VIDEO: Triumph 650 Motorcycle Engine Disassembly & Rebuild Part 5

This is the fifth part (check out part four here) in our extremely popular video series in which Todd Muller, Head Motorcycle Tech here at Lowbrow Customs, disassembles a unit 650 c.c. Triumph motorcycle engine and rebuilds it. Todd takes us step-by-step through splitting the crankcases, removing bearings and bearing races in preparation for vapor blasting. He shows you what to look for and how to know when certain parts need replaced. Plus we have a Triumph BBQ for lunch! You can check out the Triumph 650 Motorcycle Engine Disassembly & Rebuild - Part 6 to continue following along!

Check out the Lowbrow Customs YouTube channel to check out all of our videos. We spend a lot of time and effort creating motorcycle how-to videos, product reviews and event coverage for your enjoyment, please let us know what you think. Click here to subscribe to the Lowbrow Customs YouTube channel and stay in the know!

You can read a full transcription of this video below:

Last time we got the majority of the components removed from the engine getting ready to split the cases. This time we're going to go ahead and finish it off get the cases apart. We'll remove all the bearings, bushings, seals, anything else we need in preparation for rebuilding the engine. [Music] Let's go ahead and get started. Like I said we've got the primary disassembled, trannies out, timing gears all off and I think we'll get started by removing all the fasteners that hold the two halves together, just to review real quickly before we go here. We've got one here on the top, one here, one here and then we have the three bolts on the crank case.

Then on this side. We're gonna have these two this one is a stud with a nut this one is a bolt you may find different variations over the years, they did different things earlier motor will have two studs here with two nuts. Later motor may have two bolts since this is a transition year motor, this is a 1968. It does have some standard and some Whitworth fasteners I know we talked about that. I checked before I got some of my tools ready to go and these are Whitworth fasteners on here. We'll go ahead and get started by taking these three off the top here, and you may also notice these are the same size shank bolt but the head on this one is smaller and this is the correct location for the smaller head one it just makes it easier to get in there and get a tool on it. That's going to be this size Whitworth. That's kind of tight there to get your tool on it.

No problem there and just pay attention that when you're going back together because these two are basically the same length, they just have a different size head on them. Switch to our other size here and we're going to have to take it out of this fine and dandy lowbrow customs engine stand pretty quickly here to get the rest of the case fasteners out. That one had a little bit more corrosion on it than the first one. There's that one, you've got one in front of the cylinder here, tach drive is in the way we're going to take that off in a sec here. We'll just throw an extension on here. That one is longer than the other two because it goes all the way through this larger portion of the case into the threads where this one's shorter than those two.

We have those three off. I think we'll go ahead and take these two larger ones off on the other side. Again these are Whitworth. Earlier motor pre 68 is going to be Whitworth in late 68 they started switching over to SAE I know I've talked about that a couple of times. Always pay attention to what's-- The whole studs coming right out of the case which is not a problem. We can always reinstall that later that just means that this nut is stuck on there and well heck, might as well go ahead and take it off while we're there and basically if you get a stuck nut on the stud you can just throw it in your soft jaws so you don't damage the shank on the stud.

Now the nuts coming right off, there's a little bit of corrosion there that's why it didn't want to come off. This is why I left it in the stand to get these out because you see how the stand is helping support the engine to break these free. Okay, that's that one. I guess we'll go ahead and take our tack drive off next, this is this drives the tachometer is connected to the exhaust camshaft. We'll have to take this off. I have a tool right here. Basically this is a drag link socket for automotive use. This is a NAPA tool and I've modified it by grinding the edges down.

I used to use this when I worked at the Harley shop for taking the caps off of oil pumps. It fits in the slot on the oil pump very nicely but I also discovered that it fits very nicely on some of the things on this engine. I also use this to remove the sludge trap plug. This is standard thread. Take this cap off here. Sometimes these caps are really stuck on there and you may need to use a different method to get it off like pair of channel locks. I know it may bugger it up but you got to get the darn thing off. Then once we get that cap off, there's a drive gear in here and it's just the sliding fit into the cam.

