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79 cb750k - idle jet replacement compatibility

xwinterhalox

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Hello everyone! New here. I Just moved up to a 79 cb750k (technically the 10th anniversary edition) from My Last bike a 76 cb550 and I’m stripping it down, removing the airbox, and has 4to1 exhaust.

I’m about to rebuild the carbs and plan to jet appropriately for pods and the exhaust. However, the idle jets are “non removable.” Which, technically they will come out and can be swapped, but places like jetsrus won’t have the jets listed for this year since they’re technically non removable.

My question is, what year model’s idle jets actually will fit these carbs? I’ve seen several people do it through YouTube videos etc, but I haven’t been able to figure out what jets to buy that would fit this year. I’m assuming that the 77-78 K would technically fit, but I’d rather not go ahead and order them, wait for them to get here, Realize they don’t fit, and have to research and order more.

Thanks to anyone that has the info! I searched the forum but through 7 pages I didn’t find what I was looking for.
 
Last edited:
Well, I’m an idiot. I don’t need to change out the idle. Just the main and secondary main. 🤦*♂️

Admins feel free to delete thread. I would do it myself I knew how. Haha
 
Removing the airbox on these is one of the worst things you can do but you'll find out. The CV carbs need its' configuration to open the slides fully, not doing so makes them run rich and more jet commonly adds to the problem. The engine must be in good shape too and so many never got valves adjusted to then leak compression and then the pods make it even worse.

You don't touch idle jets with those mods as you found. 75-115 jets and if it doesn't run up past 9500 rpm with those you have the previously mentioned issue. The header MUST be one that 'works', just having 4 tubes and a collector do NOT a header make.

I have a '77 550F and you can remove the airbox on those and they will run well like that, BTDT. People have trouble grasping how the shared vacuum in an airbox can really wake CV slides up to work good and the OEM design there makes working on carbs while retaining the box pure hell.
 
Stock airbox... There's a reason our Japanese friends in the little white lab coats and plastic hats did it and it's called efficiency.... Or better yet vacuum that's what those carpets need I rebuilt plenty.. I would keep your primary jet#68 and start with a #102 for the secondary... And use genuine kehein jets.. the other aftermarket jets are junk you'll notice the difference immediately in size and quality and stay away from aftermarket rebuild kits more junk
 
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