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First rebuild....regret??

By Taylor Robinson,
in Yamaha 2 Stroke

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Taylor Robinson

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Well, long time reader....first time poster. I am coming back to motocross after being out of the game for about 15 years. Used to race 85cc bikes, then things happened....Finally ready to get back into it. I decided after doing a WHOLE lot of reading, that the YZ125 was what I wanted to get back on. The maintenance/cost of a 4 stroke scared me. I wanted something I could have at low cost, that would be easy to fix. Then I had to decided, new or used and after a whole lot of thought I decided that I should go used, and see how much I am actually using the bike. I was going to try and get something in the 2-3k range, but then realized buying used didn't guarantee me that the bike would seize/blow up 1 hour into use, then I am left with a POS that still needs to be fixed......So fixer upper I thought? Could maybe get something dirtcheap, put 500-700 hundred into it, and see how much I was using it, then maybe buy new in a few years. I am very mechanically inclined, do all the work on my cars. Never messed with a motorcycle engine, but I can figure it out....Right????? So after all that, I picked up this gem today. 2000 YZ125 for 500 bucks. ( He originally wanted 1000, and I wanted a >2005 but hey....). Kid had it, tried to fix it up with no luck. Gave me a tub of parts... two engine casings with it...one has been split(nothing but bearings in it) the other is still intact, a rusty crank shaft, 3-4 kick starters/springs, clutch kit, scratched up cylinder, and some engine covers. The bike itself is in absolute pieces..No idea what the cylinder looks like yet. He said that a buddy opened up the engine, and told him it only needed 300 bucks worth of parts, which he didn't have and gave up, so they tossed it back together to make it look like a bike. It is in absolute pieces......... Hope I made the right choice...at first glance I may be regretting my decision, but we will see what happens once I start tearing it apart and get started. All in all, what do yuo you guys think? 

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Taylor Robinson

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Oh, forgot to ask...Do you guys typically get parts from Motosports.com, RMATV, or what??? Is their any other site with cheap parts. Motorsport has a top/bottom end kit for 391.00. Just curious as to where people get a majority of their parts. I downloaded a manual for the bike, and my first plan is to completely tear it down, and see what I have, and what I am missing.....and how much its gonna cost. 

 

Thanks!

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MaybeMe

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8 minutes ago, Taylor Robinson said:

Oh, forgot to ask...Do you guys typically get parts from Motosports.com, RMATV, or what??? Is their any other site with cheap parts. Motorsport has a top/bottom end kit for 391.00. Just curious as to where people get a majority of their parts. I downloaded a manual for the bike, and my first plan is to completely tear it down, and see what I have, and what I am missing.....and how much its gonna cost. 

 

Thanks!

Generally it's a good idea to get the original crank rebuilt and balanced, for the piece of mind it won't catastrophically fail like some aftermarket ones, a full gasket kit, and your choice of piston. 

Shop around, it might be best to get some from Amazon, eBay, motosport, rmatv, your dealer, or the TT store. There's plenty of options and you can find some good deals occasionally. 

Don't skimp out on a piston though, buy a good quality one.

Also, check the cylinder and make sure it isn't damaged, cracked, or out of spec.

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Thump_Stump

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2 minutes ago, Taylor Robinson said:

Oh, forgot to ask...Do you guys typically get parts from Motosports.com, RMATV, or what??? Is their any other site with cheap parts. Motorsport has a top/bottom end kit for 391.00. Just curious as to where people get a majority of their parts. I downloaded a manual for the bike, and my first plan is to completely tear it down, and see what I have, and what I am missing.....and how much its gonna cost. 

 

Thanks!

I like motosports diagrams, but I've been supporting my local shop a lot more.  Especially if you're a regular (which with a rebuild you probably will be) they like to take care of you.  I am given discounts, heads up on huge sales, as well as they have done a lot for me that saved me a ton of money that motosport couldnt help with such as pulling bearings, mountings seat covers, or installing bark busters at no charge.

Especially because you're doing a rebuild and not just bolting on some parts I would recommend trying to stay local because in the end it will probably do more then save you a few bucks...

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Grand Master

YZDOC

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Ok you have the first and best tool needed, THE MANUAL.

Next up is a flywheel puller, blind bearing puller, case splitter, crank puller, caliper gauges, feeler gauges, torque wrench 1.0ftb-60.0ftb minimum, or even 2. Being an auto mechanic you should have some of the tools already.

OEM cranks and pistons are best.

Wiseco, Hotrods are ok.

Pistons after OEM I say:

Vertex, Wiseco, wossner, proX, and never Namura.

Langcourt is shut down for cylinder re-plate so it's milinium, power seal, other, never USCrhome. 

Depending on what is needed for the engine you are looking at 500-600 max.

Radiators: I find the GPI china's are pretty darn good for the money. 

Anything else, just ask.

 

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YZDOC

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1 minute ago, arnego2 said:

Millenium delivered an overbore which was not ordered and piston specs was way out of Order Piston was ordered over them. Beware, pretty bad quality control. 

Oh, believe me, I have heard all the piss poor work they have done and NEVER have used them. I was just refering to the UScrhome being a middle man. Now that Langcourt no longer does it in the USA, I will probably use power seal over Mill. 

