yooperbanshee Posted September 9, 2010 Report Share Posted September 9, 2010 Just broke in my new motor. 4mil long rod crank, Wiseco pistons, trail / dune port, fast head with 21mm domes, adjustable timing plate +4, 34 pk's 152 mains, pro circuits. I broke this motor in real nice and easy. Had at least 5 hours on the motor when this happened. Finally started to get on a little bit, not holding it wide open or anything, but hitting the trail pretty hard. About 10 miles down the trail I locked up a piston. Made a mess of the cylinder. Must have got really hot. was all messed up around the outside of the piston. Thought maybe there was a blocked main jet, they were clean. the other cylinder looks perfect like I just put it in. The top of the cylinders look brand new. It only happened on the one side. The bike really hauled ass until this happened. Would like an idea of how to prevent from happening again. Was thinking maybe of going a few thousandths over on the new bore with a new Wiseco. Any help would be appreciated. Quote Link to comment Share on other sites More sharing options...
Jereme6655 Posted September 9, 2010 Report Share Posted September 9, 2010 Did you do a pressure test on the motor after it was assembled to see if you had a small air leak? Quote Link to comment Share on other sites More sharing options...
yooperbanshee Posted September 9, 2010 Author Report Share Posted September 9, 2010 everything was good. Quote Link to comment Share on other sites More sharing options...
Jereme6655 Posted September 9, 2010 Report Share Posted September 9, 2010 Hmm......strange. What model Wiesco's are you runnin in it? Only reason i ask is cause we have a race built CR125 which requires 3 oil passages to be drilled and chamfered before installation. Im sure the guys on here can tell you what model piston that was on and whether the model you put in requires those holes... Quote Link to comment Share on other sites More sharing options...
yooperbanshee Posted September 9, 2010 Author Report Share Posted September 9, 2010 Wiseco 795M06500 Quote Link to comment Share on other sites More sharing options...
rdzbangshee Posted September 9, 2010 Report Share Posted September 9, 2010 Just broke in my new motor. 4mil long rod crank, Wiseco pistons, trail / dune port, fast head with 21mm domes, adjustable timing plate +4, 34 pk's 152 mains, pro circuits. I broke this motor in real nice and easy. Had at least 5 hours on the motor when this happened. Finally started to get on a little bit, not holding it wide open or anything, but hitting the trail pretty hard. About 10 miles down the trail I locked up a piston. Made a mess of the cylinder. Must have got really hot. was all messed up around the outside of the piston. Thought maybe there was a blocked main jet, they were clean. the other cylinder looks perfect like I just put it in. The top of the cylinders look brand new. It only happened on the one side. The bike really hauled ass until this happened. Would like an idea of how to prevent from happening again. Was thinking maybe of going a few thousandths over on the new bore with a new Wiseco. Any help would be appreciated. wiesco says 10 to 15 hours of break-in then you can run it hard as you like . what is your oil mix ratio and compression? overheating kills new engines to ,good luck next time. Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted September 9, 2010 Report Share Posted September 9, 2010 Post up some pics. I had the same thing happen. The bore was a little tight down on the bottom of the skirt. I did some heat cycles. Rechecked the torque of the cylinder head, and cylinders. Got it good and warm. Went out for a nice easy ride on some gravel back roads. Thought I would open it up for a second to clear it out. Let off the throttle and the rear tires locked up. I hurred up and grabbed the clutch and snaped it a copule times to break it free. It started back up and idled real slow. I didnt shut it down. I let it idle with the radiator pointed in to the wind for probably 5 minutes. I hoped on and took off riding it easy. I never had any problmes with it after that. I burnt a whole 55 gallon drum of race fuel. I am trail riding and notice a lingering idle. One of the cylinders had come loose and blew the base gasket out. I shut it down and get towed back. I go home figuring on pulling the jugs to put new gaskets in. When I took the jugs off I found this dammage from when it intially locked up when I was breaking it in. This was not caused because of the blown base gasket. I just it down right away when i started getting a hanging idle. The pistons were ceramic coated on the domes and a dry film luberant coated on the skirts. The coating saved my cylinders from needing bored. Just a tiny speck of aluminum transfered to the cylidner. Quote Link to comment Share on other sites More sharing options...
EvilBanshee Posted September 10, 2010 Report Share Posted September 10, 2010 Same thing happened to my 421. What happens is that when you let off the throttle at hiiigh RPM's you starv your motor for fuel/oil. and on a fresh engine, it will lock up fast ! I checked out my engine after it happened and it was ok. Just a tiny bit of metal transfer. But let me tell you its a scary feeling after you spend almost 2 grand on a new powertrain and it lock up on you. But all is good still Quote Link to comment Share on other sites More sharing options...
KickStartMyHeart Posted September 10, 2010 Report Share Posted September 10, 2010 I always rev the engine numerous times when I let off the gas just to keep fuel flowing through it. Ive gotten into the habit of this and this has saved me from ever having problems wit my engines. Also, do not run it wide open and just pull in the clutch to slow it down to a complete stop. That will weld the ball inside their and smoke the clutch. Just rev ur motor a couple times when u are slowing down and stuff to keep fuel/oil flowing. Quote Link to comment Share on other sites More sharing options...
EvilBanshee Posted September 12, 2010 Report Share Posted September 12, 2010 I always rev the engine numerous times when I let off the gas just to keep fuel flowing through it. Ive gotten into the habit of this and this has saved me from ever having problems wit my engines. Also, do not run it wide open and just pull in the clutch to slow it down to a complete stop. That will weld the ball inside their and smoke the clutch. Just rev ur motor a couple times when u are slowing down and stuff to keep fuel/oil flowing. Thats good advice! Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted September 13, 2010 Report Share Posted September 13, 2010 My advise on break-in is run your needles/pilots a lil fat so when you let off the needle stays out of the hole longer allowing fuel through.I run my drag motors that way and havnt had a problem.In my opinion your jetting sounds pretty dead on but for break-in I always run the 1st tank through fat and then jet after my rings have found there sweet spot Quote Link to comment Share on other sites More sharing options...
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