TOPIC:

I'm sure this question pops up a lot in various forms, maybe I am just stuck with an old bike. She seems to run great and perfect if I drive between Granny and Conservative. If I grab some throttle like a 16 year old idiot, it will scream, hesitate, scream, hesistate, scream......


The hesitations are only for a second, and it accelerates the entire way with significant whip lash, so the power is good, it is as if for only a micro second, the fuel is starved... or something. Again, a nice, semi-conservative acceleration will not hesitate at all, only when I crank it wide open.


I am looking for suggestions on what you all might think this could be related to, and the theory behind why it would do that.... bike is in good running order, so if I decide to start taking things apart trying to tune, we will deal with that at that time.... right now, I'd appreciate ideas on what and why this could be happening. (don't waste YOUR time explaining how to fix it since I might not fix it for 6 months)

PS: I just rebuilt, rather, cleaned out my carbs completely, and just re-installed my DYNA S elec-ignition..... might be a timing issue... though I tend to think not since it is not related to RPMs so much as rate of acceleration.

My appreciation for your responses..... Who doesn't want a perfectly running 1979 bike??

Post edited by: b4schroer, at: 2006/06/21 12:37

PS: I just rebuilt, rather, cleaned out my carbs completely, and just re-installed my DYNA S elec-ignition..... might be a timing issue... though I tend to think not since it is not related to RPMs so much as rate of acceleration.

Did you make sure your ignition timing advancer unit was working properly when you put your ignition back together? Do check the timing with a light, just to make sure. Did you make sure that the ignition components are still in spec (done with a multimeter) and that they are properly powered?

You just cleaned your carbs? Did you have this problem before and after the clean? Either way, make sure that the entire fuel system is very very clean. It sounds to me like you may indeed be starving for fuel. There are a lot of ways for this to happen, the fuel delivery system on our motorcycles are not the worlds best (I would have run two outlets from the petcock.) there are also catches on the fuel valves in the carbs that can get dirty. ALSO, check the fuel flow out of the petcock, if its a dribble, you probably found your problem. Easy enough to fix, but watch out! If you put the petcock back together with the old seals, it probably has a 50% chance of leaking. Also check the fuel filter in the petcock, and install an inline fuel filter as well for good luck.

An old bike that runs as good as a new bike is a wonderful thing indeed . Hopefully I gave you a start, PM me if you want more to go on, I'm a king of making check-it lists.

Peter

newbikekiller wrote:

PS: I just rebuilt, rather, cleaned out my carbs completely, and just re-installed my DYNA S elec-ignition..... might be a timing issue... though I tend to think not since it is not related to RPMs so much as rate of acceleration.

Did you make sure your ignition timing advancer unit was working properly when you put your ignition back together? Do check the timing with a light, just to make sure. Did you make sure that the ignition components are still in spec (done with a multimeter) and that they are properly powered?

You just cleaned your carbs? Did you have this problem before and after the clean? Either way, make sure that the entire fuel system is very very clean. It sounds to me like you may indeed be starving for fuel. There are a lot of ways for this to happen, the fuel delivery system on our motorcycles are not the worlds best (I would have run two outlets from the petcock.) there are also catches on the fuel valves in the carbs that can get dirty. ALSO, check the fuel flow out of the petcock, if its a dribble, you probably found your problem. Easy enough to fix, but watch out! If you put the petcock back together with the old seals, it probably has a 50% chance of leaking. Also check the fuel filter in the petcock, and install an inline fuel filter as well for good luck.

An old bike that runs as good as a new bike is a wonderful thing indeed . Hopefully I gave you a start, PM me if you want more to go on, I'm a king of making check-it lists.

Peter

it could be the carbs or the ignition but it could be something simple such as trash such as rust in the tank starving it from getting gas. if this is the case just clean it buy a conditioning kit for the tank and start running a little inline fule filter made for 1/4 fule line. the cone shaped ones autozone carry for lawn mowers will work just fine.

I had a simular problem with my SOHC Honda 750. Turned out to be simple carb adjustments. My Needle was set too high and the air screws needed to be readjusted.

If the fuel flow doesn't tun out to be the issue (wehich I wonder about since a conservitive twist of the throttle doesn't show the problem), then check your seettings on the carbs.

That's my thoughts anyway.