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arnego2

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1 minute ago, P84ONE said:

Oh, believe me, I have heard all the piss poor work they have done and NEVER have used them. I was just refering to the UScrhome being a middle man. Now that Langcourt no longer does it in the USA, I will probably use power seal over Mill. 

I do believe you. Powerseal does a pretty good Job and before I used USchrome, last USChrome came with a chipped port, tiny but still. To their defense I dremeled the chipped port and it still runs strong. After that PowersealUSA and then I turned to new cylinders due to better turnaround times.  

I have to ship the cylinder up north (takes 4 to 6 weeks) get the job done and have shipped back (2 weeks at best 4 normally) A new one arrives in one month top and cost me about US$ 25 more. Due to the shipping charges back south. Now with our situation it is even more risky to ship, I think it even impossible to ship up north.  

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Grand Master

YZDOC

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43 minutes ago, arnego2 said:

I do believe you. Powerseal does a pretty good Job and before I used USchrome, last USChrome came with a chipped port, tiny but still. To their defense I dremeled the chipped port and it still runs strong. After that PowersealUSA and then I turned to new cylinders due to better turnaround times.  

I have to ship the cylinder up north (takes 4 to 6 weeks) get the job done and have shipped back (2 weeks at best 4 normally) A new one arrives in one month top and cost me about US$ 25 more. Due to the shipping charges back south. Now with our situation it is even more risky to ship, I think it even impossible to ship up north.  

Shipping time: the whole reason why I have a piston/cylinder(mached) and a head all brand new on the shelf. (for 250's) 

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mlatour

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If you are wanting to get back into dirt biking IMO this is not a good route to take.

I would have rather seen this bike as a 2nd bike for someone looking for a project.

 

On the surface there looks to be a lot of neglect and questionable repairs done by a 'MacGyver' handyman

with more attention given to cosmetics than mechanical upkeep.

I can just imagine the nightmares when you open up the engine, forks, shock, chassis/linkage/wheel bearings etc.

Even with all the investment to rebuilt it from the ground up, in the end it will still be an 18+ year old bike at resale time.

 

Depending where you live, riding season (summer) is coming to an end and,

new 2018 models soon hitting the showroom floors, meaning this is usually a good time for deals on used bikes.

 

For the total amount you'll end up spending (bike + parts + tools + labor) to make this one run reliably,

you could have likely purchased a bike in running condition and be out riding rather than wrenching.

 

Just my 2 cents.

 

 

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Scottwr12345

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3 hours ago, mlatour said:

If you are wanting to get back into dirt biking IMO this is not a good route to take.

I would have rather seen this bike as a 2nd bike for someone looking for a project.

 

On the surface there looks to be a lot of neglect and questionable repairs done by a 'MacGyver' handyman

with more attention given to cosmetics than mechanical upkeep.

I can just imagine the nightmares when you open up the engine, forks, shock, chassis/linkage/wheel bearings etc.

Even with all the investment to rebuilt it from the ground up, in the end it will still be an 18+ year old bike at resale time.

 

Depending where you live, riding season (summer) is coming to an end and,

new 2018 models soon hitting the showroom floors, meaning this is usually a good time for deals on used bikes.

 

For the total amount you'll end up spending (bike + parts + tools + labor) to make this one run reliably,

you could have likely purchased a bike in running condition and be out riding rather than wrenching.

 

Just my 2 cents.

 

 

Used bikes especially bikes that are raced for a season and sold off usually end up costing alot more than there worth.. but i do have a soft spot for older 2 bangers so im probly just being biased lol.

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KDXGarage

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Too late now (why not ask before you bought??), but were you looking into getting back into riding or wrenching? All you are going to be doing is wrenching, not riding anytime soon. You could have bought one for $1,000 - $1,500 and done SOME work to it. If you decided it was not for you, you could sell it and not loose a ton of money, but end up not wrenching forever just to ride once.

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numroe

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18 hours ago, Taylor Robinson said:

I am very mechanically inclined, do all the work on my cars. Never messed with a motorcycle engine, but I can figure it out....Right?????

I hope so. You're going to have to do the full number on that motor. That's a serious project.

Don't spend big on that bike. So you don't have much to lose trying one of the full rebuild kits from Wiseco.  Bottom end kits includes: Crank assembly, main bearings, lots of seals and gaskets. Top end kit contains the usual stuff.  

I recommend fresh fork oil too. Just use cheap Dex VI ATF.  Shock oil replacement is more difficult without the right tools and know-how.

Hopefully the clutch aint too bad.  There's some $ in a clutch.  You can find lots of good used parts on Ebay from wreckers parting out bikes. I'm not sure which YZ125 years models have the same motor as the 2000 bike you have.

You might get depressed when you check the rear suspension and steering bearings. Just go looking and you'll find trouble.

For OEM or misc parts RMATVMC are hard to beat. For things like shifters, levers, brakes, cables, seals, chains, sprockets, spokes, grips, etc. Their own Tusk brand are excellent value.

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slowmoto

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If you get frustrated you could part the bike out for profit and buy something that needs less work.

I bought a non running 1999 yz125 for $600 a month ago and now have it ready to ride. The previous owner had the cylinder replated and new piston but the engine wouldn't turn over. I found a piece of ring in the crankcase that damaged the main bearings. I replaced bearings and seals and the engine runs fine. The most frustrating part was the stuck linkage and swingarm bolts. I put about $400 into it so I got a good bike for $1000.

Get the shop manual and watch these videos.

 

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