Wats up Guys,
I haven't been on here for a while but I have good news and bad news. Good News is I'm going to post picks of my "almost done" 1980 CB750K
Chop. Bad news is that my damn carburetors aren't letting any fuel through. Now I cleaned my primary and secondary jets, cleaned the needle and the floats,
and I even polished the top cap (not relevent to my problem but it looks bitchin). PLEASE HELP.
If I sit on the seat and look forward to the front tire I see Carbs (1) (2) (3) (4).
Carb. number 3 lets in some gas due to the fact that the number 3 header gets hot but nothing else.
PLEASE HELP... I can't wait to hear her on.
Thank you all..
Carburetor Problem ???
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 inkurable |
Carburetor Problem ??? |
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Posts: 45 (07/20/08 11:41:06) |
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freebyrd78 |
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Posts: 2019 (07/20/08 15:16:06) S.O.B. |
Ok, it sounds to me like the passages between the carbs may be blocked. How long has this bike been sitting? Sometimes wasps build nests in there, etc. If
that's the case, you'll have to clean them out. The easiest way to tell if the carbs are getting gas is to open up the the screw in teh bottom of each
bowl. If gas comes out, it's getting gas. another thing it may be is a blockage in either the petcock or the main line running to the carbs. Check them out
first.
freebyrd |
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LumbeeNDN |
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Posts: 138 (07/20/08 16:13:29) |
...make sure floats are the correct height...
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"I'm not a welder, but I play one on HondaChopper.com" 
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freebyrd78 |
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Posts: 2020 (07/20/08 17:50:35) S.O.B. |
there's no float adjustment on the DOHC carbs.
freebyrd |
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mstspot |
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Posts: 328 (07/20/08 18:13:03) |
It must be hitting on more than just one, I agree with free byrd, just not getting gas to the carbs, old fuel line can deteriate on the inside and plug it up.
Start from the tank and work your way done checking for gas at each connection.
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inkurable |
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Posts: 47 (07/20/08 18:31:19) |
the tank, petcock, and fuel lines are brand new. nd gas flows through. but i will have to check the passages between the carbs.
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inkurable |
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Posts: 48 (07/21/08 11:44:33) |
ok. I just got done with putting the carbs back on the bike, after tearing them down nd finding that the passages between the carbs are fine.
now i see that the carb is working the way it should. However I think maybe the coils are bad. how can I check to see if the coils are sparking the sparkplugs? |
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das31 |
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Posts: 3 (07/21/08 12:15:36) |
You can put a spark plug in one of your boots, and lay it on the engine and turn the engine over and look to see if the plug is firing.
Also check your plug wires at the coils and the boots. |
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freebyrd78 |
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Posts: 2021 (07/21/08 13:40:49) S.O.B. |
The spark plug trick works well. Just make sure that it's grounded well or it won't show the spark. The problem may not be the coils if you're not
getting spark. It may be the ignitor boxes. Also, Honda is famous for having junk connectors. You may have a plug that is corroded.
freebyrd |
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mstspot |
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Posts: 329 (07/21/08 21:27:32) |
Yup, Gotta take the time to clean, ALL the connections.
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inkurable |
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Posts: 49 (07/21/08 23:53:35) |
sounds like a plan. however I may have a shortcut. I have a set of coils on my 79 cb750 and they work fine. i'll switch them and see if that is the
problem. if so i will clean my coils. if not then I'll post again when i put back the coils into my 79.
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inkurable |
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Posts: 50 (07/22/08 17:51:02) |
SHE'S ALIVE.... I switched the coils and fired her up. it took a few minutes but she sounds great. I'm going to see if I can put a sound bite of her on
here. and it was the ebay coils that were crap. I tried the coils on my limited and it didn't work on that either.
so she fired up but she keeps turning off after she revolves a few times. what is the next step to get her to idle smoothly? |
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freebyrd78 |
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Posts: 2023 (07/22/08 17:58:54) S.O.B. |
The idle passages are TINY in the DOHC carbs. They may be clogged. You can see them at the bottom of the throttle body. They will look like specks of pepper.
freebyrd |
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inkurable |
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Posts: 52 (07/23/08 19:54:34) |
freebyrd,
im having a very difficult time finding these idle passages. are they inside the float bowl? |
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freebyrd78 |
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Posts: 2028 (07/24/08 05:18:58) S.O.B. |
they are at the bottom of the throttle body. look at the bottom near where they attach to the engine. You'll see a little black speck. that's one of
them...very easily overlooked.
freebyrd
Last Edited By: freebyrd78
07/24/08 05:21:01.
Edited 1 times.
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inkurable |
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Posts: 54 (07/24/08 08:55:21) |
I see what you are talking about. how do i make sure they are not clogged?
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freebyrd78 |
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Posts: 2030 (07/24/08 15:10:20) S.O.B. |
keep applying lacquor thinner to the hole with a q-tip, and blowing air into them.
freebyrd |
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inkurable |
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Posts: 55 (07/25/08 19:11:56) |
ok i got the idle passages clean. and I let the gas flow into the carbs and i tried starting the bike. it wouldn't start for a while so i cut off the gas
and kept trying. it finally fired up and idled for about a minute when the gas was cut off and the choke was on. but i noticed the the #1 carb is so rich on
fuel that the gas was pouring out of it ( from where the choke is ). I also noticed that the #4 carb isnt sucking in as much air as the other carbs.
my dad was helping me and he's a old timer. but when he saw that i cudn't get it to idle nicely, he told me to keep cranking it and he started putting his hand in front of the carb. he was cutting of air and letting air in ever second or so. an then the bike started ideling fine. So i thought WTF... how did he do that? i dont know why the last carb isnt sucking any air but can it be causing the majority of the gas to gather up in the first carb? Is the carb not vacuuming air going to be an internal problem? |
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freebyrd78 |
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Posts: 2036 (07/29/08 11:53:30) S.O.B. |
It's possible that the passages between your carbs may be blocked, but I'm thinking your problem may be that the carbs are so out of whack as far as
being synched. try synching them and see what happens.
freebyrd |
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inkurable |
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Posts: 58 (07/29/08 20:36:57) |
would i be able to synch them myself. or do i need some one that know wat he's doing?
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cornbrednsushi |
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Posts: 86 (07/30/08 10:13:38) |
http://slickschoppers.yuku.com/topic/2490 Here ya go.been following all the carb topics to try to
find out why she kept bogging,tried the drill bit "trick"worked like a champ took her out today for the first time this year. It was a depends
moment.wasn't ready for all 4 to jump like that.the only prob I have left is why the #1 pipe stays cold
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