it is true that removing the ridge helps the home blades move more squarely. However as Alex says if there is a bigger ridge then it may be likely the whole cylinder is either ovalized or tapered and the better solution is to bore it. Having said that years ago we took old aluminum worn out 7.5 to 1 compression ratio lawn engines, use the ridge reamer, honed them and put in 10 thousands over size pistons and rings. This was back in the days of 1960s Shadetree mechanics and actually trying to fix things cheaply when people did not have the money to buy a completely new engine or expect the old one to last forever after being repaired. Nowadays they’re just replaced. I googled some more and saw that on eBay there are used ridge reamers. However they are of unknown quality and size.

I thought the purpose of the ridge reamer was to remove the ridge prior to honing.  Otherwise, the honing tool will not ride true to the cylinder wall as the lip at the top, however thick, will cause the stones to ride at an angle.

Richard

Wouldn't you be better of with a honing tool ?

I've never heard of anyone reaming a bore, and if the ridge is that bad you're into rebore territory anyway.

Thanks, I looked on places like Amazon for it, too.  Not available. 

Based on your suggestion, I'm looking elsewhere, but I honestly hadn't thought of looking for lawnmower specific reamers.  may do the trick!

Richard

oops. I see that it is no longer available  - like a lot of things these days.

Newer lawn mower engines do not even have an oil drain plug.


Maybe there is another small engine parts manufacturer other than Stens that males a small bore ridge reamer

Here is the correct link:

https://www.lawnmowerpros.com/lawn-mower-parts-database-search.asp?searchterm=750-331

I worked in Tune's lawn mower shop years ago .

see

https://www.lawnmowerpros.com/detail.asp?id=750-331

Hi,

Does anyone have any recommendations for a cylinder ridge reamer for an 850?  The bore is 2.5" but smallest diameter ridge reamer I seem to find is 2.5625".  I would need one that maybe has a minimum usage diameter of 2 1/4" or 2 3/8" to use on the 850.

Thanks,

Richard