scott7556
12-10-2008, 11:18 AM
I rebuilt my trusty 400 last winter, and being a machinist, I did everything by the book. I double checked all work that was done by anyone other than myself. Problem is that after I put everything back together, it would start smoking after 15 mins of hard riding, but just when the engine would "rev-down" from high rpms, never while on the throttle. Especially during "engine braking".
It bugged me that it was burning oil so I tore it apart. I notice that the ring end gaps had re-staggered themselves, but not one right on the top of another. I also noticed that the cylinder had slight score marks, some traveling the whole length of the bore/piston travel. Nothing you can catch a fingernail on, but still visible and noticed.
I went with a 85.5 10:1 Wiseco, I replaced my valve seals, I had a leakdown/vacuum check done just on the head, my 400 is very mild, nothing radical at all. I lubed everything well during assembly, and I rode easy for the first 5 hours, nothing WFO.
Does anyone have any input on what I might have doen wrong, or would some of you try new rings? Throw some ideas at me fellas, I just don't want to bore to the next size for no reason and have the dang thing do this all over! Can send pics of the cylinder if you want them!
It bugged me that it was burning oil so I tore it apart. I notice that the ring end gaps had re-staggered themselves, but not one right on the top of another. I also noticed that the cylinder had slight score marks, some traveling the whole length of the bore/piston travel. Nothing you can catch a fingernail on, but still visible and noticed.
I went with a 85.5 10:1 Wiseco, I replaced my valve seals, I had a leakdown/vacuum check done just on the head, my 400 is very mild, nothing radical at all. I lubed everything well during assembly, and I rode easy for the first 5 hours, nothing WFO.
Does anyone have any input on what I might have doen wrong, or would some of you try new rings? Throw some ideas at me fellas, I just don't want to bore to the next size for no reason and have the dang thing do this all over! Can send pics of the cylinder if you want them!