|
Post by lesorubcheek on Nov 12, 2013 14:48:36 GMT -5
Started on a rebuild of a 750 and decided to post a thread to share with the progress. This one is planned to be a work saw so not worried about being too pretty, just solid and functional. First put in a new clutch side seal. The bearing was good, so left it as is, just cleaned it out well before putting the new seal. Also note the worm gear that drives the auto oiler. It's outside of the bearing but inside the new seal. The outer part of the gear piece is actually what contacts the seal, not the crank. The crank goes inside the gear piece. Here's a view from where the auto oiler sits. You can see the worm gear teeth. and here's the parts for the auto oiler. There are 4 o ring seals total. The front is largest, next is slightly smaller and the two farthest inward are smallest. You can see the eccentric groove on the plunger that causes the pumping action along with the half-moon cutout on the end that acts as a valve, opening to inlet bar oil and then closing as the eccentric causes the rod to push forward. Also note the small pin that the eccentric rides on. I had another of the worm gears laying around, so here's a pic so you can see how they sit inside the case. Here's the oiler assembled. I used plenty of oil inside to make sure it's lubed. and after installing the oiler in the case, you can see how the gears on the pump rod contact the worm gear. Next will be fitting the crank and bearing into the left case section. The bearing is in good shape, so not changing it. Also going to chance the 53444 seal since I don't have too many spares. It looks fine, and if after a vac/pressure test if it leaks, I'll replace if needed. The bearing is held in place with the special tab washers and bolts. Putting the crank into the freezer to chill it for a while. Lots easier to press in that way. Hopefully I can get it in later today. Dan
|
|
|
Post by lesorubcheek on Nov 12, 2013 19:11:21 GMT -5
After a few hours, the crank and bearing were pretty cold. Used the heat gun to heat the case to make it expand. Used a square punch to tap on the outer edge of the bearing shell. After a little persuasion, the crank and bearing were flush in the case half. Also, I used one of the seal protectors before starting. Handy little item to protect a seal from threads or sharp edges. I used tape before I found this. Here it is on the end of the crank. Next was to install the tab washers and the securing bolts. Now it's time to join the halves. There's a large o ring that seals the case halves. I oiled it along with the bearings well before starting to put them together. 5 screws hold the case halves together. After tightning them up, here's what it looks like from the opening where the cylinder will attach. The cylinder I'm planning to use has been completely dissasembled. Here's all the parts, including the port covers and the decomp. Here's one side showing the port opening. Guess for someone who knows about modding port timing, this would make it easy to get to the intake ports. That's one visible difference between a 650 and 750 cylinder. The 650 doesn't have removable port covers, only the 750. Oiled the decomp piston, and installed using snap ring pliers. Going to try Threebond on the port covers. The originals I've seen all used black silicone, or at least that's what it looks like. If they leak, I'll try somthing else, or maybe a thicker coating. Here it is back together. and the other side. and finally a view from underneath. Hopefully tomorrow I can assemble the piston and cylinder and check for vac and pressure leaks.
|
|
|
Post by sweepleader on Nov 13, 2013 8:31:13 GMT -5
Love these pics, keep them coming! Thanks, Dan
|
|
|
Post by lesorubcheek on Nov 13, 2013 21:04:58 GMT -5
Glad you like it Dan. Here's a little more. The piston and rod was in good shape, but putting new rings. Also, the rod/crank bearing is OK and those things are hard to come by. Used some grease to hold the bearing parts to the crank. Here's a tool that's handy to hold the lower section of the connecting rod when installing. Can't remember where I saw the idea... maybe here at HoH, maybe AS, or possibly in a book. Anyway, it's easier than trying to use a finger. and here's the rod bolted onto the crank. Now's time to assemble the cylinder. Going to use more Threebond for a base seal. The sides of the cylinder are close to the left case section, so the piston needs to be all the way down to allow clearance. I oiled the rings and around the piston as well as all the internal bearings one last time to make sure they're well lubed. Here it is bolted on. and another pic from the bottom. Finally for tonight will be the intake manifold. New cork gasket with a little oil to help it seal. and here it is in place. Hoped I could to do a vac/pressure test, but I'm calling it quits for tonight. Hopefully tomorrow. Dan
|
|
|
Post by lesorubcheek on Nov 14, 2013 20:46:21 GMT -5
Put on an aluminum block off plate over the exhaust, covered the intake with plastic, and connected the pressure tester to the pulse line connection. Pumped it up to 5 psi and it leaked down within a few seconds . Filled a small wash tub with water and gave it a dunk while keeing it under pressure to look for bubbles and find the leak. Looks like the right side intake port cover is leaking very badly. Thankfully I can remove it without yanking the cylinder off. I'll put an extra thick layer of Threebond and let it set up until tomorrow and try again. Dan
