Topic: CB750 K6 086A Carb Rack Shaft Sticks

[CycleRanger]

I knew my K5 had some K1 parts on it, like the side covers, but I didn't realize the stay plate had been changed since the carbs were 657B's.
I guess I lucked out when I got a replacement for parts because it had the set screw as well.

Which side is your idle screw on?

It's on the right but it could go on the left as well. That may be a consequence of swapping parts.
I also notice now that the slides are stuck.    It's been sitting for a while because it needs the pucks replaced. Oh well.
Too many projects.

[newday777]

I knew my K5 had some K1 parts on it, like the side covers, but I didn't realize the stay plate had been changed since the carbs were 657B's.
I guess I lucked out when I got a replacement for parts because it had the set screw as well.

Which side is your idle screw on?

It's on the right but it could go on the left as well. That may be a consequence of swapping parts.
I also notice now that the slides are stuck.    It's been sitting for a while because it needs the pucks replaced. Oh well.
Too many projects.

Thanks
What's the manufacture date of your K5?
My K5 is 7/74, so an early K5 and it came with 657B w/left side only idle screw rack.

[CycleRanger]

I knew my K5 had some K1 parts on it, like the side covers, but I didn't realize the stay plate had been changed since the carbs were 657B's.
I guess I lucked out when I got a replacement for parts because it had the set screw as well.

Which side is your idle screw on?

It's on the right but it could go on the left as well. That may be a consequence of swapping parts.
I also notice now that the slides are stuck.    It's been sitting for a while because it needs the pucks replaced. Oh well.
Too many projects.

Thanks
What's the manufacture date of your K5?
My K5 is 7/74, so an early K5 and it came with 657B w/left side only idle screw rack.

Mine is 12/74.

[newday777]

I knew my K5 had some K1 parts on it, like the side covers, but I didn't realize the stay plate had been changed since the carbs were 657B's.
I guess I lucked out when I got a replacement for parts because it had the set screw as well.

Which side is your idle screw on?

It's on the right but it could go on the left as well. That may be a consequence of swapping parts.
I also notice now that the slides are stuck.    It's been sitting for a while because it needs the pucks replaced. Oh well.
Too many projects.

Thanks
What's the manufacture date of your K5?
My K5 is 7/74, so an early K5 and it came with 657B w/left side only idle screw rack.

Mine is 12/74.

👍
As both of my friends who were the original and second owner have passed, I can't verify if my 657B carbs are original to my K5.

[seanbarney41]

I have seen racks that have a cast in boss for the idle screw to be in either side, but only one side was drilled and tapped.  I don't remember what model 750 or carb casting number

Just thinking it might be easy to just drill and tap in certain carb swap situations.

[HondaMan]

Well I set up my 1/16" drill bit in the drill press, did a center punch mark in the center of the locator pin and slowly drill it, and watched it walk on me on an angle away from the pin center....Arg. Chucked in a 7/32" bit(smaller than 3mm pin size), put a wedge under the rack to try to get it to center, nope...it went at an angle also....ophhh. I'm thinking, now what??? We'll it didn't clear out the pin, but it did free up the action a bit. So I squirted in some LPS-1 greaseless lubricant(Mark's fix for corrosion in electrical connectors!) in the hole hoping that it would get in the groove and help. Yes it did! So I squirted more into the bearing surfaces on either side of the rack rod boss and worked it back and forth a bunch. I'm going to find a small set screw to fit in there to strengthen the remaining section of the pin, cap it and call it a win!
So thanks for all the replies and suggestions to get it freed up. Thankfully, I didn't have to try and remove the throttle rod to go further with it.

Great save!
As Honda kept building the 750 and the margin got smaller (thanks largely to the Kawi 900 in those days) Honda kept pressing their vendors for lower prices. Having worked at building machinery for the Japanese between 1991 and 2005, this became a familiar pattern there, too. The vendors responded by installing pins instead of drilling/tapping/custom setscrews, among other things. You can "see" this all across each type of these bikes (750, 500, 550, etc.) when you work on all of them.

But, the pressed-pin racks, grrr...I think I have 2 of those in the "if I have to use them" box in the shed. My plan on that day would start with a MAPP gas torch on the pin's site, followed by freeze spray (or a douse in cold water) several times to see if the pin would work loose. The casting moves a lot more than the steel, which was why Honda didn't like pinned things, usually. I guess the combination of Yen supply, new 'hotshot' young engineers, and increasing competition pushed the production managers to pin some of the racks.

...end of rant...

[newday777]

Thanks all. And yes Mark I was a bit dismayed when the bit wandered in the drill press, but joy returned when it loosened it's grip. I still haven't gotten around to getting a set screw in it, the four letter word keeps me out of the shop......have to be able to pay to get to play....

[HondaMan]

Thanks all. And yes Mark I was a bit dismayed when the bit wandered in the drill press, but joy returned when it loosened it's grip. I still haven't gotten around to getting a set screw in it, the four letter word keeps me out of the shop......have to be able to pay to get to play....

I have a lathe and could turn down the end of a screw to make it a shaft-point, if you want to change it over? When I get a time to do something like that, I'll probably make 3 of them for the 2 in my shed, and any others out there.

[newday777]

Thanks all. And yes Mark I was a bit dismayed when the bit wandered in the drill press, but joy returned when it loosened it's grip. I still haven't gotten around to getting a set screw in it, the four letter word keeps me out of the shop......have to be able to pay to get to play....

I have a lathe and could turn down the end of a screw to make it a shaft-point, if you want to change it over? When I get a time to do something like that, I'll probably make 3 of them for the 2 in my shed, and any others out there.

Thanks but there is still enough meat in the pin holding the assembly that I think all it needs is a short set screw to hold what is left solid.