ljevans
XS650 Addict
ah that makes sense. The advance was stuck so when I set it initially it would have been with the advance stuck partially open.
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1977 xs650 - rev's hanging up when i get off thottle
- Thread starter ljevans
- Start date
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- Tags
- carburetors electrical
ljevans
XS650 Addict
I think I will have to get into these carbs again and do sync them while I have them apart. I'm just trying to eliminate issues like this sticking advance and see how well I can get it to run before I redo the carbs properly.
intermittant faults like this are the most frustrating but you are following the most sensible proceedure of only changing one thing at a time and checking things systematically.
I think there is nothing wrong with your settings or jets ...my feeling is you should leave these alone for now.
The fact is most of the time your engine is running perfectly which it could not do if your settings were that far off or your jets the wrong size.!
This fault is something that is happening intermittently so its unlikely to be heat related .
The carbs are synced and the mixture is probably not far off where it needs to be or it wouldn't be running as well as it does .
My feeling is its something sticking or binding somewhere which is temporarily altering one of your settings .
Have a close look at the slides to see if there is any fresh rubbing marks
Remove the throttle cable and check both butterflies have a strong return spring and are not binding
Check the Advance mechanism again
I think there is nothing wrong with your settings or jets ...my feeling is you should leave these alone for now.
The fact is most of the time your engine is running perfectly which it could not do if your settings were that far off or your jets the wrong size.!
This fault is something that is happening intermittently so its unlikely to be heat related .
The carbs are synced and the mixture is probably not far off where it needs to be or it wouldn't be running as well as it does .
My feeling is its something sticking or binding somewhere which is temporarily altering one of your settings .
Have a close look at the slides to see if there is any fresh rubbing marks
Remove the throttle cable and check both butterflies have a strong return spring and are not binding
Check the Advance mechanism again
ljevans
XS650 Addict
The saga continues...
I modded the second spring on the advance unit and that seems* to have sorted it out. However yesterday when I was revving it up to see if I could get the rev's to hang up again I made the comment to a friend of mine who was with me that swapping a spare coil that I had onto the right side seemed to sort out this black smoke/puff that I had going on. One of us made a joke about how that side probably isn't firing anymore. Well I felt the exhaust on that side and it was ice cold
Anyway after some "swapnostics" today I found that one of the wires from the points to the right side coil was intermittently making contact. It's the wire with the funky bullet connector Y-plug on it. My buddy who was there has all sorts of different connectors and solding equipment so he's going to set me up with 2 new wires (one for each side) and i'll throw those on over the weekend sometime and then I can set my timing and get back to seeing if I've sorted the rev hanging issue! At least it ran quite well when we had that intermittant wire held where it would make contact
I modded the second spring on the advance unit and that seems* to have sorted it out. However yesterday when I was revving it up to see if I could get the rev's to hang up again I made the comment to a friend of mine who was with me that swapping a spare coil that I had onto the right side seemed to sort out this black smoke/puff that I had going on. One of us made a joke about how that side probably isn't firing anymore. Well I felt the exhaust on that side and it was ice cold
Anyway after some "swapnostics" today I found that one of the wires from the points to the right side coil was intermittently making contact. It's the wire with the funky bullet connector Y-plug on it. My buddy who was there has all sorts of different connectors and solding equipment so he's going to set me up with 2 new wires (one for each side) and i'll throw those on over the weekend sometime and then I can set my timing and get back to seeing if I've sorted the rev hanging issue! At least it ran quite well when we had that intermittant wire held where it would make contact
troopthrowback
XS650 Addict
Have you tried it yet? Update request!
ljevans
XS650 Addict
It seems that the advance unit springs sorted out my issue with the rev's hanging. I put the new wires on between the points and the coils and fired it up and the right cyl was running fine but now the left seemed to be intermittent. I swapped literally everything I could around to try to verify the faulty part. In the end nothing that I put on the left side seemed to make it fire consistently. I had the timing light on the left ignition wire and it would only flash every so often and of course it was back firing as well out of that cylinder. The very last thing I did (my buddy's suggestion) was replace the left spark plug (I had just put a new set in a few days before) and when I put a different plug in the left cylinder it seemed to smooth right out and the timing light was flashing as normal. go figure. Anyway at this point im done chasing my tail with this old, inconsistent ignition system and im in the process of ordering a PAMCO. (it's a process because I live in Canada and mikesxs won't ship to my american address because my credit card is a Canadian one) but that's another story.
pamcopete
Ride.Enjoy.Life is Simple
ljevans
XS650 Addict
Thanks Pete. I did try there but I couldn't find the same ignition kit that I'm looking for. Mikes Xs part number 14-0905
at idle there should be a tiny gap at the bottom of the butterflys its probably less than the diameter of a 1mm drill bit but you adjust those gaps with your throttle stop screw to set your idle speed in conjunction with your mixture screws. Refer to your manual or the carb guide in the tech section on here
The hanging idle or slow to return idle is a symptom of a lean mixture and is usually caused by a tiny air leak somewhere on the carbs or the rubber stub inlets but it can also be due to pilot jets being too small especially if you are using pod or foam filters.
Try spraying some carb or brake cleaner around the carbs and inlet rubbers using the thin dispersal tube that comes with the can to direct your testing area . Any increase in revs indicates the source of an air leak
The hanging idle or slow to return idle is a symptom of a lean mixture and is usually caused by a tiny air leak somewhere on the carbs or the rubber stub inlets but it can also be due to pilot jets being too small especially if you are using pod or foam filters.
Try spraying some carb or brake cleaner around the carbs and inlet rubbers using the thin dispersal tube that comes with the can to direct your testing area . Any increase in revs indicates the source of an air leak
