Topic: 77 CB750K7 - Air box same as CB750F? or what?

[flybackwards]

I came to the very last step - install the air box but the one I have clearly does not fit. Its moulded in part id says HM CB750F-F - I h ave never seen this bike with the correct carbs and airbox - it came with pods and a beat up set of round tops.

I have a correct set of Keihins for it but the carbs and air box don't align with the top hangar brackets - I'm about an inch low and offset to one side a little - looks like I got the wrong thing from e-bay but since the head and carbs of the K7 were from the F Bike I thought it should fit.

I checked the rubbers at the head end of the carbs and it looks like there is only one alignment possible for the four of them.

K7 experts weigh in please..

I'm off to check the part numbers...thanks.

[Alan F.]

I think my K8 airbox says 750F on the side. Screw it onto the 2 frame mounts and see how it looks, you might have to prop it up to get the correct angle, it'll droop if you don't.

[HondaMan]

I came to the very last step - install the air box but the one I have clearly does not fit. Its moulded in part id says HM CB750F-F - I h ave never seen this bike with the correct carbs and airbox - it came with pods and a beat up set of round tops.

I have a correct set of Keihins for it but the carbs and air box don't align with the top hangar brackets - I'm about an inch low and offset to one side a little - looks like I got the wrong thing from e-bay but since the head and carbs of the K7 were from the F Bike I thought it should fit.

I checked the rubbers at the head end of the carbs and it looks like there is only one alignment possible for the four of them.

K7 experts weigh in please..

I'm off to check the part numbers...thanks.

The airbox I have from the F1 (with roundtop carbs) has that 'F-F' mark on it. I don't know if I have another K7/8 box, can look this weekend (it's raining out there now...). I had several at one point.

[flybackwards]

Thanks guys - I went for the parts catalogue and the part numbers are the same for the airbox top cover between the 77 K7 and the F2 - F1 is a different part. Brackets are the same too.

I am now pretty sure I have a correct air box - the F1 top has a small moulded indent on the front side - the F2 / 77K has a large one which fits the support bracket on the keyhole carbs.

My suspicion is now falling on the aftermarket carb rubbers at the head - a small offset here will make a big difference back at the airbox end - so I think I will take Alan's advice and bolt it to the brackets without the rubber trumpets and see how it lines up before I go any further - it may be that a little realignment and maybe a bit of hot air at the front rubbers will be enough.

Thanks again to the hive mind - its a great thing to have others experience to draw on.. and maybe their parts stash too..

[flybackwards]

Everything now fits - the problem came from the aftermarket carb rubbers not fitting correctly - I eventually took the carbs off again - put the rubbers on the carb side and heated them with the hot air gun and left them to cool in place. Then took them off put them back on the head end and lined them up so a straight edge went across the carb side - heated them up again - applied a bit of silicon spray on the inside diameter and pushed the carb assembly into place - took a good push but then there was a pop and it was in place..  now the airbox fits fine!

[Alan F.]

Good work there. I've seen a lot of people use a ratchet strap to pop their carbs on and off too btw.
Enjoy.