You're just going to use a magnet, pull that out of there. There's the portion that rides in the cam, this is a helical cut gear which turns another gear which in turn turns the cable and runs your tachometer. Now, the nut is in here very deep, you have to use a deep socket. 63 to 68 is going to be right-hand thread on the nut that's holding this on to the crank case. 69 and up is going to be left-hand thread. That's why it's always good to know exactly what you're working on. VIN number is going to tell you what year the motor is. Obviously if you're trying to loosen a nut that is left-hand thread it's not going to go so good for you. This is in the in the crankcase itself in the aluminum and you don't want a booger up the threads on here and there we go.

There's threaded portion that's in the crank and also a ceiling washer on here. This won't come out of the tach drive without disassembling this entire unit so otherwise I'd show you what it looks like. I'm not going to reuse this. We sell on the website, we have plugs for this, where if you want it-- If you don't have any gauges, you're building a bobber, you don't have any gauges. You can remove this and just plug the hole that early bikes, the tach drove off the transmission, bottom of the transmission, had a drive unit where a later motor had the drive unit here.

In early motors going to have the plug, but we have both early and late plug available on the website. There's that, go ahead and I put my parts back in there in case I ever want to use this on a different motor. [laughs] We have another through bolt right here. This is the one where your L brackets, where your exhaust would be attached that's why that stud is longer. It looks corroded, a little bit of penetrating oil on there might be in order. That's good, that one's loosening nicely, we just met up with our corrosion on there. I guess we could throw a ratchet on there that'd probably a little faster you know it's almost off anyway. I always put the nuts back on the studs as I take them off that keeps track of them. You throw them in your box of parts and you'll know right where that's at when it comes time for reassembly. Okay, it looks like we've taken everything off that we can really get to easily with it in the stand. We'll go ahead and remove it from the engine stand. You know what we're going to do? We're going to see if there's any more oil on the bottom of this crankcase and we'll drain that out before we remove it because it will be easier.

If it didn't already all leak out on the workbench. Doesn't look like there's enough in there to worry about draining it. There's just a little bit in the bottom of the case there so we'll go ahead and remove it from the engine stand now. Okay, we got the stand off the motor and we've got two more through bolts right here. We had taken this one out previously to put the stand on the engine. We'll go ahead and get those out. Oh, that's tight.

That one's a little stuck in there. We'll use this special screwdriver punch here, there you go.

Now, I'm going to show you the next thing we're going to remove from this crankcase. Very often overlooked by people that aren't super familiar with these engines and does cause a pretty big catastrophe. There are two screws, here and here, going through the crankcase right here in this area. If you do not remove those and you are trying to take this apart, it will break this off. I've seen quite a few of these crankcases broken there and that's probably the reason why it happened.

They are a flathead which makes it rather difficult to get in there. We'll go ahead and once again there's no substitute for a high-quality screwdriver. This is a snap-on screwdriver once again, with the shank on there where I’ll be able to get some leverage using this wrench. If they don't break free right away we'll probably remove these two studs to get a good angle on it. You'll see it's kind of a weird angle there. It's very hard to get at these things. We'll go ahead and oh, look at that ha ha. Sometimes these are really in there and this time that one came loose fairly easily.

If they are really stuck like I said you could take this off to get a better straight shot at it. You can also use your propane or map gas torch to heat this up a little bit and that may help, there's the screw. There's the first one, you got one more to go here. The triumph gods are smiling on us today. Sometimes these can be very, very difficult to remove. There's the other screw, don't forget two screws there.

Okay, now we have paid particular attention to making sure we have all the fasteners. I'm just going to double check one last time before I try to take the two halves apart, that we have all the fasteners out. A lot of times when you're taking something apart and you start trying to pull it apart and then oh, you notice oh gee I forgot one screw. Just to review, one there, one there, one there, here, here, here, here, and the two that were here and here. Last but not least the two that were there that we just took out with the screwdriver.

Now we're ready to split the case. What we're going to do is we're going to use our dead blow hammer and we're going to see if it's going to come apart easily, or if we may need to heat and beat. Look at that coming apart no problem. Once again I'm not beating the hell out of it. I'm not using a metal hammer. I'm using a dead blow. There's some dowels on here that you'll see in a sec here and with any luck she should come apart fairly easily. You can see it's starting to separate.

