Topic: greasy's re-rebuild 'the utilitarian transcendentalist' 71 cb750

[greasy j]

Is the crack directly opposite one of the bolt holes that hold the oil line fitting? If so, from what I can tell from the photos, a bolt that was too long was threaded in to a blind hole, and pushed the floor of the hole up. The oil passage is probably fine. Worst case is a minor oil leak around that bolt since it is no longer a blind hole. JB weld will probably work just fine here.

good call. I was wondering what could have done that, and it is definitely coming up from below. now that I check it, you're right it lines up with the bolt that holds the oil line fitting.

you win the prize.

I was thinking some devcon or jbweld would hold, too. mostly because it is a very rough break(plenty of teeth) and there is a pocket that it would sit in. usually in cases like that epoxy forms a really strong bond, as compared to being on a smooth flat surface. but it could still leak out of the screw hole which is no longer blind like you are saying. I haven't had any leaks, though. so I'm thinking the screw has been keeping it sealed so far. maybe I'll use one of those rubber sided washers when I put it back together.

[scottly]

I would clean it really, really good with brake cleaner, then work the JB weld into the crack. Even without the JB, teflon tape on the bolt would probably solve any leaks. 

[scottly]

you win the prize.

So what did I win??!!

[greasy j]

a free paint job. up to 4 square inches. maybe a fingernail or 2? anything you like...

[paulages]

I would clean it really, really good with brake cleaner, then work the JB weld into the crack. Even without the JB, teflon tape on the bolt would probably solve any leaks. 

teflon tape doesn't actually seal, it just lubricates the threads so you can tighten farther on a tapered pipe thread.

[greasy j]

he probably meant the pipe wrap tape stuff that you use on air tools and such..

[scottly]

teflon tape doesn't actually seal, it just lubricates the threads so you can tighten farther on a tapered pipe thread.

Huh?? Teflon tape is used to SEAL!!

[RAFster122s]

the stuff/tape used on air tools is teflon tape...comes in different colors based on use

Another thought on the bolt length...
The bolt may have been too long because they didn't use a washer and the length depended upon that washer thickness to not bottom out and crack the case.
My vote, JB Weld the hole (without overdoing it) and you'll probably never have an issue with it. 
Teflon tape may seal it but you are likely to have difficulty getting it to screw in all the way with teflon tape on the threads.
One wrap around the tip of the bolt is all I would use if I were going to put any on the bolt.

[greasy j]

it never leaked before so maybe it cracked it, pushed up, but didn't pierce through the bolt hole? or the bolt kept it sealed. maybe just grime.

I never know the technical names for things. teflon tape, now I know. I had to look up 'blind hole' too. just to be sure. it's pretty obvious, but ya never know...


hey scottly, what type of gas tank is on the bike in your avatar?

[scottly]

It's a Seeley.
http://www.seeley-register.org/

[traveler]

A real SEELEY.....very nice!

~Joe

[greasy j]

wow! it looks awesome. more pics somewhere?

[greasy j]

so I cleaned up the lower case a lot. mine wasn't painted I don't think? as far as I can tell it was clear coated? got all that yuck off and I kind of like the way it looks just bare aluminum. I might leave it that way and clear it again. keep the 'patina' as they say.

after thoroughly cleaning I tried plugging up the oil galley holes and blowing compressed air through to see if the crack would leak air. it didn't. I did the same with the screw hole. still didn't leak. so I think the screw ruptured the case a lil but it's not through all the way. I cleaned up the cracked area, wire brush roughed it up around the edges, and soaked it in lacquer thinner for a minute. then shot air at it til it was bone dry and clean as could be. filled the crack w/ jbweld, which I think will be fine since it has a pocket to sit in and lots of teeth to hold onto. and there is no real pressure working on it since the hole is not through.

when it's dry I will test it. if it fails at all, I'll dig it out and have it welded. fingers crossed, but I think it's gonna be cool.

[greasy j]

here ya go. w/out pics it quickly becomes boring, right?






gamma flats gave me some advice on using my camera, so these are a bit more in focus. he said he's writing a thread w/ tips. would be worth checking out.

[Really?]

Interesting title change there Greasy J, lol.  Perty kewl.  Or you could put it in your sig.

I think I saw that recently.

[greasy j]

Interesting title change there Greasy J, lol.  Perty kewl.  Or you could put it in your sig.

