After the Race
by John Cobb
Reprint of "Let's Do It Right" April 1973 issue no.5 of "Keeping Track" newsletter (PDF available here.)
Now that you won the race, how to prepare so you'll win next week again.
First remove air box cover and filter, put rag in carburetor boot.
Next wash the bike as soon as possible. Right after the race is best. Because if it was a muddy race the mud will wash off faster while its wet. Wash the bike thoroughly, lay it on its side and wash underneath it. Pull the tank and seat off and wash them off. Remember if you wash it good when you are going over it and you find if you have to pull the engine it will be much easier because it is clean. Also it will save much time cleaning the outside of the engine after its out. Reinstall gas tank and start engine. Run for 10 minutes. Now that its clean lets start preparing it.
Leave the seat and tank off. Take the front and rear wheels off and check the bearings, clean the brakes. Grease the brake cam, making sure it is not too sloppy in the backing plate. With sand paper lightly sand the brake drums and shoes. Check the spokes and trueness of the rims. (I know most people don't have a wheel truing stand, but a vise will work). Put the axle in the wheel and tighten the axle in the vise. Get a piece of wire and mount it along the work bench so its a little ways from the rim. Spin the wheel. Tighten spokes accordingly to true up rim. Check the tires for wear and cuts. Also be sure the valve stem isn't being pulled out by the tire spinning on the rim. On the rear wheel be sure and check the rubber bushings. If worn or cracked replace them; it could save you buying a new rear hub later. Check the rear sprocket carrier bearings making sure they are tight and well greased. If you have to remove the bearings to repack with grease or replace, make sure to heat the aluminum around the bearing and tap out lightly. If you don't take care doing this, the new bearings may be loose in the sprocket carrier.
Now, check sprocket teeth for wear.
While the rear wheel is off, check swing arm and bushings. See if you can move the swing arm back and forth or sideways. If so, either the swing arm bolt is loose or bushings are bad. Check the shocks for being bent or leaking. Now you can replace the rear wheel. Don't put the chain back on yet. Wash it off good with solvent or gas and soak it in oil until you are ready to use the bike again.
While the front wheel is off, check the fork head bearings. If you have back and forth movement or tight spots, it's best to remove the triple clamps and inspect bearings and races. Repack and tighten them. If its been 4 or 5 races on the same fork oil, you should change it. Flush the forks out with solvent and refill. 135cc for the C.M.F. (32mm Ceriani forks) and 200cc for the steel gas tank model pre 71 (and 200cc for the 1974+ 35mm Ceriani forks). Replace front wheel.
Remove the carburetor, clean and inspect thoroughly. Check air box for cracks, make sure there's no dirt inside, (clean) and replace filter if necessary. If it's a muddy race, make sure the filter element is paper and well sealed. Remember, care should be take here. If dirt or water pass thru the filter and air box, it will ruin pistons, rings, rods and cylinders, just to name a few. So take care.
If you have about 6 races on the engine, pull the top end off and inspect cylinder, piston, rings and rod for wear. Also take the tip off exhaust pipe and clean baffle in it. This can plug up causing poor engine performance.
After 3 or more races or enduros or any real wet race, you should change transmission oil. The best way is by removing the clutch cover (on the Sachs motors) and tipping the motorcycle on it's side to drain oil. Doing it this way you can inspect the clutch gear and primary drive gear. With the cover off see if you can tip the clutch wheel back and forth. If so, the bushing in it is probably bad and should be replaced. Before putting clutch cover back on, pour in 3/4 Quart of transmission oil. This is more than the book calls for but won't hurt a thing.
Pull mag cover off and inspect Motoplat, making sure it's clean and dry. Leave the mag cover off util you are ready to race again. This will let everything dry out good. Check the front sprocket and teeth while the cover is off.
Check the coil mount, making sure its tight and grounded properly.
Now go over the whole bike checking and tightening every nut and bolt on it, making sure motor mount and swing arm bolts are tight. Reinstall gas tank making sure the padding is in the right place so the tank doesn't beat against the frame. Put foam rubber blocks between seat and tank and over (not in front of) are intake opening. Now push seat in place and tighten. You should be pretty much ready to go. Don't forget to oil cables and levers. This sounds like a lot of work but if you want to be a winner it takes a lot of work!!
Editor's note: Since this article was written in 1973, I took the liberty of updating parts of it for our readers who have bikes produced after this time period Additions to this article are printed in italics. Although this article is 50+ years old, it still holds true for anyone riding their Penton today.