hey guys new here. ive been trying to search this but found nothing.. im about to install my third crank in my bike with-in the past..idk 15 hours? both have failed the same way...the connecting rod bearings are flat..no heat marks, no other signs of improper fuel/oil mixture, this is a stock bike. both times ive replaced it already ive replaced the crank bearings. got it all together and spins very nice. everything was prelubed before first start. now im at a dead end trying to figure out why this is happening. always use klotz and 93 octane. new plug every ride..idk. Anyone have any ideas??
bottom end keeps going out
- Thread starter hondaracin339
- Start date
are you having your crank trued before install? crankshafts from the factory don't come true usually.
Blaner
Your Friendly South African Ambassador
when you mean flat do you mean the little needles inside the roller bearing at the bottom on the conrod onto the crank? if so, you do need to get that crank trued as mentioned after its been split to get the rod out. if its not done properly, the whole thing will be outta balance. you seem to know what you doing so im assuming youve taken precautions with everything else.
I wouldn't waste my money rebuildin a crank either. you can buy a new one for the same price. If you are runnin a rebuilt crank i think i would stop usin that builder. got any pics?
The crank is going out but the top end is fine?
It sounds like the cylinder isn't aligned with the crank. Was one side of the crankcase replaced at some point?
It sounds like the cylinder isn't aligned with the crank. Was one side of the crankcase replaced at some point?
yeah the conrod bearings are flat on both failures. no heat discoloration. oil injector eliminated. running 32:1. a buddy asked about timing/detonation issues? timing has never been messed with and the shear key is good. i never use gas over a month old and get it from shell. these are not rebuilt cranks. they are new wiesco cranks. Im pretty sure the cranks are not whats causing this...im looking it over now to see if a notice nething but nothing yet
I was also thinkin what sicivicdude said. are your case halves a pair or have they been miss matched? what does the topend look like after this. i would go with a different brand crank also. ie hotrods, I also burnt up a new weisco crank really quickly. I blamed it on sucking up some water while ridin but never heard of that happening to anyone else before.
wait my bad first two were oem. the one i have now to put in is a hotrods..im an idiot haha. heres a couple pics of current progress.
just case half
you can see the bad crank (conrod can touch the main body)
idk if u can make out the flatness of the needles
just case half
you can see the bad crank (conrod can touch the main body)
idk if u can make out the flatness of the needles
cleaned very thoroughly. took out tranny, all bearings, empty case. used a whole can of carb cleaner on each case half. same with the whole transmission. then repeated with my 32:1 mixture then blown dry with air hose. reassembled with all new bearings/seals. put straight klotz oil in every bearing and worked it in. lubed conrod bearing same way. reassembled entire motor...did a leak down to be sure i did the seals good, and it was green across the board. motor ran great for about 6-8 hours then boom. did the same one more time and got maybe an hour more out of it and same thing. and that brings us to today. Im an ase certified mechanic and ive rebuilt many v8s, aslo briggs and stratton and kohler certified as well. lol this whole thing makes me ? my certifications haha
haha no redneck tactics here. As far as i was told they were new oems. 230 a piece. I then figured out that i can get a hotrods for 100 less..so thats what i got now. damn stealerships
