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Post by kevinharrell on Nov 3, 2018 15:34:59 GMT -5
This spring I made a posting about prepping an engine for spring and someone suggested that one of my cylinders had low compression. Well, I finally bought myself a compression tester and fond out both cylinders have really bad compression. (52psi and 48psi.)
The compression went up when I placed some oil in the cylinders, so, it appears as though the rings are not sealing. This calls for a top end rebuild, or at least new rings. I know the next step is to get the Clymer or Hayes manual and watch some U Tube videos.
But, here is my general question, what can I expect? And, what is the best approach . . . . cylinder honing, new rings, oversized pistons?
Any insight would be appreciated.
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Post by tortoise on Nov 3, 2018 15:46:05 GMT -5
Specific engine?
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Post by kevinharrell on Nov 3, 2018 16:30:34 GMT -5
The engine is the engine on a 1980 Honda CM200T also known as the Twinstar.
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Post by chewbaca on Nov 5, 2018 12:29:07 GMT -5
just a good hone and new rings should make a nice improvement most automotive cylinder hones are too big for a 100 cc cylinder so.. maybe use a master cylinder hone ?
also don't forget to check the valves
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Post by kevinharrell on Nov 11, 2018 19:51:51 GMT -5
The Clymer manual arrived, I read some of it, and decided to do an additional pressure test. Got the same results, and added oil to the cylinders to see if the pressure went up as it did as before. This time I used engine oil rather than WD40 as I did last time, so, when I put the plugs back in to start up the engine to burn off the oil I really got a lot of compression and could hardly kick start it.
Now I know that the valves are good and it is the rings.
I spent some time on line looking for and pricing new rings, looked around several more times and found some .5mm oversized pistons with rings for about the same price as I found just rings other places. So, I will have the cylinders professionally rebored to fit the new pistons. That should really help the engine.
I also found a local engine machine shop that works on smaller engines.
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Post by chewbaca on Nov 11, 2018 23:10:42 GMT -5
Going for a full rebore, nice. Refreshing your engine with a touch of extra power. if I had the money I would not mind doing some shop work myself sometimes I get tired of always having to make do
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