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some basic yz 125 questions

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well ive looked and worried foreverlong about this stuff, but i kinda need someone that knows what there talking about to help me out. i recently bought a 2001 yz 125. im 16 years old 165 pounds 6 ft tall. noob rider. i do mostly harescrambles trailsand light light motocross track. i dont race, or hold it pinned. but i do rip in fields and ride with the neighborhood guys. i just novice ride for fun. but i ride it frequently. and because of summer, i will be riding ALOt.

1. the top end has 3 races on (previous owner). how long does a top end last, and how can i tell when it needs it? (main concern)

2. will i ever have to do anything to the suspension if i dont race? (coming from a crf150f)

3. how often do i change tranny oil and what kind do i need to use ( like a heavy weight motor oil?)

4. coolant-- 50/50 vs pure antifreeze

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well ive looked and worried foreverlong about this stuff, but i kinda need someone that knows what there talking about to help me out. i recently bought a 2001 yz 125. im 16 years old 165 pounds 6 ft tall. noob rider. i do mostly harescrambles trailsand light light motocross track. i dont race, or hold it pinned. but i do rip in fields and ride with the neighborhood guys. i just novice ride for fun. but i ride it frequently. and because of summer, i will be riding ALOt.

1. the top end has 3 races on (previous owner). how long does a top end last, and how can i tell when it needs it? (main concern)

2. will i ever have to do anything to the suspension if i dont race? (coming from a crf150f)

3. how often do i change tranny oil and what kind do i need to use ( like a heavy weight motor oil?)

4. coolant-- 50/50 vs pure antifreeze

1. Top End- you should replace your top end when you get a new bike, because the most common lie on used bikes is that they have a fresh top end. Replace it for good measure.

2. Suspension-The only suspension work you'll need to do is anything that needs maintenance or goes out. Such as fork seals going out and causing your forks to leak, or shock seals etc. Its a good idea to do some maintenance on your suspension but its really not that necessary if theres no problem with them.

3. Tranny oil- search the forums because you will get a million different answers. I run non synethic 10w40 and change it ever 6-8 hours. (6-8 hours of actual riding where your bike is running). This depends on how hard your riding too, if your putting around maybe 8-10 if your riding very hard maybe even less than 6. But I change it every 6-8 hours.

4. Coolant- Run engine ice. Its radiator fluid and does not need to be mixed 50/50. I only run engine ice in my bikes, and alot of others do too. It will help keep your bike running cool.

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what are the symptoms of a failing top end? and how long does a new one last. ive known the man for a long time so i know when he sais the top end has 3 races on it, it has only 3 races on it.

also, how can i tell when the cluch goes out? what does it feel like when it slips?

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what are the symptoms of a failing top end? and how long does a new one last. ive known the man for a long time so i know when he sais the top end has 3 races on it, it has only 3 races on it.

also, how can i tell when the cluch goes out? what does it feel like when it slips?

The top end wear and signs of wear are usually gradual. That is, it is hard to notice any power difference from ride to ride. A lot like growing. People do not notice any growth in height if they see you every day, but notice a huge difference if they only see you one or twice a year. I would notice top end wear on my bikes if for example it took more kicks than normal to start or if the plugs started fouling. As mentioned, I would put a fresh top end in and then go with a normal schedule for yourself. As far as the clutch goes, normally there are two types of wear that go on in the normal life of the clutch. The first is when the friction discs wear out. The slip is felt like this. The engine will rev and the bike will not accelerate as normal. This does not mean that the clutch is shot. Simply adjust the clutch at the lever. Then when the range is out, adjust the cable near the lever. If this does not work anymore, then it's time for a new clutch kit. This means friction discs, or discs, pressure plates, or steel plate, and springs. You must change all three or the repair will not last. The second type of wear you will experience is the clutch basket wear. This will be noticed when you pull in the clutch and it does not seam to disengage. At first, you could try to adjust the clutch in the opposite way that you would for worn plate and discs. Eventually this will not work any more. What happens here is that the inner and outer clutch baskets, but usually the outer, will start to get teeth like wear, where the friction discs make contact with the basket ears. The wear will look like notches. At first you could carefully file the teeth looking notches off. Later, you will need to buy a new or newer clutch basket. What happens is that when you pull in the clutch lever, the plates want to separate but they can't, since the teeth looking grooves try to keep the plates together, or engaged, instead of separate, or disengaged.

Hop this helps.

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so like, i was planning on just a top end a year and maby throwin in a ring every now and then. what does a bad piston look like?

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so like, i was planning on just a top end a year and maby throwin in a ring every now and then. what does a bad piston look like?

Honestly the best way to do it is take apart the top end and inspect it. There are a million different ways that a bad piston can look like. Opening up and taking a look/replacing your top end will not only get you familiar with you bike, but it'll keep your mind at peace. Some people will take a different stance at this but I honestly dont bother just replacing the rings, usually when I take apart the top end its time for a whole new piston. I would rather just replace the piston then keep buying rings, thats just me though.

Its not difficult to do, and you might as well do it now and have your bike ready to ride for the whole season.

Heres a step by step how to video:

edit: one top end per season should be fine, it honestly depends how much your riding. I usually keep it at one top end per year though; some seasons I may run a top end for longer because I havent ridden as much.

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Alright. Well iride it alot though. Not hard... But still. How can I feel when the tip end goes out?

Noon question- how do. I properly warm it up, and does it matter if I only ride for like 5 mins if it iS fully warm?

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You will feel it when your bike has less power after a while, and you lose compression (kick start gets easier to push down; better measurable by hand) its tough to recognize the power loss because its usually gradual. Just replace it now and be safe about it.

Properly warming it up- If your bike idles let it idle for a few minutes with the choke on, until the top part of your radiator (solid metal) or exhaust is warm. Then you can go ride it as hard as you want.

If your bike wont idle that long without dieing then rev it gently (do not go high in the rpms and dont rev it hard). Be gentle on your motor until once again the top of the radiator or exhaust is warm.

I use the top of the radiator as a gauge for if my motor is warmed up. Also if you run a wiseco piston make sure you warm it up well because forged pistons will warm up faster than the cylinder and if you go rip around hard it will cause a cold seizure. Dont over think this, if you warm up as I said above you will be fine.

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