Author Topic: CB750 F1 Restoration Project - not for the faint hearted (Read 26525 times)

eddiebpool · « **on:** May 09, 2014, 12:53:59 PM »

Hello all

I have become the proud owner of a 1976 CB750 F1 today. I have been doing my homework on these bikes for about 3mths now and have visited this site many times. Now that I have a bike I have finally taken the leap into the fold.

Here's the story. I bought the bike off eBay, sight unseen and only grainy photos to go by. I did ask the seller lots of questions on history and current condition. Based on what I have been told:

- the engine turns over with good compression
- clutch free and gears select hand turning
- forks straight with and in good condition
- brakes not seized
- wheels will be good with a bit of work, tyres look good
- exhaust good
- no sign of being dropped
- other than a missing side cover the bike is complete and has not been abused
- 16,000 miles (believed genuine)

Now the real story:

- the bike was put away by the previous owner when it got too heavy for him. That was in 1988!
- the bike has not been started for 26yrs
- the tank fuel has turned to varnish and I suspect the carbs will need a serious clean / refurb

I have to be honest, I have done a couple of restorations recently so I am handy in the garage - but those were scooters. My last proper bike project was a modest Honda CB200 (apologies for mentioning a twin on this forum) 10yrs ago. I had loads of bad bikes when I was younger so know my way around. This is by far my most ambitious project to date. Some may say my most foolish. I didn't pay a lot of money for this bike but I really want to make it good again.

My question to the learned posters on this site, which I can't seem to get the answer anywhere else, is what to tackle first? Should I start with a teardown, or try to get the bike running first to see if it is worth the trouble? My thoughts are to tear down and get the top end off and have a look. I'm a wee bit worried that trying to start the bike might do damage. If anyone has any experience to share on bringing back a bike that has been a very long time asleep - things to do, things to watch out for, and things to avoid - that would be very much appreciated.

I expect I will need loads of help and I hope folks will be patient with a SOHC rookie.

Thanks in advance, Eddie.

katman · « **Reply #1 on:** May 09, 2014, 01:01:02 PM »

Hi Eddie,
If your not in a hurry, take it down. Ive done both mine. Just baggie everything and label it. Then you can paint, clean polish. Sounds like you know your way
around the garage. The effort will be worth it. Here's my 77 and 75
Keith

edwardmorris · « **Reply #2 on:** May 09, 2014, 01:03:14 PM »

Welcome, have any pix of the bike?

Me, I'd do a rebuild. If you have a gas tank full of rotten fuel varnish, its a tall order to get it running as is IMHO. Carbs will no doubt need some work, few good fellas here that can help you with that too. I say rebuild because who knows what has crawled into the crankcases after sitting for so long. Take a lot of pictures, download the factory manual from these forums, drop the oil pan and see how things look etc. etc. and see how it goes. Lots of great F builds too on these forums, head on over to the Project Shop and check them out.

david 750f · « **Reply #3 on:** May 09, 2014, 01:23:58 PM »

If it turns over and has good compression there is no need for a teardown/re-build.. Get the tank/carbs clean and and get it running!!!
My bike sat for 15 years before I got it running..No re-build needed

eddiebpool · « **Reply #4 on:** May 09, 2014, 01:34:49 PM »

Thanks Keith and Edward. Gorgeous bikes, Keith. I had my heart set on an earlier bike with 4 into 4 exhausts but the Mrs wasn't going to approve the budget required. That'll be the next one, hopefully.

I am in no made rush to get this done. I hoped to have the bike out on the road before the summer is out (Scotland is, sadly, a bit hit and miss for good weather so you grab the opportunity to get out when you can). I suppose an winter project would not be the end of the world, ready for next summer.

I will likely resist the temptation to make the first priority to get the bike to run. Would it be fair to say that if the engine is turning over then it is likely okay? At the very least serviceable? One thing I did want to do is test the compression for myself to see if what I have been told stacks up. Is there any risk of damage (to stuck valves for instance) doing this?