I think I saw that recently.

not sure I follow? I didn't change the title. I don't think.

anyways every reply makes me feel like people are following and gives me the motivation to keep posting pics. so thanks!

[Industrial Cafe]

I didn't notice the quoted part in your title until recently either.

[greasy j]

easy to just glaze over when there are 2 big words in a row.

[greasy j]

so I did some laundry...



if you don't get the reference;
http://forums.sohc4.net/index.php?topic=66778.0

those finned covers were chromed. I tried blasting it off, but it's not working. I'm just using the finned 'sohc' one(back left in pic) and my original clutch cover. the finned clutch cover is super heavy, pointless. not very utilitarian.

so I might have them rechromed? would rather they were just polished bare metal, but how do I get down to it? metal etch would prob ruin the metal underneath also. so it's take them somewhere to be stripped or rechromed($) or paint them black to match the head and jugs which are going semigloss black.

they were black before, but with the finned parts on the engine being black as well, will this be too busy? what about doing the tappet covers black also? opinions?

also, I've polished metal before, mostly gas tanks, but I am far from expert at polishing. usually I wet sand til it's ready to polish then just use a foam polisher chucked to a die grinder. this works more or less. I now have polishing wheels and some other goodies I picked up at HF.

how would you do these engine covers using what you see in the pics?


I know there are a lot of topics on polishing. if there is one that you know of that would help, please post a link here...

starting from the pieces being blasted rough as now, normally next I would wet sand. which will suck with all the tight spots and crevices. any advice?

[RAFster122s]

If you sandblasted the aluminum pieces then you have more  work than normal if you want them polished.
I would suggest you find some abrasive powder like rottenstone and make a slurry you can use with buffling wheels to take the textured surface back to a smoother surface and then when ithat is done you cna break out the polishing buffs with cutting and polishsing compounds. The buffs should do a pretty good job getting into the grooves if you take your time and don't try and push it. Let the compounds do the work.
A bench polisher with longer shafts would be easier & faster than the hand die grinder for the big pieces...
HF had them recently for $40.

David

[greasy j]

If you sandblasted the aluminum pieces then you have more  work than normal if you want them polished.

oops.

live and learn. I thought it would get an even surface to start with. some of the pieces had big gouges and stuff. thanks for the info david. more work. yay!

A bench polisher with longer shafts would be easier & faster than the hand die grinder for the big pieces...

I was thinkin of being cheap and putting my die grinder in a vise. maybe I'll just get the bench one, though...

[RAFster122s]

You could start with a high cutting compound like emery and see if it would knock down the texture.
If it does, then you could stick with buffing wheels and compounds...

Use a sisal wheel with the black compound to cut and level the surface. If it works then you just have more time  on with the emery (black) compound.
Then move to spiral sewn cotton buffs with the brown (tripoli) compound and when it sparkles you finish with white rouge.

The buffs stick with one color, you don't use them with other colors. Switch buffs if you need to do that...

Won't hurt to try.
I've been wrong before...

David

[greasy j]

awesome, thanks!

lookin at bike bandit's OEM section for bearing shells(crank) and roller bearings for the bottom end(transmission).

a couple roller bearings have unsmoothness about them. one is labeled 6204. found it on the parts list on BB. only $10, cool. some of the other roller bearings are up to $30, though. I was thinking of replacing them all just to be thorough, but it would get spendy.

hondaman recommends SKF or KML as the best choices. I found a SKF bearing labeled 6204 for around the same price as BB. can I be sure it will work based on the code(6204)? anyone know what brand of bearing BB stocks? know of a good place to order this stuff? better than bike bandit, that is?

also, all new bearing shells(crank) would cost me about $150! the ones I have are perfectly good as far as plastigage says. but one has a good sized scratch and another has a chip, slightly smaller than the oil hole. do I replace or not? I'm inclined to just keep them. but I'm stingy. not sure if I should be in this case...

[greasy j]

I ordered some sisal wheels and an alum polish kit w/ black, brown, red. the blasting was done w/ alum oxide, pretty fine. so it's actually a pretty smooth finish, not like w/ sand.

[Gcolgett]

Hi Joel: I went to sears and got a 1/3rd HP grinder and the fine sow-en buffing wheels which to work better than the soft fluffy ones they shred really bad. The wheels are only 1/2"down from the outer sowing band.The wheels like the ones you have pictured are the ones that shred bad!. I found the white buffing compound the best for Alu. George Colgett