1996 yz125 rebuild questions

[CSyz]

Ok, so i just bought my bike and was wondering a few things, i need to rebuild the engine, now the kid was a complete noob with motors so i am just gonna do as much as possible, this will be my first rebuild as well. now what is needed to rebuild a seized engine? he says it was siezed, and when i went to kick start it, it felt like the kick start was barely engaging, low compression?

So im wondering what is needed. Tommorrow i will be buying a manual along with the rebuild kit so im basically asking what kit to get and what extra parts. It will be a trail/mx bike.

Thanks

[char393]

You might want to tear it down first and see how much damage was done and that way you can also make sure the cylinder is within specs and not overbored or anything like that so you don't purchase the wrong parts ahead of time.

[MotoMan]

Originally Posted by char393

You might want to tear it down first and see how much damage was done and that way you can also make sure the cylinder is within specs and not overbored or anything like that so you don't purchase the wrong parts ahead of time.

Exactly. Get your manual out and tear it down to see what you got in there, it's the only way to know for sure what's needed.

[CSyz]

Sweet what kind of measurement tool do i need? at the shop in town its 300 for the topend rebuild and 800 for a full rebuild. does that sound right?

[char393]

If you go with wiseco or something like that, you can probably get the parts for around $125 or so, if it's just replacing the piston, rings, clips, needle bearing and wristpin... as for the amount of time, provided everything comes apart for you reasonably well, you can get it done a few hours.

You'll need a set of dial calipers (I think that's what they're called) for measuring the bore of the cylinder. Also a 10mm, 12mm, 8mm and a philips screwdriver...at least I think that's all I used...and a pair of needlenose pliers.

But..I'm not an expert by any means, it's just that I recently did a top end rebuild on my yz125.

[CSyz]

Sweet, well im gonna go to the parts store and get the dial calipers. thanks, im gonna try to get it done soon and get some riding in

[yzernie]

When you get it torn apart make sure the piston is complete. If it broke apart and pieces got into the bottom end then there may be collateral damage.

[ossagp1]

The calipers are a nice thing to have. You will still need to rely on your eyes a lot. The reason being that the only place you can measure is the top of the cylinder and the bottom. They should read about like they did at the factory as they have nothing running on them. Look around the ports for missing plating. It is amazing how well a machine can run with quite a bit of that missing. Gouges etc and peeling are things you really shouldnt try to run with. I way prefer replating to an iron sleeve.

[CSyz]

im trying to get it running for under 300 and have about 150 so far, where should i buy my rebuild kit. i figure if its trashed, ill just get it redone for xmas

[CSyz]

Well my cylinder was garbage, so a new one from yamaha is 340 and the rebuild kit is 120 so my budget build was just blown outta proportion.

SO I have to get the money for these parts and ill let everyone know.

I added some stickers, new grips, levers, new tire is going on so it looks awesome.

[MotoMan]

Originally Posted by CSyz

Well my cylinder was garbage, so a new one from yamaha is 340 and the rebuild kit is 120 so my budget build was just blown outta proportion.

SO I have to get the money for these parts and ill let everyone know.

I added some stickers, new grips, levers, new tire is going on so it looks awesome.

Lets see some pics man!!!

[yz250guy]

Originally Posted by CSyz

Well my cylinder was garbage, so a new one from yamaha is 340 and the rebuild kit is 120 so my budget build was just blown outta proportion.

SO I have to get the money for these parts and ill let everyone know.

I added some stickers, new grips, levers, new tire is going on so it looks awesome.

Really? No chance of repairing the trashed cylinder? That seems WAY more affordable than replacing everything! Have you looked into having the cylinder re-nikasil'd? How much did you pay for the bike? Hopefully it was inexpensive so these repairs won't end up making the bike cost $2000 or something. Good luck!

[char393]

Did you ask if it could be replated? That sucks. Will a 99 cylinder fit? I have one here that it's decent shape, I might could make you a deal...

[CSyz]

Originally Posted by char393

Did you ask if it could be replated? That sucks. Will a 99 cylinder fit? I have one here that it's decent shape, I might could make you a deal...

Thanks, i may take you up on that.

well i can get it redone but i cant remember how much that was.

the bike was 500 so i consider it now the 1500 bike thats in real good shape.

[dellaquila]

you can get everything you need to rebuild the top end for right around $100 from [Only registered and activated users can see links. ] (wiseco kit and cometic gasket kit)

i need to rebuild my top end too so i've been looking into it a lot. i want to test my compression before i start though. anyone know if autozone or advance auto stores have m/c compression testers to rent?

[CSyz]

THanks, im gonna get yamaha factory stuff because it will all be one bill. but ive checked both dealers and its just under 500 for everything so i need to get it done soon.

[daveythewavey19]

Before you go crazy buying new parts like cylinders, check on eBay for things you need. I've found lots of great used parts on eBay that got me running again for cheap.