was riding and hit a little water crossing only a foot deep and when i got back up to 3rd gear motor bogged out. went to feel for compression with my hand and it went down ease and then locked up. its a friends bike so I'm hoping i can get away with just putting some new rings in or am I looking a new top end? bike was pulling hard and running great before. thanks for any info you can pass my way.
03 yz 250
- Thread starter John92YJ
- Start date
That depends what you see in the cylinder. How old is the piston?
O burned a hole into my piston once and was still able to ride home. Needless to say that only the piston was not what I had to do. Full bottom and top end rebuild, cylinder replate plus all material came to about US$ 400.
O burned a hole into my piston once and was still able to ride home. Needless to say that only the piston was not what I had to do. Full bottom and top end rebuild, cylinder replate plus all material came to about US$ 400.
- Thread starter
- #3
ok finally took the head off and found a nice hole in the piston :bang: guessing that the peaces are in my bottom end and thats what is making it lock up? here is a pic. looks like a oem piston?
dont think it was the water that caused this. what do you think. was running 40.1 was that to lean? Thanks
dont think it was the water that caused this. what do you think. was running 40.1 was that to lean? Thanks
That depends on how you ride and how you jet.
I run now the JD red needle @ 4rth with a 45 pilot and a 178 main.
I mix @ 28:1 sometimes 25:1 even.
In my case a broken oil seal did the trick.
You are looking at:
minimum, rod kit or if cheap just the lower needle bearing with spacers plus the crank bearings and seals.
To split the engine you need a flywheel puller and a generic 3 finger extractor or engine splitter.Quite easy to do actually. You'll be surprised.
I run now the JD red needle @ 4rth with a 45 pilot and a 178 main.
I mix @ 28:1 sometimes 25:1 even.
In my case a broken oil seal did the trick.
You are looking at:
minimum, rod kit or if cheap just the lower needle bearing with spacers plus the crank bearings and seals.
To split the engine you need a flywheel puller and a generic 3 finger extractor or engine splitter.Quite easy to do actually. You'll be surprised.
Nope I would not do that as that parts end into the needle bearing and in the crank roller bearings. You could have luck and get away with only the top end but why taking the risk?
Engine is open and to do the bottom end cost you about 3 hours of work. Maybe 5 if the first time.
Could be a wiseco piston OEM as no number on the crown.
Engine is open and to do the bottom end cost you about 3 hours of work. Maybe 5 if the first time.
Could be a wiseco piston OEM as no number on the crown.
2strokerfun
Member
- May 19, 2006
- 1,500
- 1
It does look to me like it was running on the lean side of perfect. Not lean as in too little oil mix--although I would never run less than 32:1 and prefer 28:1--but lean as in too much air to fuel/oil mixture. Lean may be great for short races where you replace engine parts regularly. But it's hell on the engine and pocketbook if you want a daily rider.
Good pictures for your post, by the way. Good luck.
Good pictures for your post, by the way. Good luck.
