Author Topic: 1980 cb650 chopper / bobber project (Read 6078 times)

Barak3 · « **on:** November 08, 2009, 02:14:32 PM »

Hey, this is my first bike, my first post, and my first project. To be honest, I know nothing about this stuff. I got this bike 3 months ago, and was riding it all Fall. I live in Toronto, so with winter coming up I can either store it in my garage and let freeze to death, or go nuts with some ridiculous project!

So here we go. I'm looking for a something along the lines of a bobber/chopper look. The bike is in good condition as far as I can tell, but then again I don't know anything. I removed as much as I could until I got stuck at the engine. The main bolts holding the front of the engine seem to be stuck permanently. I ripped off the head of the bolt which allowed me to take the engine of the bike, but not back on.

My next step is to sand blast the heck out of everything starting with the tank and exhaust since that stuff is already off.

Barak3 · « **Reply #1 on:** November 08, 2009, 10:28:21 PM »

Here is it in all its glory...well not really. Everything looks pretty neat and tidy. The engine is hell shiny from the flash, but really it's just a coat of spray-on metallic paint that makes it seem this way.

Barak3 · « **Reply #2 on:** November 08, 2009, 10:40:54 PM »

I managed to get the carbs off after a long fight with the air box. It almost seemed as though they were glued on to the engine.

I drained the oil into a shoe box, which wasn't a great idea haha. I don't have the right tools and i'm trying to save money, so please bare with me.

can someone confirm if these carbs look fine? I'm no expert, but they look pretty clean for a 30 year old bike. I read some forums on cleaning them, but that seems like a mission on its own and I definitely don't have that time.

Next move, get the engine out..I heard the 'lean the bike on its' side' maneuver works well...not that I have another choice, I'm definitely not investing in a fancy engine stand.

Barak3 · « **Reply #3 on:** November 08, 2009, 10:49:56 PM »

I just ordered a set of new bolts and screws to replace the old. Since the front bolt holding the engine broke, I figure I'll run into those problems again.

I also ordered a set of air pod filters to replace the giant air box. I'm not going for a performance boost here, I am quite aware this is a 30 year old bike, and if I wanted something fast I'd buy a Ninja or something ridiculous. I know there are a lot of adjustments I'll have to make to the carbs though...can anyone recommend a forum/video that discusses this in greater detail? Also, is there a way to do this the old school way without some gadges/gismos?

I'm going to post some pics tomorrow of the broken engine bolt... at this point, it's still stuck inside the engine, and I can't get it out... so i'm in desperate need of help with that. I tried hammering it out, torching it, pouring all kinds of chemicals on it to loosen it up, but nothing worked. I think i'll bring it to a mechanic to drill out or something,I don't know..anyone have other suggestions?

MJL · « **Reply #4 on:** November 09, 2009, 12:21:51 PM »

You will want to take the bowls off the bottom of the carbs and look inside. There are screws with little tangs sticking out, leave them alone. If you must remove them, count how many turns it takes to screw them in all the way. Don't crank them down, just until they stop.

For engine removal, part of the frame unbolts on the right side. I don't think the motor was that heavy, but that was 8 years ago.

If you have pipes other than the stockers, you will probably have problems once you get up around 55-60 mph. The cure for that is easy and cheap, yank that cover off the airbox and use fender washers or little tabs to hold the air filter in.

Barak3 · « **Reply #5 on:** November 09, 2009, 08:02:51 PM »

Here is my main problem at the moment. The bolt is stuck inside the engine! What do I do?!?!?! Please help!

Barak3 · « **Reply #6 on:** November 09, 2009, 08:07:57 PM »

I managed to get most of the gear off the bike. I don't want to do much modding to the front at the moment (maybe change the bar at some point).

Barak3 · « **Reply #7 on:** November 09, 2009, 08:22:24 PM »

I also managed to cut off the rear part off, and I used the old seat and cut it into a smaller version. Getting it to stick isn't a problem, I just drilled two holes in the middle and screw it into the frame. I'll probably leave the rear shocks on for now, until I can figure out a more comfortable seat and manufacture some struts.

Barak3 · « **Reply #8 on:** November 09, 2009, 08:38:19 PM »

Some more pics of the motor...I'm starting to take it apart to clean out the carbon buildup and such..

Is the gasket reusable? It looks pretty clean to me and still in flexible shape. I read somewhere I need to use some sort of glue/sealant when I'm putting it back together, can someone confirm?

