Project Making something out of a ruined 1980 CB900 custom

got this delivered to me for $700, it runs quite well although it needs a new battery and has 5,000 miles on the clock. some minor issues though.

littered with fake chrome, detailed by a man with a can of black spray paint and some super cool "biker" stickers (skulls, etc), complete with a gross seat and even more gross handlebars

she has a long way to go.




first order of business was to remove the footrests in front of the engine. Once that was done it's on to some issues with the bike.

one of the fork seals is visibly gone, i'll need to do the fork seals before i take it out, and the rear brake wasn't working at all. when i checked the fluid reservoir i found a piece of rubber had been dissolved in the fluid which turned it all into a sticky goo which had clogged the whole system up. will have to see what i can do with the caliper and pump or if i'll need to replace everything.




once all the little problems are fixed i have some big plans (big for me anyway, i'm not a project wizard like some of you) for this bike. going to strip down the whole thing, remove rust, change just about every part on the bike aside from the bare essentials, and hopefully the finished product will be a completely different, nicer, lighter, more attractive machine.

i don't have enough weekend left to dig in yet, but expect some weekendly updates.

 

i'm in the states now so i would say it's an american model yes

if you dont mind international shipping i'd be happy to send you the seat, bars, and whatever else i get rid of. the seat's actually in very good condition, just absolutely not my style

 

will give that a try for sure

 

well i decided i ought to have a look at the oil before running the motor too much, being a 36 year old bike with only 5,000 miles on it and all, who knows how long it had been sitting.

the sump plug had basically cold-welded itself stuck and i somehow accidentally broke a fin off the oil pan trying to get the sump plug out.. need a new oil pan now. christ i'm breaking more than i'm fixing at this point. oh well. $30 on ebay but the wait will kill me. it's the long weekend and i need to mess around with the bike

anyway, what i then found was a whole lot of milky white oil, as if there was water in it.

however the bike is air-cooled?

any ideas on what thats all about?

i'll have a look at the gear oil soon too

 

took the master cylinder off and the thing is 100% stuck. I now have a new master cylinder, oil pan and choke cable on the way.


decided to put the rest of my afternoon to some use and clean things up a bit

putting a hold on the more pricey things (seat, paint job on the tank, suspension, etc) until ive put the new oil pan on and got it running and registered. don't want to risk too much on my sawmill wages haha. on the prowl for some nice drag bars

 

replaced the oil pan, rear brake master cylinder, and found that previous owner had at some point been using the rear brake with no brake pads (????) meaning the piston had been against the rotor which had bent the outer end of it a little and wrenched it past the seal and out of the caliper to some extent. jesus christ

anyway the rear caliper piston looked pretty badly damaged, but i managed to rescue it and so far (shockingly) it works just fine without leaking. did the cam chain tensioners (there are two of them, funny design), a quick carb clean, replaced the fuel line, changed the gear oil in both gear oil places. the bike is now registered and insured and rides great with heaps of power. i'd say it's got more grunt than my zx6r did.

swapped out the bars for some black powdercoated drag bars, got new grips and some bar end mirrors which all look great. waiting on some risers for those bars in the mail so they'll stop denting my gas tank

next highest priority will be a smaller and less disgusting seat, then i can start chopping fenders and exploring weight loss possibilities. pics coming soon.

 

rode it about 40 miles today, just to find the charging system isnt working at all and the battery dies very quickly. that'll be a job for next weekend if i ever manage to figure it out. pretty sure this bike uses an alternator

 

Finally got my truck running right, now i can really focus on this bike

 

tested the reg/rec with multimeter, it is toast. new one on the way

 

well, i've got a brand new reg/rec, and a new stator. both are perfectly within spec. i ran the motor today and tested for amperage through the + lead to the battery, 5 to 8 amps at 3000-6000rpm. voltage on the battery increases to around 13.5 at high rpm with the multimeter.

yet i rode it today and the battery still dies after riding. it's a new battery too.

any ideas? this seems physically impossible.

 

grounds are good, no resistance in the wires from the battery

at idle im seeing something like 11.8 volts. it only manages to charge the battery if im riding at 5000+ rpm. otherwise it drains.

i'm looking for a short somewhere maybe, but havent found anything yet.