I have attached some pics. Grainy as I mentioned. There is black paint on the front mudguard for some strange reason, and on the tank too. Any thoughts, good of bad, very welcome.

eddiebpool · « **Reply #5 on:** May 09, 2014, 01:44:18 PM »

Quote from: david 750F on May 09, 2014, 01:23:58 PM

If it turns over and has good compression there is no need for a teardown/re-build.. Get the tank/carbs clean and and get it running!!!
My bike sat for 15 years before I got it running..No re-build needed

That's how I want my bike to look, very nice job. If I have to repaint the tank I might even go yellow!

eddiebpool · « **Reply #6 on:** May 09, 2014, 02:03:49 PM »

Couple of queries, David. My bike has a fork brace and gaiters which I know is non-standard. I see you have added fork brace to your bike. I also spotted on mine what looks like a fully enclosed chain guard - a bit like a CG125 I had (if anyone remembers them). Anyone familiar with this on one of these bikes?

atm cycles · « **Reply #7 on:** May 10, 2014, 04:52:00 AM »

Well you guys have motivated me to hold into the f1 I just picked up!!!! Will need a total rebuild but I love the fact that its all original. I believe even the tires. Looks like it had saddle bags so rear blinkers were moved. The mount were cut but I have one here already.

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eddiebpool · « **Reply #8 on:** May 10, 2014, 07:31:11 AM »

srust58, excellent advice and I really appreciate you taking the time to lay a few things out. I am very excited, I have been looking at these bikes for about 3mths, considered a couple of smaller Fours along the way, but delighted to get my hands on a 750 at last. Fuel system clean up and set up, engine flush then lubricate / refresh as you suggested, find out if I have spark, then go!

I get the bike Tuesday and will put up a few more pics then. I will hopefully have some progress to report in the coming weeks - maybe even signs of life!

Advice always welcome in the meantime.

Thanks, Eddie

BeSeeingYou · « **Reply #9 on:** May 10, 2014, 10:05:58 AM »

Quote from: atm cycles on May 10, 2014, 04:52:00 AM

Well you guys have motivated me to hold into the f1 I just picked up!!!! Will need a total rebuild but I love the fact that its all original. I believe even the tires. Looks like it had saddle bags so rear blinkers were moved. The mount were cut but I have one here already.

Sent from my iPhone using Tapatalk

I forgot to mention that they aren't really very good...so you shouldn't waste your time with that one...let me come and take it off your hands.

When the photo of mine was taken it still had the OEM tires which surprisingly were not all that terrible but they have since been replaced. Still running the OEM chain, points, and while I ran new plugs for awhile I put the originals back in.

Just fired it up last weekend after a long winter...light up instantly and settled down to a nice even idle.

tlbranth · « **Reply #10 on:** May 10, 2014, 10:25:15 AM »

Mine sat for 25 years in my garage. It was damp out there and lots of stuff rusted. I decided to see how it ran before putting any effort into restoration but, like yours, the fuel system was totally gummed up. I started by rebuilding the petcock, cleaning the tank (electrolysis), cleaning the carbs. Put a squirt of oil in each cylinder, hand cranked it a bit and then fired it up. At that point I decided it was worth restoring.

Bankerdanny · « **Reply #11 on:** May 10, 2014, 12:39:21 PM »

No need to go crazy. The '77 550 I bought in 2011 had been stored with fuel in it since around 1981.

Remove the tank and clean it, there are many ways. Vinegar seems to be the most popular at the moment. I used The Works brand toilet cleaner. If you go my route protect the paint because it will lift it.

Remove the carbs and clean them and replace the gaskets. Don't bother replacing the brass. What is there is unlikely to need replacing and the brass in most carb kits is suspect in terms of the actual jet sizes and needle profile.

