Topic: Confused about my CB900F carbs?

[eofa]

Decided to take apart my carbs for a good cleaning and pine-sol bath. I've noticed this wire before but whilst taking the carbs apart I took it off. The choke shaft looks really bent up. I'm confused at what the prior knucklehead owner did or was trying to do? Anyone have any ideas? I have a youtube video of me moving the choke at the bottom of this post.

What the heck is that brass wire for?










Red line is what I think the choke cable should be. Am I correct?




Anyone have any suggestions or is this busted or something?

youtube.com/watch?v=Ry5vfMsP3Rc

[eofa]

Anyone have some close up pics of what your choke linkage looks like? Can't find anything that close in manuals or the interweb.

[Really?]

I do not know how many people will be very familiar with those carbs here because this is a SOHC forum.  Mainly for the 69-78 models.  I do not have a suggestion for a DOHC (what you have) forum but hopefully someone might have a clue here for you.  I am not one of them. 

[Bob Wessner]

Do you have a manual for the bike? If not, there are some around the net for download. It might have better pics, description of the carbs, etc.

[eofa]

Yes I have a manual and have downloaded many other docs. I think I figured it out though... I'm missing a relief spring. The knuckledhead owner before me, used the wire to replicated the spring. Now I gotta find a spring.....ugh.

[grcamna2]

Welcome to the forum eofa. It looks to me like a PO snapped off the "ball" end of his old choke cable and then attempted to use that piece of wire to "Mcgyver" a quick fix to it.That would be OK just to get you home...,but I imagine he left it on there.The red line toward the end of you're posted pictures is the correct way for the new choke cable to be attached,from the top & through the open slot & pulled toward the front of the carbs. and then attached w/ the little screwed down clamp to the metal end of the cable outer housing.

[ThomasD883]

I know exactly what thats for. On the cb650 c with the cv carbs it has the exact same choke linkage setup. The PO butchered up the spring that linked the two halves together and i had to do a similar repair to lock them in. I haven't really taken the time to find a more permanent fix , the OEM style was a small wire spring wound around the left half that pulled on the right half. Good luck with those !

[Really?]

YaY, the clued ones jumped in!

[eofa]

Thanks for the replies so far. Trying to find this spring is going to be a pain in the arse. Gonna try to find something at a hardware store and try rigging something better.

[Really?]

FOund these two 750F DOHC build threads.  They might be helpful to you.

http://forums.sohc4.net/index.php?topic=104687.0
http://forums.sohc4.net/index.php?topic=104584.0

[Magpie]

Your 3'rd picture down shows where the spring is missing, right in the middle. As Thomas says the spring joins the chokes from carbs 1-2 to 3-4. The po just wired them together. I have no idea where to get that spring but there has to be a more elegant solution that what's there. Here's some pics for you. I can email some larger resolution pics if you like. Hope this helps. Cliff.

[grcamna2]

OK..now I can see it better also. Got it 

[eofa]

Magpie, awesome pics. Thank you that helps out so much. Now to use some skills to modify a spring I can find at the hardware store.

[Magpie]

Check this out too. http://www.cb750c.com/publicdocs/SeanG/Honda_Carb_Manual_revE.pdf  It's a fantastic manual on your/my carbs. Cliff.

[eofa]

That's awesome! Great document.

[ThomasD883]

Please post pics with detail when you do the repair, I will be following suit . Can you post more pics of the carbs, I'd like to see if the 900f are close to the 650. Maybe bolt on some horsepower ,thanks!

[eofa]

I will start taking more pics tonight. Starting with rinsing the pine-sol off them.

Found a guy on another forum who said he has the spring I need! Gonna meet up with him this weekend. YAY!

[cb650]

YaY, the clued ones jumped in!

And the clueless  LOL 

[grcamna2]

I will start taking more pics tonight. Starting with rinsing the pine-sol off them.

Found a guy on another forum who said he has the spring I need! Gonna meet up with him this weekend. YAY!

That is Great News  It'll beat having to make do with any other one !

[eofa]

While I wait to meet up with fellow forum member from cb1100f.net for a choke tension spring, I've cleaned the carbs in pine-sol. I'm amazed at how well it did. Although it did leave some chalky residue but nothing a toothbrush can remedy. I posted pics of the results here: http://www.cb1100f.net/modules.php?name=Forums&file=viewtopic&t=62569&highlight=

So my issues has been a tension spring that moves both pairs of carb flaps. As I pulled out the choke rod I found a little chunk of the missing broken wire:





Getting the spring this weekend and getting this thing back together.

Here's some pics of the clean carbs.

[mrrch]

750 PD carbs use the same type of spring on the choke linkage to join at the middle.

[grcamna2]

You've got them Shining better than New..Happy Easter eofa ! It's good to know a product that's SO readily available will do that nice of a job.I've used Simple Green on different things over the years and it leaves a nice Shine on everything after done...I wonder if I do the Pinesol cleaning on my Carbs and then finish up w/ Simple Green how that would work ?

[eofa]

Ok. I'll post some more. Here's the latest.

I've been having a huge issue with my carbs. Giving it a little throttle, in neutral of course, it revs fine and back down. Give it more throttle and it continues to rev up resulting in me having to shut the bike off. Wait a few seconds, then start it back up... back to idle fine. Mind you it's not sticking or hanging, it's reving up and doesn't stop increasing until I have to shut the bike completely down.

Here's some background.

- New push/pull cables, lubed up, routed properly with no kinks. Cables even have some slack. Throttle snaps back after release with no hangups or snags.
- New OEM throttle assembly
- Took apart carbs for a good cleaning
- Cleaned all jets and openings everywhere
- No air leaks in manifolds, I tested that already
- Idle is stable and carbs have been sync'd
- Main jet is a 110 and secondary is a 68. Previous owner had a big bore kit done to it.
- I'm also running pods and not the stock airbox. (Please... those of you who hate the pods... I don't need the comments. Not very helpful.)
- pilots, lightly screwed in, then unscrewed 2 1/2 turns.

Then only thing I can think of right now is that it's the diaphram in the accelerator pump. Or maybe because it's missing the little rubber bellows? I know some of you will say.... "It's running too lean..." Yeah I get that, but should I try getting a 120, 130 or 140 jet? Maybe just shim up the needle with some washers?

Anyone have any ideas?

[mrrch]

Maybe try with the pods off and see what the vacuum slides are actually doing (staying up or returning down)

[eofa]

Maybe try with the pods off and see what the vacuum slides are actually doing (staying up or returning down)

Wow... I'm an idiot. Why didn't I think of that? Great idea. I learned something new today!