Piston rings 55537 XL-800 XL-903

[MCS]

I have a XL-903 and a XL-800 neither are complete in themselves but there is enough for one saw. Let see, 903-800=103. 103/2=51.5 and 800+52=XL-852 ;D

Look at the old ring compared to a new ring.
New on top:


Old on top:



If I squeeze the new one down to match the old one the end gap is nearly the same. The is no noticeable difference in the width of the ring.
Obviously there is very little side wall pressure with the old ring pushed into the cylinder.
Is the change in static dimension just a result of heat and pressure after many years
If I don't replace the rings I'm positive my compression will be way down.
The 800 cylinder is really worn and the piston has wear grooves from the transfer ports. Lots of slop, this saw has lots of hours on it. Bad crank keyway. Good rear handle.
The 900 has a broken rear handle but a good piston, cylinder, and crank. The 900 has compression relief but the 800 rear handle won't work with the linkage because of the side mounted oil pump.
I have a new cylinder with a part number that matches the XL-98 but looks the same as a XL-925 and the 903 piston fit in it nicely.
So, it would be XL-800, XL-903, XL-925 saw. Didn't Johnny Cash sing a song about a Chevrolet that covered several years of parts

[mikem]

I would not hesitate to use the new ring in that old cylinder in order to improve compression. Appears to me the sidewall pressure in that saw (at least with the old ring) is next to nothing. Did you happen to take a compression reading before you removed the piston ?

[OBR]

CADILLAC!

[mikem]

Craig...Did you proceed with the "FrankenSaw" ?

[MCS]

Jul 9, 2009 19:59:09 GMT -5 mikem said:

Craig...Did you proceed with the "FrankenSaw" ?

;D
Officially it is an XL-800 - that's what the tag says on the tank.
It has a XL-903 starter that has a slight modification and is using an A-94842 rewind spring and a plastic milk bottle bushing for the rewind pulley. No muffler yet, don't have one to fit it.
I cut the fuel line elbow and just stuffed some .211 tygon into the tank through the grommet.
The carburetor is a little odd. The one 903 I had for parts had a carburetor with a choke rod that came out the side of the air box instead of out the back.
I put it together with the worn rings and piston because I thought this might be a way to take compression reading and then comment on the engine power and performance.
It actually runs but that Harley exhaust is a little loud.
I should be able to get some pictures latter this weekend.

[MCS]

Anyone recognize this rewind spring Part number is A-94842. With a little modification it will work perfectly on the XL 700, 800, 900 saws and maybe others.






I have at least two more of these - they came with the stuff from the closed hardware store.