1981 CB650C Carbs

If it's broken or just needs tweaked

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Europamarc673
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Joined: Mon Sep 25, 2017 2:31 pm
Location: Santa Fe, NM, USA
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1981 CB650C Carbs

Postby Europamarc673 » Mon Sep 25, 2017 7:37 pm

Hi there,
This subject might have been discussed already but here I go again: Was given a free bike 1981 CB650C without carbs. Trying to make it a track bike for our rent-to-race program.
I put a set of Keihin V357-DF07 carbs on that I had laying around in the shop. Starts, idles but won't get past 1/2 throttle without sputtering. Played with different jets (110, 125, 130 mains) and needle positions. No change. It has some sort of "open" 4 into 1 exhaust on it and pod airfilter. Took the carbs several times apart to clean and inspect. Changed spark plugs, replaced both CDI boxes.
Unfortunately there are no OEM Honda carbs for this bike anywhere. Original parts number 16100-460-771.
Any chance that someone here figured this issue out? Could it be the ignition trigger which is also NLA 30300-426-154

Thank you,


Marc Beyer
OCD Custom Cycles and Auto Repair LLC
Kraut Racing
Santa Fe, NM
Marc Beyer
OCD Custom Cycles and Auto Repair LLC
Kraut Racing
Santa Fe, NM

'59 R50
'70 R75/5 AHRMA Racer #673
'00 KTM 640 LC4
'01 R1100S

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Folsoml
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Re: 1981 CB650C Carbs

Postby Folsoml » Tue Sep 26, 2017 4:50 am

Welcome to the forum! I wish I had a suggestion for you. :(
Have a problem with your CB650? Have a technical question? Click here!


My Current Bikes: 2005 HD FLHTCUI Electra Glide Ultra Classic, 2007 Yamaha Vino,

cb650
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Re: 1981 CB650C Carbs

Postby cb650 » Tue Sep 26, 2017 4:56 am

did you check the gap on the ignition pick ups?
Did you clean the tank out?!?!?!?!

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GeorgeSweety
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Location: UK.

Re: 1981 CB650C Carbs

Postby GeorgeSweety » Tue Sep 26, 2017 4:59 am

Hi Europamarc, have you removed and cleaned the auto advancer from behind the ignition pulser plate? right hand side of the engine behind the round cover? Relatively simple job, you will have to disassemble it to clean it properly. It will require lubricating with a high melting point grease, just make sure that it is really free moving before assembling.

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GeorgeSweety
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Location: UK.

Re: 1981 CB650C Carbs

Postby GeorgeSweety » Tue Sep 26, 2017 5:12 am

Hi again, I googled that part number and they appear to be VB44 carbs, you should have no problem finding a set on ebay. It might be a good idea to measure the distance between your inlets before you buy a set though, just in case your bike was fitted with an earlier engine, if it was they won't fit the head.

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GeorgeSweety
Posts: 323
Joined: Tue Aug 08, 2017 11:47 am
Location: UK.

Re: 1981 CB650C Carbs

Postby GeorgeSweety » Tue Sep 26, 2017 8:07 am

https://www.ebay.co.uk/p/Genuine-Honda- ... 2015716352

But it ain't cheap :shock: The thing is I don't think it is your pulse generator as the bike runs, my money is on your auto advance behind it :wink:


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