|
|
|
Post by lesorubcheek on Nov 16, 2013 21:00:36 GMT -5
Still fooling with air leaks. It's been a while since doing a 650/750 and forgot about the seal at the clutch side. To seal properly, the clutch needs to be installed to press the worm gear firmly against the crank. Otherwise, it leaks between the crank and the worm gear. Decided to at have some fun and went ahead yesterday and put the rear handle together. Here's most of the parts for the handle assembly. From past experience, one thing to remember is to keep the locknut in place in the rear of the handle before putting the rubber cover in place. I usually leave it there with a screw to keep it from falling out. Here's a pic of the air chamber and area where the goodies fit. Notice I left the manual oiler discharge line in place. Didn't want damage the grommet, so I left it in place. Here's zoomed in a bit so you can see where things will go. First, I attached the throttle rod to the trigger and set them in the general area where they'll fit. Next, the arm that connects to the decomp needs it's spring attached and sits in front of the throttle. The spring fits so it rotates the arm downward in the front. There's a special pin for the decomp arm and a roll pin for the trigger. Fit them by hand and use a punch and hammer to drive them flush. Next is the cam lever. The spring is installed so it rotates forward at the top. It's held on with a small C clip. Here's how it looks engaged, as it lifts the arm to raise the decomp. Also note the screw on the arm that sets the idle speed by the amount it presses the trigger. Here it is forward, no longer engaging the decomp. Next is the handle cover, held on with 2 screws and lock nuts. Choke linkage is straight forward. and here's the rubber handle cover in place. The decomp boot simply slips onto the opening in the bottom. Use a little cement to hold it for a good seal. Note the spring that's inside the decomp boot. The manual oiler is also fairly obvious to install. Here's one more pic from the top showing it together. Dan
|
|
|
Post by sweepleader on Nov 16, 2013 21:16:56 GMT -5
Great detail, this is good stuff!
|
|
|
Post by lesorubcheek on Nov 18, 2013 22:01:42 GMT -5
Finally got a proper vac/pressure seal on the crankcase so can start putting more parts on it. Good time for the flywheel. Here's the parts. and here it is assembled. and torqued onto the crank. Next will be the transformer receptacle. These parts apply to all the '50s except the earliest 350 and 650 saws. They were a bit different. About 3/4 of the '50 saws I've came across have at least one section split on the retainers where they encircle a retaining nut. I've found that using thick CA glue in the cracks tends to hold up pretty well. It's only an issue if you overtighten the transformer retaining screws. Anyway, here's the parts that make up the receptacle. Before assembly, it's a good idea to clean all the metal contact surfaces. It also doesn't hurt to apply some electrical contact chemical to help prevent corrosion. Here's with the contacts in place. They just slide over the plastic. and here's how it looks from the back side. next, the ground contact is slid in place, and the retaining screw tightened. Finally, the wire is intertwined as shown on the plastic and the screw holds the tab in place. One last pic showing how it looks from the outside. Ground contacts on the left side and the trigger signal from the module is on the right side. Here's the parts for the back plate and the trigger module. The trigger module needs a 0.015" gap between itself and the flywheel. Used a business card that was a hair over 0.012"... I left the feeler gauge at the farm over the weekend. Lock nuts are held in place on the rear cover with slip over retainers. Great idea to prevent the magnesium from getting stripped out over time. Same idea was used for cylinder retaining nuts. Here's the lower snubber in place. and kill switch. Always good to make sure the switch is good with a meter before putting it together. Installing the transformer receptacle is easy. Just slip one side in place and bend together to fit the other side. Here it is in place as seen from the inside. It's easier to attach the kill swith wire (from the trigger module) before the cover is attached. Here it is slipped on, and the wire from the receptacle slipped through the case on the lower end. Slide it into place making sure the rear cover goes under the black metal deflector plate. and attach the 2 bolts inside, with the aluminum holding plate under the top bolt. bend the holding plate so it secures the wire going to the kill switch. Push in the black plastic wire retainer and press in the wire that goes from the trigger module to the transformer receptacle. Slip on the wire from the receptacle onto the tab on the module. Finish it off with a tie strap to keep the wires from getting too close to the cylinder. Dan
|
|
|
Post by sweepleader on Nov 19, 2013 9:29:47 GMT -5
Beauty, thanks for sharing all your knowledge. Dan
|
|
|
Post by lesorubcheek on Nov 21, 2013 21:39:45 GMT -5
