Honda SS50 engine strip down, rebuild and start

in this video i'm gonna be stripping down a 1974 honda ss50 four-speed engine finding all defaults sorting them out putting it back together and then starting it up on the bench this little honda ss54 four-speed engine has seen better days and certainly needs a bit of work before we can make it run it does actually turn over but it's got no compression and when i when i felt for the gears i couldn't find any so it needs to come apart and also look at all these gaskets oozing out of everywhere with gasket cement the engine seems to be in fair condition externally there's a lot of gaskets cement coming out of the joints the kickstart spline looks perfect just a little bit of surface rust and dirt that'll clean off nicely so the first thing to do is drain out the oil i used my 17 millimeter socket to loosen the sump bolt when i unscrew it my finger hardly any oil came out which was quite a surprise really i was expecting some black gun oil to flow out but it didn't it was like brand new with the oil drained the next thing i want to do is clean the outside of the engine just a little bit with a wire brush get most of the dirt off so we'll be cleaning up all the parts individually but it's always nice to keep the grit on the outside the first thing i noticed was the cylinder head nuts were quite loose perhaps that's why it's got no compression perhaps they weren't up tight enough i don't know the mystery continues with the four cylinder head nuts removed i removed the cam cover but there was no gasket that's really strange i removed the two side covers and then loosen the two screws holding the cylinder head to the barrel and the barrel to the crankcase as i remove the screws i notice they're the wrong style heads but i'll replace them with the correct hexagon heads later on when i rebuild the engine so the next thing i need to do is remove the camshaft sprocket and let it slide down in the tunnel and then lift off the head the combustion chamber and valves look really clean there's quite a lot of gasket cement on the gasket flapping in the breeze i peel off the gasket then pull out the two rocker shafts this allows the rockers to be removed from the cylinder head and they look in nice condition with the rockers removed the camshaft slides out from the side of the cylinder head it looks in amazing condition i'm really pleased with that i'll take the valves out the cylinder head later so the next thing i'm going to do is remove the cam chain idler bolt and then lift off the barrel a camshaft sprocket unhooks from the chain then the barrel slides straight off revealing the piston that looks quite sorry and the base gasket is really thick made from some sort of hardboard looking down the ball it looks really good no deep scratches but the piston is really bad the rings are broken and it's all burnt down the side so i take that off for a better look i think i'm just going to replace that and here's the gasket i talked about earlier it's about four millimeters thick i am really amazed how thick that is the next thing i'm taking off is a magneto floral so i loosen the central nut then use a special extractor tool that screws in with a thread you tighten it up with a spanner and it pulls it off the taper really easily i'm careful not to lose a woodruff key because these sometimes fly out and get lost so i stick it to the magnet for safe keeping i then loosen the two screws and prys off the magneto windings the seal itself looks in nice condition on the back which is good but the wires have seen better days and i'll replace the fittings later the screw holding on the neutral switch has definitely seen better days the next thing i do is prise out the rubber bang and undo the screw inside which holds the selector in place i turn the engine around and remove all the screws holding on the clutch cover and then pull the clutch cover off the standard jis screws have been replaced with cap heads which spin out freely the first thing i notice is there's more of this blue silicon sealer on the gasket surfaces but inside the engine looks remarkably clean i fill the crankshaft bearings and they feel great so hopefully they're really nice condition and the actual oil strainer is also really clean which is a good sign i removed the four screws that hold the cover on the clutch behind this is a centrifugal oil filter and is usually crammed full of crud on high mileage engines but this one is relatively clean a special tool is required to remove the central nut these are easily available online and they fit a standard half inch drive socket and then the nut can be loosened behind the nut is a bellevue washer this is like a spring washer it has to be fitted a certain way and the outside is marked outside the clutch then lifts straight off easily the circuit holding on the drive gear was very loose and pulled off by finger and then the gear just pulled straight off the shaft i then removed the gear selector mechanism amazingly this central screw was really loose this is probably why the gears wouldn't work i then pull out the four location dowels followed by the gear change shaft i look up there's a pigeon having a bird bath with his wings stuck up and a right commotion in the bird table and a bit of pecking but not food they seem to be pecking each other very strange with the gear selector removed the next thing i need to do is loosen all the crankcase screws and separate the crankcases and everything drops out onto the floor and it all looks in really nice condition i'm actually quite surprised it's all really really good i look at the gears and there's no sign of anywhere whatsoever no broken teeth no chipped dogs everything's really good and the crankshaft spins freely in my hand the big end fell smooth the mains feel smooth so so far this is looking like a really good engine it just wasn't that well put together so now i take off the oil pump with the engine all stripped down the next thing i need to do is clean all the parts with white spirit and a stiff brush and i'm really pleased i geared just down in time before the rain came and it did rain quite hard so i got straight back in the garage back in the garage i thought i'd clean the barrel up first so i can give it a coat of paint so i scraped out all the dirt