Install a new battery, tires, tubes, and rim strips, and new fuel lines. Gap the plugs and points and I bet it starts right up.

mcpuffett · « **Reply #12 on:** May 10, 2014, 01:03:34 PM »

Hi Eddie I saw the bike you have bought on ebay looks like a good buy to me

, the fully enclosed chainguard was to make chain life last longer, not sure if it was a Honda part of aftermarket?

could be the same story with the fork Gaitors ? and a previous owner also liked his handling gadgets with fitting the fork brace and are they koni or marzzochi shockers? also noticed it looks like you have aluminium rims fitted,

my advice to you is before you attempt to start the bike drop the sump and have a look what its like in there you can also get to the gauze on the oil pump and clean that,

if its nice and clean in there you should be good to go with an oil change but if its full of sludge and dirty you might be better having a good look at the engine internals for rust etc because of it standing so long, the oil ways up to the camshaft are very small and easily blocked with debris

good luck don't be afraid to ask questions and don't forget to post plenty of photos

cheers Mick.

eddiebpool · « **Reply #13 on:** May 13, 2014, 01:08:51 PM »

The beast has arrived, and she is an ugly old girl! I will post a few pics to give folks an idea of what I am up against. Any hope I had that this might need the dust rubbed off and start it up was gone the very moment I laid eyes on her. I bought off eBay based on grainy pictures and numerous questions to the seller. More to come but here is a couple of general shots to get started:

eddiebpool · « **Reply #14 on:** May 13, 2014, 01:29:35 PM »

Quote from: mcpuffett on May 10, 2014, 01:03:34 PM

Hi Eddie I saw the bike you have bought on ebay looks like a good buy to me , the fully enclosed chainguard was to make chain life last longer, not sure if it was a Honda part of aftermarket?

could be the same story with the fork Gaitors ? and a previous owner also liked his handling gadgets with fitting the fork brace and are they koni or marzzochi shockers? also noticed it looks like you have aluminium rims fitted,

my advice to you is before you attempt to start the bike drop the sump and have a look what its like in there you can also get to the gauze on the oil pump and clean that,

if its nice and clean in there you should be good to go with an oil change but if its full of sludge and dirty you might be better having a good look at the engine internals for rust etc because of it standing so long, the oil ways up to the camshaft are very small and easily blocked with debris

good luck don't be afraid to ask questions and don't forget to post plenty of photos cheers Mick.

As you called it, they are aluminium rims and they look it good order with a good polish required. Akront rims, if anyone knows anything about them. As mentioned, I'm a rookie at this so no idea if that is good or bad. They have lasted better than any other part of the bike though so I'll call that a result. The disc looks good, but the front brake unit is horrible - cakes in nasty paint and will need the full treatment. There is black paint on the front mudguard - no idea why, though this seems to have preserved the chrome. An attempt has been made to remove the paint which has scratched up the chrome a little. Any suggestions on how to polish that up would be much appreciated. Is there something I could remove the paint with, or polish it off, that would not damage the chrome? I would like to save the mudguard if I can.

Both brakes are seized, both tyres have cracks on the walls (which is a real shame because they must have been almost new when the bike was put away). All the fuel pipes will need to be replaced and the rubber strap that holds the rear of the tank (not sure what that is called) is perished - only barely holding together. Basically, anything rubber is needing replaced.

eddiebpool · « **Reply #15 on:** May 13, 2014, 01:35:47 PM »

The rear end is very unusual - Marzocchi shocks which look in good shape though I would prefer something less "modern" looking. The fully enclosed chain is an oddity - it moulds perfectly around the existing components - an after market product by "Peter Furlong Products". Anyone know anything about this? It looks very well made.

eddiebpool · « **Reply #16 on:** May 13, 2014, 01:42:20 PM »

The engine looks cosmetically horrible. You can see the oxidisation. I rubbed the little bit on the front corner of the fin and it started to come off. There is no damage. The problem is the top cover has some nasty clear coat on it which seems to have made the oxidisation worse. It looks horrible. The engine covers at the bottom ad caked in a horrible paint - terrible. Any suggestions on a paint remover that will not damage the aluminium engine parts would be much appreciated. I know I can get it vapour blasted but I still need to get the paint out the screws!

atm cycles · « **Reply #17 on:** May 13, 2014, 01:49:41 PM »

