Author Topic: 1st Bike, 1st Project! 1981 Honda CB650 (Read 5129 times)

sethcjd · « **on:** March 28, 2015, 12:11:35 PM »

Hey all!

I'm a new motorcycle owner and just picked up this 1981 CB650 for $500 from a local owner. He purchased it a year ago in good running condition with 20k miles on the engine and disassembled it to turn it in to a Cafe Racer project. He wasn't able to dedicate the time to build the project, so here I am acquiring it!

All parts are provided to get it going except for a chain and carb boots. New battery, new clutch cable, luggage rack, and extra handle bars included. I'm pretty excited to get working on this thing and get her running again

For a bike that has been sitting for around a yr, would would your suggestions be on first steps to rejuvenation?

This is my first time working on an engine with carburetors, so I'm looking forward to learning with the help of the forums!

rb550four · « **Reply #1 on:** March 29, 2015, 05:43:25 PM »

Welcome.
I always start with parts cleaning and buffing so's not to get bored with a rusty looking project before it goes back together...
Prep and repaint the frame , thoroughly clean and paint the engine , polish the bolts.... If you're going to put it together even without a rebuild, you should still be able to take pride in your efforts . You'll feel better about the entire project and others will certainly respect your effort....and if it really is a runner , assembly will happen once, not twice with an additional disassemble, and the little things you will notice that need improvement (attention) will already be done.
Well anyways, that's what I do, cause there's just no way it won't be running after putting in the labor on the rest of it.
And being a 650 , you'll want to change those Sh1tty handlebars, it'll make you feel so much better.
What do you want to ultimately see from this machine when it's finished? what's the vision?

sethcjd · « **Reply #2 on:** April 01, 2015, 11:03:57 PM »

Thanks for the reply!

I just picked up plenty of cleaning supplies to get the elbow grease going...

Since this is my first bike (and I still have to get my endorsement). My primary focus is just restoring it to good working order so I can get it on the roads - then over time figure out what I'd like to do to make it "my own". A Cafe Racer style would most likely be where I'll be headed in time. This is my first time working with a carbureted engine, so I've got some learning to do.

So far I've disassembled everything to get a look at it all.

- The carbs seem to be in decent condition, with 20k miles on the engine I'm not entirely sure any rebuilding is in order - but would it be suggested to put in new gaskets?
- The smaller drive sprocket is rusty, I'll be replacing this.
- The right rear shock seems like it may be leaking slightly
- The front of the engine has some gunk/grease on it - not sure what this could be from - gasket seal?
- Rims are peeling - what can be done here? Is it best just to pick up new ones?

calj737 · « **Reply #3 on:** April 02, 2015, 03:51:20 AM »

Welcome. A few replies to your inquiries:

Carbs - always a very good idea to get them fully cleaned, like surgically clean if they're new to you, and been sitting a while.

Shocks - stock shocks were pretty much junk, new units are highly advisable (Hagons, Ikons, Fox ((thru Cognitomoto) are the most widely used)

Engine gunk - hard to say from the picture, but I'd leave the engine assembled until it runs to enter mine what truly needs to be done. You have yet to remove the copper exhaust gaskets still in the ports. Be sure to do so, as they are crush once, replace many items.

Rims - junk pile. Or spend the dough on having them re chromed if you can locate a shop. Replacements are available, many opt for alloy rims in lieu.

Sprockets - replace them in sets (front and rear together, with a new chain).

rb550four · « **Reply #4 on:** April 02, 2015, 08:04:41 PM »

+1 on the front rim, looks gone. couldn't really see the rear. If your into a rim you're into spokes, I wonder what brand spokes you should get and from where? Someone must know. searchbar first then ask for opinions on brands and service, you'll be more familiar with products and vendors that way.
+1 on keeping the motor together, may not be a reason to break it down, and you're not ready yet. I break down greasy messes with paint thinner and a brush, then hit it with compressed air, wire brush , and do it again. Then it is ready for paint.
Engine paint? yes, hit the search bar, that will keep you busy for a while, lots of stuff to read about this. Infact , almost everything that you may question that you can't find in your shop manual ( you must have a shop manual) has probably been asked once, so the search may give you the quick answer that you need. Although it isn't half as much fun as finding 16 different ways to do the same task.
There are no stupid questions, keep us updated and take plenty of pics. We like pics.
You can download a manual here http://manuals.sohc4.net/cb650/

sethcjd · « **Reply #5 on:** April 02, 2015, 08:30:33 PM »

I appreciate all the input! This is quite the daunting task, especially when I look in to the bucket of parts and can't identify where a good portion go - thankfully that manual will see plenty of use!

