5500mi on a rebuilt cb77 - Time for some freshening up?

[akpasta]

Hello,

Been a while since I've posted, mostly because I know my superhawk pretty well by now but I'm getting to a point where I think I might need to learn some new things.

Basically, I've got 5500 miles on a rebuilt superhawk I bought in Jan 2012 from Davo. Been a great bike and I can't thank the dude enough for giving me advice over the years. Anyways, I keep the bike in good working order. Tune-up about twice a year, store it inside, replaced the points about 800 miles ago, etc. But I'm getting to the point where a regular tune-up doesn't seem to do it and the engine doesn't seem as snappy as it used to be.

There's really only two symptoms that are bothering me.

1. There's something going on with the timing, I suspect advance springs. I usually like a smooth, low idle at about 800-1000rpms. In the past I've been able to get it even lower, but it's not practical for the city. I've gotten good at tuning for this idle. But last December, it started idling higher than usual. When fully warm, it will reach 1500-2000 rpms with the idle screws totally removed! That can't be right. Removing the idle screws should definitely make the engine shut off. I re-set the timing just as a test. What I found was, to get it to idle at 1000rpms I had to set the static timing to "T" instead of "F"... I had to retard the timing. The advance timing is still correct, however. Could this be from stretched out, finished advance springs?

2. Throttle response isn't as snappy as it used to be. Engine doesn't seem to have as much power in the low throttle ranges. Sounds lean, like boggy. I'm guessing it may be the retarded engine timing, or it may be time to replace the slides and maybe needles. Perhaps worn slides, that let hair into the carbs and combustion chambers is the reason the engine runs with the idle screws removed?

Also think it could be time to replace the battery. It doesn't hold a charge for as long as it used to. I believe the charging system is fine because the engine still charges the battery, but I've noticed if I use the electric starter a lot, it drains the battery faster than it used to, or if I run the lights a lot in stop-n-go traffic and use the electric starter, I'll have a tough time getting it started again. But, could a dying battery ALSO be a cause of my symptoms? Perhaps odd idle condition or weird "mixture/carb" conditions could just all be electrical.

Also, any other maintenance items besides those included in a regular tune-up (valves, points, carb tuning) that I'll need to add to my list now that I've reached the 5500 mile mark?

Thanks!

[bonjour]

Replacing the battery is a good 1st step, normally a battery would last for about 2years, especially on old bikes where the electric system is not advanced at all. Like having no voltage regulator, basically the battery is doing all the 'volt regulating' work.
Floppy volt come in the battery (high/low/etc.) , so it just worns the battery a bit faster.

Especially when you drain the battery more than the battery really like, because the electric charging system just isn't very good.

So replacing every 2 years, is a good start.

Also because the ignition is going via the battery, having a battery that is 100% in good shape is very important for these bikes.

[akpasta]

Excellent. I'll give it a shot. It feels like it could be a weak ignition. I recognize that feeling, when the battery is a bit low, where you'll be cruising at high rpm with the throttle closed down, and you suddenly open it, and it feels like the ignition chokes for second under the sudden burst of fuel.

Still stumped about the timing issue.

[LOUD MOUSE]

Set the timing where HONDA recommends.
Check the carb bowls and jets.
Get new battery.
Do you mean Slide or Idle Air screws?. ...............................lm

<<<<<<Sounds lean, like boggy. I'm guessing it may be the retarded engine timing>>>>>>>>>>>
<<<<<<When fully warm, it will reach 1500-2000 rpms with the idle screws totally removed! >>>>>

Hello,

Been a while since I've posted, mostly because I know my superhawk pretty well by now but I'm getting to a point where I think I might need to learn some new things.

Basically, I've got 5500 miles on a rebuilt superhawk I bought in Jan 2012 from Davo. Been a great bike and I can't thank the dude enough for giving me advice over the years. Anyways, I keep the bike in good working order. Tune-up about twice a year, store it inside, replaced the points about 800 miles ago, etc. But I'm getting to the point where a regular tune-up doesn't seem to do it and the engine doesn't seem as snappy as it used to be.

There's really only two symptoms that are bothering me.

1. There's something going on with the timing, I suspect advance springs. I usually like a smooth, low idle at about 800-1000rpms. In the past I've been able to get it even lower, but it's not practical for the city. I've gotten good at tuning for this idle. But last December, it started idling higher than usual. When fully warm, it will reach 1500-2000 rpms with the idle screws totally removed! That can't be right. Removing the idle screws should definitely make the engine shut off. I re-set the timing just as a test. What I found was, to get it to idle at 1000rpms I had to set the static timing to "T" instead of "F"... I had to retard the timing. The advance timing is still correct, however. Could this be from stretched out, finished advance springs?

2. Throttle response isn't as snappy as it used to be. Engine doesn't seem to have as much power in the low throttle ranges. Sounds lean, like boggy. I'm guessing it may be the retarded engine timing, or it may be time to replace the slides and maybe needles. Perhaps worn slides, that let hair into the carbs and combustion chambers is the reason the engine runs with the idle screws removed?

Also think it could be time to replace the battery. It doesn't hold a charge for as long as it used to. I believe the charging system is fine because the engine still charges the battery, but I've noticed if I use the electric starter a lot, it drains the battery faster than it used to, or if I run the lights a lot in stop-n-go traffic and use the electric starter, I'll have a tough time getting it started again. But, could a dying battery ALSO be a cause of my symptoms? Perhaps odd idle condition or weird "mixture/carb" conditions could just all be electrical.

Also, any other maintenance items besides those included in a regular tune-up (valves, points, carb tuning) that I'll need to add to my list now that I've reached the 5500 mile mark?

Thanks!

[akpasta]

Hi Loud Mouse, thanks for the reply.

I am referring to the idle screws, which move the slides up, not the air/mix screws, the air mix screws definitely work. I of course want to set the timing correctly where Honda says it should be set, but when I set the timing to "F," the bike idles at 1500-2000rpms with the idle screws fully removed! That's not right and I'm trying to figure out why it's doing that.

When this started happening I pulled the jets from the carbs, as well as the slides, to check everything out. All seems well. I also tested for an air leak at the connection to the engine where the intake O-ring is. Didn't find any air leaks.

[LOUD MOUSE]

Check the throttle cable at all ends and splitter.
If one is out of the top of a carb or it is pulled out of the adjuster at the lever or splitter or the adjuster is miss adjusted the slides will not bottom to the screw.
I'd do a visual of the cable and if nothing is apparent I'd look at both slides and make sure they bottom out. .............lm

Hi Loud Mouse, thanks for the reply.

I am referring to the idle screws, which move the slides up, not the air/mix screws, the air mix screws definitely work. I of course want to set the timing correctly where Honda says it should be set, but when I set the timing to "F," the bike idles at 1500-2000rpms with the idle screws fully removed! That's not right and I'm trying to figure out why it's doing that.

[akpasta]

Check the throttle cable at all ends and splitter.
If one is out of the top of a carb or it is pulled out of the adjuster at the lever or splitter or the adjuster is miss adjusted the slides will not bottom to the screw.
I'd do a visual of the cable and if nothing is apparent I'd look at both slides and make sure they bottom out. .............lm

One step ahead of ya! I did that as well when I pulled the tank, air filters/boots, slides, jets, etc. The slides definitely bottom out. The cable is still in really good shape and pulls both slides evenly and returns to bottom. I also did this to see if the slides were getting hung up somehow in the chamber. They don't seem to be.