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It's that time! 2005 YZ 125 build questions

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Bit of backstory-  I just started riding seriously in the past year or so... I have been riding my whole life on a very low level, but just recently I graduated, got a nice career and was able to afford a bike.. I picked up a 2010 CRF450 and started progressing at a pretty decent rate, until I went over the bars and tore my rotator cuff.  

 

The 450 is awesome and the power is plentiful.. unfortunately the power is plentiful.  The throttle is super sensitive and it takes a smooth (read, experienced) rider to be able to ride it without being over his head 80% of the time.  I don't have as much fun riding since I'm always in the low end of the power (can't feel like I'm letting loose and just ripping) and I'm not a fan of the engine braking as it doesn't exactly build confidence in the air when you momentarily let off the throttle and start to endo.  

 

I also don't like the weight of the bike.. even though I'm 6'1 185lbs, I sometimes feel like I'm dead sailing in the air.  Can't really adjust the position mid-air too much, at least at my riding level.

 

Enter last friday...  I drove 3 hours each way to go pick up a relatively clean 05 YZ 125 and I am absolutely THRILLED to have picked it up.  I will be able to rip into the meat of the power on this bike, and while I may not be going anywhere, I'll surely feel like I am.  

 

The only downfalls are:

 

-The suspension (especially the rear shock) is like a couch.. it sinks so much when I just sit down on it.  Is this due to my weight and also being used to a new leftover 2010 CRF450?  Is it due to it being clapped out?  Or a mix of both?  What should I do to the rear shock... service it with oil and adjust the clickers, or do I need a new spring?  

 

-There is a slight leak coming from the drain bolt.. the fluid is pinkish in color.  If I wipe the bottom of the drain bolt with a paper towl, I get a pinkish residue.  Does this sound like tranny fluid?  What are the chances this is just a washer deal?  There is also another small leak coming from the powervalve breather tube, but I feel like this drippage is normal.  

 

-The bike will not shift into neutral from first gear, only if you go to second and then half a click down.  The bike hit a false neutral on me one time during the test ride.  I haven't rode it since as I want to fix everything before I take it out on the track.  Is this the faulty shift stopper that plagued the 05/06 125s?  What are the chances there is permanent damage from the bearings possibly breaking loose?  What do I need to do when replacing the shift stopper to make sure everything is kosher and I don't have any metal floating around where it shouldn't?

 

-The bike has ZERO low end... it almost bogs anytime you aren't on the pipe, and I'm partly sure this is just due to it being a 125, but wanted to make sure. 

 

I purchased the bike knowing I'd have to sink in a few hundred dollars to get it where I want.  I want to clean it up and have a reliable bike that I can make my everyday ripper.  I want to do it right!  I will be doing the mechanical portion first, followed by new restyled plastics/graphics.

 

I'm stoked!!!!! Hope I don't get too carried away..  :devil:

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Hey Hazzy,

First figure out the spring rates for your weight and ability.

The transmission may have ATF for fluid, thats what I use it is red.  Not sure about the drain plug until you inspect the threads and the sealing washer.

Do a search on the shift stopper.  This can be a big problem if it failed and is not addressed.

I did a buildup on an '05 this past winter for my boy.

 

Hope this helps,

KC

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I replaced the shift stopper on both the 05 and 06 that I have.  It is kind of a pain to get that spring on the stopper in place, but both times I did it through the clutch cover. It really helps to have an impact gun for clutch basket removal if you do it through the clutch cover.   However, if I had to do it again, I would just probably just remove the right side case to get a little more room to work. An inability to find neutral does not necessarily mean anything on these bikes.  It is much harder to find neutral on these two yamahas than my Suzuki and KTm, and replacing the shift stopper seemed to make no difference.

 

Getting the proper spring rate will make a huge difference.  You are about the same weight as me.  You can use the spring rate calculator on the Race Tech website (although I think that has a mistake for the 05 model), or just call Factory Connection.  I bought FC springs through Amazon for less than $100 for each end, but you need to call FC to make sure you have the right model number.  You will need a couple of specialized tools to put in the fork springs, but they don't cost much.  The shock spring is easy.  After you get the correct springs you will be able to determine if the shock is functioning properly.   I once had a neighborhood kid "help" me by bleeding the nitrogen out of my shock.  He had seen me bleed the air out of my forks, so he thought he was doing the same for the shock!!!

 

Your YZ should have a solid bottom end for a 125, but it all depends on what you are used to.  I ride 125s all the time, and only the KTM is better than the YZ if we are talking stock bikes.  But it may feel weak to you just because you are coming off a 450.  Let an experienced 125 rider take your bike for a spin and see what they say.

 

Enjoy that 125!  My 250 smoker has been gathering dust lately.

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