Will I was cleaning up the engine today I notice a gasket seemed to be pressed in slightly. Could this be cause for issues ahead? Pics to be posted once at computer...

sethcjd · « **Reply #6 on:** April 02, 2015, 08:40:33 PM »

Pics:

SOHC4 Cafe Racer Fan · « **Reply #7 on:** April 02, 2015, 09:25:48 PM »

Yep. Clean those carburetors thoroughly. If the bike has been sitting without running for any appreciable time, the gas will turn to varnish and gum up your carburetors.

SOHC4 Cafe Racer Fan · « **Reply #8 on:** April 02, 2015, 09:28:49 PM »

Hard to tell if there's been a leak there or not.

I would take rb550four's advice and clean up the motor. Perform a complete service on the bike -- plugs, fluids, valve adjustment, cam chain adjustment, etc. Read the service manual.

rb550four · « **Reply #9 on:** April 02, 2015, 09:32:54 PM »

There is usually a spot for a wedge (screwdriver...) to separate the separate (Jugs, head etc..) parts that are sealed with a gasket. Don't panic , it may not be an issue yet. You'll know once you get it running...you re gonna have bugs to work out, and right now the point is to make this a worthwhile assembly, so you can see if there are real problems.
Take a notebook and write your concerns as you go along so you don't forget what they were, that way at some point you will have addressed all of the issues as you go through the running test.
This doesn't mean to hold off on brakeshoes or greasing the steering bearings or going for tapered rollers or rebuilding the mc or fixing the stuck disc piston, if you see it needs attention, go for it. What it needs you should get as you go, leaving the engine alone for now with the exception of paint and polish. So if there is no issue, you've already done what needed to be done to the engine. Do the carbs last , after you have a roller with the engine mounted...lots of small parts to lose among the other parts and that is something you'll need a stretch of time, your complete concentration and a clean area to work in.Then the 3000mile service and you'll be well on your way.
That only sounds confusing.

calj737 · « **Reply #10 on:** April 03, 2015, 04:57:34 AM »

As RB said, download a manual and use the 3,000 mile service interval as a guide for performing your inspection and maintenace to repair your bike.

Heres a link for you:

Honda stock parts catalog for your bike:
http://partstream.arinet.com/Mobile/_jW4wl5TyaiQ0tR6p7m6xs6vHATys4XAHmeNF66czCJ3E44ivRR2FKs8NJJ2o3OJ11dlF9XoZKKom3cnLSnKfyu5iY4ENVVIICw9GLRyiwd4Jdz_GLEMEsQZkB5jmZKr0.html#/Mobile/d4Sr5oUDVk-PElfxZuBGZEYVEcrdYVMLwB2xlzYcBipf-56D5LrvZa6lMmP6m6FlTVlQmLb7uwL7EglcCDHzWg2.html

Use this as a reference for exactly the part name, number, availability if you need to buy anything. You can Google the stock part number to find it for sale worldwide if you need something. Also, the parts fiche is quite handy to understand the assembly of your bucket of parts.

Once you got the engine degreased and cleaned up, make a separate pile or bin for "Clean" parts. Go piece by piece and clean what's in the bucket of bought stuff. When you clean it, identify it from the parts fiche and label it with masking tape. Group small assembly items together (carbs, clutch, electronics, etc). Makes it pretty easy to work in small stages and know what you have, what you're missing, and how it goes back together.

Yes it's daunting for a first timer. But it's not actually that hard. These motors are quite simply really and putting things on requires just a few tools. Taking these bikes apart is more difficult really.

Use only metric nuts, bolts and wrenches. And those "Philips head screws" aren't Philips. They're JIS and they are different. You can buy a set of JIS driver bits from the For Sale section from a member. It's worth doing as it will prevent you from shredding those screw heads. Especially on your carbs!

So you've got a nice long weekend, we expect major progress come Sunday PM, else no chocolate rabbit for you!

SOHC4 Cafe Racer Fan · « **Reply #11 on:** April 03, 2015, 11:48:56 AM »

That front rim is roached. You have many options. If money is no object, you can have new wheels built or source the parts and lace them yourself; check Buchanan's. If you go this route, I would recommend going with lighter aluminum rims.

