tune or vacuum?
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Cruiser
Joined: Feb 2009
Posts: 152
Likes: 2
tune or vacuum?
I rebuilt the engine on my bike of the winter, got it all back together and couldnt get it to run much at all. I replaced the fuel line and fuel filter, set the carb float to specs, it seemed to hang a little to low, and also did a carb kit. Cleaned all the jets, replaced the rings, the diapragm in the accelorator pump and put in a new needle. Now the bike will pretty much idle all day, but any sort of throttle feed about kills it. I spent a while messing with the mixture screw, doing as is written in many of the tuning instructions but it doesnt seem to make that much of a difference, unless i have the mixture wicked lean or rich then it barely idles. MY question is what should I do next to try and figure out this problem? keep up with the tuning maybe turning the screw in 1/8 increments instead of 1/4, should i check for vacuum leaks somewhere? I just used new gaskets and such for the manifold, but im quite lost at the moment.
My bike is a 1992 sportster 1200 with the harley cv carb on there
My bike is a 1992 sportster 1200 with the harley cv carb on there
Tourer
Joined: Jul 2009
Posts: 481
Likes: 2
From: Minnesota
So take the air cleaner off so you can see down the throat of the carb and crank the throttle wide open a couple times to see if the accel pump is actually squirting fuel into the intake. Sounds to me like it's not.
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Cruiser
Joined: Feb 2009
Posts: 152
Likes: 2
well the accelorator pump is definitly working, so it isnt that. I find that the first time i start it up and run it with full choke it responds 100% then after a little while of idling it wont respond as well to any throttle movements. I cleaned the pitcock and screen and everything today but the battery died on me before i could check to see if that made a difference im pretty damn sure it is something to do with the carb, although i didnt get to do the WD-40 test for a vacumm leak. Can someone describe to the side effects of:
1) vacuum leak
2)running too rich
3) running too lean
I usually am able to determine one from the other symptom wise but this bike issue i think is causing me to slightly loose my sanity and not think straight.
1) vacuum leak
2)running too rich
3) running too lean
I usually am able to determine one from the other symptom wise but this bike issue i think is causing me to slightly loose my sanity and not think straight.
Tourer
Joined: Jul 2009
Posts: 481
Likes: 2
From: Minnesota
How about the VOES (Vacuum Operated Electrical Switch)? I don't have any experience with them but I've seen several posted about them causing a lot of head scratching before discovered.
From what I understand they are kind of like the old vacuum advance on an automobile.
From what I understand they are kind of like the old vacuum advance on an automobile.
Tourer
Joined: Jul 2009
Posts: 481
Likes: 2
From: Minnesota
If you can locate the switch, you could apply a vacuum to it and with an ohmmeter check to see if the switch is opening and closing. Then just check and be sure you don't have any vacuum leak in that line.
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