Author Topic: '75 750F first timer restoration  (Read 1672 times)

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Offline jwk1414

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'75 750F first timer restoration
« on: April 13, 2011, 03:57:17 PM »
A couple months after lingering on this website and others like it (although there are NO other websites that match this one for information) I finally can call myself a sohc owner/restorer. Recently purchased the little beauty pictured below and am going to try my darndest to get the thing running in the next few weeks before I head out on a multi-month long work trip. Pipe dream? Probably, as I've never wrenched on a motorcycle before (my experience mostly being confined to age-old farm equipment.) 

That being said, originally I had planned to cafe this bike, until I picked it up and realized that it is an F, not the the K that I had expected.  From what I've gathered (feel free to prove me wrong), parts are much harder and consequently pricier on the F series.  My new goal is get my feet wet getting this one in great shape, making minor improvements where financially possible, while saving the big bills for a cafe project.  I'm a little over a grand into this project already, and if I get it looking shiny and running like a champ I think I could come even or slightly ahead.  We'll see.

So far, I have the carbs disassembled and ready for a Simple Green bath when I get home, any suggestions on what to tackle next? I'm assuming a new battery is in order, I don't think the bike has run in several years.  Gas tank is missing a petcock/fuel line, so I'll need to rustle up something there before even trying to THINK about starting.

I'll post some more pictures of some problem areas I've noticed already when I get home.  PO said compression is good, but I haven't checked it yet.  Currently, the 1 and 4 cylinders are missing their spark plugs assembly, so obviously need to get that sorted out.  Wiring mostly baffles me, but I want to learn how to do it.

So, without further ado, here are the goods:






Missing spark plug assembly



Fins are in pretty good shape excluding this missing chunk






I broke this little guy in half while removing the air-fuel mixture screw- is this something I need to replace or is it there simply to make syncing the bike easier?

Jesse

Offline ofreen

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Re: '75 750F first timer restoration
« Reply #1 on: April 13, 2011, 04:41:02 PM »
It is always good to see another '75 750F put back into circulation.  You have an example of what the well-informed believe is the best of Honda's SOHC 750s.  ;)

Yours doesn't look too bad compared to some other projects tackled on this forum.  Much depends on how sound the engine is.  If it is, much of what you need to do is cleaning up and servicing.  Go through the brakes.  Replace the tires and tubes if they are old.  Service the suspension and steering head.  How good are the chain and sprockets?  Clean electrical connections.  It wouldn't hurt to have a look at the sump screen under the engine.  Check nuts and bolts for tightness.  Clean and service control levers and cables.  And the instrument cables.  Check the wheels, bearings, and spokes.  Basically, start at one end of the bike and work to the other end.  When you get there, you'll know what you have.  How many miles on it?  How much do you know of the bike's history? 

Have fun.
Greg
'75 CB750F

"I would rather have questions I cannot answer than answers I cannot question." - Dr. Wei-Hock Soon

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: '75 750F first timer restoration
« Reply #2 on: April 13, 2011, 06:13:46 PM »
Fine looking bike!

The petcock is still available from Honda but kinda pricey. Get used to that. Let us know what you are looking for. I can easily tell you if you can still get it from Honda. Some things you can't get are body parts, rear master, muffler, dummy light cluster, etc. Correct handlebars not available from Honda either but I can tell you where to get them. One place in the US and 1 in Japan. Spark plug cap is readily available but I'd suggest checking the resistance on the remaining 3 before ordering just 1. Don't worry about the carb screw "cover" unless you need the perfect or cool factor. Not necessary. Put up more pictures and I'll provide more detail. Side cover(s) not available from Honda but there are 2 aftermarket sources that are identical. Frankenstuff on here and LPM in England which will definitely cost you more. The side cover emblems MAY still be available. Head gasket leak is very minor and I wouldn't worry about that, unless you wish to take the engine out just to torque  it down properly. Common occurence. That's all I can tell for now.
« Last Edit: April 13, 2011, 06:19:08 PM by Jerry Rxman Griffin »
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline jwk1414

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Re: '75 750F first timer restoration
« Reply #3 on: April 13, 2011, 06:33:59 PM »
Thanks for input Greg and Jerry.  My carbs are soaking right now and I'm about to head out to fiddle with my front brakes.  Pulling the brake lever does nothing but the brakes are binding so I'm assuming the pull cable is messed up somewhere. Debating just pulling everything off and going through it. I'll have pictures up later.

