yz 250 build up

[mrbb]

Ok guys I am a newbie here
I have played with mx bikes off and on for about 25 years, so i am an older guys too!

I just picked up a 2000 yz 250,
it has had some basic mods done to the suspension, and new bars, better levers,triple clamps, and fmf pipe/sil/, and reeds, and a new clutch, and after market rims.
It runs better than I can ride(for now)

As for the motor, I was told nothing has been to it,
by the last owner since he got it, 3yrs ago, and that the guy before, never mentioned doing anything to it!
SO, I figure, over the winter to do a top/bottom rebuild.
and this is where I am looking for help/advice

I want to build the bike for woods trails, and hill climbs.

so i am looking for more power on the bottom, not looking for top end speed!

since I have been out of the loop a while,
what do you guys recommend I do at the rebuild while I have it apart, that can both increase power, and be better than stock replacements!

I ain't rich, but like to add better than stock parts when i rebuild!

so what would you do /add??

 

[Patman]

Send the top end to Eric Gorr and explain what you are looking for. Problem solved and for a lot less than a bunch of add on crap.

 

[CRipper]

If the bottom end still spins, DONT TOUCH IT. just imo....do the top end yourself. its a peice of cake...just get a manuel and the right tools. As for your gearing and such you can buy a clutch kit or get a bigger rear sprocket like a 52 tooth and a smaller front sprocket i believe.

 

[Patman]

If he's looking to change the power delivery how is doing it himself going to change things? Using somebody with the knowledge and skills to deliver a product that exceeds your expectations is a heck of a lot cheap then doing yourself, screwing it up and having to buy parts and getting somebody to fix it for ya' the next time around. If he wanted to keep the bike just as it was stock maybe sure do it yourself as long as you have the tools and ability to check the bore, inspect the pieces for any abnormal happenings and properly assemble things. Any idiot can throw in a new set of rings or even piston, well let's say most any idiot I know a few that may not be up to the task.

Of course who knows how long it's been since the crank was replaced since everything else is unknown. Easier to do it now than wait for it to fail.

 

[whenfoxforks-ruled]

Anybody seen what happens when a rod bearing goes out? Ask Eric to get you all the parts required/complete engine kit. Vintage Bob

 

[CRipper]

If he's looking to change the power delivery how is doing it himself going to change things? Using somebody with the knowledge and skills to deliver a product that exceeds your expectations is a heck of a lot cheap then doing yourself, screwing it up and having to buy parts and getting somebody to fix it for ya' the next time around. If he wanted to keep the bike just as it was stock maybe sure do it yourself as long as you have the tools and ability to check the bore, inspect the pieces for any abnormal happenings and properly assemble things. Any idiot can throw in a new set of rings or even piston, well let's say most any idiot I know a few that may not be up to the task.

Of course who knows how long it's been since the crank was replaced since everything else is unknown. Easier to do it now than wait for it to fail.

so what are you talking? porting? polish? boring? From my experience with that, id leave it stock, matter fact id leave everything stock. Creates more problems down the road. If you want more power, buy a bigger bike.

 

[whenfoxforks-ruled]

so what are you talking? porting? polish? boring? From my experience with that, id leave it stock, matter fact id leave everything stock. Creates more problems down the road. If you want more power, buy a bigger bike.

Most them mods you posted do not exist in reality. Advertising and flat out bs/guy talk. These stupid little dirt bikes come about modded as far as they can go, and last about 30 minutes plus 2 laps, on any mx track. What Eric does comes with experience and facts. He can alter an engine to suit about any needs. If its stupid, he will tell you. The bike will jet easier, and on stock jetting, be way better to operate, and probably get more hours out of rebuilds with confidence. The grin factor is priceless. Do a search on this site? That bike has been modded already, in a few different applications. Vintage Bob

 

[CRipper]

Never heard of this eric gorr, i searched his site, its down for construction. In a nut shell what does he exactly do?

 

[whenfoxforks-ruled]

Try google or this site. It would take a really big nut shell!!!!! You can try Professor Blair, and Rich Rohrich threads also.

 

[Ol'89r]

If the bottom end still spins, DONT TOUCH IT. .

Just because the crank spins, doesn't mean it's good. It's best to check the bottom end whenever you have the top end off. Take both hands and grab the small end of the rod. Rest the heels of your hands on the base surface. Then, try to move the rod straight up and down. If you feel any movement in the rod, the rod, crankpin and bearing should be replaced. There are also complete aftermarket cranks available.

It is normal to have a little side to side movement but there should be no up and down movement. Rotate the crank and listen and feel for rough main bearings. NOW is the time to replace those things, not after you just buttoned up your new top end. :coocoo: No sense doing the job twice.

+3 on Eric Gorr if you are looking for someone to dial in your powerband for your particular type of riding.

 

[Patman]

Never heard of this eric gorr, i searched his site, its down for construction. In a nut shell what does he exactly do?

You are a Honda expert and have never heard of Eric? :laugh: Seriously? :laugh:

If you were interested in learning about this wizard of internal combustion (especially 2 stroke kind) just do a little searching on DRN & out in the wild wild Internet. He's forgotten more than most will ever know. He spends his time and dollars improving his craft and doing the work himself rather than dumping it in to advertising budget only to then have a trained monkey drag a die grinder across your internal engine parts, throw 'rm in a box with a sticker and a big charge to you plastic money card.

Oh and he's written a few books, you know the things you hold and read.

