BIGSNOR Posted November 10, 2012 Report Share Posted November 10, 2012 Hey guys, just got my 7 mil supercub running and everything was going good, running alittle rich but no problems. Made a few passes and all of a sudden its smoking real bad out of the right cylinder, and if u hold ur hand in front of the right stinger it covers ur hand in oily wet shit. So its blowing out oil or alcohol mix w oil, possibly tranny oil? Im thinking the seal went out on the tranny side, Compression tested it and the left cylinder, the non smoking cylinder has 135 psi, and the right, the smoking cylinder has 150??? Not sure what to think. The pressure out of the left stinger is good and strong, but the right isnt as strong? Anybody know where compression for alcohol should be? It ran out of gas on one run, and im wondering if that hurt something? Quote Link to comment Share on other sites More sharing options...
IceAlmeida Posted November 10, 2012 Report Share Posted November 10, 2012 mayb you sucked one carb dry? and now u needa rebuild ??? Quote Link to comment Share on other sites More sharing options...
ONLY2STROKES Posted November 10, 2012 Report Share Posted November 10, 2012 (edited) very possibly the right side crank seal went out and it is sucking tranny oil. compression depends on what domes and squish it has and the condition of the bore and rings. an alky engine should have alot more compression that. sounds like it needs the squish checked, then taken apart and gone over. Edited November 10, 2012 by ONLY2STROKES Quote Link to comment Share on other sites More sharing options...
BIGSNOR Posted November 10, 2012 Author Report Share Posted November 10, 2012 It was just rebuilt by k&t. Literally just got done breaking it in, and that was all the compression it had.... Quote Link to comment Share on other sites More sharing options...
ONLY2STROKES Posted November 10, 2012 Report Share Posted November 10, 2012 (edited) It was just rebuilt by k&t. Literally just got done breaking it in, and that was all the compression it had.... how are you checking compression? are you possitive the tester is in good working condition? Edited November 10, 2012 by ONLY2STROKES Quote Link to comment Share on other sites More sharing options...
BIGSNOR Posted November 10, 2012 Author Report Share Posted November 10, 2012 Yes, took it to my local bike shop and had them run the check. I did it w them. And just checked my tranny fluid again and it is most definitely getting lower. It didnt even read on the stick this last time. So id bet that seal has gone out. Is that something i can replace from the outside? Or is the motor gonna have to come apart. Still dont know why they would send it to me if it disnt have good compression numbers. And i dont know how i could have hurt it that much in 2 tanks of alcohol, is all thats been ran through it since we just got it running and broken in. Quote Link to comment Share on other sites More sharing options...
troyzstang Posted November 10, 2012 Report Share Posted November 10, 2012 What was you compression right after assembly? What size domes? Elevation? Did you do a squish band test before break in? Quote Link to comment Share on other sites More sharing options...
sprinklerman Posted November 10, 2012 Report Share Posted November 10, 2012 If ...>>>IF<< thats the compression that K&T wants it to run at,then go with what they suggest,NOT what some anonymous member on here THINKS your compression should be. That being said,why not call K&T and see IF thats what they want you to run compression wise. Also,if it is the seal thats out,you DO have to tear down the engine to replace it. Quote Link to comment Share on other sites More sharing options...
Paul M Posted November 10, 2012 Report Share Posted November 10, 2012 (edited) For Alky should be around 175 give or take 5 lbs ! what kind of head does it have ? did it blow an oring maybe ? Did you break it in on alky or gas ? you cant really get a motor hot enough to seat the rings with alky !! Edited November 10, 2012 by Paul M Quote Link to comment Share on other sites More sharing options...
Paul M Posted November 10, 2012 Report Share Posted November 10, 2012 Oh I missed that you ran it dry one run , better pull it apart and check everything out !! Quote Link to comment Share on other sites More sharing options...
BIGSNOR Posted November 11, 2012 Author Report Share Posted November 11, 2012 Initially i started it and ran it some on gas, but it was rich as shit as the carbs were setup for alky, then the next day i switched to alky and did the majority of the break in on , the old fashioned way, heat cycles, and worked gradually up to wide open. I asked k&t what they recommended and they said run it like ur gonna race it. Dont even worry about breaking it in. Also this jus happend today so i cant call them on the weekend, but that was obviously my first choice. If its the outer seal on the tranny side you DO have to split cases etc? Or can it be accessed by taking the side cover off etc? Quote Link to comment Share on other sites More sharing options...
Jereme6655 Posted November 11, 2012 Report Share Posted November 11, 2012 gotta split the cases as the crank seals have a lip on them that goes into a grooze on the machined portion of the cases. Quote Link to comment Share on other sites More sharing options...
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