Author Topic: cross your fingers for me! (Read 3211 times)

mono · « **on:** April 24, 2012, 12:11:55 PM »

so last week i'm out drinking wit ha couple buddies. one says "hey, you know josh's dad has some old motorcycle leaning against the garage with weed and #$%* growing in it?"

i zoomed inside and asked josh about it -- he had no clue what kind of bike it was, thought it may be a honda.

he just texted me and said it's a 1981 CB750 custom with under 5K mi on it. i'm arranging a meeting with his old man!

mono · « **Reply #1 on:** April 24, 2012, 12:12:37 PM »

Q: is the '81 DOHC ?

LesterPiglet · « **Reply #2 on:** April 24, 2012, 12:24:25 PM »

Yes. Good luck anyhoo. A bike is a bike.

mono · « **Reply #3 on:** April 24, 2012, 01:25:31 PM »

thanks for moving the thread. anyways, here is a pic. i asked if the ghillie suit was aftermarket lol

mono · « **Reply #4 on:** April 24, 2012, 01:29:48 PM »

short list i can see of things that would need directly replaced:

chain/sprockets
tires

- tank looks pretty good on the outside at least, pipes look functional for now.

this would be for my cafe project, so a lot of the stuff is non-essential and i don't have to consider replacement cost. of course this would leave very little to trade with, but oh vell.

LesterPiglet · « **Reply #5 on:** April 24, 2012, 01:34:26 PM »

I've never seen any bikes neglected that way over here, we must be all tight b*stards.

mono · « **Reply #6 on:** April 24, 2012, 01:53:05 PM »

i actually got the motorcycle bug about 12 years ago - a girlfriend of mine was living in a duplex her friend's dad owned, and there was an old honda v-twin of some kind out there with an equal amount of ivy growing through it. the property owner said a previous tenant had left it there a few years back and i could have it if i wanted it. BUT.... i didn't know a damn thing about MCs back then and there was a lot less info in the web, so i never pursued it.

i thought that since i didn't have a title i would not be able to register it because someone used to own it, and that person was still alive probably... oh how naive i was. i do remember looking up parts for it on ebay, and back then i could get anything on it for 10-15 bucks.

anyways, i think i'm going to buy this either way if the engine isn't seized and he's not trying to get rich off this thing. if so, she's getting named "Ivy".

70CB750 · « **Reply #7 on:** April 24, 2012, 01:59:27 PM »

Go for it, you can always part it out.

mono · « **Reply #8 on:** April 24, 2012, 06:44:51 PM »

Quote from: 70CB750 on April 24, 2012, 01:59:27 PM

Go for it, you can always part it out.

very true. it will be taken down to the frame anyways once i get it home and verify it runs!

Stev-o · « **Reply #9 on:** April 24, 2012, 08:43:50 PM »

It's possible it might start up, but dont count on it. Fuel sitting for long periods of time tends to turn to a varnish type matierial. The tank and carbs more than likely need a good cleaning. And you'll need a good battery too.
Good Luck and love the name! May need to change it to Poison Ivy!!

grcamna2 · « **Reply #10 on:** April 24, 2012, 08:44:25 PM »

The CB900 & CB1000C Custom's all had dual range transmissions which gave you 10 different forward ratio's..,but I'm not sure if the CB750C had that. It's a Nice bike.

mono · « **Reply #11 on:** April 25, 2012, 05:51:56 AM »

Quote from: grcamna2 on April 24, 2012, 08:44:25 PM

The CB900 & CB1000C Custom's all had dual range transmissions which gave you 10 different forward ratio's..,but I'm not sure if the CB750C had that. It's a Nice bike.

Hmmmm.. .not sure. i was wondering what classified them as "Custom" though. That would be suh-weeet!

To Google!

LesterPiglet · « **Reply #12 on:** April 25, 2012, 05:56:58 AM »

Quote from: mono on April 25, 2012, 05:51:56 AM

Quote from: grcamna2 on April 24, 2012, 08:44:25 PM
The CB900 & CB1000C Custom's all had dual range transmissions which gave you 10 different forward ratio's..,but I'm not sure if the CB750C had that. It's a Nice bike.