 

[CRipper]

You are a Honda expert and have never heard of Eric? :laugh: Seriously? :laugh:

If you were interested in learning about this wizard of internal combustion (especially 2 stroke kind) just do a little searching on DRN & out in the wild wild Internet. He's forgotten more than most will ever know. He spends his time and dollars improving his craft and doing the work himself rather than dumping it in to advertising budget only to then have a trained monkey drag a die grinder across your internal engine parts, throw 'rm in a box with a sticker and a big charge to you plastic money card.

Oh and he's written a few books, you know the things you hold and read.

I never stated i was a honda expert. i said ive only owned hondas and only worked on hondas so i have some experience with them. And no i dont know about this guy because whenever there is something to do on my bike it gets done by me and no one else.

 

[Patman]

Well see here's the thing. Around here if you are going to give advice as a knowledgable authority then ya' sorta' gota be able to back it up with some solid reasons. Suggesting people just throw something together based on your experience won't really cut the mustard. If you have some solid advice and can back up WHY you are giving the specific advice go for it, just expect to get called out. We''re very lucky to have some exceptionally talented individuals that are members of this site. People that you may not have heard of. It might be a good idea to do a bit more reading of their posts and searching for info on them before you jump in.

Being the nice guy that I am I'll get you started and then suggest you do a little digging on Ol '89, Jeremy Wilkey, AJ Waggoner to get started, then branch out and see what else you might learn from some folks on here that are experts.

http://www.dirtrider.net/forums3/showthread.php?t=42225&highlight=Rich

 

[CRipper]

I do have knowledge, and i will back it up with my own experience. Thats usually what a forum is about. All these people who all ride bikes and all have suggestions and answers. Im not going to try and answer someone elses questions by asking someone else. If someone is asking a question, and ive experienced the same thing or have an answer for you then i will answer with my opinion. if you want to use it, use it, if not then drop it.

 

[Patman]

Let the games begin :laugh:

 

[CRipper]

If its going to be a game then i deffinitly wont be sticking around.

 

[Rich Rohrich]

If its going to be a game then i deffinitly wont be sticking around.

Certainly your choice but it will be your loss.

These guys are just pulling your chain because you are a new guy, but if you can't take some good natured ribbing from some fellow dirt bike guys then you probably will be better off somewhere else.

 

[mrbb]

Ok guys, I see that this post didn't produce any real help.

I am thinck skinned, so no offence was taken.

But , like I said, I have been out of the MX bike game a for awhile(10 yrs) and was just looking for advice from guys into the sport NOW, thinking maybe there were some better newer items out there than what I used to use long ago.
as for buying a bigger bike(someone posted)
They don't make 500 2 stroke any more, so bigger than 250 2 strokes are just not about, (yes custom rigs are still there, but not in my budget)

I am not into the new 4 strokes, nothing against them, just like 2 strokes!
so buying bigger isn't an option more or less, and the old 500's I had were not fun all day rides either, vibrated a ton, had 3 Kx 500's, had power all one could ever ask for, but handling and vibration, were harsh!

the newer 250's hadle much better!

I plan to go bigger on the rear sprocket, to help with the gearing.

But was hoping to get advice on internal parts, up grades from stock!

I know stock parts are OK, but was thinking some aftermarket items might be better, and close to stock parts prices
and maybe a few guys on here had tried a dn found the ones that hold up best!

am I right or wrong!

seemed to me like there were a lot of guys on here with experience and knowledge, hence the post on the site!

I thank anyone for help, and advice, again!

 

[whenfoxforks-ruled]

There are only 2 ways to make the YZ250 faster, a bigger bore, YZ300. Or, push it off a cliff.

 

[Rich Rohrich]

The most popular upgrade these days is a big bore YZ300 kit like foxforks pointed out. It's the best bang for the buck by far. It combines the best attributes of a 250 and a open class 500; lots of torque and a mile wide powerband without the 500s vibration or sluggish revving. More and more you are seeing guys are going from 450 four-strokes to 300 two-strokes these days.

 

[whenfoxforks-ruled]

There are suspension technologies available now, that border alien tech! My 97 is plenty quick and runs clean. Forks that never bottom would be right up my ally, and would help me ride quicker and longer! And the rear shock to match. MX Tech has plenty of shops around the world.

 

[mrbb]

Thanks guys, I was wondering if there were any big bore kits for them

WHO make a good one, and any one on here have one on there bike??

 

[whenfoxforks-ruled]

What are you really looking to see in this thread? Have you rebuilt the motor, and need more?

 

[mrbb]

I was looking or hoping I would find a list of some name brand parts guys have used , and what they thought about them, likes dislikes, maybe what they would have rather tried, if un happy.

I have not rebuilt the bike yet, still thinking about what I want to do.
kicking the idea about a 300 big bore kit!
again, looking for thouht on that too!

 

[SpDyKen]

There are so many relatively easy steps to get great performance out of the '99 to '11 YZ250. There is lots of information out there, but it's up to you to be smart enough to find it.

Do some searches here. Proper Jetting, ignition timing, and combustion chamber set-up for the fuel you want to run, make all the difference in the world.

A properly set up, mechanically sound, mostly stock YZ250 will provide more power than most riders can use.

Eric's site isn't working 100%, but you can get lots of information here - http://www.eric-gorr.com/

No one better to perform any rebuilds or mods. you decide to do.

Get it running the way it was intended to, first, IMHO.