Posts
270
Joined
2/24/2017
Location
Fenton, MI
US
My new/used bike has an hour meter (29hrs). Ive never owned a bike with a meter so just curious what people use for maintenance or rebuilds. Ive always used a more rough timeline, like once per season, but have no idea how many hours that really was.
This bike is a KTM 150SX. How many hours of riding would you replace the piston? 10? 50? Average riding, not all racing, not all putting on trails, just average.
What about on a 250F or 450F? Or 250 2 stroke?
Thanks
This bike is a KTM 150SX. How many hours of riding would you replace the piston? 10? 50? Average riding, not all racing, not all putting on trails, just average.
What about on a 250F or 450F? Or 250 2 stroke?
Thanks
The first 100 hours was my sister trail riding and the last 20 was my at the sand track.
It was a 2013
CRF450 - About every 50 Hours
These times are purely MX practice and race use. I've heard people going to 100 hours on both 2 and 4 strokes, I just can't bring myself to go that long on a race engine. Much cheaper to rebuild the top end regularly that one that has grenaded.
The Shop
Beginner on a basic track with dirty air, 20-40 hours.
Expert on a sand track with clean air, only 5-10 hours tops.
Expert on a sand track with dirty air, a few laps!
Same story for the bottom end but multiply hour estimates by 3.
No idea what power band is in it
40:1 amsoil dominator with 91 octane
Me riding it id replace every 50 hours (track abuse)
Each bike is different as each rider is different and each ride is different, so let the compression be your guide.
Paw Paw
125 - same
250f - around 30
I stepped up on these since it's usually my kids riding and I couldn't take it if there was a wreck because I wanted to stretch a few more hours out of a motor. These are also MX race/practice hours. Usually when I pull a piston they still look good which makes me feel ok with my times. If I am in the motor for just about any reason I sually throw a piston in just in case...............
Id say probably 3-400 hours. We never kept track.. We rode all day every day when school was out. We rode to friends, girlfriends, to the store even to school when it was in.
Nobody rode bikes anywhere because it was too far.
We'd have to bump start they would be so worn out. I wore out 4 bikes a year. Completely beat.
The main thing, at least on the older 150's is to get the squish right on the cylinder gaskets. I remember the ktm guys saying that is the quickest way to grenade the motor.
However Ive been doing 50 hrs on pistons and 200 on crankshafts for the last few years and been just fine. Ride local A level... I put probably 2-3 hours of time on a bike every weekend so doing pistons at less than 50 would drain my wallet
Bottom end should be fine for 100 hours.
Pit Row
250 2 stroke rings at 20 - 25 hours, piston and rings at 40 - 50 hours
Air filter cleaned every ride, oil done around every 5 hours. Used to be fast, now kind of old and slow but never blown up a 125 or 250
Bottom end every 4 pistons
For a "non-racer", 50/50 track/trail average rider that properly maintains their bike - keeps AF cleaned and changes the oil every 5 hours of ride time (or better):
2 Strokes: 50 Hours on top end, Bottom end - as needed if crank has slop or every 200 hours
4 Strokes 100 hours on top end, Bottom end - as needed if crank has slop or every 300 hours
I've seen many people go longer- not that I'm recommending it. It's amazing how much abuse bikes can take these days. 2 Stroke top ends are so easy to do, it's insane not to just do them at least every 50 hours, if not 25 hours - again this is for a non-racer, average rider.
The 29 hrs seems legit to me on this second hand bike, original chain and sprockets and tires and reflect about 29 hrs of easy riding. I think Ill order one up today, but maybe will buy a compression tester so I can get a feel for it myself. Back in the day I remember a 125 I could feel right away when a single ring setup was in need of replacing. Ive haven't found an obvious power drop in 4 strokes or 250 2 strokes so those I just did once per season usually, maybe 30 ish hours anyway also.
Did a dyno test on a 125 when we set it up for a project and checked it at 16 hours, we had a 7.5% power loss.
Post a reply to: Top End. How many hours?