Planet Minis

dirt1016 · 01-11-2009, 02:37 PM

I bought a 83 z50 a while ago and I am now going to rebuild the motor.
I noticed the exaust port is broken so I need a new head.

I want to keep this fairly stock - maybe an 70/88cc kit.

What I am wondering is will a stock xr/crf head work with this year?

I can find more used xr/crf heads than z50 heads.

I also have a little slop in the rod - normaly this is a Split cases put in new bearings - does it matter with these little bikes?

Thanks cant wait to get this bike going finally!

LoudFastUgly · 01-11-2009, 02:44 PM

Every honda horizontal engine chips at the exhaust port. Give us a pic. If you can feel movement in the rod it should be addressed. Perhaps a crate motor might be cheaper and easier.

dirtbkr188 · 01-11-2009, 02:50 PM

You will have to use the XR/CRF piston to go with the XR/CRF head, the Z piston is slightly domed and will contact the XR/CRF head/valves.
Is the slop in the rod a slight bit of lateral sideplay, or is it and up-and-down slop? Generally, the lateral sideplay is normal, but there is no room for vertical play at all.
If need be, pick up a parts engine, they are around. A lot cheaper than having a crank rebuild.

dirt1016 · 01-12-2009, 05:27 AM

Thanks

the slop in the rod is a little side to side. Nothing up and down.

The damage to the exausts port is on the under side of the head and it a good size chip out of it. I will take a pic. It needs to valves as well.

I need a new pipe and silencer. I was going to get a used stock to keep it quiet and the $$ low unless there is a better option that is cheap.

01-11-2009, 02:37 PM	#1 (permalink)
dirt1016 PM Newbie Join Date: Feb 2007 Posts: 13	need a new head and engine rebuild Q I bought a 83 z50 a while ago and I am now going to rebuild the motor. I noticed the exaust port is broken so I need a new head. I want to keep this fairly stock - maybe an 70/88cc kit. What I am wondering is will a stock xr/crf head work with this year? I can find more used xr/crf heads than z50 heads. I also have a little slop in the rod - normaly this is a Split cases put in new bearings - does it matter with these little bikes? Thanks cant wait to get this bike going finally!

01-11-2009, 02:44 PM	#2 (permalink)
LoudFastUgly 2nd Gear Member Join Date: Aug 2008 Location: GTA, Ontario, Canada Posts: 383	Re: need a new head and engine rebuild Q Every honda horizontal engine chips at the exhaust port. Give us a pic. If you can feel movement in the rod it should be addressed. Perhaps a crate motor might be cheaper and easier.

01-11-2009, 02:50 PM	#3 (permalink)
dirtbkr188 3rd Gear Member Join Date: May 2004 Location: New Jersey Posts: 2,973	Re: need a new head and engine rebuild Q You will have to use the XR/CRF piston to go with the XR/CRF head, the Z piston is slightly domed and will contact the XR/CRF head/valves. Is the slop in the rod a slight bit of lateral sideplay, or is it and up-and-down slop? Generally, the lateral sideplay is normal, but there is no room for vertical play at all. If need be, pick up a parts engine, they are around. A lot cheaper than having a crank rebuild.

01-12-2009, 05:27 AM	#4 (permalink)
dirt1016 PM Newbie Join Date: Feb 2007 Posts: 13	Re: need a new head and engine rebuild Q Thanks the slop in the rod is a little side to side. Nothing up and down. The damage to the exausts port is on the under side of the head and it a good size chip out of it. I will take a pic. It needs to valves as well. I need a new pipe and silencer. I was going to get a used stock to keep it quiet and the $$ low unless there is a better option that is cheap.

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