Topic: 77 cb750k project, help please?

[Inkscars]

Hey guys i have a few quick questions for you on my recently purchased project.
As I have posted, I need some help.
For grins, when I got it home we tried firing it up. Had some oil in it, no corrosion or anything on any cables or linkage, gas tank was drained previous to storage. All that Jazz. I used some sea foam and clean fuel to give the inside of the tank a good rinsing (it was in pretty good shape) and drained all of it out. Fuel was coming out fairly clean. So, new battery, some clean gas and gave it a couple kicks. Nothing. So, I pulled the petcock and inspected it to find that fuel would not come out on reserve, only in on position. Ok no biggie, I'm not looking to ride the thing tomorrow. So i figure, check for spark. I grab a new plug, load it into 4's wire and kick it. Barely any spark at all. Pulled the points cover and found the one on the right side rusted. Due to the lack of any emery or sandpaper I used an old toothbrush and a business card and got it shiny. Kicked it, spark was better but not "strong". Just then I realized fuel draining out of the overflow. No biggie. I need to go through the carbs anyway, it's been stored for 12 years and not started for 7 of those. So after some .....persuasion and some bleeding cuticles i got the carbs of and found that the primary rod that is controlled by the throttle "wheel" wont budge. I've been soaking it and cleaning it for two days while I am waiting for these gaskets to arrive. Well, anyway, I'm waiting on my manual as well, I'm not a motorcycle guru, as I stated when i first joined, this is my first serious project.
Any tips on how to free that rod up? Also I had some trouble locating carb parts for my 77. I was told it was a "weird year" So, any help in directing me towards where to purchase these online for possible less than an arm and a leg would be greatly appreciated.
Thanks ahead of time!

[Gordon]

It may be that the carb slides are gummed up and stuck inside their bores, preventing the throttle assembly from turning. 

[Burke]

Could you move the throttle when the carbs were on the bike?
I am going to guess that the slides are stuck. I take the tops off and shoot some carb cleaner in there and work with them and this usually breaks them free.
The spring on there is pretty stout, so moving the "wheel" by hand is hard but possible.

[tinyrobot]

There is a manual floating around here you can print out for the 77-78 cb750k and F.  It will have all the maintenance and troubleshooting for you to help.

[bunghole]

I'm in the same boat in that I haven't been able to find carb kits for my '77.  If anyone has a source, I would be very grateful.

[tinyrobot]

Honda still has most of the parts you need to refresh the carbs.  Fitment is way better than any of the Keyster kits out there.

ServiceHonda.com works well for me.

[bunghole]

Since they don't sell it in a kit, can anyone tell me what parts I'll need so that I can order all at once?

[mustangcar]

start by ordering four packages from honda #16010-405-004 gasket kits,, i used the original float /valves ,they seemed ok for now.,pull out the slow jets out with pliers clean with a bristle wire from a steel brush,or order new from sirius consolidated (spelling?)that company has them on ebay sometimes,look under slow jets 750,i shimmed my needles on the k8,also ive done what others probably have never done,, due to a mishap i had to learn how to tap out the accelerator squirters cleaned out the tiny tiny hole on each with the same bristle wire method,they squirt beautiful now lol,,its a bit tricky getting them out i don't reccomend you try it unless you have a spare carb for practice, they'll probably clean themselves out by using the accel pump rod pressure and soaking?,i'm sure they are plugged up after sitting,good luck if you dissaemble the whole carb rack assembly,, take lots of pics

[cdwicks]

Sirius Consolidated has a lot of parts, too.  I wouldn't consider it a weird year necessarily.  However, if you have trouble finding parts for a 77 just get parts for a 78, they are the exact same.  Hope this helps.

cdwicks

[Inkscars]

It may be that the carb slides are gummed up and stuck inside their bores, preventing the throttle assembly from turning. 

Yes the slide are stuck. It appears that one carburetor is "fixed" and the others follow suit. The free ones seem to be willing to move, the fixed one does not want to pivot. I thought we had a carburetor dip tank here, but i guess not. I've been using PB blaster and lots of time, I just wasn't sure if there was a better method.

[Inkscars]

Could you move the throttle when the carbs were on the bike?
I am going to guess that the slides are stuck. I take the tops off and shoot some carb cleaner in there and work with them and this usually breaks them free.
The spring on there is pretty stout, so moving the "wheel" by hand is hard but possible.

No actually, the cable was stretched due to the position that it was stuck in. I didn't realize that until i went to take the carbs off though. Call me a novice. lol

[Inkscars]

Thank you guys for the parts resources. I must've called 5 places in town and all of them pretty much laughed at me. Ugh. I've got most of it apart now. I will take pics. Someone has been through them before. I noticed a couple of the bowl gaskets had silicone in them. A very very tedious process scraping that all off. haha

[TwoTired]

If the slides are still stuck, use a heat gun or maybe even a hair dryer to heat the carb bodies.  That usually frees stuck slides.

Cheers,

[Inkscars]

If the slides are still stuck, use a heat gun or maybe even a hair dryer to heat the carb bodies.  That usually frees stuck slides.

Cheers,

Thanks very much! I think I can handle locating a hair dryer! haha. I had actually thought of heating them but wasn't sure of how hot would be "hot enough". I'll try it and see where I can get..

[Inkscars]

Thanks very much for the advise on the heat! Worked very well, some pb blaster and about 10 minutes of heat did it. Our parts washer isn't working and someone "misplaced" our carb tank so I'm not sure how i'm gonna soak it.. ugh. One after the other right? haha