bike mathews 500T
Had the great opportunity to fettle a 1975 CB500T this past year. Wonderfully engineered vintage bike! The plan was simply to make it run its best, though it at least ran when it arrived on an eBay sale from Des Moines, Iowa. Checking air filters.
Adjusting the valves. Inspecting cam chain condition and tension. Neither were the absolute best. Checking cam timing. One of the most difficult engines to determine cam timing on.
Other cam. Timing on both is good. I had removed the tensioner because it was frozen. Would not deploy. When I removed the cam chain tensioner, found the rubber dampers for the cam chain had disintegrated. So there were foreign bits floating around in the engine.
Took a bit of work to unstick it. Found the shaft mangled by a previous person. Closer.
Its roller is good. Filed it smooth, cleaned it, greased it and reassembled it. Time to inspect the oil centrifuge.
The main pressure valve looks like it is working. Very important to inspect the centrifuge. Some debris in here. More.
Finding silicone sealer everywhere. The bike had a noisy starter clutch so this was inspected. Typical deterioration of the rotor. See the crack and the lifting of the aluminum?
Opposite side also. See the dimple? The assembly is tearing itself apart. And another view. Here a piece is actually broken off. Means the rotor has shifted in its mounts, and this means the screws have backed out. This is classic.
Mangled rotor. Several pieces have broken off. Removed the whole assembly. Even the chain guide is cracked. The whole starter clutch assembly is getting rebuilt.
The decision was made to inspect the top end more closely, and this requires engine removal. Out it comes. Just removed.
The cam chain needs to be separated with a special tool in order to remove the cylinder head. Here is that tool Here it is in action.
Ready to separate. Separated. Cylinder head is off.
Inspection has begun. More foreign bits. Pistons still on the engine.
Bores not bad, but measurement showed them appreciably worn. And some "tree rings" from seasons of sitting. More.
That is almost 0.003" piston-to-cylinder clearance. More than 3 times normal. Inspecting the all-important cam chain rollers. More.
And more stray bits. You can see it is the cam's damper rubber ring. Disasembling the valve train. Very unique system.
Checking fit of cam in its bearing. The factory put shims on the cams, up against the bearings. They are endplay adjusting shims, that is all. They will be needed on reassembly. Bearing finish is good.
Rocker arms also checked. Noticable wear. These are getting replaced. Pistons removed and inspected. Valves removed from head, seats examined.
Closeup. Valves inspected. They are reusable. After cleaning. No sign of recession.
Because of all the crud found in the engine, the decision was made to go into the bottom end. Getting ready to split the cases. Bottom case half off. Everything looks good in here, including the tranmission.
Hmm, with the transmission out, now we are glad we went into the bottom end. A lot of crud in here, and on top of that, extremely heavy sludge buildup. This engine I would say never had a single oil change. Closer. Machined the cylinders for new pistons.
Including prepping the gaskets surfaces. Head ultrasonically cleaned and ready to be machined and reassembled. Valve seats machined.
More. Valves registered to their seats. Going back together.
More. Reassembly. More.
More. Prepped carb manifold gasket surface. Cams timed.
New factory cam chain, new rivet link. Crimp connectors. Worn through at the wiring harness.
Typical alternator wiring issue, falling apart. Close up of alternator wiring. Whoa! Silicone city!
More. More. Rusty ground. Can you tell this section of the project is all electrical issues?
More. More silicone sealer. Note the worn through insulation.
Repairing by soldering and sealing. More. Almost ready.
Sealing up the alternator connector at the cover. All better. Inspecting the rectifier connector.
Gel battery. A really good battery. Bottom done, working on the top. Installing the cylinders.
Working on the clutch and shift linkage side. Centrifuge installed. Working on the starter clutch side.
New seals all over. More. Engine back in the frame.
Bike tuned up, set up, adjusted and ready to go.