Topic: cb750 tach drive

[CB750RRcafe]

hey everyone. well since my buddys purchase of a nice CB550four with clubmans and a 4-1 with a Yoshi can, Ive grown a newfound love for these sweet bikes and went out and purchased my own CB750K. Its overall a good bike and it treats me good, but I do have a couple ?'s.

1)the tach drive is effed and if anyone knows where I can get a good deal on one please let me know. and...

2)my battery keeps dying on me, and even when i charge it for an hour or so, itll only last about that long or less. now im pretty sure the alternator is good because when i rev the motor the lights get brighter. i was thinking that it may be my starter (because the start button broke and now i have 2 wires i have to rub ) or could it possibly be my stator?

any help you guys can give I'll really appreciate. Ive only been told good things about you guys on this forum. and sorry for such a long post..


peace

[SteveD CB500F]

2) Glenn sent me this link on a previous post.

http://sohc4.us/?q=node/62

Check the battery voltage at various revs - it will give a first stab at a charging fault.

Report back.

[MRieck]

 The drive in the cam cover is broken??

[rpmour]

I just saw a tach drive on ebay..............thought it might be what you need.


http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=35595&item=4540269126&rd=1

[n9viw]

It's not unusual for the lights to dim at idle and brighten off-idle. These bikes have partial-loss charging systems, which means that it doesn't charge the battery until you hit about 1500-2000 RPM. If you find you REALLY have to rev it to get the lights to brighten, check your regulator. The original regulators are adjustable, and the bimetal tang inside tends to wear out after 30 years. There's a screw inside that has a locknut and a dot of loctite on it. Loosen the locknut, give the screw a 1/8-turn tighter, then tighten the locknut again (hold the screw in position, or it will tighten further with the locknut!). Start the bike and check your voltages against the chart SteveD posted.
If that doesn't do the trick, check all your grounds, make sure they're clean and tight. With all those green wires, it can be a bugger of a job, but well worth it once you've solved it.
Nick

[gerstle]

as a side note, you can get little push button switches at radio shack for a couple bucks that work pretty well as starter switches.  They fit right into the stock starter switch hole.  They're kind of a pain to get in and situated, but they work pretty well once you get 'em in there.