Carb rebuild kits-which one is good for a CB77?

Daddykool305 · Post by **Daddykool305** » Sat May 07, 2011 6:06 pm

I have read posts on this forum for a while, when searching for info about carb rebuild kits.
I somehow picked up the impression that Keyster ones were not good in the needle jet/jet needle department for CB77. I see now I may have been mistaken and it may have been CL77 that was no good?
My bike has the rich at idle problem mentioned in Bill Silver's book. All other carb settings are correct and performance is fine otherwise. Only when sitting at idle, some unburnt blueish smoke comes out the right exhaust. (float levels have been set and rechecked)
When going along the road, there is no smoke at all. The bike is a 1964 CB77 and the needles have the correct number, 24231. I suspected the needle jets may be worn.
Anyway, I just bought a set of CB72/CB77 carb kits from Ebay. I did not know the brand name before purchase, but they turned out to be Sudco. The kits I received had 3 main jets, none of which were the 135 I need for my CB77 (were 100, 105 and 160). Also the jet needles are longer than the originals. There are no needle jets. I had asked the seller before buying, telling him I needed 135 main jets for my CB77. He assured me that the kits had 2 main jets, for either CB72 or CB77. This turned out to be false.
Buying the kits, which I thought was a simple way to overhaul my carbs, has become a nightmare.
The ebay seller was also slow to ship, like 5 days after I paid, so I waited a long time for parts that are fairly useless. And there is the anomaly with the jet needles. Having looked at pictures of the kits on ebay, it had so many parts that I assumed one was the needle jet, having never looked at one. Incidentally, the needle jets fell out of the carb when I put the needles into the jets, having taken the needles out of the slides to check how much clearance was between the jets and needles.
I thought the jet was "pressed in" from what I had read, but the fit is not very tight. Is this normal?
Any ideas where I can get new needle jets? Are Keyster kits ok for a CB77?
Another problem is that the jets in these kits have a ring marked around the heads and do not fit anyway (even if the jet sizes were right). Are jets with the right thread for me available? JIS?

davomoto · Post by **davomoto** » Sat May 07, 2011 7:10 pm

DK,

First off, blue smoke indicates oil burning, black some unburnt fuel. Some on this forum swear by the Keyster kits, I don't. I use the float needle and seat, the bowl gaskets after a bit of trimming, and all of the stock brass. Are your floats set correctly. The best / easiest method is to set the top of the float even with the top of the main jet holder.

Davo

Daddykool305 · Post by **Daddykool305** » Sat May 07, 2011 7:28 pm

Hi Davo,

I have been very careful about setting the float levels, but the needle valves are old and could be not seating properly, so maybe I will fit the new ones and reset them, possibly use the blowing through a pipe trick to determine the exact point at which they close.
Looking at the jet needles in the jets, which are out of the body now, there doesn't seem more play on one side than the other, so maybe they aren't worn after all.
Someone mentioned re-tapping the main jet holder to take ISO thread jets, is this a good idea in your experience?
I can buy any size jet locally, so it would be good if I can use them. But they are the ones with the line around the head.

Cheers,
DK.

davomoto · Post by **davomoto** » Sun May 08, 2011 9:10 am

DK,
I wouldn't tap anything in the carb. Do you not have 135 mains? They don't really wear out, so why replace them?

Davo

CL77NOW · Post by **CL77NOW** » Mon May 30, 2011 4:17 pm

Etching is very common, on man bottom jet for sure.
they never wear out with gas, but some run aid gas.
parked many times for 3 years. then purged, and ran then parked the repeat 1960 to 2011 , possible.
the fuel turns to acid (water helps)
i very good clue, to see this (seen 100s) is the size starts to etch off.
bingo.

use number dill shanks to find true size, and if etched.

im making a carb only page, this is my rough note.
it will be done in a week.

http://cl77.servebeer.com/

LOUD MOUSE · Post by **LOUD MOUSE** » Mon May 30, 2011 5:22 pm

How far back in this forum are you planning to go?. .............lm

CL77NOW wrote:Etching is very common, on man bottom jet for sure.
they never wear out with gas, but some run aid gas.
parked many times for 3 years. then purged, and ran then parked the repeat 1960 to 2011 , possible.
the fuel turns to acid (water helps)
i very good clue, to see this (seen 100s) is the size starts to etch off.
bingo.

use number dill shanks to find true size, and if etched.

im making a carb only page, this is my rough note.
it will be done in a week.

http://cl77.servebeer.com/

teazer · Post by **teazer** » Mon May 30, 2011 10:34 pm

Some years ago I needed a collection of different sized needle jets and needles for a methanol jetting conversion. At that time it was possible to buy needle and matching jets for CB750s and most models used the same needle jet as a CB77.

Bikebandit have them for 25 each which is a little steep, but looks like they are still available

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Carb rebuild kits-which one is good for a CB77?

Carb rebuild kits-which one is good for a CB77?