252wheelieking Posted August 3, 2011 Report Share Posted August 3, 2011 (edited) I need some opinion on what happen to my engine. It had 18cc domes, +6 timing, av gas, jetting was 52 pilots, CEG needle mid clip postion & 160 mains.I had 21cc domes in with 115psi with +4 timing, so I installed the 18cc for more compression but didn't check the compression after I installed the 18cc domes. My bolt-ons are in my sig. I was riding the shee normally when all of a sudden the right cylinder died. I stop & tried to kick it again & it felt like it had no compression at all. It started after about two more kicks but only ran on the left cylinder. So I decided to tear into the top end & see what damage was done & the right piston rings had stuck in the grooves on the pistons. I looked closely at the connecting rods & the thrust washer on the bottomend of the connecting rod was missing. I found alot of metal shavings in my right side exhaust pipe, cylinder & right side bottomend of the crank. So from my assumption the thrust washer from the connecting rod came loose & shattered. Then went thru the transfer & damaged the right side of the topend. I would like some opinions on what cause this to happen to my top end so I will not let this happen again if it was something I done wrong. Thanks in advance. Reek Right side damaged Left side undamaged Edited August 3, 2011 by 252wheelieking Quote Link to comment Share on other sites More sharing options...
Jereme6655 Posted August 3, 2011 Report Share Posted August 3, 2011 appears to be deto. and it also looks like you had some blow-by with those rings. Your gonna have to split the cases to make sure you get all the metal out of there.....otherwise the metal shavings are gonna come up and do it all over again. Quote Link to comment Share on other sites More sharing options...
252wheelieking Posted August 4, 2011 Author Report Share Posted August 4, 2011 (edited) What does blow by come from? Why was it detonating? too much timing I am going to split the cases cause it need a new crank. The thrust washer on the right side is shattered to pieces. Hard to see it from pics but the left side of the right connecting rod. Edited August 4, 2011 by 252wheelieking Quote Link to comment Share on other sites More sharing options...
Jereme6655 Posted August 6, 2011 Report Share Posted August 6, 2011 it could be from running a too low of octane fuel or lean jetting or even an air leak. did you do a leakdown test on it before you pulled it apart? blowby IS in every engine.......but too much can hurt your performance. blowby can come from rings that are out of spec (worn or wrong size) or it can also be caused from worn (egg shaped) cylinders. Quote Link to comment Share on other sites More sharing options...
AKheathen Posted August 8, 2011 Report Share Posted August 8, 2011 well, i don't suppose you re-checked the jetting after the switch? squish? also, did you check that your oil is compatable with the sg of the 100LL? first, though, i would check with hjr about the compression ratio and the fuel/timing you used. could have been too much. also, it's usually in the 18cc range that stock cranks start to find their limitations IIRC. Quote Link to comment Share on other sites More sharing options...
AKheathen Posted August 8, 2011 Report Share Posted August 8, 2011 it could be from running a too low of octane fuel or lean jetting or even an air leak. did you do a leakdown test on it before you pulled it apart? blowby IS in every engine.......but too much can hurt your performance. blowby can come from rings that are out of spec (worn or wrong size) or it can also be caused from worn (egg shaped) cylinders. oh, and to keep down on that much blow-by, you need to break it in hard, not a lot of free-running Quote Link to comment Share on other sites More sharing options...
