top end rebuild how often
Posted September 01, 2002 - 10:51 PM
Posted September 03, 2002 - 09:56 PM
Posted September 03, 2002 - 10:09 AM
Can't answer your first question, I'm hoping a top end will be years away for me.
BUT, to do YZ timing on these things is totally easy, check out Motoman393's site for very good instructions.
Posted September 03, 2002 - 10:33 AM
I pulled the spark plug, and the grounding rod was touching the electrode.
As it turns out, a portion of the slide plate from the carburator had broken off and was injested buy the engine.
My bike has a minimum of 8,000 miles on it, and the cylinder walls were perfect! The only marks on the walls were the swirl marks from a hone. No vertical scars what-so-ever.
I could not get my pressure gauge in the bike (did not have an adapter the circumfrence of the spark plug hole) but I don't think people really need to worry about top end rebuilds like you do with 2 strokes.
yeah, that is some great info for ya!
Posted September 05, 2002 - 12:23 AM
Posted September 05, 2002 - 01:38 AM
If you are going to do the YZ timing thing (or just inspecting your cylinder) and toying w/ new rings, it is easiest to do it at the same time.
As an FYI: If you have started your bike in water past the head vent (that runs down along your main frame's downtube) or started it in sand after biting it, you MAY just have SUCKED foreign material into your engine.
When starting your bike, the engine sucks on the tube. While running, the engine blows out this tube. I had 4 engine seizures AFTER starting my bike in 18" of water. I now have scoring in my cylinder and HAVE to repair it. I am opting for Eric Gorr, http://ericgorr.com/ , to do his magic and install his 420 kit ~ $350.00.
If anyone wants to do the YZ timing thing, or pull the top end, there are a couple of VERY NICE things to know ahead of time, before it's too late. Feel free to ask!
Posted September 05, 2002 - 02:10 AM
anyways, it wasn't cheap. had to have cylinder replated (millenium cylinders, very nice job, $165), new piston rings, wrist pin (usual top end stuff)(all oem yamaha), gaskets, spark plug. runs like new now. estimated damages... $400-$500
and that's without a valve job, mine were still okay.
gained a lot of compression, runs better in general, don't smoke no more.
happy till the next expen$ive repair comes along. i'm guessing it will be the clutch. gonna wait till spring if i can.