Buying 1992 YZ250 with original piston - is this bad?

hammerface77 · Feb 25, 2005

Buying 1992 YZ250 with original piston - is this bad? Pls Help?

Ok, here's the deal. I'm really consdering buying this bike just for trail/bush riding. The bike is owned by the original owner who is a Yamaha mechanic (and apparently a pretty good one from what I've heard from other people). It has new bearings in the rear tire, new pipe/silencer & pipegaurd, renthals, good chain/sprockets and good tires. They guy rode it trail riding occaisionally and now rides it with his 3 little kids but is selling it to get something more trail friendly.

Overall the bike is in great shape (minus the PINK seat and some frame paint flaking off). BUT, my concern is that he has never replaced the piston/rings. He said he check the piston twice a year by pulling of the exhaust and looking into the cylinder and also checked the compression. He said it has always had gobs of power and never given him a single problem. There was never any problems with it fouling plugs or hard starting and there was never any scoring on the pison..

Is it bad to have not replaced the piston/rings in 13 years or does it mean it's just been well taken care of?????? It's at a shop now and they are checking the compression on it. Any ideas what the compression 'should' be?

Any advice anyone can share with me would be GREATLY appreciated as I 'might' pick up the bike this weekend if they call me back and the compression is up to snuff. Thanks :)

crazyYammi · Feb 25, 2005

There is a big difference in wear between an A or Pro rider and a guy putt-putting around on his bike. I wouldnt be suprised if a topend can go for 200 or 300 hours with light use.

mtk · Feb 25, 2005

Because it was owned by a mechanic means nothing. Many mechanics have the crappiest equipment themselves because the last thing they want to do when they get home is "work" some more.

Frankly, I'd be very leery of a 13 year old bike that has never had a top end. At the very least, I'd put a top end in it before I ever rode it. Yes, I said "ever." A friend bought his son an RM85 which was going to be due for a new piston. He put it off and took his son out on it a few times. The piston grenaded and he got an expensive rebuild instead of a cheap piston replacement.

Also, looking at the piston is about useless. You really need to measure the skirt to see if it's going south or not. At least that's what Honda tells me in the Service Manual for my CRs. "Gobs of power" also means nothing as the bike will run fairly strong right up until it explodes. After all, it's a two-stroke 250. Even a poorly running example will still get up and go pretty well.

What else did he not bother with doing? When was the last time he cleaned the air filter? How long has it been since he tore the chassis apart and lubed all the bearings?

If he puts with his kid, why did it need a new pipe? Even better, why does he have a pipe guard on it? How do you dent a pipe when you're putting with your little kid?

My bet is that in addition to the new top end it will also need some of the chassis bearings replaced because they long ago dried out and rusted.

As for putting 200 or 300 hours on a 250 top end, I'll bet money against that one, no matter how gently you ride it. Moreover, two-stroke motocrossers don't inspire one to ride them gently, they practically beg to be abused. I know Honda recommends a new piston and rings every 7.5 hours of race use. A friend with an hour meter is getting 32 hours out of a top end on his CR before they start to go south on him. No way you'll get ten times that much no matter how gently you ride it.

If you buy it, make sure the price is right.

hammerface77 · Feb 25, 2005

Well when he first had it he rode it in the bush. Now, in the past 4 years or so all he's been doing is riding with his kids. I'm thinking that if I do buy it, I would just buy a new wiseco piston/rings and put it in just for preventative measures. I've blown up a lot of bikes in my time and I'd rather spend $100 on a new top end than have the piston shatter sending shards all through the bottom end....

Overall, for a 13 year old bike I get a pretty good 'gut' feeling about it - other than the top end. When buying a bike of this age it's kinda hard to know which to choose. I'd buy a newer one but for what I need it for this will work fine. Plus I don't want to have too much $$ invested at this time - maybe in a couple years - right now I just NEED something to ride.

I was also looking at a KX250 '95 - the guy races it cross country. has all the works skid plates, frame guards, pipe, silencer, bars, new top/bottom end, bearings, shocks done, new bars, reeds, rebuilt carb, wheel bearings, sprocket/chain, needs brakes by end of this season, powder coated frame. i'm guessing he rode it hard as he rebuilt the engine after he crashed it into a lake during a race........ 3 years newer but much more abuse, yet more new parts.....

I'm confused.... :think:

blanc · Feb 25, 2005

get the guy that you are buying the Yamaha to put a piston into it since hes a mechanic! When you get it grease all bearings, wheels, steering stem, swingarm, linkage, shock. Clean her up, put new tires on her and get riding. Can you get a pic for us to see. How much is he looking to sell for?? How much is the kx??

mtk · Feb 25, 2005

While I can appreciate not wanting to spent too much, keep in mind that you may very well be buying a money pit. You know it needs a top end for sure. That's about $125 with gaskets and all.

