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Discussion Starter #1
Hey everyone, I purchased this bike about a month and a half ago and finally got it running after tearing the carbs apart twice. During my second teardown, I noticed that there were no springs, and only one washer (out of 4) for the pilot jets on all 4 carburetors. I tuned the pilots the best I could, referring to my Clymer manual. The motorcycle will run with the choke engaged, and at high rpm's, but will not idle. I plan on putting these springs in the carbs, but could there be another problem as to why it won't idle? I cleaned the carbs pretty thoroughly...
Any ideas or suggestions are appreciated!!
 

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If the bikes have been sitting for awhile replace the needle valves. they are neoprene on that cb and if you take them out and look at then it will look like a faint ring around them, that's all it takes for them to blow by... cheap fix!
 

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Discussion Starter #3
Thanks BadDog, I will look into that. I inspected them before, and the neoprene tips all looked okay, but there were some rings around them- from varnish I'm guessing? Also, could i somehow get the rings off with a dremel tool with a fairly soft tip? I understand it's a cheap fix, but I'm even cheaper :) if not, then i'll have to spring for new ones. Thanks again
 

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Thanks BadDog, I will look into that. I inspected them before, and the neoprene tips all looked okay, but there were some rings around them- from varnish I'm guessing? Also, could i somehow get the rings off with a dremel tool with a fairly soft tip? I understand it's a cheap fix, but I'm even cheaper :) if not, then i'll have to spring for new ones. Thanks again
Actually those faint rings are a slight indent in the tip of the needle.. I seriously doubt if you could polish them to work for you but then again I never tried to... I guess you really have nothing to lose but be real careful you could probably do more harm than good.


:71baldboy:
 

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Discussion Starter #6
well, i looked into getting some new nedle valves, and they were like $25.00 a piece. I think when I take the carbs apart again, I'll have to buy a carb kit as well, cause the other day my bike was leaking fuel from the carbs. :( Oh well, I guess you can only reuse the old ones so many times!!!
 

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Angel's Realm Where Evil Fears To Tread
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If it only runs with the choke on the low speed or idle jets are clogged you need to clean them out they are 3 very very tiny holes in the carb throat I believe they connect to the plastic pcs in side the carbs. I still have all the old plastic parts from my carbs but the pcs I am referring may or may not be in good condition I know bike bandit sells a rebuild kit that includes the plastic parts, needles and all rubber parts l think the springs might be it it as well. for around 20 bucks each.

I have some pics but will have to locate them of what I am talking about.
I had the same problem with my bike it would only idal with the choke on after I ran a tiny wire through the ports it worked with out the choke.
 

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Discussion Starter #8
Just today, i ran some echron carb and fuel injector cleaner through it, but still no change. I guess I am gonna have to pull the carbs apart again. Archangel, are the jets you're talking about part of the top end of the carb or the lower end? Just trying to get feel on where you're talking about. Thanks for the input.
 

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Angel's Realm Where Evil Fears To Tread
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the slow jet is in the top of the float Bowl area on the carb but the ports I am talking about are in the round opening where the Choke is in the middle of the carb area there is 3 very small holes in a triangle shape like this.


. .
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There may even be a 4th hole I can not remember but the one that I am talking ends up going in to the area under neath the Carb top cover under the spring, needle,Vacuum cylinder

Here is a part list of the carbs check out part # 1 the one below # 17
#1 is the complete gasket set so look for the part 1 next to the # 17 screw it is the part the screw 17 holds in the carbs.
either way the holes come out under here also sub assembly 11 is covering part # 1 the one below #17 so they have to be removed to see part # 1 the one below #17
the ports lead into the carb air intake side I believe if not that side it is the other side I can't remember It has been over a year since I did mine I hope this helps

Here is a parts list of the carbs

http://www.bikebandit.com/houseofmotorcycles/1981-honda-motorcycle-cb650c-carburetor-component-parts/o/m1978sch39747

All ports and internal connecting tubes must be open for the carbs to work correctly. Just make sure you don't make them larger cleaning them or you will damage your carborator so be carefull
Hope it helps you.
sorry if it is hard to under stand but maybe the part list can help you if not let me know and maybe I can find a pic of the holes I am talking about and post it for you.


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Discussion Starter #10
Archangel, I apprecitae you taking the time to type out so much info. When I took those parts out during the teardown, I sprayed all those ports with carburetor cleaner pretty good. They should be nice and clean... A friend said something about it possibly being the diaphragm? I'm guessing he means the one on the #2 carb... but I think mine is working okay. Have you experienced anything like that? I just don't know what to do about it. By the way, what type of tiny wire did you use to clean yours out? I really don't want to mess the carbs up. I think I know where you're talking about, so i'll have to see. There's a big street rod show this weekend that we have a car in, so I may or may not get online! Thanks for your help!
 

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Angel's Realm Where Evil Fears To Tread
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I used the smallest wire from a guitar to break mine loose along with carb cleaner in a can .
I stuck the end of the spray tube in the hole and held it tight in place and sprayed then used the wire to scrape in the hole then repeated with the spray just make sure you have on eye protection and a long sleeve shirt is a good idea.

My bike would not idle with out the choke even after I rebuilt it and removed all the needles and removed and cleaned all the jets that are removable , The slow speed jet is pressed in and can not be removed so all you can do is clean it.

I had to take my carb back off and clean the tiny passages where the cleaner came out the other end of the passage after then my bike started right up.

One thing to remember You have to choke it to start the bike once it warms up no choke should ever be needed at all.

My bike will go from cold and needing the choke on to runing and no choke needed in 4 min or so , even in the 32 deg temps I have to remove the choke in 5 min max or the bike cuts out and won't run well.

As to the diagram on # 2 carb that will not cause your problem not running with the choke off.
that is for sudden take offs it adds extra fuel during acceleration.

If the carbs are leaking fuel it can be from the bowls not sealing or from a stuck float either thing will cause an over flow of fuel.
The carbs have a overflow built in so if the rubber tiped stopers on the float does not seal the fuel off completly and they leak you will have a overflow.

I will look around I have a pdf file on how carbs work and some advice on rebuilding carbs I just need to find it.


As to the springs missing if the ones you are talking about it the ones on the bottom screws on the carbs I lost one of mine and found you can use a ink pen spring for a while it will get you by tell you can find the ones made for the bike also there are some o rings in the carbs as well that seal the screws make sure you have them.

I have a few extra o rings for these from my rebuild kits If I can find them You are welcome to them again I will have to do some looking for them. as to the other seals you will have to look else where.
 

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Discussion Starter #12
Archangel, I really appreciate the info and the offer on the o-rings. This week I will probably rip them apart and clean them once again :) hopefully soon I can post some pics of my bike to show you what I am doing to it. Thanks again
 

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Discussion Starter #13
so i ripped them apart today and cleaned them again. After I put them back on, it sounded like it wanted to idle, but wouldn't. I talked to my stepdad's friend who said the pilot JETS are clogged. I thought he meant the pilot SCREW, but I never thought of the pilot jet... either way, I need to take them apart once more. :( lol oh well!
 
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