Topic: Cb650 high idle

[DaveBarbier]

Is it worth tryin to pull out these jets to clean them or will it just ruin them? I may just get a set of 82 carbs and go from there instead

If you're going to get a rack of carbs with the removable jets anyway you can try to remove the ones you have and see how clean they are. In my pressed in pilot jets in my 550k I had to remove them to get them really clean. I then soaked the jets in carb cleaner for a few hours and used a tiny copper wire to get all the crud out. Careful though, maybe soak the area in PB Blaster for a bit. You need to grab strong with pliers but if you use vice grips you risk collapsing the jet.

In that post I sent you earlier there's a link to a site where a guy shows how to convert the press type into a threaded type...if you're so inclined.


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1978 Honda CB550K

[70CB750]

The suspense is killing me, cant wait when you finally find the problem   

[Davecb650c]

Yeah ill try pulling them, unfortunately on the 81 cv style carbs the jets are wayyy down in that tube so it looks like getting them out is a major pain.. Guess ill try it, and it works, great, if not ill slap the 82s on there and give that a try
 

The suspense is killing me, cant wait when you finally find the problem   

You and me both! I'm really itchin to ride it!

[Davecb650c]

Ok so I still haven't had any luck with these carbs, ordered a set from an 82 off ebay and the spacing is all wrong, and they're larger in general. I think they must be off of a 750 or something. Can anybody verify? I'm gonna contact the seller I guess unless anyone on here has any interest in them

[trueblue]

What is the number on the side of the carb?  Should be VB-XX if memory serves correctly.  Definitely not SOHC 650, could be off an '83 DOHC 650 or 750. 

[Davecb650c]

They are 750 carbs, I contacted the seller he said he had a couple sets of them for 650s and 750s and mixed it up so he's sending the right set to me

[cb650]

What is the number on the side of the carb?  Should be VB-XX if memory serves correctly.  Definitely not SOHC 650, could be off an '83 DOHC 650 or 750. 

The 83 dohc went back to a diaphragm style.  No big domes for the "piston".  And yes the spacing is off.

[trueblue]

What is the number on the side of the carb?  Should be VB-XX if memory serves correctly.  Definitely not SOHC 650, could be off an '83 DOHC 650 or 750. 

The 83 dohc went back to a diaphragm style.  No big domes for the "piston".  And yes the spacing is off.

Fair enough, I haven't had anything to do with the DOHC models, I was only throwing it out there 

[Davecb650c]

Well I got the right carbs on there and that seems to have fixed the problem! I set the idle at a little over 1000 an it seems to run good at idle now. I rode it down my road and back and it seems to run decent but it has a bog if I go wot from about 1/4 throttle suddenly, but it revs smoothly if I gradually open it up. I don't currently have an air box or anything on it so ill have to get that all squared away before I screw with it much more. Thanks for all the help!

[DaveBarbier]

Good to hear. I hope my idle issue is as easily resolved. Having to tune the carbs seems normal considering your setup. Get it dialed in and hopefully you'll be good as gold.


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1978 Honda CB550K

[Davecb650c]

Just an update, thing runs like a top! Got new tires, chain and bars and she looks pretty good. Thanks for the help everyone!

[juntjoo]

hey so you never resolved the issue with the original carbs?  have the exact same problem but I'll be damned if I gotta get a new set of carbs. I've got the 82's with the removable slow jets and all mine are clear. Exact same idle issue.

[juntjoo]

I got it, it's the fast speed idle linkage, the one bendable arm, if adjusted too close to the throttle it will open it too much.