Now, another thing worth mentioning at this point in time, we are just about ready to pop it open. Seen a lot of crankshafts with hammer marks on them, mushroomed over, pretty much ruined, from people beating on the end of the crankshaft. Not a good thing to do. We're not hurting the crankcase, and there we go. Hear that little noise it made? That means that either the crankshaft is out of the bearing, or the bearing has generally this side bearing stays on the crank, and we're ready to just pop it apart.

Once again always very careful with your rods, you don't want your rods banging around. We have a little bit of an oily mess, not too bad. There's our two cams, go ahead and move our stuff over a little bit here. Cams just come right out like so. Since this is an earlier motor this is our crankcase breather, right here. On a stock bike, you're going to have a hose connected to this which will, in turn, go come up and join with a tee which goes to the vent on the oil tank.

Then another hose going along the back fender and that's your venting system. On this type of system, later your motor you'll have a fitting back here, but on this type of system down inside the hole for the intake cam, is your time breather disc. You want to make sure you take that out now so you don't lose it and put it with your cams and your box. Now we'll go ahead and take that out with a magnet, should come right out, hopefully.

You've got a spring and there's your timed breather. See how it has a couple of windows in it. Then if you look in the crankcase, you'll see there's a couple more corresponding windows. The way this works, is the intake cam has these slots, and the breather gear. When you're assembling it that goes like that, and the spring goes in there too. As the camshaft is rotating its opening and closing those windows and letting the crankcase pressure come out of this tube here.

Usually, on a custom bike, I’ll just run a piece of hose off of this to the ground on a stock bike like I said it'll be connected to the oil tank. Like I said, you don't want to start take your crankcase out in the driveway where your garden hose is and start washing it and then when it comes time to put it back together you're like hmm something's missing. One other thing worth talking about with the breather system is. If you do have this style breather system, with the little windows and the pipe sticking out here. You will have this seal on the crank case. Basically, when you slide the sprocket for the primary drive that seals this off. That seals the crank case. I'll grab a later year crank case, I have one over here on the work bench. We'll show you later the way the later year breathes and why it does not have a seal. One other thing is, you'll notice how this seal is closed side, facing in, because it's trying to seal from the inside out.

That's why you're going to see here is the lip, here is the little spring. On reassembly when you're putting this seal back in the crank case you want to make sure you orientate it in this direction. You don't want the closed side out because then it's not going to seal correctly. We can go ahead and knock that seal out. Whoa Nelly look out, careful. We can go ahead and just knock that seal out.

This seal is all metal and it says, "Made in England." On it. I'm fairly certain this case has probably never been split before because the replacement seals that you're going to find on the website are rubber. They will still do the same job. They're just not made the same as they used to be. We're basically done with this half of the case for right now. We'll get that out of our way. Here's the later breather system. I believe this is a 70 crank case. What you're going to see here is three little tiny holes. Right there. Basically, there's not going to be a seal here.

So, that basically it breathes into this area and then goes out a fitting right here where this hole is. See my finger there. On a later breather system, no seal. Basically, this equalizes the oil level if it gets above those three holes it'll go back into the crank case and go back to the oil tank. It's always good to know which type of breather system you have, whether you need the seal or not. Of course if you were putting a belt drive in you would want the seal, you would plug those three holes.

Then you would make it breathe in some other fashion like maybe utilizing this hole here for a breather. Just something to be aware of what type of breather system you have on your engine. We'll go ahead and remove the crank shaft from the right side case. One of the things about the fitment of this to the bearing, it's a very tight fit. Where if it's not coming perfectly straight out, it's going to get cocked and you're going to be fighting it.

There's a couple of different ways to do this. We can check and see if it's going to come right out or not. If not we'll try a different method. You can look on the other side and see if it's coming out of the bearing or not. It does not look like it's coming out. What we'll do is, what I'm going to do is, I'm going to clamp this in my soft jaws and then try to work the case of off the fly wheel while it's clamped in the soft jaw. Because, once again, we don't want to beat on the crank shaft.