Hmmmm.. .not sure. i was wondering what classified them as "Custom" though. That would be suh-weeet!

To Google!

Tank shape, seat height/shape, 4 into 4. Hi rise bars is all I can see.

onepieceatatime · « **Reply #13 on:** April 25, 2012, 06:02:31 AM »

Quote from: mono on April 25, 2012, 05:51:56 AM

Quote from: grcamna2 on April 24, 2012, 08:44:25 PM
The CB900 & CB1000C Custom's all had dual range transmissions which gave you 10 different forward ratio's..,but I'm not sure if the CB750C had that. It's a Nice bike.

Hmmmm.. .not sure. i was wondering what classified them as "Custom" though. That would be suh-weeet!

To Google!

the comstar wheels instead of spokes, and 81 on it was also dual disc front brakes and air forks at least on the 650s

mono · « **Reply #14 on:** April 25, 2012, 07:04:11 AM »

yeah Google said dual-disc fronts also. too bad about no spokes, but oh well. less polishing.

LesterPiglet · « **Reply #15 on:** April 25, 2012, 12:37:03 PM »

Didn't they all have Comstars after 78 or so?

onepieceatatime · « **Reply #16 on:** April 25, 2012, 12:46:35 PM »

Quote from: LesterPiglet on April 25, 2012, 12:37:03 PM

Didn't they all have Comstars after 78 or so?

The CB650 standard model had spoke wheels '79-'82. I would guess the 750 did too.

LesterPiglet · « **Reply #17 on:** April 25, 2012, 12:54:20 PM »

But the 750 became DOHC and I think they came with Comstars. And my bro's CB650 had them too.

mono · « **Reply #18 on:** April 26, 2012, 05:42:52 PM »

well i got out there today to check it out.

the guy had kindly removed the ivy from it, but i don't know of that makes it look better or worse lol.

anyways, there was still 1/2 tank gas in it, no fuel was visibly leaking from anywhere, and there was still clean oil in it and it was full.

he was the original owner, bought it in '81 with 6 miles on it, parked it with 4600 on it.

we settled on $300 - i have the title and a bill of sale in my hand, and i go haul it home on Saturday afternoon!

Stev-o · « **Reply #19 on:** April 26, 2012, 09:20:58 PM »

Sounds like a fair price. The fuel n the tank is bad, but may have kept the tank from rusting?
What's your plan once you get it home?

mono · « **Reply #20 on:** April 27, 2012, 05:34:07 AM »

first thing is to remove the sissy bar and luggage rack lol. then i'll wash it.

after that i'll drain the gas + oil, check the plugs, see what the float bowls have in them, and if they don't look too horrible, try and run some new gas through it and see if it'll start (or at least try and turn over). *shrug*

if i can get it running i'll probably ride it this summer a bit, but i'm guessing it'll need a lot of love before it wants to be roadworthy.

grcamna2 · « **Reply #21 on:** April 27, 2012, 08:14:03 AM »

It wouldn't hurt to spray some PB Blaster down each spark plug hole..let it sit for overnight and spray some more and then turn it over w/ the starter w/ no plugs in it.
Then do the rest of the work after that step...that's what I'd do.

mono · « **Reply #22 on:** April 27, 2012, 08:26:48 AM »

^ lubes up the dry/possibly stuck cylinders? yes good idea. i will do this. thanks!

grcamna2 · « **Reply #23 on:** April 27, 2012, 10:13:52 AM »

The PBBlaster or WD-40 will help to brake up Any rust on you're cylinder walls,valves & valve seats plus leaving it sit like that in the cylinders will help to get the piston rings loose from being stuck in one position on the pistons and help them seal better when you do get her started.It's a good idea to check you're air filter element to be sure it is still able to work...sometimes mice get in the air box and wreak havoc on the filter,wires,etc.

mono · « **Reply #24 on:** April 27, 2012, 11:17:08 AM »

^yeah that does make sense - i guess all the oils would have settled long ago... :/ this is why you guys are priceless!

also, good call on the air filter, and i should have thought of that myself. when i got my 550, the air filter was a stock fiber filter thst the PO must have oiled, and it had tons of crap in it and was suffocating the carbs. added to my list.

