Is this fix really dumb or sorta smart?

fozzy_gump

New Member
I couldn't get my cb500 to idle after messing with the both the master idle adjustment and the air/fuel mixture screws on the individual carbs, so I tried something else. I just took the spring off the master idle adjustment so I could screw in the screw as far a I wanted. Now it's idling anywhere between 1-2 grand depending on where I put it. Granted after riding a while the screw starts to come loose because it's not held by the tension of the spring anymore, but for the most part it's seemed to work. Any thoughts on if this is a solid fix or should I find another more sound solution.


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The spring puts tension on the screw and stops it back out (which you've since discovered).


Is the tab that the screw is in bent? Or what about cutting the spring down?
 
deviant said:
Sounds to me like you're just covering up another issue.


You're probably right - thinking about it some more they're non CV carbs so the adjusters at the slides might be adjusted all the way down which in turn requires the throttle shaft to be further up than normal.
 
I figured so. I'll probably keep this fix for now and start working on the carbs to see if I can find out the real problem.


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When my bike idle speed started to race (2,000rpm) it was due to the carbi mounting rubbers being perished and cracked!
 
XS750AU said:
When my bike idle speed started to race (2,000rpm) it was due to the carbi mounting rubbers being perished and cracked!
He's got the opposite problem. He's turning the idle adjustment all the way in which is pulling his throttle open.
 
One rule of thumb that has served me well with carb work and older bikes in general: When putting things together that are adjustable, the final setting should be somewhat close to "the middle". Usually, taking an adjustment to one extreme or the other in order for the bike to work correctly means that something is broken, worn, or being negatively affected by something else.
 
Yeah good advice. I know for a fact the carb innards are pretty worn and need replacing. Can any of you guys speak to the generic rebuild kits you can find on eBay? I'm leaning towards one of those.


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I have used them on a few occasions and they have worked out fine. But...perhaps I was just lucky as I have heard some opposite reports. However, going with a kit from someplace like Dime City is pretty much guaranteed to be superb or they will replace it. I have been known to buy one generic kit from ebay to see if it is as advertised, then purchase the other 3. Spend less and roll the dice...or spend more for peace of mind...the age-old question!
 
I hear ya. I'm building on a budget though and the $40 kits speak to me a little better than buying four $25 kits from DCC. No hurry though. I'll do some more research.


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Have you cleaned the carbs? Take them apart and spray carb cleaner through every orifice and jet before you buy new parts. Get seals and O rings first.
 
Yeah I've cleaned them. Some of the o rings on the jets are going bad though and not creating a good seal. Also I wasn't sure but should you be able to see long ways through the slow jet? ( I think that's what it's called ) probably makes me sound like a dumbass but I couldn't see longways through any of them after a good scrubbing so I just put them back in as is. If so, that could be my problem too.


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fozzy_gump said:
Yeah I've cleaned them. Some of the o rings on the jets are going bad though and not creating a good seal. Also I wasn't sure but should you be able to see long ways through the slow jet? ( I think that's what it's called ) probably makes me sound like a dumbass but I couldn't see longways through any of them after a good scrubbing so I just put them back in as is. If so, that could be my problem too.


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Definitely a problem. Get an E string for a guitar and run through them. Makes sense why you're having to push the throttle full on to idle.
 
If budget is really tight, you could purchase just the viton o-rings from various internet sources, or get lucky at a hardware store. If you do enough research on parts lists and diagrams, you can eventually find the actual measurements of the o-rings. Give everything else a real good cleaning and maybe just have to purchase new float valves if they are a problem?
 
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