrumental in making my plans of restoring my father's long lost CBX back to its original might. This has been a long and frustrating process, especially that I have come so close to the end, yet so far... I have used all of your advises, restored carbs, cleaned the seats, replaced all the seals, needles, jets and I'm in a final stage of making it work. Per Dave's recommendation, I decided to leak test the carb rail and what a great call! I have not been able to fight the leak, that I'm assuming is the result of wrong floats adjustments. The leak ONLY comes from the valves, so I have crossed out any chance of o-rings or seals leaking. It only leaks from 3 carbs which are not in one line, therefore I'm certain it must be the result of the wrong adjustment. The worst part of it is that I have adjusted the floats with the manual, with a measure that is extremely precise therefore the current adjustment is by the book, precise to a decimal! This is so frustrating I have been to the point where I simply let it go for weeks at a time without any work, as nothing seems to make sense. Is there anything I'm doing wrong or would you Gentlemen have any recommendation to check things I may be missing?

Thank you once again for all your help...

Airborne

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Re: Immaculate 1981 Surprise

Post by jnnngs »

Hi,

The float valves / seat need to be really clean so worth double checking those. Also, on the valve, there is a spring plunger / damper on the top. If that has "lost it's spring", then it won't seal properly. Check that the plunger depresses and springs back, if it doesn't it will need replacing.

Paul.

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Re: Immaculate 1981 Surprise

Post by Airborne »

Hello Paul,

Thank you kindly for the prompt response and advises. What you have referred to, was the original problem, 5 out of 6 springs (float needles) seized therefore I had all of them replaced and they are brand new. I've also been advised to clean the seats well and I have actually done a very thorough job on this and polished them to the point they actually shine right now. There is definitely movement there and no chance for anything to be sticking.

Is there anything else that I may have missed?

Airborne

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Re: Immaculate 1981 Surprise

Post by jnnngs »

Airborne,

I would check:
- that the floats are inserted the right way up (unlikely, but they do fit upside down and wouldn't work properly)
- that the floats have no leaks (again unlikely)
- I would then start swapping parts between a chamber that leaks, and one that doesn't. So, swap a float, and then a valve / seat assembly.

When I am setting up the floats, I look to get the seam on the side of the float to be parallel to the carb base when the float is just resting on the valve. That gets the height about right.

Paul.

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Re: Immaculate 1981 Surprise

Post by Airborne »

Hello Paul,

Certainly, I will try to swap floats and seats with those that don't leak and will keep you posted with pics.

In response to your checks:
* floats are inserted the right way up
* no leaks in floats
* I have actually started with the seam tactic before I got the precision tool, therefore I feel I have done a really good job at adjusting this.

Your recommendation for swapping the seats and floats might be the best way to narrow down the culprit, I will do my best to have that completed this afternoon and will let you know as soon as I can.

Thank you once again for your assistance!

Airborne

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Re: Immaculate 1981 Surprise

Post by daves79x »

I'm guessing you have some cracked standpipes in your float bowls. Very common. They will be hairline cracks and often can hardly be seen. Test by closing drain screw (bowl off) and blowing brake cleaner on the drain hole while holding a finger tightly over the top of the stand pipe. Cleaner will spray out any cracks.

Dave

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Re: Immaculate 1981 Surprise

Post by jnnngs »

daves79x wrote:I'm guessing you have some cracked standpipes in your float bowls. Very common. They will be hairline cracks and often can hardly be seen. Test by closing drain screw (bowl off) and blowing brake cleaner on the drain hole while holding a finger tightly over the top of the stand pipe. Cleaner will spray out any cracks.

Dave
Yes - stand pipes would explain it. Would be somewhat unlucky / unusual to have three that are cracked?

daves79x
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Re: Immaculate 1981 Surprise

Post by daves79x »

No, very common.

Dave

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Re: Immaculate 1981 Surprise

Post by herdygerdy »

daves79x wrote:No, very common.

Dave
+1 Had one appear out of the blue, fortunately on No. 6, so was able to remove the bowl easily and repair in a short(ish) time.

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Re: Immaculate 1981 Surprise

Post by Airborne »

Gentlemen,

Thank you kindly for a very good advice, it should be illegal to be so good at this! I think we finally got a break in this!
Dave, you were spot on, I do have at least one standpipe cracked (please find photos attached).
The first standpipe pissed like a fire hose upon performing the test, with a long thin crack on its side.
The other one did not seem to leak through any cracks, however at its base I could see the fluid gradually appearing upon applying full pressure to the spray, therefore I'm assuming there is some minor leak there too.
Surprisingly, all the other standpipes did not react at all, even with fully pressed spray, which makes me think they may be in good shape.

I am still under the impression that I had 3 leaks, however now I'm doubting myself, as gasoline leaking from these two, definitely cracked standpipes, may have wetter all the other ones, giving the false impression. The only way to test it is to fix the cracked ones, which leads me to the other question... A preliminary search online showed no float bowl replacements, therefore how do I fix/replace these cracked standpipes?

Once again, thank you so much for your help, I've got a breath of fresh air in me, hoping that at least i'm getting somewhere.

Thank you and I look forward to hearing back from you!

Kind regards,
Airborne
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daves79x
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Re: Immaculate 1981 Surprise

Post by daves79x »

OK. You can try soldering them but I have had mixed success doing that. I got some brass tubing the same size at a hobby shop an drill out the old pipe, cut and fit and epoxy in a new pipe.

Dave

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