Unstable running (comes and goes)

Hi All,

In the winter I have rebuild my engine from the top side, so all mechincal shall
be good when it comes to compression and valves etc...

Last season I replaced the coils and spark plug and wires.

Carb holders / inlet is also replaced with new.

During the rebuild I upgraded from 750cc to 810cc.

When I started up the bike I felled there was a issue with the mid range throotle,
so we tested different things, I have lifted the needle to the highest point.
I has also increase the pilot jet one step and not don anyting with the main jet.

These weekend I have been on long trip, driving 3-6 hours (each day) Friday, Saterday and Sunday.

My engine is not going perfect all the time, as I see the problem comes and goes....
When everyting is perfect, the RPM is follow the throotle quick and nice on the whole RPM range...
Everything is perfect !

When the problem is active, and it can be active for hours....

First I want to inform I can drive the bike, so I`m able to use it,
so the problem is not so big that you need to stop.

Examples:
1. It always goes ok on idle.
2. It goes not good driving slow in the traffic on low RPM (2-3k).
3. When I`m driving aorund 50-60 in 5 gear, and have stady throttle it sunddely loose som power
and I compensate with more throotle..
4. If I try to give full throttle It respons good and the RPM clim... and sydenly it stops like I hit a RPM limit....
If I use the clutch to help it fly over the current RPM...
5. When I accelarte form stop sometimes I have the same feeling from vibration and sound when you running out from gas...

Next morning it can be back to good and I can drive to lunch without any problem and example after lunch it is back again.
I have not find any pattern yet....

I have a feeling I missing 1 piston or 2 sometimes ? but it just drop out for a short perioded or something?


What can the problem be ? need more info ?

I have a feeling about the IC box or the pickups sensors ?

On Sunday during the trip I got a probelm with the start motor, it will not start the engine so I needed to push the bike to start
the engine, when I come home I discovered bad voltage on the battery. when I measured with no load it was good, but when I turn the light on it
dropped and was falling.... I think the battery is bad, but I will check the voltage under charging.

I don`t think the power issue can be the problem ? When I have high RPM I shall have enoufh power still if the battery is broken?

Get a new battery and start from there.
Steve

So you think there a risk for det battery makes the problem?

I have started the process replace it, just wantef to run two processes in parallel to save time

If the battery has one bad cell, the problem can be intermittent.

Where I live, most auto parts stores, and probably all battery stores will load test the battery, and test the battery fluid for specific gravity for free. Maybe somebody near you will test it.

One thing at a time then move on.
Steve

New battery, has not solve the issue.
I have found out the float level to not be stable, everything can looks good and then suddenly when you steering on the carb it start leak out from the overfill...
I have ordered new needle and seat now OEM, the one I have from previous owner is not OEM... rubber on the needle etc...

I have also found a charging issue, but don`t think they are related to these issue ?

Summary:
I will first get control over the float level, and then see what happens with the bike.

Had a longer tour today, and bike behave so different respond quick to throtle and have much more power in low and midle range. Goes good in whole RPM range....

Seems like my unstable problem has been wrong needle / float height..,,

I’m so happy now need to start prepare new weekend tour

Thank you all for your inputs!.

gordone wrote: Had a longer tour today, and bike behave so different respond quick to throtle and have much more power in low and midle range. Goes good in whole RPM range....

Seems like my unstable problem has been wrong needle / float height..,,

I’m so happy now need to start prepare new weekend tour

Thank you all for your inputs!.

Funny how that works! When you take care of the obvious stuff, the other things just seem to magically fix themselves. I see this daily.

My bike had an off-idle stumble at the stop lights, and as it turned out, my bad shorted stator, combined with low idle charge voltage were contributing factors. It all miraculously disappeared when I fixed my charging system. It is now back to it's fire breathing self, once again.

old_kaw wrote:

gordone wrote: Had a longer tour today, and bike behave so different respond quick to throtle and have much more power in low and midle range. Goes good in whole RPM range....


The needles was new from previous owner, but thats not help when its wrong type

Agree with you, have learn you need to start in one end check one by one thing
Seems like my unstable problem has been wrong needle / float height..,,

I’m so happy now need to start prepare new weekend tour

Thank you all for your inputs!.

Funny how that works! When you take care of the obvious stuff, the other things just seem to magically fix themselves. I see this daily.

My bike had an off-idle stumble at the stop lights, and as it turned out, my bad shorted stator, combined with low idle charge voltage were contributing factors. It all miraculously disappeared when I fixed my charging system. It is now back to it's fire breathing self, once again.

Hehe

The choke start working better also
Only need it for some second and then can I switch it off before must I used the throotle first