01 yz250 motor problem

Hi, i just tore down my 2001 yz250 and I'm a little flustered. I broke the piston skirt and it damaged the cylinder also. Not just the sleeve. I don't know the terms for the different parts of the cylinder but it cracked the bottom skirt (for lack of a better word).

I'm torn on what to do. Is there any place that could repair that? I know they fix the sleeves and stuff but i never heard of fixing this. Obviously I would also need a rebuild kit so I'm needing suggestions on that if I do rebuild it.

Also, there is a small amount of up and down slop in my lower rod bearing. Is there a acceptable tolerance there? Basically why I'm flustered is because I don't know if the bike is worth sticking the money into. I also need a new right radiator..... (separate situation there lol)

I can't seem to find a used cylinder to lower cost and its looking like roughly $700 to replace everything if that's what it comes down to on a bike that isn't worth much in the first place. Sorry for being so long winded in this post but I'm all wound up before bed and had to tell someone. My wife don't seem to care (imagine that LOL)

Thanks for your ideas in advance

As for the cylinder, Powerseal USA i heard does a great job:


If you dont want to go that way, then why not a EG(Eric Gore) big bore kit?:thumbsup:


I heard excellent reviews on his kits and ask a lot of people like Rcannon, :confused: They all really like his kits.

Its not very good to have any play in the rod, i would look on ebay and just replace it man, it will be your best bet in the long run.

Plus since you might have to split the cases to get the extra piston pieces out of the motor, it just might be worth it to throw a crank in it.

BTW be happy its not a four stroke and the price will easily double or triple that. Butlook on ebay and see what they got, but still that EG kit should be something to look into.

thanks and god bless


Even with the EG kit I have to have a good cylinder don't I? i did see a weisco crank, rod, and piston kit for 320 but that wouldn't work with the big bore and I actually heard that weisco kits come with hot rod cranks? I also heard that hot rod cranks come with way looser tolerances then OEM so not sure if I should do that.

Even with the EG kit I have to have a good cylinder don't I? i did see a weisco crank, rod, and piston kit for 320 but that wouldn't work with the big bore and I actually heard that weisco kits come with hot rod cranks? I also heard that hot rod cranks come with way looser tolerances then OEM so not sure if I should do that.

You know what man, i would call EG and see what he or his workers think, they maybe able to hook you out. Also is there any ways you can post a pic of you cylinder?

About all of the replating services do welding for damaged cylinders as well, so they may be able to fix the issue. Got any pictures? You may want to snap a few, call one of the replating companies and send them pics.

I bought a Wiseco crank kit off of ebay for around $150 + shipping. Good deal and haven't had any issues so far.

Call millennium.....good work and fair price. Not too far either

Thanks for the replies. Yes, I can get some pics just didn't have time at the moment. i'm gonna go take some right now. I'm just torn on whether the bike is worth the money or not. Probably looking at close to $700 for repairs if it can be fixed? on a bike that is maybe worth $1500 running. I have been thinking about getting a yz450f also so its just terrible timing lol. If I'm gonna turn around and sell it at the end of the season I might just be better off parting it out or selling it as is right now? Any thoughts on that? I will be right back with some pics

I put a wiseco crank in my first yz125, with a brand new OEM cylinder, and prox piston, basically a full rebuild just like you are thinking about doing. The bike ran like a scalded dog, but 22 hours later, the bottom rod bearing went, chucking bits and pieces all throughout my motor. Lesson learned: OEM motor parts ONLY. Wiseco pistons are the exception however. I went to cheapcycleparts and picked up the entire OEM rotating assembly (crank, piston, bearings, etc) for around 400 shipped. Luckily a good friend of mine is a retired engine builder (granbury motorsports) and helped me through the rebuild.

Check out ebay and craigslist, and search the classifieds here too, there are bound to be a couple people parting out bikes.

what about just taking my crank into the local shop and having a new rod and bearing pressed on?

hmm..... never tried to post a pic on here. Thought I was just gonna attach it like an email lol.... I need to host is somewhere else ehh?

I'm trying a single pic


Look at me go now! lol

I don't know whether to laugh or cry about this. I wouldn't mind so much if it was winter coming. This isn't the time to have this thing looking like this.






I have never seen one break like that. Damn that is gnarly I hope you can get somthing worked out man.

I wouldn't know. But he cylinder can be repaired without problem I would believe. Welding that part, stripping the old plating and replate.

if not I did find a used cylinder that needs to be ground and plated but not broke.

Man that sucks bad... Forward those pics on to Millenium (or whoever you plan on using for plating)... They may be able to weld that. Or you could go find a cylinder with damaged plating, buy it and send it in for plating.

Yet another option would be to get a new OEM cylinder.

I rode a honda crf450r a little a week or so ago and really liked the power delivery. Would a EG kit come close to that?

Well, i ended up buying a reconditioned cylinder from US-Chrome for less then anyplace would repair mine for plus this way I don't have to wait. Thanks for the help on that. I also purchased a new wiseco crank kit with bearings and seals. Now I just need to order a Piston kit. A wiseco STD bore would be what I want right? Thanks again

If the cylinder they are sending you is the stock bore, then order the stock sized pisnron bit I think wiseco is one size fits all sort of deal. But anyway get stock the stock piston size

the right answer is to measure the bore on the cyl you get. it can get costly to guess.

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