from between the fins and gave it a good wire brush and then i blew it off with an airline warmed up with my blowtorch and took it outside to give it a cut of black paint i'm only heating the barrel to about hand hot this helps the paint dry quicker and prevent runs it's really nice spraying an old cast iron barrel it turns from a sort of rusty color to a nice gloss black in a few seconds with an aerosol can and it looks really nice so when it's all done i take it over to my barbecue to bake it on the gas bbq works well as a low bake oven especially when it's cold the paint dries really quick and after about five minutes i come back and check and it's all dry on the way back in i pop in to see what tracey's up to in the kitchen because sometimes she's making cupcakes but she wasn't she's in the lounge doing crochet she's making this blanket and it takes ages and she's knit all these little tiny bits and put them together using this little piece of wire with a hook on the end and some colored string i think it's called wool it's sort of like knitting but you only use one needle you sort of hook the wall through pull it around and over and down the other side and it clips back on somehow it's far too complicated for me to understand anyway back in the garage i'm going to sort out the cylinder head so i've just removed the two valves and had a good look at them and they look in really good condition although the valves look clean i'm going to put them in my lathe spin them up with some fine abernet cloth to give them a good polish before i grind them into the cylinder head with grinding paste well that looks a lot better if you haven't got a lathe you can always do this using an electric drill here's the two valves all polished up shiny ready to go back into the cylinder head so what i do is smear a tiny bit of grinding paste on the valve seating area of each valve and it can be ground into the head using a suction cup i then place the bowel back into the cylinder head and press down very slightly and rotate backwards and forwards with smaller cylinder heads it's sometimes better if it's put back in the vise to hold it secure and then you can use two hands on the suction cup this makes it much faster to grind the valves after several minutes of grinding i remove the valve and wipe the valve seat clean with a piece of cloth and have a look for a nice gray continuous surface all the way around which i've got so that's just perfect with both the valves ground in i'll put a bit of oil on the stem and bit on the valve seat area put the valve back into the cylinder head turn it over and then i can put on the valve springs there's two of them and the valve cap and then i can compress the valve cap down with my valve spring compressor and fit the collets this is quite a fiddly job this is my dad's old valve spring compressor he used to use it on his austin cambridge estate i remember using when i was a little boy and it's a great piece of kit but i had to adjust it to make it fit the little honda engine and i have to use tweezers to put the valve carts in they are so small but eventually they go in and the valve sits nicely and that's that job done with both the valves fitted the next thing i need to do is fit the camshaft so first of all put a bit of oil on the camshaft bearings and the lobes and it slides into the cylinder head with a camshaft fitted i rotate it around so the lobes are pointing downwards and then i can fit the rockers the rockers slide in quite nicely they're a little bit fiddly and you have to push the rocker shafts in from the side as well making sure the threaded portion's on the outside so you can pull them back out again if you need to with the first one fitted i'll put a drop of wood on for lubrication and then fit the second one well that's the head assembled now so i can put that up to one side because next i'm going to clean the crankcases ready to put them together the crankcase has had some light corrosion on the surfaces this comes off really easy with my rotary wire brush in my pillow drill the rotary bar brush gives a near to original finish on the aluminum surface and looks really cool with the crankcases cleaned first thing i'm going to do is put in the crankshaft into the magneto side the main bearings are a sliding fit into the crankcase and the crankshaft's dropped straight home so next thing i've got to do is put the gearbox in this has to be done in one piece with the selector mechanism and with a bit of a wiggle it drops down into the bearings nicely and the gears rotate so that's good so the next thing i fit is the kickstart shaft and its mechanism followed by the oil pump drive with all the internal parts fitted i can drop on a new gasket this fits nicely over the two dowels i put a bit of oil around the bearings and shafts and then i can lower on the right hand crank case and that slides down just nicely and snaps into place i then carefully turn over the assembly to put in all the screws and tighten them up there's quite a few the crank case screws have been changed from jis to cap head at some point in the life of the engine this was a common mod that many people did but they tighten up nicely with a five millimeter allen key i then replace the selector drum screw tighten it up top with my m10 socket and then replace the rubber cup and push it in tight the next thing i need to do is fit the kickstart return spring so i hold the crank cases in the vise on the rear engine mounting boss then i can fit the spring and the metal sleeve lining up the two dots and then when they're lined up i can twist the kickstart shaft round whilst i push back the sleeve and it snaps into place and finally i can put on the circlip before i fit the circlip i just check that the spring works and it works perfect with the kickstart shaft fitted and tested i can now take the engine out the vise lay it on its side and fit the oil pump i tighten those three screws then turn the engine over and rotate the drive sprocket just to make sure it's engaged correctly and it is so that's really good so now i can slide in the filter screen i then start to assemble the selector mechanism by first inserting the four hardened steel pins then pushing in the gear change shaft making sure it engages nicely with the ratchet pins then i can put on