Posts
8
Joined
12/26/2017
Location
Stevensville, MT
US
Edited Date/Time
12/27/2017 8:01pm
I am thinking of buying a used yz250f 2009.
The bike looks very clean and well maintained. $2000 USD.
However, many people online have made me a bit hesitant in buying a used 250f.
Everyone seems to think they are ticking timebombs.
What exactly would cause a 4 stroke to have a complete failure?
How would you prevent that.
The bike looks very clean and well maintained. $2000 USD.
However, many people online have made me a bit hesitant in buying a used 250f.
Everyone seems to think they are ticking timebombs.
What exactly would cause a 4 stroke to have a complete failure?
How would you prevent that.
Typically lack of maintenance and beating the shit out of them.
The biggest failure rate comes from broken valves. This is due to not replacing them when they start to grow and closing up the valve clearances. The valve breaks and then that in turn takes out the piston, head, rod, crank and the cases.
If you should elect to get one used, then if you have starting problems and find the valves need to be re-shimmed, then it's time to have the head reworked with new valves , springs, retainers, clips and have the valve seats cut or replaced as well as replacing the cam chain.
Also don't forget to replace the crank on as regular maintenance as well.
Paw Paw
The Shop
Oh, and welcome, I see you just signed up. Interesting to see what perpetual circle you will take the users on that think this is real.
Much ty
The general condition of the bike is your best gauge of how its been looked after and rode. If I was going for a used 250f my biggest concern would roughly how many hours on the crank/if its ever been changed. Other stuff like valves and pistons can be checked/changed much easier.
Take advise online with a pinch of salt, different brand loyal guys will slag off other brands, and 2 stroke guys will slag off 4 strokes. Reality is there are no basket case brands, they are all fairly solid with good maintenance, and a 4 stroke won't grenade itself as soon as you kick it over.
How could me asking about dirt bikes not be real?
I said USD because I'm very international. Even though I am from Montana, I'm currently living in South America.
Stop being a troll.
Pit Row
correct jetting, and regular oil. really its just simple maintenance
Never believe the previous owner about any work being done. People will lie abou anything when theres thousands of dollars waved in their face.
I'd try to get the bike for $1500-1800. Check the footpegs and shifter for excess wear, wiggle the chassis and see if anything is moving that shouldn't, and look at all of the wear items like chain and sprockets, tires, and brakes.
Those older Yamaha 250f motors are bulletproof. No one wants them anymore so you can buy parts on ebay for nothing. Mine is trick, and I love it. I'm very competitive on it in local hare scrambles against much newer and more expensive bikes.
GOOD LUCK!
By " grow " do you mean that the valve stem itself is stretching leading to lack of clearance?
I always thought that loss of clearance was due to wear on the valve seating face and the valve seat, effectively allowing the valve to be pulled deeper into the seat, closing up the clearance until proper valve sealing is lost resulting in burned exhaust valves and hard starting.
I always thought that the valves themselves broke due to metal fatigue or from hitting the piston when a keeper failed causing the spring to be released or the timing chain being too loose and jumping the timing gears?
Are these modern titanium valves stretching then fracturing? I've never considered that or heard of it before?
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