Can I try to start it yet?

[JustcallmeMrT]

1977 cb550, been sitting for 13 years.  Got the tank lined, carbs cleaned, and have the parts for an oil change, filter change (air and oil) and new plugs.
After all the recent advice, I've decided I do need to do a teardown of the engine before running the bike regularly.  Before beginning this, should I try giving it an initial start, or skip go and just pull it apart?

[K2-K6]

Have you turned the engine over at all and or is it difficult to turn?

Also have you put any oil down the plug holes into the cylinders?

[JustcallmeMrT]

Have you turned the engine over at all and or is it difficult to turn?

Also have you put any oil down the plug holes into the cylinders?

Engine turns over fine, seems nice and smooth with good compression

[Lobo]

I'm no experienced engine (re) builder, but am left wondering, "what's the point" in trying to start an engine that's been sitting 13yrs .... if you then intend to immediately tear it down?  (though I can sure understand the temptation!)

Likelihood it'll be fine... but if some major part (eg a chain) doesn't like being rudely awoken from its Rip-Van Winkle slumber - and "lets go" - you may have far more on your hands than you bargained for...

Furthermore, there may be rust / swarf / debris / dirt in there which is best left in situ versus circulated about the innards...

Just my thoughts Mr T, but will happily listen to those of seasoned experience.

Simon

[bike-pusher]

I work on the basis that if it starts and runs fine, leave it alone.  Or: "If it ain't broke, don't fix it".

[matthewmosse]

Personally I would, fire it up, I would then decide on if any action was required. Even engines that have started off with oil leaks after long term lay up, have after a few hundred miles come good, the leaking crank seals on my last usa inport engine self healed after about 1000 miles of being ridden, saving me the cost of a gaskett set and seal set as well as the time stripping an engine. Also the more times an engine is taken appart the greater the risk of stripped threads, and rounded fasters etc, personally I don't get too bothred by these, I have the kit to resolve most such issues, but prefer not to have to.
 Only time I have regretted not stripping one down wax cb500/4 usa inport engine reputedly low mileage that ate it's camchain tensioners and wasn't very good at running, needing thevehicle running as my only transport I just fixed the tensioners and associated gubbins oly for a repeat of the tensioners self destructing. One day I will open it up and look - expecting to see something to explain the dammage. Even then, it ran like a bag of dog do, so were it not for having no other form of transport I could have used it would have been a strip down very soon after installation.
milage is not so much of an issue as how a bike has been ridden and maintained, my 500/4 covered a lot of miles, well over the 100,000 mark in my ownership with no engine work other than oil, filters and a check of the clearences, and camchain tension. When the gearbox started jumping out of gear I fonund the internals were not very worn in most places. Pistons are well inside tolerance, new rings are going in cos I have a set though the old ones seem within servicable limmits etc. Conversly I have had 30k mile engines that are goosed, normally thanks to things like gaskett goo from a rebuild clogging an oilway. Back when I was keen and single with spare time on my hands I removed, rebuilt my 550k3 engine in a day, had it back installed and rode to Scotland the next day. These days I avoid doing it as I find keeping the dust out of the engine between work sessions too much of a chore, so that is a consideration.

[tom400f]

Sorry if you stated it already Mr T but what is the mileage of your engine (if you know)?

It has to be your decision. If you want a new finish to the engine then it needs to come apart. If it is high mileage then replacing cam/primary chain [tensioner] and servicing the clutch would be worth while.

I'm not sure that age alone is a reason. Me and bike-pusher are running three unrestored sohc bikes between us and we're happy.

If the external state is acceptable to you and compression is OK then start it and see what it sounds like. Against that, the only way to be sure about everything is to take it apart to assess and renew as required. What end result are you looking for?

And so on. You get the idea I'm sure

[JustcallmeMrT]

Personally I would, fire it up, I would then decide on if any action was required. Even engines that have started off with oil leaks after long term lay up, have after a few hundred miles come good, the leaking crank seals on my last usa inport engine self healed after about 1000 miles of being ridden, saving me the cost of a gaskett set and seal set as well as the time stripping an engine. Also the more times an engine is taken appart the greater the risk of stripped threads, and rounded fasters etc, personally I don't get too bothred by these, I have the kit to resolve most such issues, but prefer not to have to.
 Only time I have regretted not stripping one down wax cb500/4 usa inport engine reputedly low mileage that ate it's camchain tensioners and wasn't very good at running, needing thevehicle running as my only transport I just fixed the tensioners and associated gubbins oly for a repeat of the tensioners self destructing. One day I will open it up and look - expecting to see something to explain the dammage. Even then, it ran like a bag of dog do, so were it not for having no other form of transport I could have used it would have been a strip down very soon after installation.
milage is not so much of an issue as how a bike has been ridden and maintained, my 500/4 covered a lot of miles, well over the 100,000 mark in my ownership with no engine work other than oil, filters and a check of the clearences, and camchain tension. When the gearbox started jumping out of gear I fonund the internals were not very worn in most places. Pistons are well inside tolerance, new rings are going in cos I have a set though the old ones seem within servicable limmits etc. Conversly I have had 30k mile engines that are goosed, normally thanks to things like gaskett goo from a rebuild clogging an oilway. Back when I was keen and single with spare time on my hands I removed, rebuilt my 550k3 engine in a day, had it back installed and rode to Scotland the next day. These days I avoid doing it as I find keeping the dust out of the engine between work sessions too much of a chore, so that is a consideration.

I was going to go with the "fire it up first" strategy because the PO said it was a great runner when he parked it up, and it seems to turn over fine, but as I've disassembled the bike I've found more and more "creative fixes", like components held on with string, wire, tape, etc, and after removing the tappet covers, found that they had been replaced without gaskets.  Overall,  not inspiring confidence. 
As for mileage, I have no clue.  The clock says 60k,  but the engine has been replaced at some point, so no real idea.

[Lobo]

Just to be clear on my behalf.... Mr T has stated that he WILL strip it down; come what may.
Armed with this info I still question the 'wiseness' of an unnecessary start.

If Mr is unsure whether to press ahead with a tear down... or not... then I guess a fire up can only help with this decision.

Generally, what a PO tells you can probably be discounted, his only thought is maximising the sale. The bike might have stood 13 yrs with zip oil in the sump.... probably not... but even so it'll likely have suffered significant moisture (= rust) in the engine. (esp UK climate)

Tom... you KNOW the history of your lovely 400F... you told me it was kept in a living room! Furthermore, a cursory glance at your machine & you know straight away it's been loved...

But yep Matthew, take your valid point about stripping it & making it all worse..

A dilemma!

Simon.

[mickwinf]

I have a similar dilemma as I have a 550 import with no history but looks very original and un-messed with, so I am going to try a start up and hope it is ok. My 500 however came already in bits so I did strip the engine, and it was in good condition except for a gear selector fork and the odd oil leak. A complete engine can be cleaned and painted to look good, depends on what standard you want it to be.

[JustcallmeMrT]

Just to be clear on my behalf.... Mr T has stated that he WILL strip it down; come what may.
Armed with this info I still question the 'wiseness' of an unnecessary start.

If Mr is unsure whether to press ahead with a tear down... or not... then I guess a fire up can only help with this decision.

Generally, what a PO tells you can probably be discounted, his only thought is maximising the sale. The bike might have stood 13 yrs with zip oil in the sump.... probably not... but even so it'll likely have suffered significant moisture (= rust) in the engine. (esp UK climate)

Tom... you KNOW the history of your lovely 400F... you told me it was kept in a living room! Furthermore, a cursory glance at your machine & you know straight away it's been loved...

But yep Matthew, take your valid point about stripping it & making it all worse..

A dilemma!

Simon.

It's the making it worse that I'm worried about, as I've never attempted this on my own.  However, having now watched a fair few youtube videos and thoroughly read the manual, I think I can do it... though I will need an impact screwdriver, a puller and a torque wrench.... and someone mentioned a clutch tool?

[matthewmosse]

Impact screwdriver and circlip pliers are pretty well the only tools other than assorted spanners and socketts that I recall using, appart from bits that weng wrong needing helicoil. Cb550 is a good engine to learn on, quite simple. Rather than use special tools for pulling the alternator rotor to do that seal I just left that in place. Only ever seen one leak, it self cured inside thd first 1000 miles. Been a while since I tried buying bits but last time I needed an engine it was cheaper to buy a spare complete unit off ebay then buy the gasketts and seals and the rest of it. Of course this also relives the stress from potentially mucking up a rebuild or blowing an engine in service too. On the other hand it also means my loft has about 10 spare viable engines stashed in there. Every time a gearbox got stiff to change gear or whatever, out it came, in went a spare. Having this forum now means I have access to know how of the likely causes of a fair few of these issues - oly thing is I don't remember which are simply un tested and which were faulty, though there are a couple where I have a fair idea, the one with a snapped camshaft or that ate camchains are distinctive.

[Lobo]

Mr T... my old dad always used to point out, "you can't make a cake without breaking eggs "; yep, obvious.  Ok, there's a chance you might make it worse... but you have to balance this off against the fun & expertise gained from the job. Chances are, and with this forum at hand, you WONT make it worse, but likely come out the other side with a fresher engine and a great sense of achievement.

And frankly, if you screw it up... at the end of the day, it's only an engine. Remember this...

I paid through the nose to have my CB400F engine professionally rebuilt... regrettable, but the only option as I live / work abroad. But the day I'm home for good the CB750 comes apart for a major...

Simon.

[bomber]

I would recommend to keep it running first, if it's healthy it will run, if something is wrong you will find out soon enough.
I took my engine apart and just today managed to put it back together but it is still long way for it to run.
Mind you, without any experience in mechanics, just with knowledge from the forum and manual, you can fix it up yourself.

[K2-K6]

It's easy if you are going to strip it down completely and change absolutely everything that doesn't come up to spec as you don't then need any prior knowledge of a running condition to get going on, just pull it apart and get going.

If on the other hand you intend to go toward a general "maintenance" rebuild eventually then it would be really useful to get it going for a decent as is asseement I think.

I would do a start by putting a electric fan heater toward the sump for 20mins or so to warm the motor and oil, remove plugs and spray WD40 into the bores, change the oil and filter when warm, put some oil into the cam/ tappet access covers, crank it without plugs to see if the oil pressure comes up, then plugs in and try a start.

This should let you see what you've got there and at least make a more informed decision.