If money is a consideration, you can go as cheap as buying a used wheel on ebay or craigslist.

rb550four · « **Reply #12 on:** April 03, 2015, 07:34:25 PM »

Couldn't tell from the pic what the rear rim condition is, need better pics. If it's real crappy , I might have a rear wheel, but I'll have to run out and check the shop just to be sure.

sethcjd · « **Reply #13 on:** April 07, 2015, 09:26:39 PM »

Thanks all! This is a ton of great information. This whole engine cleaning deal sure takes a lot of diligence

.

rb550four - if that's a possibility I would certainly be interested - the rear rim is really not too much better than the front.

After a little cleaning I decided to drop the oil pan to check out the general condition there. It had a bit of sludge and residue as to be expected, however one thing that worried me a bit were some chunks of metal lodged in various places. I tried to take some photos before I removed the shards. Also, one final photo has a quarter to show a scale

Would this be something to be worried about in regards to the health of the engine or transmission?

In the meantime, I'm going to keep elbow greasing away - and may start looking at a location to get it blasted to speed things up

sethcjd · « **Reply #14 on:** April 07, 2015, 09:44:45 PM »

After some research I found this thread:

http://forums.sohc4.net/index.php?topic=114577.0

I tested the shards with a magnet, and they do stick to it... which means it's most likely part of a bearing? $:-\$

sethcjd · « **Reply #15 on:** April 09, 2015, 08:26:17 PM »

After seeing this, does it seem like the engine needs some closer inspection?

calj737 · « **Reply #16 on:** April 09, 2015, 11:25:37 PM »

Yes, definitely.

rb550four · « **Reply #17 on:** April 16, 2015, 03:35:22 PM »

For sure, I want to know how many quarters were in that crankcase.

rb550four · « **Reply #18 on:** April 16, 2015, 04:56:32 PM »

I just checked out that extra 650 rim, it still has a tire on it ( tire NFG) , doesn't have near as much rust on it (from what I can see with the tire on )as yours. It has had rust on it before as the chrome is thin on some of the inner line.....nowheres near show quality, but it would get you around, have seen worse....let me know if you are still interested after you track down where those metal chunks came from, so we know if you're going forward with the project.
You never know when a decent 650 parts bike may show up at a good price, they're out there, and they aren't America's favorite of the 4's.Good hunting.
http://forums.sohc4.net/index.php/topic,146886.0.html I would check here and see if it hasn't been sold. or , same bike in parts http://forums.sohc4.net/index.php/topic,146887.msg1672269.html#new or check with member tom witt, he runs into 650's allot and parts them out.

sethcjd · « **Reply #19 on:** April 17, 2015, 12:12:09 AM »

Thank you rb550four, I'll keep certainly keep it in mind since they'll be a necessity at some point!

For the time being, it looks like I've got my hands full unfortunately. For a first time project, this is turning in to quite the ordeal! By now I should have expected that after what I've gone through working on my cars, haha.

I'll let you all take a look for yourselves, photos will explain enough...

calj737 · « **Reply #20 on:** April 17, 2015, 05:08:49 AM »

Is the damage to that sleeve and piston how you found it? Geez, somebody tore that motor up! I would begin to tear the entire thing down and plan on a full rebuild with new crank bearings, all engine oil seals, new sleeve, new pistons (4) and a rebore. Not to mention some head work. Hope you weren't planning on riding really soon?

JimJamerino · « **Reply #21 on:** April 17, 2015, 10:14:13 AM »

That engine is pretty thrashed. Given the scarcity of some CB650 parts, you may want to consider buying another engine. Just be aware that not all CB650 engines are identical... the 79/80 engines are a little different from the 81/82 engines in terms of which carbs you can use.

rb550four · « **Reply #22 on:** April 17, 2015, 03:11:21 PM »

Sorry to see that. I was thinking piston skirts until I saw the cast iron piece lodged up by the primary chain. Sucks that it happened on your first bike engine but this one will be the best to learn on.
And it ran when the PO parked it? and was taken all apart so he could restore/modify/cafe it but just didn't have the time? A$$ kickin time! Hope you don't have to drive to far for that. It's so stupid, to lie about it's condition, like you'll never find out. Amazing.

sethcjd · « **Reply #23 on:** April 25, 2015, 04:12:07 PM »

Definitely an unfortunate situation! As you guys mentioned though, I'll certainly be learning more from this...unless I find a replacement engine for cheap

.

I've notice there are also some pretty decent dents in the crank case - presumably from the road slamming in to it. Looks like just about everything is getting redone!

News:

Author Topic: 1st Bike, 1st Project! 1981 Honda CB650 (Read 5129 times)