1981 CB750 Super Sport

[Butcherblock]

I think your brake light may be dimming when you pull the brake because the writes are hooked up backwards. I did that with mine and the same thing happened. Reversed them an all was good!

[Johnnylevi]

the connectors were definitely not connected in the front headlight assembly... , BUT heres the good news.
I took her out today for the first time in 2 years! Boy did that feel good! and it was sort of scary too.. I'm not used to riding with cars around. Sounded really good. of course it couldn't be all good...
When I got to my church to show it off to a friend we started it up and i took it around a bit and then it wouldn't pull anymore.. and it would slowly die at idle. So, we revved it to 6k for about 10 seconds and it idled strong again for a little bit, then slowly died. Tried to ride it back home, but thankfully i didn't even make it out of the parking lot. Took it back close to the church where we found an outlet and I let it charge while i went to class. Came back and  So much better! Hopefully this isn't a charging system thing. Seems like it works judging from the 6k thing. leme know if im just naive. Oh and only last thing, I need new fork seals

[Johnnylevi]

Can anyone help me with pictures of how to change the fork seals? I keep reading and i have no idea what these things look like!

[shinyribs]

Two years!?!? Wow, I bet that did feel good. And yes, sadly, that does sound like a charging issue. As far as the fork seals, once you get the outer dust cover off, you'll be able to see what's up and it'll all make sense.

[Johnnylevi]

did i mention that I hadnt charged the battery since i got it and let it idle for roughly an hour and a half before riding it 2 miles and then let it idle more? Should it have charged a lot in that time?

[Beekeeper]

Here is the fiche.  http://www.cmsnl.com/honda-cb750f-750-super-sport-1981-usa_model7242/partslist/F++0801.html#results
 I think Tools has a pretty good description in his buddy's build log.  http://honda-cb750-s.456789.n3.nabble.com/My-Buddie-s-POW-MIA-K-3-and-How-to-do-fork-seals-duel-disc-breaks-and-engine-rebuild-td3283036.html

[sgtslag]

Anything below roughly 3,000 RPM, and the bike will run off of the battery, not the alternator -- the alternator is not putting out enough juice to charge the battery below 3,000 RPM...  Letting it idle for any length of time, will drain the battery.

To check the charging system, connect a Digital Volt Meter across the battery terminals, and rev the engine to 3,000 RPM:  you should read at least 13+ Volts across the battery, if the charging system is working.

If you have drained the battery to the point where it won't start your engine (deep discharge), take it to an auto parts store to have it load tested, for free.  Deep discharging will kill a battery, rather quickly.  If you can afford one, an AGM is the best, longest lasting type:  extremely little discharge over long storage periods (electrical accessories, like clocks, will still drain it, however); maintenance free; can be used in any position, won't leak; virtually immune to lower temperatures; last 2+ times as long as flooded cells, but will cost up to 2x as much, also.

When you buy a new battery (any type:  flooded, Gel Cell, AGM), they must be properly charged before usage!  Failure to do so, will shorten the life of the battery -- might as well light your wallet on fire...  Follow the manufacturer's directions for their battery, carefully; do not exceed the maximum charge rate (Amperes:  if it says 2 Amps, do NOT connect it to a 5-10 Amp charger!).  Pay attention to the rest period recommended, as well:  typically, flooded batteries require a period of time to 'cook' after adding acid, then they need to be charged slowly, until full.  It varies by maker, and model.  The Battery Tender Jr. is a tried, and true friend to motocyclists, and their bike's batteries: it can double the life of any battery, if it is connected after each ride, to top off, and maintain the battery, for optimal performance, year-round...  Cheers!

[Johnnylevi]

Thanks both of you guys! really helps out. I'll test my charging system hopefully tonight. My headlight gets brighter when i rev so thats a pretty good sign i think. As for the fork seals I just realized that the ones i bought from shiny are only dust seals... haha my bad! Ordered a pair of all balls oil seals! should be here on the 21st says the estimated shipping.

[shinyribs]

 Oops on the dust seals. But you'll need to replace those as well,anyways.

Oh,and don't let your bike idle for too long sitting still. She really needs that moving air over the fins to stay cool. Anything more than a few minutes and I'd put a fan on it to keep it cool. You probably already know that but I just figured I'd mention it just the same.

[Johnnylevi]

Thanks shiny. Yeah that time was just a total  I put a fan on it when I was syncing and tuning the carbs. Getting the fork seals Tuesday hopefully I'll be riding again by Wednesday!

[Johnnylevi]

Got the seals and everything and then forgot about the "special tool" to drive them in with. Went down to ace later on wednesday and got a 1&1/2" PVC pipe to drive these bad boys in, but since this last week was finals week I didn't have enough time to put em in. Gonna do so tonight. Hopefully finish up bondoing/ painting the tank too. I'll post some pictures of all that went on tonight sometime! It's gonna look sick...

[Johnnylevi]

Fork seal change




Pictures from my day out




Unfortunately I didnt have time to paint the tank tonight... forkin issues. I definitely filled the forks up too much thinking i memorized the number or something and then forgot to put the air hose line on before i took it off the center stand  it was a relief to see that thats what it was and not my new seals. I've been working on it for about 4 hours now on and off. So close!

[Johnnylevi]

Hey guys, so i took the bike out today and it ran great, except it would sometimes die at a stop... Not even consistently. it would idle fine at almost all stops and then 2 times it just died right before... what the heck?

[shinyribs]

 I want a black DOHC F so bad!

Is the bike idling real slow? Like,less than a grand?

When it dies is it instant or does it seem to load up or run out of gas?


Would it start right back up,did you have to crank on it to get it to fire?

[Johnnylevi]

hey shiny, It idles just fine at 1k still. It just kinda dies slowly and it starts right back up with a push of the button. I think I figured it out. Where I live is very windy and I didnt have one of the screws holding my airbox cover on. Put a screw in today, but didnt get a chance to ride. Does that sound likely? That the wind could come in and make the mixture extra lean? It happened once while I was riding at about 6k it was popping, which never happens, but later on it was not like normal.

[Johnnylevi]

new discovery. It appears I have another oil leak. On the left side where my gear shifter is. Is there some gasket that usually fails there that I can easily replace?

Also, I just paid for some F3 coils  $43 woot woot! Those will work well with the new iridium plugs i got

[shinyribs]

I guess what you're describing with your airbox is possible. IDK really. But since it dies slowly I think you can rule out a loose electrical connection. Probably not fuel delivery related since it fires right back up. <-Same reason,it's probably not your tank vent. I was gonna suggest maybe your coils are getting hot and dying,but firing right back up doesn't compute with that either.

Sounds like you've got a gremlin! Try and make friends with it????

[Johnnylevi]

Update. Charging system +14v @3000 rpm.
Took it for a ride today and after awhile it became really difficult for me to start from a dead stop. Wouldn't want to go unless I revved to 4k then it would drop down to about 1k when load was put on it. I'm thinking its the air fuel mixture. Since I replaced the missin screw on my airbox cover it's probably running a bit rich. Does that seem logical?
I'm just glad my charging system is still working well

[shinyribs]

Accelerator pump working?

[Johnnylevi]

...good question. To test this I have to take the airbox off right? And a little squirt of fuel should come up out of a little brass thingy.