Topic: 1977 CB550F IDK (first build)

[minimo]

The minus 1V at ignition is still a mystery...
Meanwhile, I upped the main jet size to 110. Carbs synched. Going out for a test run.

[minimo]

If it were me, I'd abandon the stock intermediate plugs and simplify the wiring. I'd run the RR straight to the battery (Red) and the remainder of the wires to the stock stator plug. This removes all doubt of connections, insures charging, and guarantees a ground.

[snip]
This was my starting point for troubleshooting. I isolated the r/r RED and ran it to the solenoid (battery) and the r/r GREEN to frame ground - still approximately minus 1V at ignition compared to battery.

I'm riding the bike daily as-is.with no problem other than my speedo gauge making me worry that the charge is "14.8V"! But nothing has exploded yet, so I guess that is good

I received this email from Shorai today:

I wanted to tell you that while the V is not unreasonable, it is a bit high (even for leads, especially without accessory loads).  Although the LFX doesn’t begin to experience any heat stress until right after 14.8, that voltage of 14.6 to 14.8V DOES keep the cells saturated.  So actually the voltage is ideal.  ALTHOUGH if the LFX starts out low voltage, the bike is cranked (even lower starting voltage after starter load applied) the charging system will charge it up at a higher amperage (voltage drops, amperage raises) and yes thatcan damage the battery and cause outgassing.  The key would be to keep the LFX charged nearer to its 14.4V or at the very least 13.3V and it should be fine.

Before cold start, I meter the battery at around 13.3V (reads 12.3V on my speedo - at ignition) so I guess that's healthy?

This long weekend I plan on studying the wiring diagram and will begin to eliminate some wires in my headlight bucket and elsewhere to see what the deal is... Any clues/ideas, please don't hesitate to chime in Thanks!

[calj737]

Obvious places to check on BLACK for voltage drops due to corrosion:

Key switch connector in main harness
RH handlebar control
Horn
Flasher relay
Stock regulator connection
Idiot light power feed

It's all a matter of piece by piece until you locate the drop. You should also consider running yr gauge voltage feed to a different source. It's quite possible that it is actually reading a drop due to its connection. (At a minimum, check its connection for accuracy).

[minimo]

Thanks for the running list.
I like the idea of running my gauge source to another feed - I may try that first.

Thanks, calj!

[minimo]

New problem:

For whatever reason, I decided to yank out the aftermarket petcock filter from the gas tank - I noticed that the base flange of it had been mangled and tiny bits of it were floating around inside the tank. I fit an inline filter and now I'm having an issue with the float bowl overflow tubes dribbling fuel. I have since buffed the float tangs (smoothed down the dimples - per goldarrow's suggestion) and cleaned out some of the carb components and I'm still getting dribbles (a considerable flow) coming out of the bowls. It seems to dribble out of the carb depending on how I lean the bike - even upright.
What the heck did I do? Was it the in-tank petcock filter that I yanked out? Something else here? Complete carb cleanup/rebuild?

[calj737]

Sounds like you may have some debris stuck in the float valves?

[minimo]

Thanks, calj.
Carbs are pulled and I've got the Berryman's Chemdip on tap.

[minimo]

I blew out the passages to my carbs and lo and behold, a long and funky piece of white plastic came out - looked like the same type of plastic from the petcock filter. Slapped everything back on, put in a new inline fuel filter, resynched the carbs and voila, no more dribbling fuel B-)

Also picked up a new part and excited to test it tonight:

The build doesn't stop. I still have the tank to rebuild :-)

[minimo]

Went 2up for the first time last night with a lady. Something very intimate and sensual about the experience. I imagine it's akin to maybe salsa dancing but with a better view. I'd hit bumps intentionally to get the tight squeeze

So, I was met by an old-timer recently who ran a boat-load of useful suggestions on my rebuild but one of them that he seemed adamant about was learning how to bypass the ignition and get the bike started in case I was stranded without the key. Calj, any idea how I would go about doing that with some wire clips or a paper clip even (if in a pinch)?

[bwaller]

Back when we were smokers, some wrapped up foil worked to jump between fuses.  Anyone remember cigarrettes? 

[calj737]

Really you only need to connect BLACK from the key to RED. That provides power to the coils. You won't have the lights and such, but thats the fastest way.

I don't like the notion of "hot wiring" bikes, based upon a "pinch". Stash a spare key in your helmet liner if you think you might need a spare. Or in your jacket, or glove, or on the backside of the side cover.

