REMOVING AND SPLITTING A
(this scenario presumes that the engine WILL be torn down and the crankshaft replaced/rebuilt to ensure that the crankshaft seals and bearings are good).
Chances are that if the bike that you have acquired/or currently own has “sat” for any extended period of time (outside especially) – the cylinders are going to be “stuck” on the engine case and difficult to remove. Usually the “worst stuck” one will be the RH cylinder. I would suggest that you DO try and remove the cylinders while the engine is still in the frame and the tires/wheels are still on the bike, as that allows you a little more room under the cylinders that you won’t have if you pull the engine and set it on your workbench and it also helps to hold the engine firmly rather than it “moving around” on your workbench. Of course, the “ideal” set-up would be to run the bike up on a lift, and raise it to a good working height.
First, of course, remove all the head bolts and all 3 heads/head gaskets. Next remove the 3 exhaust pipes/mufflers. Then remove all 3 carburetors and carburetor mounts from the back of the cylinders. Then try to get the cylinders off.
There are a couple of ways to remove these stuck cylinders – I’ve had the best luck using a mixture of 50-50 Acetone and Power Steering Fluid (or ATF) and heat. The details are located elsewhere on this Board. Here's the link.
After I get the cylinders off, I usually stuff paper towels or rags down alongside the pistons and inside the cylinder studs to help prevent damage to them or crap from getting into the crank area. I DO wait to remove the pistons/rings until I get the engine out and it is on my workbench.
Drain any transmission fluid by removing the drain plug on the bottom of the engine and drain any oil into a container. If the liquid is milky or watery – be prepared for rust to be inside the tranny/clutch area!
I usually try to remove most engine parts while the engine is still in the frame. I remove the LH sprocket cover, the engine sprocket nut, the engine sprocket and the drive chain, then remove the clutch cable from the clutch actuator arm and pull out the clutch cable. I also remove the 2 screws that hold the clutch actuator in the 2 engine halves and pull out the actuator assembly. You at least NEED to remove those 2 screws in order to split the engine cases. Then I remove the LH stator cover, remove the rotor bolt and rotor, remove the screws that hold the stator to the engine cases, then remove the stator and unplug the stator wiring from the wire harness and then remove the “big” rotor that sits on the crankshaft so you are down to the taper on the crankshaft. Make sure and keep the “half-moon” key that sits in the groove in the crankshaft taper. Then remove the driver’s LH footpeg and remove the shifter and linkage from the shifter shaft.
Then I move to the RH side and remove the kicker arm, then the oil pump cover, then unscrew the tach cable and pull it out of the clutch cover. (IF you are working on an early H1 - you also will have to remove the distributor cap and wires and get them out of the way). Then I remove the oil feed line at the oil pump, pull off that banjo fitting and thread in a 6mm bolt/screw to “plug” the oil line and prevent oil from coming out of the oil tank. You can then pull that oil feed line out of the clutch cover and carefully bend it back out of the way. Then I remove the 3 cylinder feed oil lines at the pump, then the 2 screws that hold the pump on the clutch cover and remove and set aside the oil pump. Then I remove the bolts at the other end of each oil line (at the back of the cylinders), pull the 3 oil lines out and set them aside. Then I remove ALL the clutch cover screws and the rubber “boot” on the RH side of the shifter shaft and gently pull out on the clutch cover (be prepared to have to “catch” some more tranny oil, as some WILL come out along the bottom of the clutch cover). Usually the brake pedal has to be held down to allow the clutch cover to slide off.
Then I remove the little (10mm) bolt that sits on the end of the crankshaft and pull off the oil pump drive gear, then I use a thick rag (some use a penny) to go in between the large clutch gear and the gear on the crankshaft to prevent them from turning and then remove the nut/washers/collar/gear that are on the crankshaft so you are down to the “bare” crankshaft. Again, keep track of the half-moon key on the shaft.
Then I remove the 10mm bolts that hold the clutch outer plate on the clutch basket and set aside all those bolts/washers/springs/cups. Then I carefully pull off the outer plate and then slide off all the clutch friction/steel plates and expander rings (if the expander rings are still there).
Then I use an inner clutch basket “holder” (mine is just an old clutch steel plate with a piece of #4 (1/2”) rebar welded onto it as a handle) to hold the inner basket as I remove the clutch nut – this will take some force, as it SHOULD BE on there pretty tight. Then remove the "lock" washers and thrust washers (pay attention to the order they are in) and then slide off the clutch basket with the large gear, there is a separate smooth collar inside the center bearing of the basket, so be aware of it.
Then I remove the oil receiver – this also HAS to be removed in order to split the cases. This is a “half-moon” shaped aluminum piece that sits slightly above and to the left of the clutch. It has a “protrusion” that sits inside a tranny shaft, so pull it straight out. It has a single Philips head screw that holds it on. Then you can remove the shifter shaft that runs all the way through the engine by pivoting “down” the arm that engages the shift drum so it clears the shift drum outer plate - and then pull the entire shift shaft assembly out the RH side of the engine.
You should then be ready to pull the engine out of the frame. Remove all the motor mount bolts from the frame and lift the engine out of the frame and set it on your workbench with the pistons facing you. The next step is to remove all 3 pistons/rings/needle bearings/wrist pins. The crankshaft cannot be removed from the engine cases without removing the pistons.
First it is necessary to remove at least one of the piston pin circlips on each piston so you can push the piston pin out that side of the piston. A piston pin “puller” is usually necessary to remove the pin, because you do NOT want to hammer/hit the pin or you could damage a connecting rod.
Then turn the engine “upside down” (so the cylinder studs are on the workbench and “away” from you). Then remove ALL of the large and small nuts that are visible on the bottom half of the engine, EXCEPT – the outer 4 large nuts that sit on the outside of the crankshaft area – these you can leave on, but have the nuts unscrewed far enough so they are “flush” with the end of the studs. NOTE: IF your engine is rubber-mounted, you need to pull out the metal tubes that have the rubber mounts attached to them, as there ARE additional small nuts underneath them that HAVE to be removed before you try to split the cases. It’s best to just pull those tubes straight out – twisting them as you pull them out will not help. Try to pay attention to the shape and orientation of the outer metal portions “washers” of these rubber mounts as you remove them.
Once you have the nuts removed from the studs, you are ready to try and split the cases. What I do is grab just the lower engine half and lift the engine up while pulling up on it and then tap those outer studs with a hammer. What you are trying to do is to have the weight of the crankshaft help you separate the halves. If you alternate tapping one outside first and then the other side, they usually will begin to separate. I would not pry on ANY area of the halves that need to seal together. Once they begin to separate, then you can remove the last 4 large nuts and gently tap on the studs and they should allow you to pull the lower case all the way off the studs. I leave the kicker bolt spring retainer bolt in, and as you pull apart the cases, you will hear that spring “unwind”. Don’t be alarmed by that.
Once the halves are separated, you should be able to lift the crankshaft out of the upper case - sometimes the rubber seals "stick" to the upper case - if you carefully wiggle the crank by alternately pulling up on each end while pressing down on the upper half, it should come out. Protect the connecting rods - package it up carefully.