Scratch that.  No brake fluid in the master cylinder.
« Last Edit: April 13, 2011, 06:53:30 PM by jwk1414 »

Offline jwk1414

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Re: '75 750F first timer restoration
« Reply #4 on: April 14, 2011, 01:00:25 AM »
I can definitely take all the help I can get with part sourcing.  I'm looking at a fuel petcock on partsnmore for about $30, some braided steel from bikebandit and a guy over at slingshot-cycles.com. My carb bowl gaskets are toast so I'm probably looking at some of those and a master cylinder rebuild kit. Rear socket looks pretty good... to me. I'll gladly accept dissenting opinions.

Right now, my jets are soaking in acetone, and the carb bodies and bowls are clean and shiny while the rest of the carb assembly bathes in Simple Green. 

Master cylinder piston seems to work pretty good.  Debating whether the rebuild kit is necessary? Advice there would be greatly appreciated.

I'll post a picture below of the wire that attaches to the no 4 spark plug- looks like it has been chewed off.  Do i just need to strip it down and solder on the plug assembly? Thanks in advance for the advice.


ahhhh


Some corrosion on the left side but otherwise good


Teeth seem to be in pretty good shape.




Fork seals appear to be in good shape. Fork oil... probably not so much.


Offline Jerry Rxman Griffin aka MuthaF'er

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Re: '75 750F first timer restoration
« Reply #5 on: April 14, 2011, 03:05:19 PM »
Clip the plug wire back a little and install new cap - no solder required.

If the rear master is working and not leaking then you're good to go.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline BeSeeingYou

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Re: '75 750F first timer restoration
« Reply #6 on: April 14, 2011, 04:52:06 PM »
If your master cylinders are working ok it's debatable whether they need rebuilding but I would replace the seals in both calipers and check the condition of the pistons.  The front caliper is not fond of dirt, brake dust, and lack of lubrication.  Most of the parts you will need are not that hard to find as long as you have the functioning core of the bike.  Things like calipers, master cylinders, gas tanks, stock exhaust, left hand controls, you will not find new but rebuild kits are available and there is after market options for others.  Don't worry too much about parts.  You will find what you need.

Offline jwk1414

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Re: '75 750F first timer restoration
« Reply #7 on: April 14, 2011, 06:26:07 PM »
The last 24 hours have been spent looking for parts.  Bowl gaskets, braided steel lines, outer carb boots, brake pads, and three vanity purchases.  I bit the bullet on clip-on bars because the idea of buying another set of shorter brake lines after the bike is up and running and ready to cafe doesn't appeal to me. Also bought a mini speedo with a built-in light cluster and a mini tach.

I need some help with a petcock question- I'm eyeing this one [http://www.partsnmore.com/images/parts/480/20-0100.jpg] one on partsnmore but am not sure if it will fit.  I've pored over old posts here but haven't come to a conclusion- do I need an adapter plate/nut? Petcock measures .779 outside diameter and .556 inner diameter. Seems like this shouldn't be a hard problem but I'm not seeing clearly.

srust- thanks for your interest in the build.  I'm still working on getting the frozen brake pad out of the front caliper, system was totally dry so I need to get some brake fluid to pump it off of there.  I'll post pictures when that happens.  Looks pretty filthy so some

Jerry- thanks. That is a relief.  I was going to buy new coil wires but I think I'll just wait to see if I can get these to fly.

Petcock threads: