Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: Genniker on August 29, 2019, 09:50:46 PM
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Just at the end of a 6 month process to get a long-stood bike back on the road; carbs, ignition, electrics, valves etc all sorted.
Thinking that some sludge might be lurking the the oil galleries and mindful of the important oil feed to the sohc, together with possible gummed piston rings, I did wonder whether to run through a quick flushing oil cycle as part of the 'return the the road' procedure.
Never done this before, but wondered what thoughts and opinions on this may be?
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Flushed my CB750 K1 through as it hadn't been used for 3 years, used the same product I use on my TRs - I also squirted a few drops of engine oil down the bores and a few squirts on valve gear etc and let it stand for a few days and kicked it over a few times without plugs fitted before starting on the button. Then I ran the engine up to temp and drained the oil overnight (also removed the oil canister/filter), checked for any nasty stuff (like swarf or silvery shimming in the oil) and luckily there wasn't - refitted the canister/filter the topped up with flushing and ran it for a few minutes until warm then drained it again overnight, replaced the filter and topped up with oil, job done.
https://www.ebay.co.uk/itm/SAE-20W-Flushing-Oil-4-55-Litre-Mono-Grade-Engine-Oil-4-55L-Flush-System-Carlube/302141176880?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649 (https://www.ebay.co.uk/itm/SAE-20W-Flushing-Oil-4-55-Litre-Mono-Grade-Engine-Oil-4-55L-Flush-System-Carlube/302141176880?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649)
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Thanks for the insight, it strikes me that there's nothing to lose from adding this extra (safeguarding) step into the process. After being stood for 30 years, one extra job doesn't strike me as being an unreasonable thing to do.
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If it has been standing that long, I would not take the risk, I would drop the engine out and strip it down and check everything. Some of the oil ways are tiny. That way, if there is anything that needs servicing you will be able to do it and then have full confidence in the machine. A friend of mine ran a 550 that had been standing. He came back from the first test ride with it smoking like a bonfire. I stripped the top end and found all the piston rings had shattered, the longest bits being about 3cm.
Whilst in there I would replace the timing chain and, if worn, the tensioner. Sorry if this seems very cautious but it is expensive if it all goes wrong.
I don't know what others think?
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If it's been standing 30 years I would urge extreme caution if you plan to merely flush it trough - turning over for valves and timing is one thing, but running and riding may expose you to problems as outlined above.
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As well as flushing the motor, don't forget the oil tank.. there will be sludge at the bottom of the tank. Remove it and slosh a bit of petrol around a few times, also get a big pipecleaner type brush in there if you can.... Look at the rocker tops and in the sump to assess the cleanliness of the motor before you decide if it needs a strip down…. Stripping is a major job and is not always necessary depending on how clean the motor is inside. turning the motor over manually and looking for fresh oil emerging through the cam shaft feeders will also give some indication if a strip is necessary.
This is how I assessed my motor, all was looking ok so I ran it.... no rattles, no burning oil and since then no problems after 2k miles of running.
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Its in 500/550 section so guessing wet sump - no tank.
I've just picked up a motor that had been stood for years, looked Ok, crank turned smoothly but I didn't spin it much. Luckily someone had snapped a spark plug so I removed the head and found a valve sticking, glad the plug needing doing otherwise I would have bent a valve or worse had I spun it over.
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Well spotted Tomb.... i tend to get fixated on the 750. Yes regarding the stuck valve...there can always be a lurking problem on any motor.... any advice given is only general 😁
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It's only got 9000 miles on the clock and the oil in it is very clean, so tempted to trust that all is well within the engine.
I had intended to wipe clean all the rockers as a test to see if oil gets back to them.
Compression good, so hope rings ok.
I think that I will risk a start-up without a strip-down. I'm going to take things slowly, with no load put on the motor in the first instance.
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If it looks clean inside the rocker and inside the sump...and the rest of the bike suggests that the milage is accurate... and if the compression is good...and the oil light goes out quickly...chances are it will be ok. Take it slowly... 8)
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Never trust a engine that has been stood for years. The rings can be glued in there housings and it doesn't mater how much flushing you do, you will never release them. valve seats pitted from rust and a shed load of other issues ;)
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Stuck rings will surely result in low or no compression.... if so it wont run properly and will then have to be stripped. If the compression is good on all 4 cylinders i would suggest the rings are ok and its worth running... not every engine needs stripping !
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Such false information !
I have stripped shed loads of engines with good compression and the rings have been stuck, liners rusty. You can get good compression with carbon build up.
Compression testing is not very reliable and will show if you have a holed piston or a badly bent valve. just look a Julie's rebuild thread and the mess her pistons were in (some with no rings left, the compression test on her engine was 148 to 157 psi and started first time on the button, every time ;) ;)
I have just been reminder by another member that we did a compression test on a SOHC engine some years ago, that I built with no rings on the pistons and because of the piston to bore clearances being less than a thou, we were still getting 130 to 150 psi across all four.
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Got to ask this Graham, why did you build an engine with no rings?
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rings rub on the barrel.....friction....saps power. Building with no rings gives less friction and more power...stands to reason. A racer told me ....... all the fast lads were doing it back in the day....
ahem....
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Got to ask this Graham, why did you build an engine with no rings?
Experimenting with aftermarket pistons in a engine with no rings on a test rig. This tells you if the pistons clearances are good or if they will seize at Honda clearance ;)
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😂😂😂
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Such false information !
I remember you advising a guy that he must strip his engine to change a drive shaft oil seal because the “60 psi oil pressure behind the seal would push it back out” if he just tried to press it in..... that was false information mate... and your an expert. Lots of people successfully resurrect old bikes and cars without total engine strips, each project has to be assessed individually.
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And to assess a engine fully, it need to be stripped. Unless you have one of those OEM Honda crystal balls ;)
Not a drive shaft seal, a crank seal ;)
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Or...... as what happens in the American car programmes such as Fast & Loud when they dig out a rusty 30's Model A from an old shack and minutes later they utter the immortal lines, 'We put a new battery on it, fresh fuel and oil and it fired up first time'! Yeah, sure it did🤔. Then they rev the nuts off it and do burn-outs and doughnuts around the yard. Such a load of tosh, of course they checked it over before the cameras rolled and I bet this included tacking the head off.
I'm refurbing my original 400/4, it's been stood 10 years in my insulated and de-humidified garage, hardly any sign of corrosion but I've still used an endoscope camera to check the bores (no sign of rust in there), checked all the valve's are moving & not sticking, dropped the sump and going to use flushing oil. This thread Cound not have come at a better time for me. I'm not going to take the head off though as the engine only has 5k on it and the bike has been kept in my garage.
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When the drive shaft seal blew in my CB250RSA I had to split the cases, no way could I have got a new one in otherwise.
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All the bikes I have built have all had full engine rebuilds - but... its about risk analysis I suppose. I am risk averse and so I am more likely to not take any chances. its down to the individual. If you spend the time and money stripping a motor and rebuilding it compared to 'if' something went wrong after doing precautionary checks (as per previous threads), is there much difference. Particularly the miles most of us do on these old bike.
That said, I will no doubt strip the 500 engine despite me saying I will go the precautionary check route!
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Left my CB750F1 for 10 years in the garage while I was away working, I covered it in grease and dust sheets, when I came back I was going to give it a quick check over and get it back in the road, however a closer look showed that it needed a lot more work.
I broke a stud on the head getting the exhaust off so I took the engine out, and removed the head to fix the stud.
While I was there I decided to check the pistons and rings as I was concerned about stuck rings and found a stuck compression ring on one of the centre pots, it may have been like that for years before I went away or the result of me leaving the bike standing, who knows, but for the amount of effort required it was worth checking.
Cheers
Dennis
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http://www.sohc.co.uk/index.php/topic,14243.15.html (http://www.sohc.co.uk/index.php/topic,14243.15.html)
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At least you can get the top off the 500 in the frame
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Not looking for guarantees, but if the rings are gummed up and the value seats pitted, is the worst thing that would happen is that it wouldn’t run right; or could it cause damage?
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Gummed up is not so bad but broken could be disastrous
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While I'd not argue with any inspection / replacement that were needed to recommission a stored bike, I think flushing oil needs closer scrutiny in this context.
The position, naturally given by the manufacturer of "flushing oil", is that using their products will gently and considerately remove unspecified contaminant along with various wear / worn materials resident inside your engine. Leaving it as pristine as could be and ready for further excellent service from then onward.
It's one of those odd decision, if there's enough of a problem inside the engine, then flushing isn't going to fix it. If there isn't a problem in there that needs flushing out, then it shouldn't be put in there. Neat a?
A contra view may give that you are about to put into a Honda engine with tolerancing smaller than most believed possible in a production engine during the era of manufacture, a mix of Kerosene/Paraffin /Diesel in approximately 85% quantity, to which is added 10% thin mineral oil, plus solvents like Acetone and MEK (that's more or less the makeup of flushing oilsover the years) in the vain hope of desolving unspecified detritus. This is in the oil system that we agonise over which oil is best to protect our precious engines! this mix is supposed specifically to break down oil and oil film, the very quality that the oil uses to keep those fine tolerances apart in the first place to avoid wear.
I seriously doubt that any Honda instructions would call for any product like this to be put into one of their engines. More to the point, the manufacturer of flushing oil has no idea whatsoever of material composition, tolerance, age, wear characteristics or any other pertinent detail of the engine that's sitting in front of you for consideration. It's most unlikely to fix anything.
Two sides to consider, whether it would influence a decision to flush or not to flush would be interesting to see, comments appreciated.
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+1. I have never believed in flushing the engine. IMO it has more to do with our desire to care for our bikes. This can lead to overcare. Flushing is one manifestation of it, fitting unnecessary and often problems causing inline fuelfilters another.
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Very intersting read as always Nigel and a very good point made re:tolerances.
I have been reading this thread with added interest as I have been re-commissioning the 400/4 I originally restored 28 years ago over the past month or so.
I havent used the bike for 13 years as its been laid up due to other bikes/work/DIY etc getting in the way. It was always a case of 'I'll get that running in the spring' only for it never to happen! The bike has only covered 7.5k miles between 1992 and 2006 after the engine was fully rebuilt. Oli changes were completed every 1000 miles and its always been kept in my garage. I drained the old oil a couple of weeks ago and it looked like ATF, I remember when I bought it at the time and it was that colour, I have no idea of the brand but it was the correct motorcycle oil and bought from my local bike shop. The condition of the oil was as-new and so was the filter but I am changing them anyway as the oil is too old to leave in there.
Having read the start of this thread I bought some flushing oil but to be honest, after reading your reply and the potential damage (IMHO) of what flushing oil could do Im not going to use it. Instead I'll buy some cheap oil (to the correct spec) and run the engine for 200 miles, drain it and change the filter.
I've had the rocker cover off, all the valves are moving and I have no rust in the bores (using my endescope). I'm going to drop the sump and take a look at its contents and check the tensioner horseshoe is ok. I know there has been discussion about sticking rings/ gummed-up rings etc but this is a chance I'll take.
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As they say, if it aint broke, don't fix it... wise words... will probably get shot down again lol