xrjoe Posted October 2, 2015 Report Share Posted October 2, 2015 a buddies problem, running mostly stock motor, with Toomey t5's, stock carbs with 350 main jets, stock needles, weisco pistons, cool head. hes run it all over glamis, not counting numerous trips, then under a good warm daytime load, it scorched the right piston. he got the motor top end redone, new weisco's, and out in similar conditions, with a slow relatives daughter riding it, same clutch side piston comes out with a hole and top ring landing melted down, supposedly she never rode hard, he never had a chance to check the plugs for any lean condition, im having trouble beliving a hole could melt at lower power level activity, theres no visible vacuum leaking around carbs, if the crank seal was pulling air it would include oil from the trans right? anyway im helping to hopefully prevent reoccurrence, talked to Toomey about correct jetting, his needle kit has slimmer needle and 280 main, for sea level operation. so im wondering if im overlooking something else, to check seal integrity, would pouring solvent in case to monitor for any loss indicate seals ability, well enough to rule out failure? Quote Link to comment Share on other sites More sharing options...
fastbanshee8 Posted October 2, 2015 Report Share Posted October 2, 2015 Do a leakdown test before tearing it apart again, and then do another leakdown test on it once it's back together.http://bansheehq.com/forums/index.php?/topic/110585-leakdown-tester/ Quote Link to comment Share on other sites More sharing options...
hoppedupandcutdown Posted October 2, 2015 Report Share Posted October 2, 2015 Search "Banshee leak down test" How to build - and how to do. ^^ that above, damn I type slow Quote Link to comment Share on other sites More sharing options...
xrjoe Posted October 2, 2015 Author Report Share Posted October 2, 2015 too late, top is disassembled. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted October 2, 2015 Report Share Posted October 2, 2015 Most air leaks aren't visible. The fact that a mostly stock motor needed a 350ish main with toomeys and a couple bolt ons, That tells me there was an air leak. If you did just the top end and it happened again, I would lean toward crank seals. I'm normally not one to preach the leak down as I'm advocate for checking the details twice and assembling once and that type of practice usually builds a solid engine assembly. However, it seems you guys are still trying to sort this out, so I reccomend tearing it all the way down. Split the cases and start over. Once you guys got it back together, a leak down would be wise. Quote Link to comment Share on other sites More sharing options...
Larry's Shee Posted October 3, 2015 Report Share Posted October 3, 2015 Got a dollar says leaking boost bottle. Quote Link to comment Share on other sites More sharing options...
xrjoe Posted October 3, 2015 Author Report Share Posted October 3, 2015 from the grommet or bottle itself? seems like that would affect both cylinders. Quote Link to comment Share on other sites More sharing options...
willaduncan Posted October 3, 2015 Report Share Posted October 3, 2015 Got a dollar says leaking boost bottle. Hahaha looks like we got a winner!! Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
oldskool Posted October 4, 2015 Report Share Posted October 4, 2015 Most air leaks aren't visible. The fact that a mostly stock motor needed a 350ish main with toomeys and a couple bolt ons, That tells me there was an air leak. If you did just the top end and it happened again, I would lean toward crank seals. I'm normally not one to preach the leak down as I'm advocate for checking the details twice and assembling once and that type of practice usually builds a solid engine assembly. However, it seems you guys are still trying to sort this out, so I reccomend tearing it all the way down. Split the cases and start over. Once you guys got it back together, a leak down would be wise. Quote Link to comment Share on other sites More sharing options...
xrjoe Posted October 4, 2015 Author Report Share Posted October 4, 2015 for what its worth, I filled the crank case with diesel solvent 2 days ago, both cylinders, and theres no loss from the initial level, if the seals were leaking under load, I would suspect they wouldn't hold liquid either, test obviously not under pressure, but being the clutch side, a pull of air would include trans oil, there was no sign of loss on dipstick. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted October 4, 2015 Report Share Posted October 4, 2015 for what its worth, I filled the crank case with diesel solvent 2 days ago, both cylinders, and theres no loss from the initial level, if the seals were leaking under load, I would suspect they wouldn't hold liquid either, test obviously not under pressure, but being the clutch side, a pull of air would include trans oil, there was no sign of loss on dipstick.Oh, looks like you got that figured out..... At least post pics the next time it melts down. Quote Link to comment Share on other sites More sharing options...
xrjoe Posted October 4, 2015 Author Report Share Posted October 4, 2015 yeah, I hear ya Quote Link to comment Share on other sites More sharing options...
xrjoe Posted October 4, 2015 Author Report Share Posted October 4, 2015 also I want to say, thanks for everyones interest, problems like this are always good to hear others thoughts, in relation to others experiences, just wasent an option when I was younger, these forums are an incredible asset. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted October 4, 2015 Report Share Posted October 4, 2015 I was being facetious about your experiment with solevent in the cases. Quote Link to comment Share on other sites More sharing options...
willaduncan Posted October 7, 2015 Report Share Posted October 7, 2015 I was being facetious about your experiment with solevent in the cases. Apparently that was only unclear to him..... Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
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