HondaCB650

Hi guys...
I was cleaning my carbs this weekend and noticed Both T air vents broke off...I am not sure what to do now...

Should I replace with new one which I think its going to be a pain since it appears you need to remove the carbs from the rack... Or should I leave as is???

I am not sure of the consequence if any if leaving it as is though.

Any suggestions are appreciated...!

Bike: 1982 CB650sc
Carb: VB44A

Typically cracked T-vents cause trouble up to leaking carbs and not running correctly although their definite function is not that clear.
May be replaced by aquarium stuff as they are available but very expensive at Honda.

You'll need to separate the carbs which typically implies also replacement of the small O-rings of the short connection tubes between the carbs.

Volker_P wrote:Typically cracked T-vents cause trouble up to leaking carbs and not running correctly although their definite function is not that clear.
May be replaced by aquarium stuff as they are available but very expensive at Honda.

You'll need to separate the carbs which typically implies also replacement of the small O-rings of the short connection tubes between the carbs.

Thanks Volker...
I have read mixed feedback in the forums on riders not replacing the "T" vents and how the bike runs just fine...and a few other have had issues by not having the "T" back in place.

I will try running them first as is (without the "T") as it is easier to do first...if that fails I shall separate the carbs.

How hard is the separation process? Is there an easy process I can follow on how to do so other than following the Honda Manual?

My Honda Manual (Clymer) says DO NOT DO IT
I did it twice already and carburetors are doing well. Foundation for me is a set of good screwdrivers.Screws are easily damaged and a little WD40 helps to loosen them a bit.To install new T fittings you do not have separate carburetor in the middle, at least I did not do.Need to unscrew the choke plate of the carburetor 1 and 4 and then spread them enough to do the job.

bolo79 wrote:To install new T fittings you do not have separate carburetor in the middle, at least I did not do.Need to unscrew the choke plate of the carburetor 1 and 4 and then spread them enough to do the job.

I am having trouble imagining how this is done without separating the carbs... Do you first loosen them from the rack then spread them?

I think the point of bolo79 is that you have to separate 1 from 2 and 4 from 3 but not 2 from 3, which at least avoids the fight with the choke cam spring mechanism.
Don't forget to use something to fix the throttle and choke flap bolts reliably as you won't like to have them and the flaps sucked into the engine!

Volker_P wrote:I think the point of bolo79 is that you have to separate 1 from 2 and 4 from 3 but not 2 from 3, which at least avoids the fight with the choke cam spring mechanism.
Don't forget to use something to fix the throttle and choke flap bolts reliably as you won't like to have them and the flaps sucked into the engine!

Thanks for clarifying Volker... that makes more sense now and much easier to do than separating all of the carbs. The cheapest I can find those "T" vents are $35/each X 2 = $70... Ouch!!!

Any other parts than the "T" vents I should replace since I'm in there already...? If I use bolo79 method do I need to change the small O-rings (connection tube) out?

I am waiting on my OEM Service Manual to arrive...The previouse PO gave me the Haynes Book but its light on the the CV carbs tear down process.

I broke my t vents as well but the bike seems to run fine with out them. I did not want to take my carbs apart like you =). only bad thing i can think of is maybe carbs flood for some reason and set your bike on fire =)

Volker_P wrote:You'll need to separate the carbs which typically implies also replacement of the small O-rings of the short connection tubes between the carbs.

I went ahead and ordered the "T" vents from Honda...however I am having trouble locating the smal O-Rings of the short connection tubes you mention above...

I looked up a Honda parts schematic (Part labeled #1 is the O-Rings in RED Circle) but it appears they only come in a KIT??? Is that correct?? I hope not.

http://www.powersportsplus.com/parts/se ... parts.html

New T-vents total luxury

Volker_P wrote: the small O-rings of the short connection tubes between the carbs.

TicoCafe wrote:I looked up a Honda parts schematic (Part labeled #1 is the O-Rings in RED Circle) but it appears they only come in a KIT??? Is that correct??

unfortunately you're right but you can always look for a replacement in the auto store.Maybe you can find something similar to the original,will definitely cheaper.

Here is an online manual for the 1981CV carbs. http://www.scribd.com/doc/48739487/additif-1981
BTW, the site appears quite strange (not only in my browser), I solved it by a complete download and then watch the pictures offline.

Volker...i would say 90% of the questions asked on here is about carbs ...it would be a lot of work but you ought to set up a carb tab on the index page...so ALL the flow of carb question and facts can go there! beside what happens if your not around to direct to what exact page to go to...we would all be lost

I'd say there is more than the remaining 10% for charging alone, too.
However I am just a mod which means I can clean up messages but may not change the structure of the forum. One has to convince the admin (Tidd650) for things like that. However threads starting as carb problems often turn into ignition threads and vice versa, so I am not that convinced.

In the link section, always on top, there is an internal technical links thread where you find the most important threads I usually refer to for repeated questions.

Beyond that, when I am offline, you guys may learn something for life: how to use the search function!
Guess this is about half of my job here.

Got the replacements "T" in the mail...got them installed with no major Fuss.
I did find the O-rings for the small Tubes between carbs..the dealer was nice too luck through other non-Honda parts and found some that matched. And I did a quick/small polish job on the Tops.

Next will be the Bench Sync.

Is there a carb exhibition somewhere? Really impressing cleaning work!