Author Topic: Charging OK according to Clymers, But?  (Read 343 times)

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Offline ckahleer

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Charging OK according to Clymers, But?
« on: March 05, 2020, 04:46:56 PM »
81 CB650 stock
I checked battery voltage the other day and it was 12.2v. This seemed too low considering I put in a new fully charged battery in just one month ago.
I put a Battery Tender Junior on it and it took at least 8 hours to fully charge.
I have been doing a lot of tinkering on the bike. a lot of time idling.
At the battery, at 5,000 rpm I'm getting 14.7v. At 2,000 rpm 13.00v. At idle (1000 rpm) I get below 12.6v, so the bike is running, at least partially, off the battery.
Is this normal?

Offline bryanj

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Re: Charging OK according to Clymers, But?
« Reply #1 on: March 05, 2020, 07:27:54 PM »
Yes, you need revs to break even
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline PeWe

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Re: Charging OK according to Clymers, But?
« Reply #2 on: March 05, 2020, 09:17:17 PM »
A fully charged battery will show correct voltage.
14.7V @  fully charged and 5000rpm?
If not it will increase and you need to adjust the regulator a little to reduce the level a little.
14.7V is max for old type of battery.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967