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New member from CA with a question about the choke.

nightwolf0215

CB750 New member
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Hello everyone. It is my first thread here, so please excuse me if I overstep any bounds.

I recently got an 81 CB750 Custom with the intention to make it into a custom bike of my liking. This is my first CB750, and I am very inexperienced with the platform. The bike ran fine according to seller. He put it away for the winter, and now it has some problem starting.

Today I hop on it and tried to start it. With full open choke, I'd have to keep pressing the start for about 5 sec before the engine would run. At full choke it would idle at about 3k rpm. I'd let it idle for a little bit to warm up, then close the choke. As soon as the choke is closed, the engine would die immediately. I tried it again a couple time, and the result was the same. When I close the choke a little bit to let the engine idle at around 1k rpm, I can hear some strange moving noise. That noise scared me a little so I decided ask for some advice before I damage something. Does anyone have an idea how I can get it running again?

Picture for your viewing: :D

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If it really ran fine before being stored then the most likely suspect is gummed up carbs. The carb bowls should be drained before a long storage period to avoid this. If they weren't, the gas can turn into a gooey substance and plug up the many tiny passages.

CB750's make a lot of strange noises, particularly when idling about 1000 in neutral ;) Make sure it's full of clean oil and try running it while in gear with the clutch lever pulled in or just with the clutch pulled in in neutral and see if the sound goes away.
 
If it really ran fine before being stored then the most likely suspect is gummed up carbs. The carb bowls should be drained before a long storage period to avoid this. If they weren't, the gas can turn into a gooey substance and plug up the many tiny passages.

CB750's make a lot of strange noises, particularly when idling about 1000 in neutral ;) Make sure it's full of clean oil and try running it while in gear with the clutch lever pulled in or just with the clutch pulled in in neutral and see if the sound goes away.

Thanks Dave. I just pulled a couple of manuals off the internet and will try to do this asap. I'll update once I get that done. :D
 
Set the timing chains, and don't strip out the front bolt, it does it super easy. If the main primary chain is making noise then syncing carbs will stop some of the noise but it may simply be from clogged carbs. These do it if they sit with fuel in them at all. And hard to get truly clean so be ready for doing it more than once.
 
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