Topic: Papp's 1971 CB500 Rebuild. *LOTS O PIX!* Updated 5/08/09

[papp101]

So I had started a blog, but realized I could probably get more input from the experts around here if I run an old school rebuild thread.

Picked up the bike with no title for $175.00. Plates are from 1975, and the bike has 3300 miles on it. Engine was seized, and there were no plugs in when I got it.





Tank looks decent, but I hope to "dish" it when I make a bump seat to match, and paint them both. Maybe some low-profile sidecovers as this didn't come with any.





The engine wasn't too hard to un-seize, put some blaster and a little 2 stroke oil in the cylinders and waited 5 days. Used the ingito object on the left hand side with a tie-down and a nice wooden lever.








Gently used a screwdriver to monitor the first movements of piston 1. Rotated back and forth until full rotations became easier, then used the kickstart. Unfortunately, with all that oil in there it's essentially a glorified oil-squirtgun,  but it's still victory! 

[oldhondarider]

Sweet... I'm in the middle of a 71 cb500 rebuild as well... I'll be looking forward to seeing your progress... Love'd to see pics of tank work as it's going... I'm interested in seeing how it goes for you..

thanks

[papp101]

When I got it turning, I decided to check for spark.

Battery in, key on, blinkers sorta work, no spark.

Checked the coils with a multimeter between the two high tension leads that go to the plugs, and got "0" continuity. As per the honda manual, this means they're kaputt.





I have never really had to tackle both the carb/engine AND the electrical sides of a fixerupper, and the more I read HONDAMAN and TWOTIRED's information on how the resistance builds up in crappy connectors, I realized this was going to need the WHOLE 9 YARDS.

ENGINE SIDE
The plan is to replace the rings, as I'm sure they're rusted and disgusting, and the same with the valveseats, meanwhile do some porting.

ELECTRICAL SIDE
The plan is to replace the coils with something cheap but effective, verify the points, disassemble and cleanup all the connections/rotted wires. Relay-wire the coils direct to the battery and move all the electrics and battery either to the seat hump or just readjust under the center section.

INSIDE FOR THE MINNESOTA WINTER
Well, it was a nice fall day so I had the intentions of just lifting the bike down the stairs for this going through of the engine and electricals. There is no way in hell this 450lb beast was going to make it down the steps without killing one of us.

So I "lightened it up a bit."

BEFORE








AFTER







DOWN IN THE BASEMENT COMPLETE!

[papp101]

Sweet... I'm in the middle of a 71 cb500 rebuild as well... I'll be looking forward to seeing your progress... Love'd to see pics of tank work as it's going... I'm interested in seeing how it goes for you..

thanks

Yah man, funny enough YOUR 500 rebuild really inspired me! I realized how important it was to do a detailed pic-oriented one as well, and it's gonna be great. I've got my head disassembly to post still, wait till you see the gunk in this baby!

[oldhondarider]

I'd love to see the head disassembly...  I want to take mine off and buff it out to a high gloss....

[papp101]

Thanks to this page, I downloaded and printed the step-by-step for cam/head removal.

Check out the gunk in this baby!









Didn't want to attempt running it without verifying clean cylinders. And it looks like SH!T.

Here we go!

Took off the carbs just to take a peek - rust and muck galore. Will probably be ordering carb rebuild kits. Also, the little metal things that sit in the bottom of the bowls were rusted to nothingness.





It was only 35.00 and is fit to perform only 2 tasks. Blowing out carbs, and filling motorcycle tires. At that, it's just fine.



I've decided to take care of the engine first, and the carbs second. So I'll be dealing with these guys later on.

Needed to go gentle on the wires for the magneto, so that needed disconnected. It looked like crap. I will need to learn how to test this to see if it's still good!








Needed to remove the sidecover to get to the connecting wires.







Once off, I could turn the engine with a 19mm socket like normal.

[papp101]

I'd love to see the head disassembly...  I want to take mine off and buff it out to a high gloss....

Yes! I want to do a good polish job on everything as well - I thought I was going to have to paint the main case, but gosh as I wipe it I realize how good the finish still is - prolly just gonna buff the sidecovers, and paint the mid-jug or the head high heat black. Didn't you do that on yours? I think it looks awesome!

[papp101]

To the manual!

