ckn

My DZ170 is making intermittent squeaky noise when running so I suspect the bearings. I need to take the whole engine apart. I have already removed the backplate and carburector assembly, the cylinder head assembly, the fuel pump assembly, the cam. Now I need to remove the cylinder liner but I was stuck. I cannot take it out. There is no place to wedge it out of the crankcase. Please help.

ckn

ThumbSkull

My Feedback: (57)

You have to remove the head. It comes out through the top of the cylinder.
It WILL NOT come out through the crankcase end of the cylinder.

The random squeaking is most likely not the bearings. Usually from a pushrod or cam that's dry if you are sure it's not the engine mount or something else that's squeaking.

mtcarey

My Feedback: (2)

Heat it a llittle and it comes easly
out the top

spaceworm

If the liner ports are smaller than the exhaust or intake ports in the cylinder, lower the piston until it is lower than the port and then place a piece of popsicle stick into the port and then raise the piston carefully. The piston will push against the stick which will lift the liner out.

If the liner ports are the same size as the cylinder openings, make a piece of popsicle stick that is rounded at the ends with a diameter equal to the outside diameter of the liner. Lower the piston below the ports and insert this stick into the ports and then raise the piston. Again the wood will push the liner out as the wood and liner are pushed up the inside of the cylinder.

Sincerely, Richard

ThumbSkull

My Feedback: (57)

4-strokes don't have ports in the liner.

spaceworm

Oh, sorry, I thought it was a model of the British four stroke aircraft sleeve valve engine with valve ports in the liner that rotated to open and close for operation. Some four strokes do have ports in the liner.[8D]

Sincerely, Richard

ckn

Thank you ThumbSkull, mtcarey and spaceworm.

I have already taken out the head assembly.

The problem is that there is nothing on the liner that I can wedge or grab.

I think I shall try the heating method, with a hair dryer, and see whether the liner will "drop out".

ckn

petec

My Feedback: (58)

You might need a little more heat than a hair dryer to get the case to expand enough. I have a toaster oven in my shop for use on stubborn bearings and liners. If you are comfortable doing this kind of work and have a good pair of welding gloves to keep from burning your hands a preheated oven to 300F and put the stripped down case in there for 10 to 15 minutes time can make life easier on you. If you are not comfortable doing this then maybe the YS agent in Australia would be a good bet.

Spaceworm - What you describe would work on the YS 2 strokes, but not the YS 4 strokes.

ckn

Hi gentlemen, I finally got it done !

I pushed the bottom of the liner through the opened rear cover witha flat screw driver, slightly tapping with a mallet. This results in the liner moving upby a small amount (about 2 - 3 mm) and then no more. I hesitated to use more force for fear of damaging the liner. There is a flange at the top of the liner which I can wedge but it was very tight.

Then I put the stripped down crankcase (with the cylinder, piston and crankshaft) into the kitchen oven (while my wifewas having an afternoon nap) and cooked at 150 deg Celsius for 20 minutes. Then with the aid of a pair of kitchen mitten I managed to take the cylinder liner out by grabbing in hand !

I then stripped the whole engine down. The culprit is confirmed to be the rear bearing.

Thank you for your help.

ckn

petec

My Feedback: (58)

I think I speak for eveyone who participates here when I say "Glad to help".