What's the bottom end look like? They don't last forever either. Nor do things like crank seals. If one side leaks you burn tranny oil. If the other side leaks, the engine grenades. If he never touched the top end, you know the bottom end is untouched as well.

Speaking of tranny oil, how often did the guy change it?

Most likely, the forks or shock haven't had the fluids changed in them, ever. That means rebuilding both ends. Neglect like that can also mean wear on internal parts of both. You can bet on the chassis needing, at the very least, a good lube job, but more than likely some of the needle bearings in the linkages are shot.

I don't mean to rain on your parade, but I'd rather do that than see you post in a month about all the money you've sunk into this bike only to have a 1992 YZ250 worth half what you have in it. Been there, done that, and learned my lesson.

hammerface77 · Feb 25, 2005

Thanks for all your input guys. It's a tough call. I could get lucky and end up with a bike that would last me for a few years or I could end up with at POS - it's a gamble buying a used dirtbike.

I'm still weighing my options. I don't mind doing some work on my bike but at the same time I want to spend more time riding than fixing stuff that has failed due to age and/or poor maintenance.

I'd post some pics but I don't have an online host - sorry.

The 95 KX 250 is $2600 - the 92 YX is $2000 (Keep in mind I'm talking CANADIAN bucks here :) I was thinking if I bought the 92, put in a new top end, new rear tire, new seat cover, grease everything I'd have maybe $2500 into it. Then I'd just hope for the best that that suspension isn't shot or something..... DECISIONS DECISIONS.. :think: :|

Good thing it's Friday - I need a cold one :)

marcusgunby · Feb 25, 2005

I wouldnt spend 2K on a 92 if a 95 was 2.5K as the 95 is light years ahead in design, the 95 isnt really any different to a 05 -it has similar power and the supension can be tuned to work well.

gottamoto · Feb 25, 2005

Having new rear tire bearings does you no good if the wheel bearings were not replaced at the same time :coocoo: :nener:

mobrown · Feb 26, 2005

Whew!

$2000 CDN is about $1650 US... that's a lot of money for a 1992 anything. I have a 91 CR250 that I paid $950 for. Engine and everything were in great condition but within 2 months I had to buy a rear wheel because the one on it was rusted. I didn't find out until I needed a new tire so I'm lucky that it didn't go while I was riding it. The point is that you will assuredly have to repair something and even if it's small things they add up quickly and before you know it $2000 has gone up to $2500!

I don't know market value for bikes up there but both of those machines seem overpriced to me. Whatever you decide do be prudent, and if need be, take a friend with you who knows bikes to check it out with you... best of luck!

motoxpress · Feb 26, 2005

A '95 KX 250 is actually a great bike. I would absolutely go for that over the '92 YZ. A lot of the parts up to the '02 KX 250 are all interchangeable so you would have a lot of availablity for a good while. I had a '94 and really enjoyed it.

Get the KX *if* it checks out in terms of maintenance and condition.

mx

reknelb · Feb 26, 2005

Not sure where abouts in Canada you are. I'm in NY about 15 min. from the border. I could easily get a nice shaped 95 kx250 locally for around $1500 or less, and the 92 yz250 for around $1200 or less. Year 2000 250's (any brand) go for around $1800 to $2000 locally. If the yz is in good shape and needs only a top end, I would pay no more than $1000.

Blue book values on the 92 are $1600 Retail, and $1080 on trade-in. Right now that bike is in trade-in condition. If it were in retail condition, it would have a semi fresh engine, like new tires, like new brakes, like new chain and sprockets, everything works with no major dings or scratches in the plastics, pipe, or rips in the seat cover.

i_955 · Feb 28, 2005

I'm in Southern Ontario, dirt bike prices are generally high in this area.

I just bought a 95 KX250 for my wife. The bike is not in good cosmetic shape and I have no idea of it's mechanics. I plan on going over it with a fine tooth comb and expect to spend a bit of $ to make it safe. I pranced on it for $1500.

Another 95 KX250 became available soon after I bought the one I did. A good buddy wants into the sport so we took a look. It is in much better cosmetic shape and $500 in parts (bearings chain/sprokets etc) would make it a safe flier. He was asking $2300.00 CDN.

hammerface77 · Feb 28, 2005

Thanks for all the input guys - I'm trying to be as patient as possible to hold out for the right bike. And yes, prices of bikes in Alberta do seem fairly high. But what can you do?

The latest one I'm looking at is a 1998 KX250 - I've only see pictures of it he's emailed me. Everything looks good on it except he said by the end of this year it will need rear brakes. New top/bottom, renickesilled (sp?) cylinder, tires/chain/sprockets good, light kit, protapers, umm... That's about it. Asking $2800 CAN - could probably get it for $2500. Only problem is he's 3-4 hours away so I'd have to be pretty serious about it to drive down there. I'd hate to get there and have something not look right and have to come home empty handed.

motoxpress · Feb 28, 2005

98 was probably one of the best years for motor of all the current KX 250s (excepting perhaps the 05). If it's clean, I would think seriously about that one. Very strong motor.

mx

hammerface77 · Feb 28, 2005

motoxpress -

that's the direction I am leaning too. The fact alone that it is 6 years newer helps. Are there any specific 'glitches' with the KX I should look out for - should I actually get a chance to see it in person?