Every single phillips head bolt I had to use my harbor freight impact wrench. That thing has paid for itself about 15 times over just in these next few pix. I'll have to find a great selection of metric bolts to replace all of these.

I already knew I'd be replacing the exhaust studs, so I cracked them loose with a pair of channel locks, and took them out the quick way.



Off with the tach cable.



Off with the breather tube.



The order of screws in the top of the breather cover:



Breather cover:




Side caps were a biatch. I whacked my hand with the hammer I was using on the impact. It's nice and red today.



Short screws in the front of the valve cover, Long in the back.




Order of screws for the 2nd round of fasteners on the valve cover.




Off with the cam cover! The o-ring looks pretty good still!





The cam itself was pretty easy.







Don't forget a screwdriver to hold the chain.

[papp101]

Now for the best part. I've been dreaming about this for 2 weeks, and finally off it comes!

Inake tracts come off:



The 12 Head bolts (2 flange bolts)



Strong but gentle, strong but gentle, . . . . screw it. HEAVE!



There we go! Don't diss the headlamp, that's 10 bucks of genius right there.



There we go! There's no scoring under the cam cradles, the cam itself looks great, I haven't inspected the valves.

There's about an 1/8" of junk on top of the pistons.






QUESTIONS

At this point, would you pull the jug and replace the rings? I couldn't get a compression reading beforehand, so I can't offer that point of reference.

Would you do anything to the cam, aka advance by 3 degrees, or replace with a 650 cam?

Thanks for the help everyone! Comments are always welcome, as this is my first teardown!

[rachet]

CB500/550's must be all the rage these days.  I have one of each sitting in my garage/driveway with the glorious dreams of building a tight little cafe racer.  thanks for the detailed pics! (I hate being on camera duty!)

Keep us posted!

Rachet~

[papp101]

Well if two large posts in one day weren't enough, let's go for three.

Here's some closeups of the head with nearly 1/4" of grime on it!







And the little o-rings, one on each side.




And the additional grossness once again of the ports:









I decided it would be best to get the jug off, as I need to be able to properly clean it, and that will make it easier to paint black and bake in the oven.   

With that, I removed the nut, washer and o-ring for the cam chain tensioner:



Used the screwdriver slots to create some leverage. Man, I felt like I was really gnarling up the edge of that block, I'm hoping I didn't do any damage to it!




Got it up an inch or so and removed the cam chain tensioner:



Boy, it was TOUGH to get the jug off there. Pain and suffering for the edges I hope I didn't beat too badly.

I took a hammer wrapped in a tee-shirt and worked it both ways to scoot the jug off.




It looks decent, the cylinder sleeves are quite beautiful, no signs of scoring except and the top, which might be just a bunch of caked sh!t.








Piston 4 & 3 look good despite the loads of crap on them.




Piston 2 & 1 look in a little more pain. Stuck rings for sure.




Will probably need a new head gasket, and most definitely the gasket that goes between the jug and the case.




Removing the pistons was a royal PITA.   I removed the snap rings, then ended up using a c-clamp and some sockets to coerce them at the beginning. Finally used a 3/8" rachet extension to bludgeon them the rest of the way.








Again, 4 & 3 are decent, while 1 & 2 have issues.







Lonely case with a prophylactic of sorts to prevent the incurrence of "junk".






QUESTIONS

Would you replace just the rings? or pistons as well? Any help is appreciated.

[oldhondarider]

between you and I.. I think we have almost ( or will have) a complete photo blog of a 500 teardown...  HA!!  I've PDF'd each page so I can print them out.

Thanks!

[bunghole]

Your cylinders look like a leprechaun latrine. 

[martino1972]

hmmm....first off,with all that water and crap in there i would also take the rest of the engine apart!!!

and about those pistons,i would have the cylinders bored over and a set of new pistons aswell...

but first i would pull the rest apart,to see what else is all rusted up....

just my 2 cent's....

[papp101]

Overbore with new pistons, eh?

I'm considering it. It looks like I'd need at LEAST 2 sets of rings which will run me 80.00 plus shipping.  I see an overbore kit for 150 with pistons, rings and gasket on ebay, but then I need to pay someone to bore it!

Suggestions?

[KB02]

Take a full set of measurements on the cylinders. You're right, they do look pretty good, but looks can be deceiving. You might be able to get away with just honing them out instead of boring them out. Either way, you'll want four new ring sets at the very least. Depending on what your cleaning efforts achieve, you may want four new pistons, too.