There we go. No harm, no foul. No beating on crank shafts. Here's something else I would like to show you. This is your filter screen for returning oil going back to the oil tank. You see right here there's a screen. As the parts of the engine get lubricated the oil falls to the bottom of the engine then it gets picked up by this tube right here, which in turn goes to a port on the oil pump that is the return side of the system. We'll go ahead and remove this now. Once again, Whitworth.

Sometimes these are really on there. This is also something that if you've just dragged home a bike, it is running and you're doing an oil change on it. You should probably remove this filter and clean it. Check to see if there's any debris in it. If the motor is in the bike, you're going to look underneath from the primary side. Then you'll see that plug is at an angle. You can just get underneath the bike and remove it. There it is. Filter screen. Sealing washer.

Then notice, this goes, the tube that connects to the oil pump goes in that hole so that all the oil gets filtered. So far, pretty good. There's some shiny metal there, folks. That's the kind of thing you're looking for on a used bike that you've just brought home and you're going to change the oil. Make sure you take this off. Clean it out real good. A lot of times you get some brake clean, spray it all down in the bottom.

You'll see some shiny stuff. You don't want to see a lot of crud on there. If you see some big chunks and some real shiny stuff it may be time to disassemble your engine and figure out why. Just for the heck of it, we'll go ahead and blow some brake clean in there. There's just a little bit on the outside there, nothing to be super alarmed about. I don't really see anything going on there. A lot of times you'll find there's a bunch of sludge in the bottom of this. Always a good idea to clean this out.

On a rebuilt motor it's probably a good idea to take it out every couple of oil changes and just make sure it's clean. Not too much there. Okay, so in preparation for rebuild obviously we're going to wash everything scrupulously clean. We can go ahead and remove this seal. We can remove these two bearings and these two fittings here for the transmission, and this bearing. This half of the case will be stripped and ready for vapor blasting.

I'm not a big fan of glass beating aluminum motor cycle parts, leaves a less that desirable finish on the metal. I believe it kind of opens the pores of the aluminum, where if you get any grease or oil on the aluminium on the outside part of the case where we're going to clean it. It doesn't wash off easily. Where if you look at this other motor I have here on the bench here that's going together now. You can see what the vapor blast process, the finish it leaves on there. It's a nice smooth even finish and repels stains and oil.

We need our seal puller for that one. Basic tool available just about any auto part store. Hammer time. That seal, look at that thing. It's just the rubber portion of it is hard as a rock and breaking apart. I'm pretty confident that seal probably wouldn't have sealed a darn thing. Here she comes. That seal is pretty much junk. Okay for this bearing there is a snapper in there. Right there. Then we have these two fittings here. This is your plunger. We'll see here in a sec when I take that off for the transmission. That's tight. Once again this would have been a lot easier to take off when the motor was together, I should have done it then, but no sense crying over spilled milk. Oh boy, oh goodness [bleep] gracious

Okay, this plug here is your drain and level plug. If you take the entire assembly out that will drain the tranny. If you take just this smaller hex off it joins up with that. When this is all together when you're filling your tranny, as the tranny level gets up to that top of that tube it runs out the bottom, and then you know your transmission level is correct. A little tech tip for you there, take that one off and we still have this stubborn plunger stuck in here acting like it does not want to come out.

Hopefully, we don't have to tear it all up. We do have those available on the website if it gets tore up. This one's getting pretty [bleep] tore up. Well, sorry to say I had to put a pipe wrench on her but I got the mother effer out of there, there she is. This whole unit doesn't seem very happy. It's not a good practice to reuse any of the bearings in this engine. Since we are going to rebuild it, we're going to go ahead and remove this is one of the crank bearings right here, crankshaft. Whoa, that thing is not very happy feels very notchy.

Then we have the transmission bearings, lay shaft and main shaft. We'll go ahead and remove those three bearings. I have this seal driver kit, bearing and seal driver kit. Now, these are basically different sizes for doing different bearings. I’ve already went ahead and set up the one I need to remove this one, this one, and the smaller one. Now we'll grab our mapp gas. I talked about that earlier I like mapp gas it does heat up faster than propane. Costs a little more, but in the long run it's worth it.

