Cr125 flat power

2/9/2018 8:07am Edited Date/Time 2/12/2018 5:23pm
I have an 05 cr125 and it rides like it has no Powerband it just revs to the moon while not making the power it should usually you would assume this would be a clutch issue but it’s not the same feeling as a toasted clutch I have a feeling it may be an electrical issue (as the whole wiring harness is 13 years old) maybe some corroded wires Inside their casing any ideas?
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kb228
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2/9/2018 9:34am
Is your spark plug fresh & gapped right? If the gap is even slightly off it will fall flat on top. If its within range, try adjusting it to get the best performance.
2/9/2018 3:59pm
Yea I checked the plug gap is good. I’m thinking it may be the power valve
moore433
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2/9/2018 4:10pm
My son had a 04, and it was a turd dragging a brick!!!!!
It hand a powerband though, it was called off!!!!!
I always heard the 05 ran great. Hope you get it fiqured out...

The Shop

moore433
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Denton, TX US
2/9/2018 4:15pm
Make sure the air filter is clean and not too oily. I saw a kid one time and his 85 wouldn’t run right, he way over oiled the filter. Cleaned the filter and it ran great..
kb228
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2/9/2018 4:59pm
hancock138 wrote:
Yea I checked the plug gap is good. I’m thinking it may be the power valve
Yea clean that up and see what happens.
YamahaJT1
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2/10/2018 10:44am Edited Date/Time 2/10/2018 12:37pm
Don't forget to replace seals....




When did you last replace your piston/ring? Carb jetting? Compression check? Crank seals? Leaky exhaust/crappy packing?

Others here have given sound advice as well.. You will get advice tantamount to what you offer.

Take it apart and find the issue. 05'-07' CR125 units are "frisky" if well kept after. They can propel my fat 210 pound ass to 65 mph rather quickly...





YamahaJT1
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2/10/2018 11:09am Edited Date/Time 2/10/2018 11:56am
Do inspect your clutch as well....





Let us know what you find.




EDIT: Lotsa folks just slap the "Torsk" clutch holder tool on any splines that it'll fit on. NOPE! Grind/bevel the "Torsk" tool to fit accurately between the splines and ONLY position it so it is fitted between only the THICK hub splines, whether off or on. Do not squeeze the heck out of it and distort it, albeit it looks like a Vise-Grip.

Pressure distributed only between the thick/wide splines. Don't use the thin splines. Folks bend the shit out of the thin splines, then bitch that their new clutch is crappy... "Werd" to the wise.
2/11/2018 4:29pm
Why pay money for that junk clutch hub holder ? An old steel clutch plate, with a length of steel rod welded to it, makes a much more precise fitting holder.
YamahaJT1
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2/12/2018 4:17pm Edited Date/Time 2/12/2018 5:23pm
Why pay money for that junk clutch hub holder ? An old steel clutch plate, with a length of steel rod welded to it, makes a...
Why pay money for that junk clutch hub holder ? An old steel clutch plate, with a length of steel rod welded to it, makes a much more precise fitting holder.
Hard to argue with your approach... Cheap, easy, accurate. Like a less fancy EBC hub holder version. I fabricate a few tools as well.

Nonetheless, I can grind/fit the $14 dollar piece of junk with a Dremel tool in 5 minutes to fit perfectly across the full thick splines and have no issues or hub indentation/deformation/scarring with my work. Doubles as a fly wheel puller holder, and sprocket/gear holder as well.

I know, two precisely placed drilled/swaged/welded pins on a hand cut/bent/ground curved stick of steel so one can access the bolts/nuts for removal/installation...Yep, one can also make such things themselves. And add/fit a pivot to fit multiple applications. That is a lot of work. $14 was well spent in my case, as I only work on CR125 motorcycles.




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