Before this bike, I've been all about 2stroke.
So. I bought a YZ450F 2006, and brought a friend of mine along who knows all about dirtbikes because he's been riding for a long time. He bent and tested most of the bearings that you can check and all of them was OK, and then he did a test run of the bike. Then I did a quick test run. Everything looked fine. It said 57h on the hour counter. sounds like few hours on such an old bike, I'm now the 5th owner.
(Other trivia: my friend knew the third owner, he'd never had any troubles with this machine and when we talked to the fourth owner (the seller) my friend would discover that they had a mutal friend, so he called him up and asked why he was selling the bike, and that wasn't because of troubles with the machine, just lack of interest).
Since the bike has very expensive suspensions (Månsson/Enzo, something Swedish) we'd both assumed it was one of Niklas Granström's old bikes (he always had those suspensions and ended his career back in -06, and always had two bikes). Can't know for sure though. My friend was looking at all parts that wears quickly and he thought that the 57 hours could be correct due to the contidtion it was in.
As soon as I bought it I changed oil, oil filter, air filter and coolant.
Now to the questions that I'd hope someone might be able to answer, since it's my first 4stroke machine:
1: I have a whistling noise that sounds kinda like a turbo charging when I go from low throttle to medium/max throtthle. It sounds like it's coming from the left side, can't tell for sure. It's not as loud as a turbo charged car, but it is kind of how it sounds. Read something about the skid plate making that noise due to the wind? No sound like that on idle and full throttle. I am concerned that it is a bearing in the engine or something.
2. Anything I would take a look at out or replace on this machine before I ride it anymore? Except valve clearance of course, but the valves would be okay since it starts very easily I guess?
3. When I go from almost full or full throttle and then releases the throttle, it goes BANG BANG BANG. Is that backfiring, and if so, is that bad?
Thanks in advance,
Edited by ericus, March 15, 2013 - 09:23 AM.