High-hour, high-mileage YZ. What to look for, and repair tips.

[CaptDan]

We recently bought a well-used late-model YZ250. Though it had been well maintained by the previous owner, I was surprised by how much wear it had, and where that wear had occurred.

This thread is not intended to be so much about things to look for when buying a used bike, but how to refresh a high-hour, high-miles bike. Please feel free to add any additional observations or tips.

REAR SUSPENSION BEARINGS: Pay attention to the swingarm pivot thrust bearings. These bearings are positioned right behind areas on the frame where water can accumulate and sit unnoticed. While most of the other bearings may appear to be holding up just fine, the thrust bearings generally rust out early.

REAR SUSPENSION BOLTS: While the rear axle has two ‘flats’ machined on its end – to allow you to spread the wear by flipping it over -- the suspension bolts do not. This leads to the load and wear being continually placed in the same area on these bolts. Grinding a new flat opposite the factory flat will let you flip the bolts over to expose unworn bearing surface. Its like getting fresh pivot bolts for free!

STEERING BEARINGS: The seal for the top steerer bearing on aluminum-framed Yamahas has always been too flimsy to really do its job well. Expect to re-grease or replace the steering bearings, then get a 2010 YZF top seal – it is a much beefier design.

FRONT NUMBER PLATE MOUNTING: The two studs on the lower triple clamp ('06 and up) that the front number plate mounts on can get worn. I know it sounds crazy, but those two studs can get serious notches worn into them from the front number plate vibrating around. Drill out the lower mounting holes in the number plate and install grommets. Aim for a tight fit on the studs to quell the vibration, thus eliminating any additional wear.

WHEEL BEARING SPACERS: The spacers between the bearings in the wheels can compress over time. Frequent wheel removal & re-mounting and torque-ing speeds this up, and the spacer ends up being ‘short’. This subjects the bearings to higher loads, higher friction, and greater wear. Install new spacers if you have to replace wheel bearings.

BRAKE DISCS: My rear disc was wasted – grooved, chewed, and blued – and the front had already been replaced once. Worn discs go through pads faster, so consider new discs if they look bad.

FASTENERS: Every nut, bolt, and screw on this bike was tight, REAL tight. Like, I-hope-this-thing-doesn’t-break- “PING!” tight. Use Loc-Tite or some sort of never-seize on the fasteners. And don’t tighten 6mm screws with a ½”- drive ratchet! Gad! These bikes don’t vibrate THAT bad. Broken screws and stripped threads indicate poor mechanical skills. Don’t be that guy. You and your bike will be happier.

SEAT: Yep, the seat! The ‘keyhole’ on the underside of the seat was worn oversized. Not a big thing, but the button on the tank had also been ‘sawed on’ by the seat, so those two things together allowed the seat to slide side-to-side too much. I bought a new button, then padded the end of the keyhole with a few strips of duct tape. This tightened things up nicely.

REAR MASTER CYLINDER: Another crazy one, boots rubbing on the rear master cylinder can wear all the details off the aluminum body. Not a service issue, but it sure shows the bike has lots of time on it.

FOOT PEGS: Many YZs came with cool titanium footpegs. A few early versions had pegs breaking, so be mindful of what year the bike is. Also, titanium wears faster than steel, so check for smooth, worn-down teeth. The footpeg pins can get worn as well, and that makes for a sloppy feel in the pegs, so consider refreshing those.

FRONT AXLE: The right end of the front axle is a precision-machined cylinder, designed to be a nice smooth sliding fit into the lower right fork leg. There should never be a need to hammer on the axle, but if someone did, the smooth surface was most likely damaged and deformed -- ruining the slip fit into the fork -- and possibly introducing fork binding and misalignment. Use a flat file to remove any burrs or lumps on the cylinder that hammering may have caused. Ensure that the axle slides unfettered through the lower fork leg. Fork action will be smoother and bushings will last longer when the fork is allowed to align easily on the axle.