252wheelieking Posted August 8, 2011 Author Report Share Posted August 8, 2011 (edited) it could be from running a too low of octane fuel or lean jetting or even an air leak. did you do a leakdown test on it before you pulled it apart? blowby IS in every engine.......but too much can hurt your performance. blowby can come from rings that are out of spec (worn or wrong size) or it can also be caused from worn (egg shaped) cylinders. Well I doubt that it was too low of octane, cause I was running 100LL straight using Klotz R50. I didnt do a leak down test before I tore it down, but I do remember it use to leak around my spark plug. It use to blow bubble around the spark plug washer/gasket. It also backed out one time while i was riding it, but I thought it maybe came from not tighting the plug good enough. So I replaced the spark plug & tighten it a little more & it never happen again. My jetting was a little on the rich size far as the main jet. From the looks of the middle of the piston it don't look like it was running lean too me..JMO tho. I do believe that the blow by probaly came from an egg shaped cylinder, cause I brought the cylinders used & just got them ported. I just got kevin to hone them really good & re ringed the pistons. It's Not Kevin's fault at all cause he told me to get a fresh bore with the port job to insure best performance. I didn't do it cause the cylinder still had good compression at the time. well, i don't suppose you re-checked the jetting after the switch? squish? also, did you check that your oil is compatable with the sg of the 100LL? first, though, i would check with hjr about the compression ratio and the fuel/timing you used. could have been too much. also, it's usually in the 18cc range that stock cranks start to find their limitations IIRC. I did rejet from the switch of pipes. I ran a 158 mains with the T-5's & 160 mains with the shearers. I plug chop & it was on the rich side. So I let it stay there. No I didn't check the squish & I didn't check to see if the Klotz's R50 was compatable with the 100LL. I don't usually run R50 I always used Supertechniplate but didn't have access to any supertechniplate. That maybe true too cause now that I think about it evertime I install my 18cc domes it don't be long after that something happens to one of my cranks.......Good point....Im sticking with the 21cc domes from here on & pump gas..... The recommendations was referred by Kevin 18cc, domes +5 or +6 timing on 110 race gas. He said I should be ok with 100ll but keep playing with the timing to see which one the bike likes the best. & I didn't I just set it & rode it. That's why I said earlier was it too much timing oh, and to keep down on that much blow-by, you need to break it in hard, not a lot of free-running Ok...now give me an example of breaking it in hard cause im usually a little rough on my shee.... Edited August 8, 2011 by 252wheelieking Quote Link to comment Share on other sites More sharing options...
AKheathen Posted August 8, 2011 Report Share Posted August 8, 2011 well, a plug backing out is a good sign of deto, to start with, and the plugs shouldn't be real tight. as for a hard break-in, some guys like to take it real easy and mix extra oil durring break-in. that method comes from the old school coarse hones you used to get, which created a lot of extra material durring ring seat. modern hones do not have that problem, and the rings will dull before break-in done that way. the best seal you can get, imho, is to ride it hard and keep it under load, aside from warm-up and heat cycles. Quote Link to comment Share on other sites More sharing options...
252wheelieking Posted August 9, 2011 Author Report Share Posted August 9, 2011 well, a plug backing out is a good sign of deto, to start with, and the plugs shouldn't be real tight. as for a hard break-in, some guys like to take it real easy and mix extra oil durring break-in. that method comes from the old school coarse hones you used to get, which created a lot of extra material durring ring seat. modern hones do not have that problem, and the rings will dull before break-in done that way. the best seal you can get, imho, is to ride it hard and keep it under load, aside from warm-up and heat cycles. Thanks for the help now I feel a little better about what happen to my engine. I going to just stick with the 21cc domes, pump gas & +4 timing where I know im safe. Quote Link to comment Share on other sites More sharing options...
252wheelieking Posted April 13, 2012 Author Report Share Posted April 13, 2012 Thanks for the help now I feel a little better about what happen to my engine. I going to just stick with the 21cc domes, pump gas & +4 timing where I know im safe. I found out why my motor blew this time & the second time.....The carb on the right float level was incorrect & was running float bowl dry on the right side. Thanks for all the help & remember to set your floats to the correct height. Quote Link to comment Share on other sites More sharing options...
Strm Trpr Posted April 14, 2012 Report Share Posted April 14, 2012 Hey man sucks you lost a motor. But thanks for pointing out how important it is to have correct float heights. Quote Link to comment Share on other sites More sharing options...
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