[Walt Gifford]

I’ll tell you this, you can’t do it with just hand tools and the tools you need are a big investment. Do you want to get into the engine building business? The KT100 book is a good place to start for some general knowledge but, there are allot of details you learn from being brought up in the mechanic/machinist trades that are hard to learn from books or the internet.

Gif

[Glenn L Riggs]

Hey Walt have a question and thought you would be the guy to ask. How much wear on the crank main  bearing is allowed before performance start to degrade? Replace at .001 ? Whats your findings? I am sure you would know. Thanks

[John Mulvihill]

Hi Glenn,

 

Not Walt, but here is my opine.

I usually tear things apart at 6 hours (road racing).   If I find that the ball bearings are no longer mirror shiny, I replace (usually).   I also go 12 hours on the crank pin roller bearing unless it looks funky or the rod looks like it has run hot.

 

John

[Walt Gifford]

Are you talking about wear between the crank and the ID of the main bearing? I use to worry about that until I saw how they clearance the shaft on 125 shifter engines to loosen it up.

[Glenn L Riggs]

As a matter a fact I am talking about a tm special balanced crank 125 icc engine. when you make the wheels and shafts straight dead on the bearing on the pto is worn to a little over .001 on the journal. Engine has seemed to be a little unhappy pulling much over 13800 my other tms pull 14400 and was just wondering if the crank could be the reason. I remember somewhat the same happening back in the day with kt100. When we ran pipe and twisted the heck out of them, cranks didnt last long.  Thanks for looking Glenn

[Walt Gifford]

A customer had 2 Comer ICA reed engines, one built in Texas turned 500 rpm higher than the one I built but mine got lower lap times. At some point it’s hard to quantify these things.

Gif

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