REAR BRAKE CARRIER: The mount on the swingarm that engages the rear caliper carrier can get surprisingly worn down. This allows the carrier to flop around, accelerating the wear at the mount and the swingarm hole. The quick, cheap fix is to adjust the rear wheel so that the caliper carrier engages a less-worn area of the mount, chain slack permitting. I’m not sure of any other way to fix this, short of welding and machining, or buying a new carrier and swingarm.

More?

[dzamo]

SWINGARM CHAIN SLIDER: Vibration can wear a hole in the swingarm. You can use silicone or shoo goo to keep it from moving.

[RCannon]

Agree with the slider. Flue it to the arm, then put the bolts in. Its also a piece that looks good when its badly worn...check the front edge, near the sprocket.

[singletrkstar]

I just posted a question about the brake carrier yesterday. Mine is worn pretty good, the brakes work, but I need to get that fixed at some point.

[Sierra_rider]

The bottom of my forklegs are pretty hammered from rocks and badly picked lines. Also agree with items worn by boots. My frame, rear master cylinder, and clutch cover are highly polished from contact with my boots.

Also check the clutch cover for hairline cracks. Mine has them from impacts but they don't go all the way through, probably should replace it soon.

[waz]

I just posted a question about the brake carrier yesterday. Mine is worn pretty good, the brakes work, but I need to get that fixed at some point.

My carrier is getting worn also. This was my issue a couple of weeks ago,

as I thought my transmission was locking my rear wheel up, it turns out I was

having some serious binding issues. ?

With that said, I feel that this thread is a valuable one. Its making me re-evaluate Yamaha and their products. I'm sorry, worn swingarms should not be happening on a 5 year old bike. I was a die hard Yamaha when I was employed, now not employed, I need reliability. So far Yamaha is getting a low grade IMO. I know one thing, I miss my older YZ.

[Sierra_rider]

My carrier is getting worn also. This was my issue a couple of weeks ago,

as I thought my transmission was locking my rear wheel up, it turns out I was

having some serious binding issues. ?

With that said, I feel that this thread is a valuable one. Its making me re-evaluate Yamaha and their products. I'm sorry, worn swingarms should not be happening on a 5 year old bike. I was a die hard Yamaha when I was employed, now not employed, I need reliability. So far Yamaha is getting a low grade IMO. I know one thing, I miss my older YZ.

I wouldn't say Yamaha's are unreliable. They have their weak links like any bike does, but overall are reliable, durable bikes. My 05 is a very high hour/mileage bike without the carrier issue. It's been ridden almost every weekend for years and has never left me stranded, just the usual stuff like top-ends and suspension servicing. I've been very happy with all of my Yamaha's that I've had and will continue to buy them in the future.

[CaptDan]

With that said, I feel that this thread is a valuable one. Its making me re-evaluate Yamaha and their products. I was a die hard Yamaha when I was employed, now not employed, I need reliability. So far Yamaha is getting a low grade IMO. I know one thing, I miss my older YZ.

Over the years, ALL bikes have become lighter and more maintenance-intensive. I'm willing to bet similar issues are happening to many modern bikes, no matter who built it.

My trusty '96 YZ was as reliable as a brick, but compared to today’s bikes, it was also build like a brick and as heavy as a sack full.

We need to recognize that our newer bikes are far more refined machines, with elegant – sometimes almost delicate – solutions to design challenges.

And that is partially why I wanted to have a thread like this. Many “worn” areas I found on our high-hour bike could have been drastically reduced, if not completely eliminated, by early detection and action.

Keep the observations and tips coming!

Excuse me while I go to slip a rubber pad between the swingarm and rear brake carrier on my ’06 to keep it from wearing down like our ’08!

[RCannon]

I agree with what captdan said. The Yamaha is reliable, but all of this stuff has limits. Also, the sliding surfaces need to be kept clean. The dirt and sliding on the aluminum surface is bad news.

ebay swingarms dont sell for much..

[waz]

Okay, I know that things have limits. But a swingarm and hubs should

have the most roboustness. I take real good care of my mc. Washed every ride and so on. I'm just a little dis-gruntled I guess with Yamaha.

