Topic: 72 CB750 Cafe build

[72hondacb750]

So I'm new to the board and cb's but I've got myself a 72 750 and I aim to do a cafe racer style build on it. Going to do satin black powder coat and paint , some clubman bars, fenderless .. . keep it simple. Here are some pics from getting started. I've only had it a day and already I have a ton of questions .. Advice is warmly welcomed

now what I know about the bike so far is that it was previously wrecked and the person put a new frame under it. . . it then proceeded to sit in a garaged covered for several years, I'm not sure why. The person that I purchased it from was 3rd owner after the guy that wrecked it and a diff guy that garaged it. Here she is...




Started tearing it down...



Got the Engine out..

On the work table .. .

Valvetrain..

First look at the valves..


and the pistons..


muck on the 1st piston..


inside the cylinder walls was very clean .. no grooves .. well oiled .. no signs of wear that I could see at all.



I didn't get any pics of the carbs but they seem completely functional, they must've been well oiled before the bike was stored away. Everything on the bike seems like it was properly prepped for storage and the only place I ran into any concern was with the goop on the 1st cylinder.

From here my big question is how much further into this engine should I really dive? Without signs of cylinder wear should I bother with rings at all? In every way I could tell they looked to be in great health.

What should I do to clean out the head and pistons? Is a wire brush to much to take to the combustion chamber in the heads? If I drop the valves out will I have to replace the guides? If you even just have links to these topics they would help, there is so much on this site I have trouble finding just the things I need.

Here are some things I could use some help finding for this part of the build ..
I need ..
-- The covers for the engine, generator cover, timing cover, clutch cover, ect.
-- all the exterior bolts , the covers mentioned and the valve cover, ect.
-- complete engine gaskit set.
-- 4 carb rebuild kits
-- k&n style air filters
-- both throttle cables
-- oil lines

If anyone has sites/merchants they use for any of these parts let me know, I'm looking for a good place to start ordering stuff from.

Just as soon as I can get this engine underway I'll be starting on the next batch of stuff... Brakes, cables, lines, and wiring..

Thanks guys!

[andy750]

Welcome and looks like a good project. Before you start Id verify it really is a 72 engine...I only ask as the fork ears on the bike are from 73 and up. Whats the engine number? To check engine number versus year go to www.hondachopper.com

For ordering parts I like servicehonda.com and bikebandit (AMA discount). Honda dealers also carry most of your stuff. Check the FAQ for more vendors. David Silver Spares is a great resource as well and fast shipping.

good luck with it, the 72s are the best year 

cheers
Andy

[Johnny5]

Nice platform and pictures. Looking forward to following another cafe build.

I've had good luck with z1enterprises and bikebandit for various parts.

[72hondacb750]

so the engine was 1103XXX which is K1 right?
And the frame was 2041XXX which is K2 ??

[andy750]

so the engine was 1103XXX which is K1 right?
And the frame was 2041XXX which is K2 ??

Yes that would be correct. Then I wonder why your fork ears have been replaced? Was the front end in a crash? Curious.

cheers
Andy

[72hondacb750]

Yes I know for sure that the bike had been wrecked all of the engine covers are in need of replacment because of it. Those headlight ears will be coming off soon ... for good.

The guide on that site said K1 is 1971 and K2 is 1972 .. Should I be looking at engine parts for the 71 model year ??

Anyone have a link to a good valvetrain rebuild guide? I'm thinking of tearing it down but not the pistons/rings. I'm pretty satisfied with the quality of the cylinder walls but want to give the head a good cleaning while it's off.

thanks,
Phil

[72hondacb750]

Ok, Tonight I ordered;

-- Complete gasket set.
-- Bolt set (all visible)
-- Can of engine paint <shrug>
-- 4 cheap air filters
-- 4 carb rebuild kits
-- oil filter..

I need to find a good source for the covers, I still need alt cover, timing cover and clutch cover. Any leads?

[Johnny5]

4 cheap air filters? Im assuming pods. If so, you'll need to rejet the carbs once the bike is up and running. There's lots of information in the forum on doing this.

[captaincrash80]

I may have the covers you need, I'll look tonight and see what I have.

[72hondacb750]

got some work done on the bike .. just waiting on that first order of parts to get here next week .. cleaned up the pistons and the valves .. removed all the old gasket .. soaking the head in degreaser.

Here's more pics .





Carbs look great but I'm going to do a rebuild just to be sure..



I'm not sure what to do for exhaust ,, I like the 4-2-1 exhaust without a muffler ,, satin black into a nice chrome tip ...
This is what i have right now .. A set of 4-2-1 and a set of 4-4.



or




still not sure what to do about all that though .. I'm pretty handy with a welder .. I was thinking I may do something customer with the 4-2-1 but it's got a few dents that will make it interesting.

Brakes, chain and sprockets are next.

[ksmith0034]

Nice start 72hondacb750.  You guys who do this stuff fast make me sick 
I've been working on my '71 CB750 cafe build for a year and a half now.  Check it out at www.stocker2rocker.com

[KB02]

Nice start 72hondacb750.  You guys who do this stuff fast make me sick 
I've been working on my '71 CB750 cafe build for a year and a half now.  Check it out at www.stocker2rocker.com

Shoot, I hoping to at least have "significant progress" at my two year mark. My next cafe build is going to be a quick, cheap and easy job. That way I can look at the one that took me two years and say "That one's much better."   

Engine's looking good, man. Those pistons cleaned up nicely.

[BuffaloK3]

What to do with the exhaust?

