Brava34 0 Posted March 19 Anyone have any ideas why my Honda 350 just quit running after rebuilding the top end a year ago ? I’ve checked the basics lots of spark and fuel . I did a compression test on it and it’s showing 50 but everything I read so far says that’s normal. Not sure where to start from here ? Unit is not really worth putting a lot of money into it as the motor has been rebuilt 4 times already . HELP PLS Share this post Link to post Share on other sites
Fishfiles 19,750 Posted March 19 Hi Brava , Welcome to the forum >>>> I would ask , after being rebuilt 4 times >>> what you calling a rebuild ? was it all just upper rebuilds ? was the case ever split and cleaned out ? , was a new crank ever installed ? >>> if the connecting rod is loose , or trash is in the lower , a upper rebuild is not going to last 1 Share this post Link to post Share on other sites
Brava34 0 Posted March 19 to my knowledge it has only ever had the top end done . i know it had new piston and rings and the cylinder replaced last time. to my knowledge there has been nothing done to the bottom end or crankshaft. oil is clean. the last rebuilt was done because it was smoking really bad . Share this post Link to post Share on other sites
shadetree 5,543 Posted March 19 1 hour ago, Brava34 said: Anyone have any ideas why my Honda 350 just quit running after rebuilding the top end a year ago ? I’ve checked the basics lots of spark and fuel . I did a compression test on it and it’s showing 50 but everything I read so far says that’s normal. Not sure where to start from here ? Unit is not really worth putting a lot of money into it as the motor has been rebuilt 4 times already . HELP PLS ummm..50 psi is too low for this trx350 rancher. Share this post Link to post Share on other sites
Brava34 0 Posted March 19 thats what i thought but i was on here reading and seen a bunch saying that it was normal . i always thought they should be no lower than 130 psi Share this post Link to post Share on other sites
shadetree 5,543 Posted March 20 4 hours ago, Brava34 said: thats what i thought but i was on here reading and seen a bunch saying that it was normal . i always thought they should be no lower than 130 psi anywhere between 90 and 100 psi is normal for that model. you can down load the service manual from our site here, the psi specs will tell you what you should aim for. 1 Share this post Link to post Share on other sites
Fishfiles 19,750 Posted March 20 12 hours ago, Brava34 said: to my knowledge it has only ever had the top end done . i know it had new piston and rings and the cylinder replaced last time. to my knowledge there has been nothing done to the bottom end or crankshaft. oil is clean. the last rebuilt was done because it was smoking really bad . If the wrist pin journal has a loose fit , the piston will wobble , which will in turn egg shape the bore , you won't get very long from a rebuild , I find it is about 100 hours of time ------ the wrist pin journal is the end of the connecting rod where the piston mounts , which the connecting rod is pressed onto the crank , very good chance you need a crank after 4 rebuilds that were short lived ---- 1 Share this post Link to post Share on other sites
jeepwm69 7,232 Posted March 23 This is a 420, but is a pretty thorough video on a crankshaft replacement in a Honda, and the 350 is laid out pretty similarly to the 420 (biggest difference being the cam gear in back on the 350 vs front for the 420). If you tear the engine down, knock out the crank, and send it to Vince at Mr Crankshaft he can install a new connecting rod on your crank much cheaper than buying a new crankshaft. Good time to clean everything out in the engine, install a new timing chain, and of course, you'll need a bore/hone/ new piston, or maybe a whole new cylinder and new piston. If you have slack in the rod, a new top end won't last long before it's smoking again. If you pull the top end, slide the wrist pin into the top of the connecting rod, and wiggle it. You should have no perceivable play between the wrist pin and rod. If you do, you'll have to rebuild the crank. Share this post Link to post Share on other sites
shadetree 5,543 Posted March 23 along with what jeep said ^^^^^, also replace all the oil seals while you have the engine apart !. Share this post Link to post Share on other sites