[Retro Rocket]

Back when we were smokers, some wrapped up foil worked to jump between fuses.  Anyone remember cigarrettes? 

Yes...   On the 750, the foil trick on the fuses bypassed the charging system, so you couldn't ride too far...

[minimo]

Thanks for the suggestions and starting ignition w/out key.

Meanwhile, it's no surprise that I'm having waaay too many battery issues. I'm sorta convinced that this Shorai LiFePo is giving me more grief than it should. I mean, it should be simple plug and ride - which it does for a while but... My bike ran out of juice today while I was running idle in town. I guess my charge was below the nominal 12.3V or whatever it is and it simply crapped out in front of a lineup of #$%* cars - couldn't even kick the bike it over it was dead. So I had to pull over and wait around to get my battery jumped; the experience of stalling is hardly ever any fun.

I'm thinking about getting a regular bike battery now but that would be so uncool especially it's mondo size. As a temp workaround instead I was thinkin to maybe try to run a 3-pole switch that's able to withstand the amps (a kind of kill switch) so that I can kill the headlight/gauge/signals and all other peripherals to get the bike at least kick started - enough to turn the engine over and charge my system. Does this kind of setup sound familiar or doable?

[calj737]

The Shorai is not your problem; electric draw and charge is. What is the wattage of the spanky new headlight in low, high, and fully on?

Without looking back through your thread, remind us what the voltage at the battery is at idle, 3k, 4k and 5k please? And repeat that test with the headlight unplugged.

But do this after your battery is fully charged and rested, and reading 13.2v or better. If you keep discharging fully the Shorai, you will damage it.

[SOHC4 Cafe Racer Fan]

Yes, if the Shorai (or any other lithium) discharges to a certain level 3-4 volts, it's NEVER coming back.

[minimo]

So I've been getting some extra slack in my chain lately and upon investigating found that the drive sprocket is stamped "750". It is a 17T but is this correct/compatible with my 550? With this sprocket attached to the countershaft, i notice there is a little play when I turn it back and forth. Think it might mean replacement? Here's a vid:


Another thing to note since it's been a while here is that I've got a 16" Harley rear on this 550. Stock is 18". I have Dunlop D404, 130/90-16 M/C 67H fitted on.

What could be causing my chain to slacken when I have the adjusters locked and axle but torqued down to spec?

[strynboen]

the spokes must fit your type thain...nott type of bike bike..there is 2 types vho can be used on 550

[minimo]

The chain is a 100 Link 530, but I see what you mean about it having to be a good fit on the teeth of the sprockets and not just the bike... Perhaps I have a mismatch of chain & sprocket(s)?

[strynboen]

try a new front/rear... sprocket..often seen some be aut of center..it give strong forces vho can loosen all up..have you turnet the hveel slovly..and thekket for the chain go Loose /teight at you  turn.. it there is..then there is serius problems..the chain must be the same height..teightnes,,, turning the vheel more rotations..and thek many times..

[minimo]

Thanks, strynboen.
The chain does seem to tighten upon turning slowly. It's only upon riding and when there's a load that it slackens over even a short ride.

[minimo]

Made it safely on a 20 mile commute... Well, one stall on Harbor 110S from the 5 South interchange; on the uphill. For those who can imagine the bullets I was sweatin...
Anyway, caught a glimpse of the morning glow on my baby...

[SOHC4 Cafe Racer Fan]

Made it safely on a 20 mile commute... Well, one stall on Harbor 110S from the 5 South interchange; on the uphill. For those who can imagine the bullets I was sweatin...
Anyway, caught a glimpse of the morning glow on my baby...

I once had my electrical take a dump on my on the 405N about 1/2 a mile from Brookhurst at 9:30 pm.  Pitch black and had to limp across 6 lanes of cars barrelling at 75 plus.  No fun!!  I know that sweating feeling.  No bueno!!

[minimo]

Yikes! I think you got me beat, CB750. Mine was just a low gas stall on a narrow two-lane. I had to run it up the hill partially so I could merge over to the sliver of shoulder space to lean the bike and get some more reserve gas to fill up the petcock. I was kicking like mad to start the thing and she finally turned over.
But yeah, not fun stalling on the freeway.

[SOHC4 Cafe Racer Fan]

Yeah, I did not like that one bit.  I felt like I was threading a needle looking over my shoulder.

[minimo]

Btw, I put a shim washer behind the drive chain front sprocket to see if that would tighten the slop a bit and so far, even after now some 50 miles of travel, I've not noticed the chain to slacken. I will continue to check though to make sure.


Sent from my iPad using Tapatalk