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Powervalve question...

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I have an 02 RM125 and it is sooo slow right now.. It has hardly any torque and only has power when the RPMs are built up. It cant even keep up with my cousin's 01 YZ125 and I heard the 02 RMs were suppose to be fast. I posted this question in this section because I need an answer in the next hour. What could be wrong with the powervalve and what do you look for on it to see what to fix?? thansk a lot

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When did you last clean it (the pv)? Could be frozen with gunk.

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could also be time for a rebuild, pick up yourself a pro lite wiseco piston kit and some gaskets and you should be able to get a new motor for under $150, the advantages of 2 strokes! (but I still love my fourbanger) And clean out your powervalve, and maybe clean out the carb and get some fresh gas.

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I have an 02 RM125 and it is sooo slow right now.. It has hardly any torque and only has power when the RPMs are built up. It cant even keep up with my cousin's 01 YZ125 and I heard the 02 RMs were suppose to be fast. I posted this question in this section because I need an answer in the next hour. What could be wrong with the powervalve and what do you look for on it to see what to fix?? thansk a lot

From the sound of it, I doubt it's the powervalve. At closed position, the powervalve benifits low end. However, as it begins to rise.. it allows the engine to build more power in the mid-high RPMs.

When the powervalve isn't working on my RM, the low-end power is good... but there is no mid-range pull, and then it falls on it's face completely WFO. In fact, it has no real hit anywhere, it just feels like a four-stroke... a really, really slow four-stroke.

Since your 125 only comes to life in the upper RPMs (where it would be suffering had the powervalve not been working) it is probably functioning normally. RM125s in the latter years tend to have awesome top-end pull and basically no power elsewhere in the powerband, as opposed to the YZ, which has decent bottom, good midrange, and good (but not as good) top end.

That could explain why the YZ seems to be faster: it makes power everywhere and is easier to ride fast. Although if you can keep your RM on the pipe all the time, it would probably be quicker.

But like Honda said, probably time for a rebuild. Put a new piston and ring in there (wiseco, pro-x, vertex.. whatever you choose, all good) and clean the powervalve, all the carbon deposits, and make sure the powervalve linkages are all in place. Might as well check the reeds while you're in there too. Then once it's all back together, re-jet.... thing should be faster than when it was brand new!

If you want to improve power elsewhere in the powerband, getting it ported by someone, an aftermarket reed cage, and exhaust system will give it a much better spread.

Or, join the dark-side and get a 250f, all problems solved.... until it blows up, anyways.

.

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hey thanks a lot.. i think it could be the jetting too because it seems to smoke quite a bit even thought i'm mixing 40:1..i'll try that first because the top end seems to be good since it starts right up on the first or second kick every time

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DIRTRIDER007 If you are a pretty good wrench and in good standings with your local shop follow the service manual while you take it apart VERY SLOW take your time its not time to race now especially on the first tear down. Do work in a area on table/bench that has no other items on it and keep only the tools needed for the job on the table/bench extra tools can hide parts and be pulled off or dropped taking parts to the ground, and I always work on a old white towel that its clean(shop clean).The towel is there for three reasons one is so you can see the little things that may come out or apart so you can find it easy, things don't roll off the table to the floor on the towel and the towel is easy on machined areas/ parts. Taking one step at a time and keeping up with the manual and keeping a mental note how it comes apart. Keep all the pieces in a box and identify the parts with the manual during disassembly. And if you have friends at the shop they should be more than happy to give some direction in a tough spot. And when working on the power valve clean the cylinder and take off the accesses cover to the P/V and use carb cleaner if you don't have a parts cleaner table it is going to be very dirty and things may be frozen because of carbon and oil build up use good judgment. Remember to clean all the parts good before putting it back together and keeping all the pieces in a box and having clean parts if you cant get it back together take it to the shop in the box your keeping it all in.

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It has hardly any torque and only has power when the RPMs are built up.

Sounds like a typical 125 to me. :lol: However, assuming you and your friend have equal skill on a bike and he still smokes you, most likely you are due for a rebuild.

Do a compression test and see where your bike is at. The beauty of a 2-stroke is that when something in the motor wears out its usually a pretty cheap fix. :applause:

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