bikebitzofvt · « **Reply #25 on:** April 27, 2012, 03:52:26 PM »

I did a bunch of work to one of those for a buddy a few years back. The inside of the fuel tank was rusted terribly, carbs were filled with crud. He drove it running on the choke only for several seasons! After I got it all mechanically right (tires, chain, sprockets, fork seals, battery, carbs overhaulled & ultrasonic bath, tank POR 15'd, fuel valve rebuilt, new clutch and a lot of new bearings) I had to replace all the fuses 'cause they were fracturing, etc, etc, etc I took it for a shake down ride. The bike would only accelerate to 5K rmp then shut off like it had a rev limiter! It took many, many hours to figure out there wasn't enough voltage to the coils! I added a 30 amp relay directly from the battery to the coils, (think fog light relay) triggered by the stock power to the coils. Bike woke right up after that, surprisingly fast!

I'll follow along and offer any pointers as you go along.

Good luck and good find, those are a great bike!

BTW - www.CB750C.com is a great forum full of support for your new bike.

mono · « **Reply #26 on:** April 28, 2012, 03:53:23 PM »

haha well i got it home at about 4:30PM EST, hosed her off and put her in the garage. the rear wheel won't hold air, so it's up on the center stand.

lock on the tank would not accept the key (tumblers were totally rusted), so i pulled the tank. had to cut the fuel hose because it was too stiff to slide off the petcock. petcock was frozen on OFF, so i unscrewed it. tube on the petcock was covered in slimy rust, and i dumped about half a tank of dark brown watery gas out of it. after it drained i shook the tank and there was so much rust in it that it sounded like there was a handful of pennies inside. too bad too cause the tank is 99% rust free on the outside and has no dents or scratches in the paint.

i could not get the camera to capture it, but there was actaully moss or lichen growing on some of the aluminum tins and on the fins of the engine. i'm pretty concerned about whether it is frozen at this point, but we'll see.

going to pull the plugs tomorrow and look inside, spray some PB in there as suggested, and let it cure for a couple days. also going to pull and clean the carbs. am also going to drain the oil and pull the oil pan to see what has rested at the bottom.

amazingly there is very little pitting on any of the chrome - just rust "sweat" which is coming off easily. the rear fender and lights are probably 95% clean, although they are getting removed. should be able to resell them OK.

sissy bar and luggage rack are removed. ack the 80s were ugly.

grcamna2 · « **Reply #27 on:** April 28, 2012, 04:19:42 PM »

You've got a fresh start on it

Wait to remove the oil pan & change the oil & filter until after you allowed the PBBlaster to sit in the cylinders for the required duration you choose;if you put in fresh oil too soon the PBBlaster will soak down into it and wash down the quality of you're new motor oil,you want the oil to be as good as it can be to lubricate that old engine.
I'm hoping you're carbs will clean up nice..sorry to hear about the inside of the fuel tank,see if you can soak the gas cap w/ PB to loosen the tumblers up & it'd be good to spray WD-40 or the PB on all the exposed electrical connectors to help fight some of the corrosion so they can make good contact..

mono · « **Reply #28 on:** April 28, 2012, 04:37:18 PM »

^ thanks - i'll hold off on the oil then. i already sprayed WD40 on the tank tumbler because if it frees up it would be nice to use the cap at least (since i have the keys). also, i may have to resort to trying to salvage the tank since i checked the old internets and there are very few tanks for sale (not sure about crossfit from other models, though). i'd ideally like to stick a 750F tank on it, but i'm pretty sure they do not mount anywhere near the same. may need to go with a hawk tank or something. just wanted something kinda cafe'ish, but it looks like the Ks are mainly used for the cafe projects. if so, i may just be shining this bike and selling it

grcamna2 · « **Reply #29 on:** April 28, 2012, 06:06:27 PM »

