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Discussion Starter · #1 ·
So the other day I though my Petcock went bad because the bike acted like it ran out of gas 25 miles into a run with a full tank. Went to drain the tank and barely had 1/4 tank of gas in there, after only riding about 30 miles. Let me give you a recap of my headaches over the past couple of months.



1) Bike was extremely hard to start cold. When I got it to run finally one of my float bowls was leaking like crazy. I pulled the Carbs and cleaned them using Larry's method and a Ultra-Sonic cleaner. I had just done this 8 months ago so they looked pretty good, but last time I hadn't pulled the low jet tube which I did this time. When putting it all together I broke a idle mixture tip off int e carb body. Finally got it removed with only some slight "coning" inside the crab tunnel. Note, before I pulled the crabs the bike ran ok, choke worked etc. On this rebuild I did not split the crab bodies. When I installed the crabs I noticed that the choke was not working at all. Checked that the cables was ok, not binding, all outer mechanisms seemed to be working ok. Pulled the carbs and checked the butterfly's worked. Put the carb back on and same problem, choke does not work. Once the bike is warm I got it to run great but noticed that the idle mixture screws were only 1/2 turn out from bottom to do this. At this point all I thought was I had a choke issue.



2) Went for a ride the other day and apparently my fuel consumption is down to about 10-12 miles per gallon. I checked the Petcock and it is running fine. Cleaned it to make sure.



Here is a list of parts that were replaced on the carb build. 1)replaced both idle mixture screws. 2)replaced both float bowl gaskets. 3)had to replace both rubber plugs as one kept falling out on me. The only other thing I have done different in this rebuild over the one 8 months ago was to pull the low tube using a screw extractor as per Larry's method.



As you can see, I feel like a dog chasing my tail here. I did pull the carbs apart today and rechecked (for the 4th time) that all was installed correctly internally.



ANY IDEAS?????????
 

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check for a leak from the drain tubes .If it was running that rich to get 12 mpg it would run much better cold than hot.Check your plugs if it is a rich condition they will be black.If they appear normal it has to be a leak.As to the choke I just don't know.
 

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I would check the oil level and make sure the gas is not in it. If the float stuck open while you were driving you may not notice gas coming from the overflow,,you would probably notice the bike working bad.



Are you sure that both overflow tubes are unobstructed? When I first started driving my 1980 CX I lost a lot of gas on the ground one night when it was parked. It went from a full tank to reserve because the float valve stuck open and I left the petcock on. I noticed it right away because there was a big stain under the bike and a strong smell of gas.
 

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Discussion Starter · #6 ·
Have you reversed the Main jets?112/115 into the Brass emulsion tube,78 into the carb body.


Shep, that is what caused me to pull the carbs today to verify this. They all were int he correct spots.



I would check the oil level and make sure the gas is not in it. If the float stuck open while you were driving you may not notice gas coming from the overflow,,you would probably notice the bike working bad. Are you sure that both overflow tubes are unobstructed? When I first started driving my 1980 CX I lost a lot of gas on the ground one night when it was parked. It went from a full tank to reserve because the float valve stuck open and I left the petcock on. I noticed it right away because there was a big stain under the bike and a strong smell of gas.
I always keep the petcock off whenever I am not riding it. Checked it to make sure and the oil is fine. Also checked the floats, float needle springs were all working fine. I have had not gas leaks whatsoever with the new gaskets.



I am starting to think I may have to throw in the towel on this set and get a rebuild set from the master carb guru, aka Larry. Funds are tight right now so I am still hoping that there might be something out there I havn't tried.
 

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Did you check to see if the choke butterflies are closing when the carbs are on the bike,,either before you connected the air box boots or by taking the boots off to see the plates close when you pull the cable?
 

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Discussion Starter · #8 ·
Did you check to see if the choke butterflies are closing when the carbs are on the bike,,either before you connected the air box boots or by taking the boots off to see the plates close when you pull the cable?
Yes, they close.
 

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Discussion Starter · #10 ·
OK, got everything back together, AGAIN. Noticed that the choke spring was slightly loose. So when the bike was idling with the choke on, the butterfly's would bounce slightly open and closed. Put another round into the spring which I think will help that issue. Check out the spring in this photo,




Also so everybody can see what I am speaking about with the right carb idle hole being slightly coned, look here,




and here is the left side which is normal,




Finally, here is the inline fuel filter I installed,




And just for giggles, Does anybody see anything I might have missed with all the linkage?




Keep the ideas coming, maybe someone will hit on something I missed.
 

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OK, got everything back together, AGAIN. Noticed that the choke spring was slightly loose. So when the bike was idling with the choke on, the butterfly's would bounce slightly open and closed. Put another round into the spring which I think will help that issue. Check out the spring in this photo,


That is why I asked if you were sure the butterflies were closing,,I wondered if there was enough tension on that spring.



Are you sure you didn't post the same pic twice of the of the right carb?
 

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Discussion Starter · #13 ·
That is why I asked if you were sure the butterflies were closing,,I wondered if there was enough tension on that spring.



Are you sure you didn't post the same pic twice of the of the right carb?
Sure enough, I posted the bad carb twice, here is the left side where the hole is normal.




As for the Plug Boots, I replaced them last fall and have done the resister replacement using a piece of brass rod. I pulled the plugs are they are a little dark, not too much and no gas smell to them. They look like what I would expect after trying to get everything working right for awhile.



I got the bike back together late last night, but haven't started it as it is in the basement and the wife gets REALLY upset if I start it down there.
 

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When I saw that 12/15 MPG my 1st thoughts were stuck choke cable/plates?


More like cracked carb overflow tube and it's dumping the gas where he can't see it right away. Been there done that.
 

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Exactly how does the fine choke spring attach?



I took my carbs partly apart the other day to fix a massive leak - the o-rings on the tubes that connect the carbs were bad - but I think I got that little spring in wrong. It's a very weak little spring.
 

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Is there any chance that the brass jet that the vacuum needle enters is missing? They have a tendency to fall out sometimes and if that was the case, the metering of fuel thru the secondary would be much too high. You should be able to see the end of it in the venturi where the vacuum slide needle enters it from above.
 

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Discussion Starter · #19 ·
Since it appears that the excessive fuel consumption was a one, or maybe two time event, without any indication of where it went, is it possible someone has liberated it?
Not unless they broke into my basement, stole just some of the gas (while ignoring the 3 gas cans sitting 10 feet from it). This problem has gone away, gettingf about 36 mpg as of now, which is due to a carb issue I have.
 
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