jon015 Posted January 22, 2015 Report Share Posted January 22, 2015 Overheated my techno. Piston, barrel and compression all Ok, but waters getting forced out of the rad cap. Took the cylinder head off and you can see that the o rings have pushed into the damaged areas letting the exhaust gasses in/water out. Anyone know of a way to fix these damaged areas as a new cylinder costs more than the value of the bike? Quote Link to comment Share on other sites More sharing options...
jon015 Posted January 22, 2015 Author Report Share Posted January 22, 2015 Quote Link to comment Share on other sites More sharing options...
huski Posted January 22, 2015 Report Share Posted January 22, 2015 A good engineering workshop could weld it and re machine it Quote Link to comment Share on other sites More sharing options...
suzuki250 Posted January 22, 2015 Report Share Posted January 22, 2015 Some chemical metal or epoxy filler should make a decent repair of that Quote Link to comment Share on other sites More sharing options...
dadof2 Posted January 22, 2015 Report Share Posted January 22, 2015 (edited) Agree with #3 but make sure it is a GOOD engineering shop preferably one that is used to head / barrel repairs. Aluminium contracts a lot on going from liquid to solid. The barrel will need uniform preheating and controlled cooling along with a minimum heat input welding technique to allow contraction to take place as the weld proceeds and then finish on a run out plate. I have seen successful cylinder block repairs with epoxy but would not try on a thin edge like your beta barrel. Edited January 22, 2015 by dadof2 Quote Link to comment Share on other sites More sharing options...
ask greeves Posted January 22, 2015 Report Share Posted January 22, 2015 (edited) The root cause of your problem isn't that the o ring has failed, rather the compression joint between the cylinder head and barrel has failed, the neoprene/rubber o rings job is only to retain water and not to contain compression. If it's possible to lap the head to the barrel, to recover the compression joint, then as previously stated jb weld or similiar would probably be OK for the low pressure o ring water joint. Edited January 22, 2015 by ask greeves Quote Link to comment Share on other sites More sharing options...
mcman56 Posted January 23, 2015 Report Share Posted January 23, 2015 How deep is the damage? If not too deep, you may be able to remachine the top surface of the barrel including the o-ring grooves. It would be a simple machining task. You would then run a thicker base gasket to compensate for the shorter barrel. This would alter the port timing a little. A head spacer as sold in the past to reduce compression and soften power would be another way to compensate for the height and it would not alter timing. (I ran a 1/16" head spacer on my daughters Techno with good succcess.) If going with a thicker base gasket, you would want to make sure the threads in the head were still deep enough for the bolts. Worst case, you could run 2 copper washers on each bolt. Quote Link to comment Share on other sites More sharing options...
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