Retro fitting after market exhausts from another model year.

[Steve78]

Good evening,

I recently aquired a 78 cb750K. I'm in the process of modifing my bike, (winter project). I've allready chucked the air box for four K&N filters. My next step is the exhaust. I've seemed to of found the only company which has the complete system I'm looking for. The problem is, (which I've never received a clear response from the company itself), the exhaust I'm looking at is for a 76 model year and older. The style of the exhaust changed for the 77-78 model years. Would anybody know what the changes were on the bikes between those years? Did Honda change port size or angle of the engine? If it's only brackets... that's not much of an issue.

Thanks,
Steve78

[Re-run]

Other than modding the heads to take the 76 spigots, the pipes are the exact same spacing.
Also, why chuck the airbox? Are you looking to make it hard on yourself? Get the bike running right first, THEN chuck the box and proceed to curse for hours till you hopefully get the jetting right and every time a strong cross breeze comes and causes the bike to stumble.

Your bike but pods are very difficult to tune right and really have no performance gains over a good filter in the airbox. not on the street anyways.

[Steve78]

If I understand correctly, the ports are different? What about foot pegs? I know that they are higher on the pre-76's. Would that also change pipe placement? As per the air box, about a week after I purchased the bike I decided to do the big tune-up. you know, oil, plugs, filter etc. When it came to the air box I noticed that the previous owner seemed to of done some "repair" work with epoxy! When I tried to open the box to get to the filter, the bolts that held it together just spun freely in place...Yippy! Anyways, I needed to find a new air box, which was unsuccessful, at least around my part. That's when I came across these pods which ended up cheaper than the boxes I found online....also, they look neat. Once the jets are adjusted everything should be fine, no? What about changing jets? If I'm correct, you can purchase sleeves that fit over the pods to prevent wind distortion.

[Re-run]

The pod thing is common. If it is totally trashed I understand that but if the bolts just spin, ,no biggie. Just weld or even use an epoxy such as steel stick and put a larger nut on the bottom to allow you to tighten and loosen.

Now if you got K&N pods, they are ok but tuning is still a pain. If you got the cheap ones, most people end up giving up on those. I also have not seen any sleeves that go around pods. if someone has though, most likely they or someone they know made em.

Jetting is only part of the work. You have to remember with the 78, you have press in jets and while the fuel screws and accel pump are awesome, tuning is more than just chaning jets. You have to completely retune the idle mix.

The exhaust from all years is the some on the K bikes except the 69-76 used spigots on the engine to mount the pipes. You would need these. You also need to remove the exhaust bolts you currently have. the double nut method should do it. I am pretty sure all the K foot pegs are the same too. the F2/3 uses a different system that might cause issues.