Modern Buddy

just finished insalling my DR 177 piston and before I put on the cylinder, I pushed down on the kick started slowly to make sure I get smooth piston action and it stops at the bottm of the stroke. Like its hitting something. I have it in neutral and cannot figure out why the engine doesnt spin freely. Any ideas??

Its easy enough to pull the gudgeon pin back out and look inside the crank chamber. There should be no foreign objects for certain and the crank should turn smoothly with you guiding the connecting rod from banging against the side.

Second make certain that the rings are not getting hung up on the ports in the cylinder. Push the piston down in the cylinder without having it on the connecting rod. It should be smooth.

I don't know why it doesn't come this way, but did you chamfer the ports in the cylinder wall?
https://www.scooterwest.com/port-chamfe ... amfer.html

I didnt even put on the cylinder yet. The assemble rotates almost to the bottom of the stroke then hits something. When I reverse the rotation it comes back up the does the same thing on the other direction. Could the elect start cog be the issue? It didnt do this prior to the assembly.

shouldnt the rotating assembly spin freely?

Was the decision to upgrade to the DR177 just an upgrade, or due to some failure with the original cylinder?

I would agree, the crank should spin freely when the gear selector is in neutral.

Pull the fan cover and make sure nothing has fallen down in there. Check the bendix on the electric starter to make sure it isn't catching on the flywheel teeth. Of course you've looked in the crank chamber itself with a flashlight. There should be no foreign parts in there.

Beyond that, any obstruction would have to be inside the gearbox section of the engine.

It could be anything. Had to open a friends back up and found a woodruff key in there. Don't force anything.

Agree with chamfering ports when you are at that point.

I would pull the clutch out and see what happens. At least you will know if it's in the motor or gearbox.

Unless you get lucky and it's something that can be flushed from the trans open it back up.

I will examine more closely regarding those tips. Thnx

Went back to look further and the crank stops at t the bottom of the intake stroke and towards the top of the compression stroke. I know nothing dropped inside cant figure this out. I may have to drain the gear oil just to see if that helps. Starter bendix is free. Sounds like its hitting a solid wall.

well I finally found the obstruction. I got lucky when after blowing inside the intake under the reed valve , a small washer that nbarely could fit through the oil drain hole c, came out into my drain pan. I thanked God that I didnt have to take apart the engine bottom. Got real lucky. Everything is back to normal. Now back to the 180 kit install. Thnx to all your responses.

Wow. I'm glad you found it. You'll love the DR kit once it is sorted.

Yep. I just retarded the timimg all the way to 18 degrees to keep the temps and detonation down. NThis week Im going to jet the delorto 20/20 and get some results.