My Saito 120 had a bo bo, now the pushrods and covers and severely bent against the cylinder fins. To replace, will I simply put new ones in or will I have to disassemble nearly the whole engine and worry about timing, etc.???? Thanks, Jim

At the most you'll have to take out the 4 cylinder bolts and lift the cylinder a little to remove and replace the tubes and rods. Timing won't change. I would check valve adjustment when done. Don't lift the cylinder too far or you'll pull it off the piston.

Make sure the rods go in the right way. Pointy side up, I beleive.

You will probably have to retime the cam. It isn't all that difficult though.

Since you said the pushrod tubes are bent all the way against the cylinder, the pushrods themselves are most likely bent too. I'd still check them before replacing them, but they are probably bent. I have never tried straightening pushrods myself, but I've heard it doesn't work very well.

Make sure you clean up any dirt or debris before you start. No sense in getting crud inside your engine. Remove the carb and the backplate first. Take the glow plug out while you are at it. Take the bolts out of the cylinder, and raise it enough to get the pushrod tubes and pushrods out. Leave the piston inside the cylinder. Make sure to identify the pushrods. Label them with a piece of tape or put them in baggies labeled which one came from which side, in case you can reuse them.

You might not have to take the cam cover off to get the rods and tubes out. If you can get the pushrods and tubes out without removing the cam cover, you won't have to retime it. However, I would take this opportunity to check the bearings, and you do have to take the cam out to change the bearings.

Anyway, when you get the pushrods out, roll them on a sheet of glass to see if they are bent. If they are, you should replace them. If they aren't, you are very lucky!

If you do have to remove the cam, all you have to do to retime it, is position the piston at top dead center, and the dot on the cam gear straight down, as you reinstall the cam. You can check the timing by watching the action of the rockers while rotating the crankshaft. One will start to operate before top dead center, and the other one will start to operate after dead center. When they start operating at nearly equal distances from top dead center, your timing is correct.

Good luck, and come back here to ask questions when and if they come up.

Good info Ken.

David

I've only worked on the 82 and the 100 but I don't see that the 120 would be any different so chances are you won't have to re-do the timing because you can leave the cambox intact.

As others have said, just lift the cylinder enough to get the tubes/rods out and put the new ones in.

The pushrods run on lifters that will stay in the cambox.

I'm sure both pushrods are bent and I've already got the parts on order. I will try to replace them by lifting the cylinder first. If that doesn't work and I have to remove the cam mechanism, I'll retime the engine when done. Thanks for the help.

Lifting the cylinder should work.