Next, here's the starter parts. Note the nylon part on the starter spring retainer pin. It helps prevent the spring from wearing directly on the pin. The starter bushing is pressed into the pully. 650s and early 750s used a 2 piece bushing. Later 750s used a 1 piece. A shield sits in the bottom to go under the spring. Next goes the spring. Its not too difficult to wind by hand and slip it into place. I put the retainer next. The spring is a bit off center, but when the top shield is in place, it'll hold fine. Outer shield goes next. The retaining ring slips in the groove to hold the shields and spring in place. Starter rope is threaded through the pulley. There's a nylon washer that goes on the end of the knot. Now wind the rope. There's a washer bushing that goes under the pulley, and one that sits on top. A metal washer then holds the pully on with the screw. The debris shield goes next. Sure would be nice if these were available since they're extremely scarce. This one has one break in it, but it's fine for a work saw. Thread the rope and attach the pull handle. Now assemble and rotate to preload spring tension. Attach the 3 screws and that's it. Here's from the inside. Will wait to attach the starter since its easier to install the clutch with the starter removed. Dan
|
|
|
Post by lesorubcheek on Nov 22, 2013 23:02:45 GMT -5
Here's the fuel/oil tank parts. The rubber snubber is still attached well enough so not re-gluing it. Cut two 12" pieces of 5mm OD Tygon with the ends at angle to make it easier to get started through the holes in the tank. Measured the old lines to see how far they went in the tank. The fuel was about 8" and the oil about 6". Using the fishing line method for pulling the lines through. Rotate as it's pulled and it goes fairly easily. Here's the fuel line pulled through to the mark of 8". Snip the end straight across and insert a new filter. Do the same with the manual oil line. Here's the auto oiler fitting with it's line and filter attached. Apply a little sealer and tighten. End with it pointing straight back. Finally, put on the caps. I won't show duckbill replacement since it's already around here, I think in the 925 thread among other places. Dan
|
|
|
Post by tribulation138 on Nov 23, 2013 7:57:04 GMT -5
The 750, my dream saw to have one day.. everytime they are on ebay they sell for so much..
|
|
|
Post by sweepleader on Nov 23, 2013 12:48:16 GMT -5
|
|
|
Post by lesorubcheek on Nov 23, 2013 20:51:06 GMT -5
Here's some more odds and ends including the muffler. Decided to paint it along with the muffler cover. The cover is still tacky, so it'll need a few more days. Here's the brace between the rear cover and the crankcase. Here's the lower heat shield. You can see I left the exhaust block off plate on to keep the cylinder from getting something inside that doesn't belong. Removed the block off plate and sat the muffler in position. Two 1/4 screws hold it underneath. and two 10-24 screws hold it on the side. The spark arrestor screen and cap are held on with 3 screws. Used some anti-sieze to make 'em easier for any future removal. Here's the standoff spacer that adds the 5th attachment point for the starter cover. The 5 anti-vibes. Note they are unique to the 650 and 750. The 450/550 look similar but are not the same. I'll also use some anti-sieze on their threads. Two go on the rear handle. One on the starter side of the tank.... and two on the clutch side. Good time for a new boot. Here it is with the garter spring. The boot slips onto the manifold. The garter spring goes over the top of the boot easy enough, but to get it down into position, you need to lift up on the boot to narrow it's width and then roll the spring down. Here's the spring in position on the boot. Dan
|
|
|
Post by lesorubcheek on Nov 24, 2013 17:55:01 GMT -5
I found some grommets that fit for the opening for fuel, oil and the impulse line, so decided to use 'em. They're not original, but figure it can't hurt to keep the chamber cleaner. Using an original impulse line since they're thicker than the Tygon. I used some glycerin to lube the grommets and make the lines slide easier. Before putting the handle in place, need to make sure the decomp lever is pointing up to go through the decomp boot. Here it is sitting on top of the engine case. I also removed the screw from decomp lever. A handy item to have for installing and especially removing the anti-vibe parts are some spacers. These are from 0.08" aluminum. They are just a hair thicker than the button on the center of the anti-vibes. Makes it much easier to slide them into position. With the spacers in place, the handle can be pushed onto the case. Note it's still tilted slightly back so not to mash the carb boot. Also, as it's eased into position, make sure the decomp boot goes over the decomp part on the cylinder. Anti-vibes in position and spacers removed. Now to seat the top part of the carb boot. Just lift on edge, pull up and through, then work it around. This is how it looks seated. Also note the decomp boot seated in the rear. Next, press the impulse line onto the nipple on the crank case. Tighten the discharge line for the manual oiler and insert the rubber line for the auto oiler. Start the oil and fuel lines from the tank through the grommets in the carb chamber. Work the tank in closer to it's final position. Before it's too close though, need to attach the auto oil pickup line to the tank fitting. Some small piers or forceps can help alot. Once the oil line is connected, the tank can be moved up to the point the anti-vibes are next to the seats in the case that will recieve them. Using the spacers on the bottom anti-vibes, slide them into position. Then use a spacer on the top one and rock it into position. As far as I'm concerned, these steps are probably the most difficult things to do working on a 650 or 750, but with spacers, it's not bad at all. Four screws hold the carb chamber/handle to the fuel/oil tank. Don't forget to attach the decomp system with the special shoulder screw. Each anti-vibe has a screw to hold it securely. Three on the clutch side and two on the starter side. Dan