Trying to save money where ever I can without too much damage..

Gorms · « **Reply #9 on:** November 10, 2009, 07:18:55 AM »

Quote from: Barak3 on November 09, 2009, 08:02:51 PM

Here is my main problem at the moment. The bolt is stuck inside the engine! What do I do?!?!?! Please help!

It looks like the head is broken off that bolt. If so just bang it through. The inside of that bolt hole isn't threaded. Penetrating oil and heat will make it easier if its stuck.

Barak3 · « **Reply #10 on:** November 10, 2009, 07:22:16 AM »

Quote from: Gorms on November 10, 2009, 07:18:55 AM

Quote from: Barak3 on November 09, 2009, 08:02:51 PM
Here is my main problem at the moment. The bolt is stuck inside the engine! What do I do?!?!?! Please help!
It looks like the head is broken off that bolt. If so just bang it through. The inside of that bolt hole isn't threaded. Penetrating oil and heat will make it easier if its stuck.

I used a small blow torch to heat it up and bang the bold through, but it seems to have rusted shut. I also tried WD40 with no results. I'm thinking of bringing it to a shop so they could drill it out somehow.

Barak3 · « **Reply #11 on:** November 29, 2009, 04:29:23 PM »

I've cleaned out the engine. The carbs still need some work. I'll get the air compressor out sometime this week and blow out all the rust out. It appears the gas tank is in bad shape with a lot of rust built up inside..

Here is what it looks like so far with most parts back on..

I'll try to get better pics soon..

Barak3 · « **Reply #12 on:** November 29, 2009, 04:32:36 PM »

I'm still looking for struts, and I'll have to replace the #$%*ty seat that I managed to construct from the precious one. Need to start looking for a new tail light as well...but it's just minor work from here on

joec3613 · « **Reply #13 on:** November 29, 2009, 06:04:05 PM »

I like the look. Did you move the upper shock mounts or are they stock? I think a set of drag bars would look killer on the bike. At least you have a long winter ahead to do the work. I'm in Florida. The good part is e ride year round, but the bad is we don't have winters for projects! Good luck!

Barak3 · « **Reply #14 on:** November 29, 2009, 11:37:12 PM »

Quote from: joec3613 on November 29, 2009, 06:04:05 PM

I like the look. Did you move the upper shock mounts or are they stock? I think a set of drag bars would look killer on the bike. At least you have a long winter ahead to do the work. I'm in Florida. The good part is e ride year round, but the bad is we don't have winters for projects! Good luck!

It's all stock. Drag bars would look awesome, Thanks!

MickeyX · « **Reply #15 on:** November 30, 2009, 12:29:13 AM »

Those carbs have press in jets. You can't get various jet sizes for these, really. You can't adjust the carbs very far anyway because the air/fuel mixture on these adjusts both at the same time. They aren't separate. These had a lot of EPA crap on them and run lean to begin with so putting pods on will make it even leaner, from my understanding. It is very hard to tune that far enough with these particular PD carbs. I think someone here was running pods but it really is almost impossible from what I've read here to get it right. I think he went back to the airbox eventually. Oh, if they look clean, clean them anyway. Then clean them again. Then, at least one or two more times. It is a running joke here but it is very true and will be easier on you in the long run. Make sure they are bench synched pretty well before putting them back on so it's easier to gauge synch them on the running bike.

As for the tank, you need to really clean the rust out, not just use an air gun. Any little bit of anything unpure in these tanks will gum up your carbs, over and over and over and over.... don't ask how I know this.

Try "The Works" trick. Do a search on it here. It's cheap, fast and really works. Or if you have the extra time, you could do the molasses trick. Just as cheap but is nicer to the environment.

Yes it is possible to reuse that particular gasket if it looks pliable. While you were in there, did you check your clearances? It would be a good time. I would use anti-seize on the bolts when you put it back together, too. These old Honda bolts snap and get stuck all the time.

Just curious, what did you mean when you said you "cleaned out the engine"?

Good luck with the bike. We have 2 of this particular year and model. They are, to say the least, a challenge. It is the in-between bastard child of the 650s. If you order something, be sure what you are getting. Some of it is compatible with '79, some of it is compatible to 81/82. It was the change over year. If you are unsure, just come on here and ask. Quite a few of the forum members have them and can help. Many sellers will say something is good for all 650 years when they aren't.