Well you could always sell the 4-4 to me, for my K2 project (Sorry, Im a vulture)

Hey, what is the set back of the handle bars?  Dont seem stock, and look to be about what I have been thinking of going for.

If you get a chance, thanks

[72hondacb750]

So I spent the evening cleaning things up still .. here's some pics.


finished cleaning the head up as best as I could without tearing it down further. I've decided that maybe next winter I'll do a more in depth engine build up when I can concentrate more on it as it's own project and not a small part of a bigger deal..



cleaned in the exhaust valves what I could without getting down into the valve or guide..



After finishing up with the head I got to taking the front brake caliper down .. It was pretty seized .. The seal was terrible and had a ton of crud around it .. I polished up the piston with a wet sand of 1000 grit sand paper there is very little pitting so I'll reuse it. The caliper I cleaned out with a dental pic and it's soaking in solvent.



Anyone have a good source for new brake line? I need upper and lower, would prefer stainless but depending the cost may go rubber.

ordered more parts tonight as well..

got cables ..
--throttle push and pull
--clutch
--spedo
--tach
master cylinder rebuild kit.
caliper seal
spark plugs
front and rear sprokets (17-48)
and x ring chain

here are a couple pics of those handle bars ..




would be willing to sell .. pm me ,,

the exhaust is alright but I think it was on the bike when it was wrecked because it has some clear signs of stress. I'd be willing to sell but I don't think it would be worth your while to have it shipped clear across the country .. (I'm in phoenix) but again pm me we can talk.

If anyone has a site for brake lines that's not over the top prices please let me know : )

[72hondacb750]

First big order of parts came in last night so I got to work on the bike tonight, Reassembled the top end of the engine with new gaskets and some lucas assembly lube. Then pulled all the carbs from the carb cleaner and brushed them down and started to take them apart for rebuild.

After that I set in to doing some bead-blasting .. Here are some pics of everything.

Here is the engine ready for paint and polish.


Here is the carbs getting ready to be rebuilt



New chain and sprockets also came today..
front sprocket is already on the trans in the pic above.


Here are some pictures of my home made bead-blasting booth .. With beads and a gun this cost less than $50 to setup and works like a charm.







It's not the easiest setup on earth but effective for sure.

Tomorrow I'll try and finish the carbs, maybe get to work on the wheels and the back brake. Has been a fun project in a stressful time in my life so I'm very happy with things so far.

Still looking for a good source on a front brake line though.

[DollarBill]

That's the kind of ingenuity that give people like me a smile.  I've been thinking about putting a blasting cabinet together for a while and this proves to me that it can be very simple, inexpensive, and most importantly effective.   When you finish blasting do you just sweep the media back up and pour it into your hopper or do you have another recovery system?

[dagersh]

Give us some more details on your blasting booth!

Have you tried HEL for your SS lines?  They make great lines and his service is great as well.  I think in the Spring he was backed up, and tough to get a hold of, but I think at this point in time, he will be real happy for the business.

Gersh

[72hondacb750]

Inside my make shift blasting cabinet I have a dustpan and very fine strainer. I gently scoop it up and strain it before putting it back into the hopper. I don't have a huge compressor so this reloading process gives some recovery time : )

See bottom right corner of this pic.


Thanks for your suggestion on HEL Lines .. A search of the forums for them turned up a retailer and a number of other companies that sell what appear to be great lines..

[72hondacb750]

Worked a little tonight ,, Finished bead blasting and repainted the caliper ,, also finished tearing down the carbs and taped off the valve cover to paint the engine. . .. Here are some pics from my iphone .. sry for the bad quality

caliper drying in a nice dust free bucket . .


Carbs after tear down.. some cleaning still needed.. Started polishing the float bowls.




Took this shot of where I keep my compressor .. Inside this cabinet with foam you can have a normal conversation in my garage without your ears bleeding from the racket 


Here's a shot of my work table


Hopefully tomorrow night I'll decide if I want to paint the carb bodies black or not and maybe put them back together.

[72hondacb750]

Bought a 6inch benchtop Buffer on craigslist today for $25 ... Seems to work great and came with these two little 4inch wheels on it.

I'll replace them this week and get some better polishing compounds



Polished up the bowls on my carbs and started putting them back together. I know I'll have to rejet them later but just assembling them with all stock rebuild kits for now.

The bowls aren't polished to perfection but they have a decent shine going. I don't really want anything on this bike to be tooo clean anyway.



Still can't decide if I want to get all crazy and try to paint the carb bodies flat black or not. so much to tape off ..

[Ricky_Racer]

Nice job on the float bowls!  Which buffing compounds seem to work best on the carb metal?  Thanks. RR

[72hondacb750]

I did a light bead blast and then wet sanded with 1000grit ... After that the only compound I used was the white kind. I have mothers aluminum polish and it gives a better shine but it was more shine than I wanted on the them.

[greenjeans]

For aluminum, pretty much all you need is some brown Tripoli....its for aluminum

If you get some stiffer buffing wheels and put them together on the same spindle (making a wider buff vs 1)
you can cut some time down....same goes with the softer ones.

Keep cleaning the wheels often - use a screwdriver or something....I use an old wire brush

I have yet to sand anything on my parts, and some/most were very nasty.   Let the compound do the work
and another tip - get some of those tight leather mechanics gloves....helps keep a grip on things.

[72hondacb750]

is tripoly something I'd have to order on the internet or is there somewhere that would carry it locally?

[andy750]

is tripoly something I'd have to order on the internet or is there somewhere that would carry it locally?

Plenty on the internet..for example...

http://www.hobbytool.com/aluminummetalpolishingkit.aspx