mono,
You can pretty well coat the inside of that tank w/ some good heavy sealer;I've found from a sub contractor that use to do them for me,that a product called Redkote will work good if the tank is rusty.Google it and then try to find a good shop or member here who uses it regularly and find out the careful Preparation that is required to fully coat the inside of that tank you have.
I remember the man telling me he would wash it out w/ wash fluid(gas,denatured alcohol,etc.)a few times.He had to remove ALL the loose stuff first w/a chain or a bunch of nuts & bolts and he'd shake them around in there until he removed the loose rust that was hanging on the verge of flaking off anyway & then he'd wash it out a lot after he removed all the loose stuff until it washed out clear.I'd be careful how much shaking you do w/ a very thin tank from the heavy corrosion it has.The last step was he washed it out w/ MEK and then he'd do a SUPER job of COMPLETELY drying that tank out inside in every crevice;he'd put a low pressure air pump hose inside it and leave it for 24-48 hrs...,yeah,it's got to be REAL dry.Then he'd coat it.
If you're interested in the rest of the process,I'll tell you the final steps.You can save that tank w/ that RED KOTE..even w/ the rust problem you've got,but it's a big Job.

It's a Nice looking tank..why not make it last for the duration ? !

mono · « **Reply #30 on:** April 28, 2012, 07:21:47 PM »

depending on the availablity of a different tank, i may end up trying to save this one. what you're telling me is good news, though! i am just trying to avoid having to seal a tank since i have heard that after a few years the sealant tends to goo up and needs to be redone. if i can find a clean tank that will work, great - if not, i'll redo it.

if i *do* end up cleaning and sealing this tank, i was going to scrub it with the nuts+bolts method (small ones i guess so it doesn't punch a hole) and then use the electrode method to draw off any remaining mocro-rust before sealing. i'm confident that i could do this on my own ( i have the tools, and if i don't it's a good excust to buy more tools! ) but the tips you're giving me are awesome. i've never done it and don't know what brands are good.

any info anyone can give me about cross-fitment using tanks from another honda model that would be super helpful! i'm surprised i haven't been able to find a list out there of what frames will accept what tanks.

thanks again,
mono

onepieceatatime · « **Reply #31 on:** April 28, 2012, 07:24:21 PM »

You may want to check out this sealer too.
http://www.caswellplating.com/restoration-aids/epoxy-gas-tank-sealer.html

wedoo2 · « **Reply #32 on:** May 01, 2012, 08:29:54 AM »

That was my last project, and although the fairing and seats do not appeal to most people here, they are a plus on a long ride. I agree with bikebitzofvt about the Custom forum. There is a busy, and informative, following there but they do not suffer fools gladly. Make sure the valves are done soon, no matter when you think they were done last. They are the shim type and a PIA if you don't know what you are doing. And don't even think of putting pods on those CV carbs. When you get running on the bike you are going to be forever looking for a 6th gear.

mono · « **Reply #33 on:** May 01, 2012, 09:17:02 AM »

thanks wedoo - i have already joined the DOHC Customs forum, and you're right - they are very.... "honest and straightforward" on that forum.

honestly, though, i think i've decided to just get it running and sell it. from what i've found, there are very limited cafe parts for this bike, and i don't feel like making my own. i think a mid-70s 750 would do me better for a cafe bike.

also, as i've been working at this one, i'm finding that time has taken more of a toll on it than outward appearances suggest. lots of super rusty hardware inside - i still haven't been able to free the battery bolts! - and many other things that make me not want to try taking it apart any more than i have to. i'm terrified that all of the gaskets are bone-dry and rotted too.

i may feel more inspired to wrench on this one after my 550's put back together, though.

and thanks for the advice about the pods. i wasn't planning on using them right away, but was considering it for later on. now i am not!

wedoo2 · « **Reply #34 on:** May 01, 2012, 06:24:21 PM »

I sold that bike for $1800. Running good, good Honda fairing and clean from head to toe. Not showroom, mind you, but I made a nice profit and had a great winter working on it. I agree that the earlier 750s make a better cafe platform.

One guy on that site, fasterspider, really knows what he is talking about when it comes to those bikes. He has a new handle now, but Ray is great and happy to help anyone who has an interest in the bikes. He has quite a CBX. Can ride too. Seen a few of his California freeway videos. I'll never be on the back with him in control.

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Author Topic: cross your fingers for me! (Read 3211 times)