Between hubs, swingarms and such, I guess I'll just have to keep working the bugs out. Maybe all this talk about CR brakes are so good, maybe we should stuff a YZ 250 motor into a CR frame.?

Captdan, fill us in on the rubber pad trick. What are you using!

[waz]

Looking at Captdan list.

I forgot about the footpegs, I had to replace one back in 07'

I had a friend that had after market IMS he gave me and intalled them.

I have about 3 or 4 things on the list that needs to be looked at.?

[waz]

Captdan,

Sorry if I put a negative spin on your thread. ?

waz

[adam728]

I sometimes think too that bikes seem "less reliable" as we get more abusive. My RT100 was indestructible when I was 12. I bet I could destroy it in less than an hour on some of the trails I've hammered my YZ down. My first KDX was an anvil. My second one I got at a time I really increased in speed, and that one required constant maintance and parts replacement.

I've got another "odd place for wear", which really isn't any bike could do it, you just don't usually think about it. Pipe-to-cylinder junction. Loose mounts, sacked out pipe springs, torn up o-rings, whatever. That gets a little loose, maybe some dirt works in there, and suddenly you can really take some material off the cylinder from vibration. I've seen it whether the pipe in the male piece (my KDX's) or the female piece (like the YZ250).

[waz]

I sometimes think too that bikes seem "less reliable" as we get more abusive. My RT100 was indestructible when I was 12. I bet I could destroy it in less than an hour on some of the trails I've hammered my YZ down. My first KDX was an anvil. My second one I got at a time I really increased in speed, and that one required constant maintance and parts replacement.

I've got another "odd place for wear", which really isn't any bike could do it, you just don't usually think about it. Pipe-to-cylinder junction. Loose mounts, sacked out pipe springs, torn up o-rings, whatever. That gets a little loose, maybe some dirt works in there, and suddenly you can really take some material off the cylinder from vibration. I've seen it whether the pipe in the male piece (my KDX's) or the female piece (like the YZ250).

Yep, another one to look at. Cylinder to pipe, Actually mine wore out

in short order:banghead:

You know another place that I have to watch, is the lower bracket mount

for the pipe. The back side worked its way through the welded piece.

Any suggestions there?

[ricky_h]

Subscribing.... ?

[CaptDan]

Captdan,

Sorry if I put a negative spin on your thread.

waz

No worries, waz! ?

[OldMechanik]

Even though this seems more like an "odd parts that wear" thread....don't forget about cylinder plating and reeds on the smokers.

Fasteners and plastics (the eyes that the screws go through) are another overlooked group.

Rubber mountings can dry rott.

Cables can wear grooves into the housings.

[Sierra_rider]

Even though this seems more like an "odd parts that wear" thread....don't forget about cylinder plating and reeds on the smokers.

Fasteners and plastics (the eyes that the screws go through) are another overlooked group.

Rubber mountings can dry rott.

Cables can wear grooves into the housings.

Yep, check for missing eyes that the bolts go through on the shrouds and front fender. Also look for cheap hardware store SAE bolts replacing metric's. Both can say a lot about the previous owner.

Also broken down seat foam can be a guide to how much "seat" time a bike has!? ...but I stand up most of the time and my seat still feels like it's brand new, not like a bike with hundreds if not thousands of hours.

[CaptDan]

You know another place that I have to watch, is the lower bracket mount for the pipe. The back side worked its way through the welded piece. Any suggestions there?

Another great one!

Some of those inserts pull through, some loosen up and fall out, and some just get stripped threads.

This is what I'm going to try;

Knock the insert out of the welded plate (if it hasn't already fallen out), get a flanged hex nut and press it through the hex-shaped hole from behind.

Finding a nut that will fit nice and snug may be a challenge, though.

[motomanp58]

After always buying brand new off the floor bikes, I bought my first used bike(07 250). Its funny to read this thread now after i tore that bad boy down. You couldn't be more on target