Soda blaster works great on paint and will not mark aluminum

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eddiebpool · « **Reply #18 on:** May 13, 2014, 01:50:46 PM »

Confirmation that the bike was last on the road was 1988. The engine does turn over as the seller said, and compression seems to be there. I gave it a wee turn by hand - I'm not going to kick it yet. I took a shot of underneath too. No idea if there is anything significant there but I'm a great believe that the bits you can't see are usually the worst.

atm cycles · « **Reply #19 on:** May 13, 2014, 01:54:20 PM »

Pull air cleaner before kicking it or using starter. You don't want to suck anything in

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eddiebpool · « **Reply #20 on:** May 13, 2014, 02:24:57 PM »

And another couple of shots of that horrible engine. Maybe I'm an optimist, but I see the positives. The engine is undamaged. The crappy paint / clear coat on it has probably given some protection during the 26yr sleep. The engine turns, has compression and has no leaks I can see. I'm hoping that I can get it running a little before making a decision on how much to do. I would appreciate any thoughts.

Forks are a little rough at the top though the gaiters fitted have protected the business end of the forks and they are fine.

I'm thinking as a gentle introduction I will strip down the front end - fork seals, strip down and refurb brake caliper, clean up fork legs, polish fork leg stanchion, polish mud guard, polish up the front wheel, and see how it looks. Any advice always welcome!

I need to start a shopping list ....

Jayelwin · « **Reply #21 on:** May 13, 2014, 02:32:43 PM »

Can I recommend starting with removing and completely disassembling the carbs and ULTRASONICALLY cleaning them. I invested in a 7 liter ultrasonic cleaner that cleans 2 carbs at a time. A long cleaning at 175° in dilute dish soap and ammonia works wonders and takes carb issues out of the equation for the most part.

Jerilee · « **Reply #22 on:** May 13, 2014, 05:20:11 PM »

Can't wait to see your restoration! I'm working on an F2. : )

I have done the 'make it run' thing a few times in the past and if you want to ride it asap, it is most likely the fastest way there, nothing wrong with that!

If your ultimate goal is a full restoration: Especially if you mean to do frame off and pretty detailed... and you can wait to ride.

then just pull it apart now.

My first CB was a long series of maintenance and repairs to keep it in riding shape. My icon is a picture of it. It was a fine bike with a few weekends of effort every year.
My next bike, a Goldwing, was the same way.

I've gone for a full blown tear down for this one because I want to have it in as close to, or better than 'like new' condition in most respects, I don't want to think about rust or paint failing or fading, I don't want to mess with unknown wiring gremlins or a valve train I haven't laid eyes on myself at least once. I want to have the feeling of knowing every nook and cranny of the machine I ride and have bike that looks as beautiful in real life as it does in my head.

So that's why this third time is the whole enchilada for me. : )

Good luck with your project!

eddiebpool · « **Reply #23 on:** May 15, 2014, 01:47:36 PM »

A very small update but such small things can give you hope. The top cover, as shown in earlier photos, had a horrible clearcoat on it that was oxydising underneath. I decided to polish up a corner of the fins and the clearcoat started to rub off. I managed to clear a small section just with rubbing with autosol and paper towels. I found beautiful polished aluminium underneath. I'm hoping the horrible paint covering the bottom of the engine is hiding similarly shiny goodness.

It is a small thing, but made me happy.

s7paul · « **Reply #24 on:** May 15, 2014, 02:24:57 PM »

Quote from: eddiebpool on May 13, 2014, 01:35:47 PM

The fully enclosed chain is an oddity - it moulds perfectly around the existing components - an after market product by "Peter Furlong Products". Anyone know anything about this? It looks very well made.

I had a Furlong chain guard on a CB500 about 35 years ago. It didn't look very sporty, but I was doing 2000 miles a month at the time, so function won over fashion. As you say, it fits well, and I found that it kept the chain in good condition and undoubtedly prolonged chain life.

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Author Topic: CB750 F1 Restoration Project - not for the faint hearted (Read 26525 times)