BUT, I've seen worse:

From this swamp: to a running engine can be done.   

[papp101]

Wow man, I had seen that pic in your avatar before and now up close I don't know if it's inspiring or scary! 

I agree on the honing.

I need to figure out if I'm going to spend 150 on a bore kit plus machining costs, or 120.00 on a set of rings.

[papp101]

So my intake valve on #1 is bent from a knock on the cylinder when I was unsticking the b-hatch. The valve itself will NOT come out of the valve guide, and I feel like I'm just bludgeoning the sh!t out of it, even though I'm trying to be gentle.

Questions

I know there's a valve guide removal tool - should I even worry about taking those out?

Will a 550 head fit on a 500 direct swap? I'm looking at the price for a replacement valve on BikeBandit, and it's more than this ebay auction.

Bikebandit:
http://www.bikebandit.com/houseofmotorcycles/honda-motorcycle-cb500-1971/o/m9140

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=260307859719&fromMakeTrack=true&ssPageName=VIP:Watchlink:middle:us

Input is greatly appreciated! I can post pics if anyone's interested.

[dagersh]

Looks like you got it!  It should be fine.  Also, see if your seller has the CAM cover as well.  There were improvements over the 500 designs that made the 550 units last much longer.  I wish I could be more specific.  I am sure someone can jump in here and clear up what I mean and help with the thread that talked about it.

[tbpmusic]

So my intake valve on #1 is bent from a knock on the cylinder when I was unsticking the b-hatch. The valve itself will NOT come out of the valve guide, and I feel like I'm just bludgeoning the sh!t out of it, even though I'm trying to be gentle.

Questions

I know there's a valve guide removal tool - should I even worry about taking those out?

Valve guides can be replaced.
Normally, you heat up the head, then knock it out.
The new guide is installed, then it is reamed out with a precision reamer.
Do not attempt to use the new valve guide without doing that - they are not machined to give the proper fit without precision reaming.

bill2

[dagersh]

Papp

Look for this thread:

A Noob's 75 CB550 Cafe Project Thread ------- Stick a fork in it... ;-)

It explains what I meant above!

Gersh

[papp101]

Dagersh: I will look at that thread right after this post for sure! I do have the cam cover and it's in decent shape. MAn you've gotta lotta bikes! I'm slightly jealous. . .   

tbpmusic: I wish I would've read your post about heating up the head first. I totally nailed the end of one when trying to "tap" it out. Luckily I have this on the way which should give me more than I need in the world of replacements. Next time I will heat it up! Would you recommend a torch or a hot lamp or a hot water bath? Here's my spare part farm. Has 9000 miles on it.



So to remove the bent valve, I grabbed my dremel:



And took to it!



Easy as pie! I love that thing.




I then used part of the tool I rented with my own c-clamp, thank god for that. Worked quite well.



Ugly Ugly goop.




Then into the bath to sit overnight. Unfortunately, I had to dilute the solution to totally submerge the part, 1 to 6. Hopefully it's not to weak! Pistons, Head, Valves and all.



I ordered a Honda Spark Plug Tool so I can actually get my D7EA's in and out, which is impossible with a regular plug wrench socket head without turning it down to a thin-wall.

Also ordered a gasket set for 40.00 or so bux off e-pay that included valve guide "umbrella" seals.

Next up is honing the cylinders.

[DCopp]

buy this from me...



$10 plus actual shipping.
PM me if interested...from a 1974 550

[tbpmusic]

tbpmusic: I wish I would've read your post about heating up the head first. I totally nailed the end of one when trying to "tap" it out. Luckily I have this on the way which should give me more than I need in the world of replacements. Next time I will heat it up! Would you recommend a torch or a hot lamp or a hot water bath? Here's my spare part farm. Has 9000 miles on it.

None of the above - just put it in your kitchen oven for a while.
Maybe 250 F or so, should do the trick.

bill

[papp101]

TPBMUSIC: I like the way you talk. Done and done!

Dcopp: Looks like some nice stuff you have there? How many miles on it, and why'd you remove it? Very interested. Will it bolt right up to my 500 block? Come to think of it I just purchased major gaskets for a cb500, which means I would need to "bore" out those gaskets to fit the bigger sleeves, correct?