the outside cover and the d-dent plate followed by the screw in the center this needs to be tightened really tight i then fit the spring-loaded lever that engages with the selector drum this is used to hold it in a particular gear with the selector mechanism fitted i make sure i can select all the gears by hand by moving the selector shaft backwards and forwards until the selector drum rotates through first second third fourth and neutral and i'm really pleased to find all the gears work and select crisply so now i can get on with the rest of the assembly by putting on the transmission drive gear and its circlip with the primary gear fitted the gearbox spins freely by hand so now i can get on with fitting the clutch this goes onto the end of the crankshaft the clutch drops on nicely engaging with the spline on the end of the crankshaft so then i can put on a tab washer the bell view washer and the carcillated nut and secure it tightly with a special tool with a castle not tightened i use a pair of pliers to bend over one of the tabs on the tab washer into one of the slots on the castle nut this locks in place preventing it from coming undone i can now fit the clutch pressure plate and tighten the four screws i check everything rotates freely then i fit the oil injection stub pipe onto the center of the clutch this is spring loaded i'll leave the clutch cover off for now so i'll turn the engine round and fit the cam chain over the crankshaft with the cam chain fitted the next thing i'm going to do is fit the piston rings to the piston these are very fragile and delicate and they're marked t at the top which faces upwards so you gently use the piston rings over the pistons they snap down into their groove starting with the oil ring i always check they rotate freely on the piston as well on four strokes there's no real reason it's just something i've always done the top compression ring is slightly different from the second compression ring it has like a chrome plated surface on it and this must be put on the top of the piston in the number one ring position with the piston rings fitted i next engage the gadget pin lining up with the inside of the piston then i apply a bit of oil to the little end and offer up the piston and engage the gauging pin with the little end eye and push it through making sure the little arrow is pointing downwards i then replace the circlips into the piston with a pair of pliers i then carefully grip the engine in my vice with a cylinder pointing vertical i find it easier to assemble it like this so i put the base gasket on followed by the rubber o-ring then i can put a bit of oil on the barrel and drop it down over the piston gently squeezing the rings in with my finger and thumbs as i apply some pressure downwards and the barrel slips straight over just perfect i loosely tighten the barrel retaining screw then go fishing for the cam chain with a hook i eventually find it pull it up through the cam tunnel then i can insert the cam idler wheel push it down and engage its pivot bolt i check the idler wheel rotates freely and it does so i turn the clutch until the piston is at top dead center then i can insert the camshaft top sprocket making sure the little o mark on it by the teeth is vertical while the piston is at top dead center i then fit the cylinder head gasket and two rubber o-rings one goes around the oil return gallery and one goes around the right hand bottom stud this is the high pressure feed to the cylinder head with the head gasket in place the cylinder head can be carefully lowered down the studs engaging the camshaft drive sprocket with a camshaft i secure the sprocket to the camshaft by doing up one of the screws by hand then check the timing is still correct which it is so now i can put on the cylinder head cover and tie in the fourth nuts with the fourth cylinder head nuts tightened i can now set the cam chain tension by releasing the lock screw on the adjuster mechanism this allows the plunger to fly out and tension the chain to the correct tension i then re-check the timing marks still align and they do so that's really good i can now tighten the camshaft sprocket retaining screws and cylinder head and sit in the barrel side bolts i take the engine out of the vise and put it back on the bench and then tighten the camshaft adjuster lock nut and fit the magneto stator this just pushes into an o-ring seal and is held in place with two screws i then fit the flywheel being careful to engage the woodruff key and tighten the nut i check the engine still rotates freely and it does so now i can fit the two side covers to the cylinder head securing the screws tight i'm now ready to fit the clutch cover to the engine so i tip it over onto its side fit the gasket over the two dowels and refit the oil injection stub into the middle of the clutch then i can gently lower the cover over the kickstart shaft being careful not to damage the seal with the splines and put in screws i tighten all the screws evenly with an allen key then trim off the excess gasket with a craft knife i fit a temporary ignition coil to the engine so i can check for a spark and i get a nice fat blue spark so that's great so now we can top the engine up with oil and see if it will start the engine takes point seven of a liter of semi-synthetic 1040 oil so it doesn't take long to fill up i fill up the carburetor with some petrol from a plastic bottle and we're all ready to give it a kick over and seal sure fire up to help it start for the first time i squirt a tiny bit of fuel straight into the carb the compression feels really good and after a couple of jabs it starts [Laughter] so [Laughter] well thanks for watching i hope you enjoyed the video i was really pleased how the honda ss50 engine started up and ran it sounded so cool and i've just found a set of four carburetors for my kawasaki s1 550 four-cylinder engine build so hopefully in the next video i'll show you how i get on restoring the carburetors sorting out the ignition timing and starting it up for the first time

Channel: Allen Millyard

Views: 661,621

Keywords: Honda 50, Honda SS50, 1974, Allen millyard, millyard, shedtime, recycle, repair, kawasaki v8, kawasaki v12, restore, restored engine

Id: 548RzO8LZ_E

Length: 19min 46sec (1186 seconds)

Published: Sat Jan 15 2022