Topic: 1980 honda cb650 custom carb jets

[weltzing]

hi, im having trouble with my carbs on my cb650 custom, and I've narrowed it down to the pilot jet being clogged. now this jet i believe is the one right next to the main jet, and is a pressed in jet since it is just a tube going into the carb body.  I need to know how to remove this jet without damaging it so i can clean it up!  thanks for any help!

[cb650]

I used a pair of vice grips with a rag.  Just enough pressure to get it to rotate and pull as rotating back and forth.

[weltzing]

alright that worked and yes they were clogged pretty badly. now everything is put back on and the right two pipes just dont get as hot as the other two as quickly? i dont have the air box on so that could be part of it and im waiting for pod filters to put on and probably will run better then.

[MJL]

IMHO the best things for a 1981 650 are a jet kit (http://www.dynojet.com/jetkits/motorcycle/honda.aspx) and removing the lid from the airbox if you have an aftermarket exhaust.

[Frankenkit]

the carbs from an '80 are pretty different from the carbs for an '81 though.

[dancaudill]

ive got a 1980 650 also..i fought that same problem for months ive used pods and never could get them to work right had alot of fuel problems with them...but honestly i fought the same 3 problems uneven exhaust temperatures,carbs overflowing and jetting problems for months before i finally went back to the stock airbox and replaced the coils and all of the problems went away and the bike runs like a new one now

[weltzing]

the only problems i was having was # 3, 4 carbs werent getting fuel into the cylinder thus they werent firing so the pipes werent getting hot. now that i cleaned the pilot jets my pipes do get hot bu # 4 doesnt get hot as fast so im wondering if i maybe have to adjust the air screw?

[weltzing]

ok so i cleaned the carbs and all the jets very well, i put the stock air box and filter back on and everything is all hooked up. the bike wont idle without the choke at least halfway out. all the pipes get hot with the choke on but it does alot of poping on the 3 and 4 cyclinders. im thinking the carbs need to be synced? Im hoping the vavles are seating correctly, idk what to do other than take it to a shop $$$      

[Frankenkit]

that's pretty common. I fire up my bike and let it idle with the choke half way out and nudge it back down very slowly, just to keep it at 2k or 1500.  Usually by the time I'm 1/4 mile down the road or so, I can totally put the choke knob all the way in.  

syncing these carbs does wonders, it will run much more smoothly. Another thing to bear in mind is that the air screws are actually mixture screws and will just give you more or less of the given air/fuel mixture instead of more or less air.

these PD50 carbs are very, very lean on the idle jet.

[MickeyX]

For the price (or less) of having them synch your carbs once, you can buy a synch tool, like the Morgantune, and do it yourself when ever you need to. It's not that hard. Even we figured it out.  

Most with the PD carbs on the cb650s never get it running right with pods. Replacement jets are almost nonexistent. As Kit said, there is no separate air screw. It's tied in with the fuel mix on these so when you adjust, you adjust both in the same direction equally. Thank you EPA rules and lean carbs.  

bench synch them until you get a synch tool, hook up a gas line to a bottle and get them even. you will notice a big difference.

Going to the K&N air filter helped with the lean situation on Kit's bike. Hondaman was the one to pass along that info.

Goodluck.
 

[weltzing]

ok so where do i hook up the line to sync each carb and what am i looking for when i sync them and what to adjust.....yeah this bike is soooo frustrating!

[MickeyX]

Kit probably has some pics from when she did hers. Same exact bike. They may be in her build thread. Search crabby old timer. No, I'm not kidding.  Anything and everything you never wanted to know about these bikes. If not, we can probably take some on the parts bike if you need it. Soos, Hush, Paulages and many others on here could talk you through it too. Everything is a "doohickey" to me so I'm no help on descriptions. 

[The_Crippler]

Going to the K&N air filter helped with the lean situation on Kit's bike.

Well, I'm glad to hear that.  Mine needed a new air filter when I got it, and K&N happened to be having a sale at the time.  Haven't run the bike much, but hopefully it will head some problems off at the past.

As for syncing tools, I see them fairly inexpensively on Ebay pretty often.  Also, Harbor Freight has been known to stock them as well.  (I've also seen people make them with several soda bottles.)