Barak3 · « **Reply #16 on:** November 30, 2009, 07:55:10 PM »

Quote from: MickeyX on November 30, 2009, 12:29:13 AM

Those carbs have press in jets. You can't get various jet sizes for these, really. You can't adjust the carbs very far anyway because the air/fuel mixture on these adjusts both at the same time. They aren't separate. These had a lot of EPA crap on them and run lean to begin with so putting pods on will make it even leaner, from my understanding. It is very hard to tune that far enough with these particular PD carbs. I think someone here was running pods but it really is almost impossible from what I've read here to get it right. I think he went back to the airbox eventually. Oh, if they look clean, clean them anyway. Then clean them again. Then, at least one or two more times. It is a running joke here but it is very true and will be easier on you in the long run. Make sure they are bench synched pretty well before putting them back on so it's easier to gauge synch them on the running bike.

As for the tank, you need to really clean the rust out, not just use an air gun. Any little bit of anything unpure in these tanks will gum up your carbs, over and over and over and over.... don't ask how I know this. Try "The Works" trick. Do a search on it here. It's cheap, fast and really works. Or if you have the extra time, you could do the molasses trick. Just as cheap but is nicer to the environment.

Yes it is possible to reuse that particular gasket if it looks pliable. While you were in there, did you check your clearances? It would be a good time. I would use anti-seize on the bolts when you put it back together, too. These old Honda bolts snap and get stuck all the time.

Just curious, what did you mean when you said you "cleaned out the engine"?

Good luck with the bike. We have 2 of this particular year and model. They are, to say the least, a challenge. It is the in-between bastard child of the 650s. If you order something, be sure what you are getting. Some of it is compatible with '79, some of it is compatible to 81/82. It was the change over year. If you are unsure, just come on here and ask. Quite a few of the forum members have them and can help. Many sellers will say something is good for all 650 years when they aren't.

Thanks for the tips. I'll probably have the carbs in this week, and I'm still looking for 'The Works'. Someone mentioned filling the tank with small rocks and shaking it around to get the rust out, but it sounds crazy, can anyone confirm?

For the engine clean out I took apart the cylinder heads and valves to see if everthing was up to size. It looked clean and the measurements passed. I decided not to go further because the work was too much for me as this is my first experience with an engine. My main problem was leaking oil from the gear shift arm, so I thought it was just a broken gasket. The entire thing was filled with gunk when I unscrewed the casing. I cleaned it out, but never had a look at that gasket or or the crankcase due to time constraints.

I was trying to fit a drag bike that I took off from my bike. Probably a stupid idea, but I wanted to try the look. The bar is only 25 inches though, compared to 28-30 that are more common. It looks kinda awkward, but I'll post pictures soon and you guys can comment.

With the clutch and break levers off, I also thought it would be neat to try out the suicide clutch. I'll probably cut another bike bar to fit the lever on it and attach it to the gear shifter. Just as an experiment

Frankenkit · « **Reply #17 on:** December 01, 2009, 01:18:15 AM »

the gear shift arm leak is seriously easy to fix. $5 seal that pops right in where the leaky one comes out. No fuss, little mess, just make sure all the surfaces are nice and clean lest you damage the new seal and perpetuate your leak. Much cheaper than taking your whole engine apart.

Suicide clutches don't have that name just for fun y'know. I can't recommend it. Marti might have done that to his bike, but that doesn't make it safe or smart. (sorry, Marti, you know I love ya, right?)

When cleaning out your tank, I'd more recommend a piece of chain or something, so when you go fishing for it later you can know for sure you've got 'all of it'. You'll have enough 'fun' getting the little crumbs and crusties of rust out. Try to get everything because I've unracked/dismantled/cleaned/reassembled my 650 carbs at least 10 times now JUST because of tank deposits, until I said "#%^# it!" and got a new-er, professionally cleaned tank. Even still, I'm a little paranoid about keeping my carbs clean and run seafoam pretty often. It just takes a little nudge to take a normal, conscientious person and turn them into a paranoid, carb-cleaning maniac.

MickeyX · « **Reply #18 on:** December 01, 2009, 01:28:43 AM »

here ya go, the thread for "The Works"

http://forums.sohc4.net/index.php?topic=31970.0

or you can shock it...

http://forums.sohc4.net/index.php?topic=21623.0

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Author Topic: 1980 cb650 chopper / bobber project (Read 6078 times)

Barak3

Barak3

Barak3

Barak3

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Barak3

Barak3

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Barak3

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joec3613

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