Franco
1979 cb 750k
Hi I have just bought a 1979 750k in mint cond however it has not run for 7 years. Can anyone please give me advice on what to do before I start her.
Thanks Franco
Thanks Franco
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New owner of a honda CB750k
- Thread starter Franco
- Start date
Niagcool
CB750 New member
Hi Franco.
I just picked up a CB750K too. Mine is an 82 and sat for 10 years. Not mint but nice condition. I plan to go through the entire bike before spring. Here is a list of what I plan to do. You might not need to do all of this and I've probably left out some things that I'll find out about as I go along.
Remove and drain fuel tank. Gas is badly varnished. I'll have to find a way to get it all rinsed out of the tank.
Remove rust from inside of tank using electrolysis and/or phosphoric acid.
Seal tank with Kreem or similar sealer.
Remove Carburetors. Disassemble, clean and rebuild with new parts from http://randakks.com/collections/honda-dohc4/products/randakks-own-dohc-four-master-carb-overhaul-kit Get the booklet.
Replace fuel lines and install a fuel filter.
Rebuild or replace petcock.
Replace rubber insulators. (Connect carbs to cyl. head) These get hard and crack, causing leaks.
Replace air filter.
Remove cylinder head. Inspect cylinder walls.
Replace valve stem seals with new viton seals. The seals get old and crack. Doesn't matter if they're low mileage. Can get them from APE http://cbrzone.com/valves.html or from US Seal http://www.valveseal.com/# Part No. is VSHO-KL4. These are proven to last and are inexpensive.
While head is off lap valves. Check seats and springs, re-assemble and install with new OEM head gasket.
Inspect cam chains and tensioners. Replace if necessary.
Install cams from a CB900 motor to increase performance.
Adjust cam chain tension.
Check and adjust valve clearance.
Replace valve cover gasket.
Check and set ignition timing.
Replace spark plugs.
Check ignition coils and replace with Dyna coils if necessary.
Install a fused relay to connect coils direct to battery when ignition is turned on. Ignition switch creates a voltage drop to coils hurting performance.
Check condition of charging system.
Replace brushes in alternator if worn.
Ohm out stator and rotor and replace if not to spec.
Remove bottom oil pan and check and clean pick up strainer.
Re-install pan with new gasket.
Check/replace chain and sprockets.
Drain and replace brake fluid.
Replace brake line with stainless line.
Check front brake pads and rear shoes.
Recondition master cylinder and caliper.
Replace all fuses and light bulbs.
Replace tires. (Never run tires that are more than 5 years old).
Replace battery with AGM or Lithium Ion.
Start engine and synchronize carbs.
Go for a ride.
I just picked up a CB750K too. Mine is an 82 and sat for 10 years. Not mint but nice condition. I plan to go through the entire bike before spring. Here is a list of what I plan to do. You might not need to do all of this and I've probably left out some things that I'll find out about as I go along.
Remove and drain fuel tank. Gas is badly varnished. I'll have to find a way to get it all rinsed out of the tank.
Remove rust from inside of tank using electrolysis and/or phosphoric acid.
Seal tank with Kreem or similar sealer.
Remove Carburetors. Disassemble, clean and rebuild with new parts from http://randakks.com/collections/honda-dohc4/products/randakks-own-dohc-four-master-carb-overhaul-kit Get the booklet.
Replace fuel lines and install a fuel filter.
Rebuild or replace petcock.
Replace rubber insulators. (Connect carbs to cyl. head) These get hard and crack, causing leaks.
Replace air filter.
Remove cylinder head. Inspect cylinder walls.
Replace valve stem seals with new viton seals. The seals get old and crack. Doesn't matter if they're low mileage. Can get them from APE http://cbrzone.com/valves.html or from US Seal http://www.valveseal.com/# Part No. is VSHO-KL4. These are proven to last and are inexpensive.
While head is off lap valves. Check seats and springs, re-assemble and install with new OEM head gasket.
Inspect cam chains and tensioners. Replace if necessary.
Install cams from a CB900 motor to increase performance.
Adjust cam chain tension.
Check and adjust valve clearance.
Replace valve cover gasket.
Check and set ignition timing.
Replace spark plugs.
Check ignition coils and replace with Dyna coils if necessary.
Install a fused relay to connect coils direct to battery when ignition is turned on. Ignition switch creates a voltage drop to coils hurting performance.
Check condition of charging system.
Replace brushes in alternator if worn.
Ohm out stator and rotor and replace if not to spec.
Remove bottom oil pan and check and clean pick up strainer.
Re-install pan with new gasket.
Check/replace chain and sprockets.
Drain and replace brake fluid.
Replace brake line with stainless line.
Check front brake pads and rear shoes.
Recondition master cylinder and caliper.
Replace all fuses and light bulbs.
Replace tires. (Never run tires that are more than 5 years old).
Replace battery with AGM or Lithium Ion.
Start engine and synchronize carbs.
Go for a ride.
That's quite the list. I'd probably change the oil, put a little oil in the cylinders and turn it over by the crank a few times, drain and clean the gas tank and carbs, new fuel line, check carb holders, check air filter, make sure the front brakes are working, put in a new battery and try to fire it up.
Franco
1979 cb 750k
Thanks guys for the advice I pretty much followed Travis advice and it runs like a dream. The next thing is to fix the slipping clutch. Tried the clutch cable which was binding fixed it, tried adjusting the cable which helped a bit, but I think I have to change the clutch plates. I have seen a number of vid's on other models showing how to replace and it seems easy as long as you follow the same sequence as the existing plates when you install. Any advice, does anyone know of vids showing the replacement of a 750k clutch?
Thanks Franco
Thanks Franco
Niagcool's list is great when you really want check everything out and make sure you're going to have a reliable bike. Plenty of those things are worth doing even though you have the bike running. As far the clutch, you might want to put a few miles on before tearing into it. Sometimes after a bike has been sitting a long time they need a few miles on them before they act normal again. If after a few good rides things are still weird, I'd dig in. Check for grooves in the fingers of the clutch basket, warp plates, and swollen or worn friction discs.
Niagcool
CB750 New member
I guess if it was summer, I'd just want to get out and ride so I'd follow Travis' advice, too. Here it's -15°C, there's snow and I don't expect to be riding any time soon, so I figure I might as well get this stuff out of the way so it doesn't come back to bite me in July.
There are a few basic maintenance procedures that are fairly simple to do and can save a lot of problems down the road. Cam chains, tensioners and guides will wear out prematurely if not properly adjusted. Valve clearance is important too. With wear the valve clearance is reduced and this causes the valves to run hotter. Too little clearance can result in burnt valves so the clearance needs to be checked and corrected periodically. After setting valve clearance it is important to syncronize the carbs.
Chapter 3 of the Honda Factory Service Manual provides procedures for period maintenance that should be done on all of the 750 dohc bikes. You can download it, using the link.
https://drive.google.com/file/d/0B9sWaH30GIYVWGxKWk50SUhlZ00/edit?usp=sharing
There are a few basic maintenance procedures that are fairly simple to do and can save a lot of problems down the road. Cam chains, tensioners and guides will wear out prematurely if not properly adjusted. Valve clearance is important too. With wear the valve clearance is reduced and this causes the valves to run hotter. Too little clearance can result in burnt valves so the clearance needs to be checked and corrected periodically. After setting valve clearance it is important to syncronize the carbs.
Chapter 3 of the Honda Factory Service Manual provides procedures for period maintenance that should be done on all of the 750 dohc bikes. You can download it, using the link.
https://drive.google.com/file/d/0B9sWaH30GIYVWGxKWk50SUhlZ00/edit?usp=sharing
