f#^€!ing bike won't idle (CARB EXPERTS LOOK AT PHOTOS)

[alexmac]

I took out the carbs today. This is what I found

They didn't really look that dirty but I opened them up.

They have been opened recently by the looks of it the metal has the patina of carbs boiled in lemon juice.
This one the o-ring was not installed properly... there is a break in the o-ring and also this gray sticky melted crap
on the float bowl.

This is the difference between the 2 floats. The one on the left is from the one with the damaged o-ring. It also has
a big dent in one of the float halves. The other float looks new.

This is what it looks like underneath the float area. The 2 brass things are the jets. They have a slot that retains the black
clip. I can't remove the jets! There is supposed to be a slot for a screwdriver to screw them out... but there isn't!

This is the carb that had the good o-ring. Looks good as new. ... but I can't unscrew the jets either

It appears to me that the jets were installed upside down. I am not sure so I posted this for you guys to look at.

I didn't want to fuck with it anymore before I had an expert opinion.

I went on to take off the tops. This is the bad carb. The slide is a little grungy but the rubber part is perfect.

This is from the good carb. Also looks like new. It was gassy and wet when I opened it. (the other was dry)

I decided to take a break for coffee before I attempt the jets again. What do you think?

 

[crazypj]

Those jets don't unscrew, they pull straight out. Don't break the spring thing, they are unobtainable.
Pilot jet is under rubber plug, that does screw out

 

[alexmac]

Thanks PJ.

The YouTube vids I watched showed them being removed with a screwdriver. Different model Keihins I guess.

Does the damaged float look useable? Or does it need replacement ?

 

[crazypj]

I've seen worse being used without problems, may need extra 1mm on float height?
I tend to go extra 2mm with pods anyway ;D

 

[alexmac]

No pods on this bike. I'm stock air box only here.
I might order a new float anyway. The weather is so shitty here... the bikes in the garage anyways for awhile.

 

[whataulooknat]

Float should be useable. just make sure it doesn't leak or else you'll have a sinking float. Been there before it's a real headache if you dont realize what it is.

 

[trek97]

I understand I am a little late to this game now. but here is a list I made up, and posted on my blog of things to check before starting carb adjustment. The tech specs part is for the cb360...So, they may not be correct for your 350. double check your manual.

Getting ready to tune Keihins 754 on the 76 Honda cb360

Carbs can not be clean enough, clean them. Clean tank and fuel tap. Gas cap venting properly?
1 are your carb diaphragms good?
2 do you have the original stock Keihin air/fuel adjustment needle springs installed (BEST) OR Did you file sharp edges off new carb rebuild kit air / fuel adjuster springs ? link to more info on my blog.
http://www.hondabrat.com/2012/05/kehein-754-carbsso-close.html
3 Do you have in line fuel filters or screens on fuel tap? clean tank ? vented gas cap?
4 Do you have good stock coils or new coils ? good condenser ?
5 Good plugs set proper gap (.7 - .8 mm), NGK B8ES, (NOT NGK BR8ES) and 5 or 10 ohm plug caps ? I have 10 ohm (pjs recommendation w stock coils) works great.
6 Timing set properly w timing light ? good points ? properly adjusted .3 - .4 mm gap
7 cam chain adjusted properly ? trap crank w wrench while setting cam adjustment bolt.
8 Valves adjusted properly?
9 Rubber carb insulator boots and gaskets in good shape (no cracks or leaks). Best price I found for New boots and gaskets is my local Honda shop.
10 carbs properly synchronized w gauges?
11 throttle cables properly adjusted and lubricated?
12 Ensure fuel lines/filters do not contact engine, engine mounts or frame.
13 make sure carbs are level to engine.
14 Tank or tap not getting hot. From what Ive read online, the boiling point of most gasolines is 90 - 400 degrees F
Is there anything else forgot ?

It would take a big day to check all this...but it would only take a day. and its a great place to be sitting when getting started on carbs. Because if something is not right it can produce false plug readings.

 

[redwillissuperman]

Could have verified the float height before pulling it apart but....things look rather "new" in there. Since its extremely gassy but the fuel bowls don't look to have been overflowing, I would tend to think they are set in the realm of "OK".

I have a few suggestions:

- spark plug leads on backwards or ends not terminated correctly
- timing way out of whack- like the chain jump some teeth or the previous owner set it 90deg out
- Gas cap not venting and building pressure when you take it out in the sun from the garage
- bad battery or no cover so the seat is contacting the positive terminal

 

[crazypj]

What numbers are stamped on the jets? (you did get them out OK?)
They could have been drilled or reamed during a previous 'cleaning', it may be better to replace them?
Set float height to max number in service manual

 

[alexmac]

What numbers are stamped on the jets? (you did get them out OK?)
They could have been drilled or reamed during a previous 'cleaning', it may be better to replace them?
Set float height to max number in service manual

I got em out ok. I have new jets that are factory spec for these carbs. I am not going to mess with reusing anything that I pulled out. I got the Keyster top dollar kits. They have everything. Excellent quality. I got a brand new float bowl from CMNL.COM. today... to replace the one with the busted brass piece. Brand new....still has that weird zinc shine on it.... in the factory box.

I am just waiting on my float gauge to arrive by mail.

 

[alexmac]

What numbers are stamped on the jets? (you did get them out OK?)
They could have been drilled or reamed during a previous 'cleaning', it may be better to replace them?
Set float height to max number in service manual

When I remount my carbs and hook up the throttle cables: A question.

Is there an easier way of hooking up the cables without trying to get a wrench in there from the side of the bike? That's how I took them off. It wasnt easy.

Is it easier to do if you take off the tank? I am concerned about making them open at same time when the throttle is twisted.

 

[crazypj]

Remove tank, it always makes life easier
I'm pretty sure you can fit cables before fitting carbs, you can check throttle plates and the choke link slides in

 

[alexmac]

new float bowl !