We're just going to heat around this area where the bearing is. Basically when you're heating up aluminum it will grow ever so much. Makes the bearing come out easier. You don't really want to pound these out without putting some heat to it. That should probably do it. Big hammer time. [banging] There's that one. Heat this portion of the crankcase up to get the other ones out.

This one I'm going to send in rather than out so it's not BC, you can see it's already recessed in there I'm going to send it this way. This one's going to come out going this way because there's a lip on there and you don't want to try to go that way or it’ll break the crankcase.

The past I’ve noticed the needle bearing up generally is not as tight as the larger roller bearings. We'll go after that one first. Silly me I was going to push this the other direction until I realized that it is recessed there. So I went ahead and took this off of there and I'm just going to use a regular punch. There's that one and we're going to go the other way round for the other one. We are going to heat this up a little bit more.

All right let's give that a whirl.

Like that. Okay, we have all three of those bearings removed. Here's the needle bearing, crank bearing, tranny bearing. Once again it's not a good idea to reuse these bearings. I don't care if they feel fine in there we're rebuilding the motor we're doing it right. We're not using old bearings that are from 1968. Okay there is two more bearings in here we are not going to remove those at this time we are going to check the fitment on those. You have two cam bushings, they're not bearings, they're bushings. You have a cam bushing

for intake and exhaust. These are probably a least wear item in here. They are a bronze type of bushing. If I do find those are within specification as far as fitment I'm not going to change those. If I determine that they are worn, they will also get heated, driven out, replaced. Basically, this side of the crankcase is ready to be washed. Okay, I gave the left crankcase a quick bath out in the driveway with some LA's totally awesome from the dollar store, that stuff works really good.

Get the oil off it, a little gasket scraping tip for you real quick. A razor blade anytime you're scraping a gasket surface. You want to hold the razor blade at a 90-degree angle that way you don't gouge into the metal and get all that old gasket material off of there. We got it pretty clean. Now next thing we need to do with this, is we need to remove this race right here. If you look on the other side of the case there's no way to pound it out of there.

This is the special tool for removing this race it is an expandable collet basically, you put the collet in the bearing. Well, it's got to be loosened up but at any rate, you put this in there and then you tighten this up and heat it and pound this out. The tool and the race doesn't work very good, we're going to show you real easy way to do it. Let's head back to the deck and we'll show you the good way to do it.

I have a natural gas grill here on my deck in my back porch and it has a temperature gauge on the lid. I like to get it at right around 300. I’ll basically heat it uplift the lid, let the heat out, put it back down, get it at about a constant 300. I have this awesome cookie sheet and we're going to bake this crankcase. We're going to bake her at 300 degrees for about eight to 10 minutes. We're having us a barbecue today ding ding.

[music] Almost done. All right, let's have a look here. Let's see here, she done yet? Yes, I think she might be done. Safety first. Oh, yes. She's nice and hot now. There you go. Look at her. All right. Now that we had baked triumph 650 for lunch, this sides all stripped. All we need to do is give it a good thorough washing, cleaning, before it goes to the vapor blaster. I do like the vapor blast all my parts so they come out looking very clean and tidy before we're going to reassembly. The last thing we need to do is take the rods off the flywheel and remove the sludge trap plug and inspect the sludge trap.

2 thoughts on “VIDEO: Triumph 650 Motorcycle Engine Disassembly & Rebuild Part 5”

  • I’ve been a customer for a couple of years. Great place to shop and learn.. got a big bore kit and Newby clutch and countless other purchases. The videos are fantastic as I’m learning as much as possible about triumphs . Tyler is already in a Triumph group that I am a member of and I just want to invite any of you to join British motorcycle mechanics. Todd would be a welcomed wealth of knowledge. The group is 11,000 and growing. Greg scoffield is the founder and admin and is very serious about it being for guys that work on Brit bikes.. so if you guys join someone’s gonna learn something of value.. and I’m sure it would be good for business at the same time. I hope to see you join.

  • I will join

Leave a Reply