Yeah, from reading on this board the 98 motor does sound to be very impressive.

Wish me luck if I go for this one :)

blanc · Feb 28, 2005

Good luck....Jump at it great bike....I rode the 97.

oldguy · Feb 28, 2005

I had a 92 YZ250 a couple years ago and it was difficult getting some parts for it. They could be found but iften after some serious searching. BTW I sold it 2 yrs ago for $750 (US) with a 3 hour old topend and all new swingarm bearings.

hammerface77 · Mar 1, 2005

Well, the '98 KX is gone and so is the '95 KX. Around here it seems that unless you can go look at the bikes within a day or two of them being advertised then they're gone - sold for pretty much asking price. So for me, living 2 hours away from the nearest major city, it's pretty hard to just take off to look at a bike (with work and all). Pretty damn frustrating :bang: :bang: :bang:

Had my hopes up for the '98. :( Just have to be patient I guess. I just don't want to rush either and end up with a POS.

THanks to everyone for all their help. I'll let ya know when I find something...

Yfox05 · Mar 4, 2005

I own a1996 yz125, I have a question, what exactly happens when your motor blows up? And what makes it blow up? Is there any way to prevent it totally?

CJG · Mar 5, 2005

Yfox05,
There isn't one thing that happens when a motor "blows up", nor is there a single cause. But the most common cause of all engine failures is probably dirt in the engine. The most important things you can do to prevent a "blown" engine is to keep your air filter clean and properly oiled, and to keep your tranny oil fresh.
Of course, at some point, your bike will wear out no matter what you do. The key is to stay ahead of any massive engine failure(service the top and bottom end before the parts wear to the point of imminent failure). There is no way for anyone to say when that time is, it all depends on your bike, your maintenance, and how/how often you ride it. Usually a bottom end will last at least two-three seasons and often much longer. Top-ends, particularly on 125's, usually need to be serviced/replaced once or twice per year. Again these are generalities and it all depends on how/how often you ride. But if your lower end has never been inspected/replaced, I'd recommend that you do it/have it done(inspected) soon.

It might be better for you to post this in the General Bike Repair forum, where someone like Rich, who knows alot more about engines than I ever will, or one of the other resident engine guru's, might see it and respond. You could also search through the archives, as there is no doubt a wealth of information on the topic in there. :cool:

Yfox05 · Mar 5, 2005

Ok, thanks, that really helped.

mxprep007 · Mar 5, 2005

I also agree on the price being high. I bought a '90 rm250 last summer for $750 and found a '95 kx250 for my buddy for the same price. Sounds like a money pit if you're going to spend that much and still have to service it right off the bat...

83MX80 · Mar 6, 2005

to me, it sounds like having the original piston and rings is a good thing/ bad thing. like its good cuz its been taken care of. but a bad thing cuz it could blow soon. i'd pick it up for 2000. and ya it will need/ should replace the piston and rings if you buy it. hell my dad's 72 Honda XL175 enduro bike has the original chain from 72 on it still.

hammerface77 · Mar 7, 2005

Well I finally found something!! I picked up a 2000 KX250 in VERY nice shape. :cool: Has all aftermarket black plastic and new seat and graphics kit (yellow/green/yellow flame/tribal) - has original plastic almost like new. Everything seems tight on it and looks to be well taken care of. I checked it over the best I could and it started up great and seemed to run good. Doesn't need a single thing right now but I'm going to spend the next month going over it to grease all bearings, tighten spokes, clean carb, air filter, change all fluids, lube chain, change bars and put on bark busters, etc, etc. Mostly preventative stuff more than anything. The pipe has a pretty good ding in it so I'm going to replace the orings and the brass gasket where the pipe joins to the cylinder. Other than that she should be good to go.

I just trail ride on it so I hope if I take care of it that it will last me a long time without any major repairs. I've searched all I can on this board for info but if anybody has any other suggestions I'd gladly accept them. Such as how to prevent the cylinder plating from flaking off etc...

I'd like to post a pic but I don't have an online host. :(

Buying 1992 YZ250 with original piston - is this bad?

hammerface77

crazyYammi

mtk

hammerface77

blanc

mtk

hammerface77

marcusgunby

gottamoto

mobrown

motoxpress

reknelb

i_955

hammerface77

motoxpress

hammerface77

blanc

oldguy

Always Broken

hammerface77

Yfox05

CJG

Yfox05

mxprep007

83MX80

hammerface77

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