|
|
|
Post by sweepleader on Nov 25, 2013 8:14:06 GMT -5
We know it takes a lot of extra effort to shoot these clear pictures and post them, thanks so much. Dan
|
|
|
Post by lesorubcheek on Nov 26, 2013 13:43:44 GMT -5
We know it takes a lot of extra effort to shoot these clear pictures and post them, thanks so much. Dan You're welcome Dan. It's fun sharing information about these saws. Several years ago when I first got into them, I was constantly hunting for answers about working on them. These forums are a great place to pass along things you've learned. Just wish there was more time. Good a time as any to put the clutch together. Debated back and forth whether to use the 3 shoe or 6 shoe, and then whether to use a 7 pin hub or 6 pin. Just because I like the 6 shoe better, it won out, and since I only have a few 7 pin hubs and plan to use them on a few 2100s, going to settle on the 6 pin hub for now. Here's putting the shoes onto the spider. Slide the shoes into position and start the spring at one spot. The roll it around and down. Inside is done. Also note here the scess on the center of the spider. Not sure why it was made this way, but a special sized washer is used to fill in the recess during assembly. Then do the same on the outside to fir the spring. A washer goes first. Then the inner race with bearing. Plenty of grease on the bearing for lube. Slide the rim sprocket on the hub and drop it over the bearing. Another washer goes next. Then a wider washer that helps keep the shoes in place. and the smaller washer that fits inside the groove of the clutch spider mentioned above. Use the starter cord method of holding the crank and tighten (counter-clockwise) the clutch onto the crank. Then the outer shield is held on with a couple screws and bellville washers. Here's the parts used in the bar cover. Note the latest cover (and case also) no longer have a place for a screw to hold on the bar guide plates. The early style case on the 750s and all the 650s had a place for a retaining screw. No idea why this was done away with. Always liked them being held in place since it's one less thing to bobble around when removing the bar. A bushing fit's into the cover first. The adjuster screw and worm gear piece slides through the bushing. Went ahead and greased it too. Guide bar adjusting pin screws onto the adjustment screw. Put the front of the adjustment screw in first and then lower the geared end down. Also put a little more grease on top. Put on the cover and secure with the 2 screws. Here's from the outside. Dan
|
|
|
Post by lesorubcheek on Nov 26, 2013 17:44:25 GMT -5
It's became a fairly common bit of info the WB-2 carb that 650s used had a larger venturi than the WB-9 used on 750s. Thought seriously about sticking a WB-2 in here, but I'd need to either plug the vent hole in the carb chamber shield or swap the metering diaghram cover, so decided to just put the WB-9 that came with this saw back in. There were two different circuit plate gaskets in the D10-WB set. The one that was used originally has only a slot where the other has a larger opening. The one being used is in position and the one not used is to the right. Circuit plate is held on with 2 screws. The screw that holds the lever in place is started, and needle and spring sat into position. Lever slides onto the needle and pin is held down by the screw. Using a Walbro tool, set the metering lever height by bending up or down as needed Gasket goes first then diapragm. Cover is held on with 4 screws. Decided to put a little paint since the plating had flaked off. Here's the other end. Gasket on top here then diaphragm so it's against the body. 4 screws to secure the top. Hi and lo needles are the same. I started them each at 1-1/4 turn from seated. There's an insulating spacer that sits under the carb. It's easier to remove the choke linkage (at least for me) so you only need to hook the throttle rod first. Then the choke linkage can be hooked and the lever reconnected. Manual oil discharge line needs to be tightened and the inlet line attached. Press then both down so the cover will fit on top of the carb. I used one of the carb screws at this time to keep the carb from shifting around until all the lines are attached. Impulse line fits next and the fuel inlet. Good time to set the initial throttle speed. Screw in the adjustment screw until contacting the carb and then another turn or so. Remove the carb screw, place the cover and bracket with the 2 screws into position. Tighten 'em and it's done. Dan
|
|
|
Post by sweepleader on Nov 27, 2013 13:08:43 GMT -5
|
|
|
Post by Brian VT on Nov 27, 2013 14:42:30 GMT -5
You don't have that thing running yet ? Just kidding. Great job on the build and the posting here. Be sure to post vids with sound. Jeez I love that sound (almost as much as a 500cc 2-stroke dirtbike).
|
|