Will not rev over 6K

[Anonymous]

Ok - here we go....

1981 GS550T. Just got the beauty -
Tuned up - new plugs, oil, brakes checked, etc. Carbs synch'd to an inch of their lives, etc.

Took the bike out tonight for first test run.

1. Bike has plenty of power and pick up in 1, 2, 3, and 4th gear. In 5th and 6th will not rev over (or dosen't want to) 6 - 7K.
2. In neutral will go to red line.
3. During tonights run, I noticed that the rpms would drop lower and lower when at a stop. I made it home. Shut off bike, and tried to restart. Battery dead. I had lights, but not enough juice to start bike.
4. Just added a nice ground from R/R to neg on battery.

Soooooo..after looking at tthis thread:

http://www.thegsresources.com/_forum/viewtopic.php?t=27619

I'm thinking 2 things.

1. The charging system is dead, not getting any juice to the battery as :

Possiblities: Low battery voltage. If it is under 12v then your bike can display the symptoms you describe.
Other possiblities:
1: Do you have the original air box/filter installed?
2: No load stator output voltage a 5k rpms <70vac.
3: Air intake leak.

Or:

Battery is a lemon - no real suprise if it is, as it was on the bike when purchased and will not hold a charge even if the R/R was good.


What are your suggestions, o great gurus of the GSR. I will be doing the electrical test tomorrow, as well as seeing if it will run better with no airfilter in the box. 8O 8O 8O[/url]

[Anonymous]

Sounds like its running lean on the top end. Have you checked for lean symptoms (plugs)? What is the airbox like? Is it the stock box?

Technicaly, shouldn't the bike run even though the battery is dead and not charging? Because, the spark comes from the points or elctronic ignition, not the battery.
This is why I think its a lean problem and not electrical.

[nabrams]

Air leaks are something you must check for. Do a search for "air leak" on this forum.

[earlfor]

The stator produces AC voltage. The rectifier converts that to DC voltage and charges the battery. Everything on the bike operates on 12 v DC current. (including the electronic ignition and coils) If you have no battery, you have no power. Without a functioning battery, its the same thing as removing your car's gas tank and expecting it to run. :-)

Easrl

Sounds like its running lean on the top end. Have you checked for lean symptoms (plugs)? What is the airbox like? Is it the stock box?

Technicaly, shouldn't the bike run even though the battery is dead and not charging? Because, the spark comes from the points or elctronic ignition, not the battery.
This is why I think its a lean problem and not electrical.

[earlfor]

Re: Will not rev over 6K

The first thing necessary is to install a new battery. Its impossible to accurately measure the charging system characteristics without a steady baseline (good battery) do not consider making any carb changes or ignition changes until you have a steady 12v voltage supply. The 1st thing to always check is the electrical system. It must be correct for anything else on the bike to function properly. Your stator should be outputting 80 v AC at 5000 rpm. If that is correct, then reconnect the stator to the R/r and check the R/R DC output to the battery terminals at 5000 rpm. Low range should be around 14.2 at idle and max DC output should be 14.7-14.8 at 5K rpm. At no rpm may the charging voltage be above 14.9 volts steady.
A new battery, just off the charger and fully charged will show between 12.9 and 13.1 Once the battery is installed in the bike, a correctly operating charging system will keep battery voltage between 12.6 and 12.8
Battery capacity will decline as the battery ages. Anything less than 12.4-12.5 is time for a new battery.

Earl

Ok - here we go....

1981 GS550T. Just got the beauty -
Tuned up - new plugs, oil, brakes checked, etc. Carbs synch'd to an inch of their lives, etc.

Took the bike out tonight for first test run.

1. Bike has plenty of power and pick up in 1, 2, 3, and 4th gear. In 5th and 6th will not rev over (or dosen't want to) 6 - 7K.
2. In neutral will go to red line.
3. During tonights run, I noticed that the rpms would drop lower and lower when at a stop. I made it home. Shut off bike, and tried to restart. Battery dead. I had lights, but not enough juice to start bike.
4. Just added a nice ground from R/R to neg on battery.

Soooooo..after looking at tthis thread:

http://www.thegsresources.com/_forum/viewtopic.php?t=27619

I'm thinking 2 things.

1. The charging system is dead, not getting any juice to the battery as :

Possiblities: Low battery voltage. If it is under 12v then your bike can display the symptoms you describe.
Other possiblities:
1: Do you have the original air box/filter installed?
2: No load stator output voltage a 5k rpms <70vac.
3: Air intake leak.

Or:

Battery is a lemon - no real suprise if it is, as it was on the bike when purchased and will not hold a charge even if the R/R was good.


What are your suggestions, o great gurus of the GSR. I will be doing the electrical test tomorrow, as well as seeing if it will run better with no airfilter in the box. 8O 8O 8O[/url]

[Anonymous]

earlfor, I understand what your saying about everything running on 12v, including the electronic ignition. But, dirtbikes dont have a battery and/or stator and they run no prob just off the ignition.

The stator produces AC voltage. The rectifier converts that to DC voltage and charges the battery. Everything on the bike operates on 12 v DC current. (including the electronic ignition and coils) If you have no battery, you have no power. Without a functioning battery, its the same thing as removing your car's gas tank and expecting it to run.

Easrl

[Anonymous]

juice

old dirt bikes runoff of a points fired magneto ignition, others may have an ac/dc conversion unit, and/or a capacitor, that takes the place of the battery witch is fine were the only draw is the ignition and not lites and accesseries,

[earlfor]

The ignition systems are completely different. If you have a magneto type ignition, you dont need a battery as with some CDI setups. GS's do not have magneto or CDI ignitions. They have electronic ignitions.

Earl

earlfor, I understand what your saying about everything running on 12v, including the electronic ignition. But, dirtbikes dont have a battery and/or stator and they run no prob just off the ignition.

The stator produces AC voltage. The rectifier converts that to DC voltage and charges the battery. Everything on the bike operates on 12 v DC current. (including the electronic ignition and coils) If you have no battery, you have no power. Without a functioning battery, its the same thing as removing your car's gas tank and expecting it to run.

Easrl

[Anonymous]

Check your air filter. I was having the same problem - only my bike wouldn't make it past 5000 rpms in any gear. But, it would make it to redline in neutral. Took the air filter out and cleaned off the crud between the filter fins. Ran it down the road and allowed the bike to rev past 5000. I ordered a stock filter as I am running the stock air box.