Author Topic: Mild restore, on a 78 CB-750K. Ran into a few issues.  (Read 884 times)

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Offline JerrodR

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Mild restore, on a 78 CB-750K. Ran into a few issues.
« on: June 04, 2020, 08:24:22 PM »

What's up everybody, so I bought my first CB-750 around 2 weeks ago. Didn't spend alot on it, the guy claimed it ran, and it does start, and will even ride up the street under its own power, but clutch is slipping pretty badly, and it runs just horrible at low RPM, all the cables were bad "ordered them all" so I don't know the exact RPM it clears up but when it does it's a strong motor. It's a 78 and is all around a solid bike, besides the clutch and the low speed sputter. I know it's carbs, what I don't know yet is if their just dirty, or is it incorrect jetting, because it came with a 4 into 1 header with baffle. It's a great little bike, and all parts are very affordable on eBay. Probably have over a dozen parts in the mail on their way now, but can anyone help with my carb issue? I can handle the clutch. But 4 carbs is about 2 more then I've ever felt with before, and I know nothing about jetting or tuning after an exhaust change. Really hoping that's already been done, and it just wasent winterized properly and carbs need cleaned. But have no clue. Any theroy's welcome, Thanks.

Offline BenelliSEI

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Re: Mild restore, on a 78 CB-750K. Ran into a few issues.
« Reply #1 on: June 04, 2020, 08:39:53 PM »
The float bowls on your carbs are held on with screw and you really need to pull the carbrack off you get into them. Heat the manifold rubbers with a hot air gun, really warm, to make pulling easier. If they look original, do yourself a favour and get 4 new ones!

The idle jets are impossibly small on these carbs, and probably plugged up. Pull them (and the mains) and soak, clean, blow with air. Don’t be tempted to push anything through, you will wreck them. Only use Honda press if you have to replace anything, most aftermarket kits are very poor. Float heights are critical, and a carb synchronization with the correct tool is invaluable. I’m sure you’ll get more suggestions. Start with stock jetting and keep the std. air box and filter.

Offline Alan F.

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Re: Mild restore, on a 78 CB-750K. Ran into a few issues.
« Reply #2 on: June 04, 2020, 09:11:35 PM »
I've recently bought my first K8 too, still waiting on parts orders here too. I've got quite a lot to do on mine, plenty to keep busy with if you feel like following along the link is in my signature line.