CR125 Build up

[MyckMcClung]

Man I tell ya, most people just don't know, WHEN YOU BUY A NEW BIKE, YOU STILL HAVE TO PACK ALL OF THE BEARINGS!!!!! Then the linkage bearings still get over looked. I repack mine every six months with marine grade wheel bearing grease, for boat trailers.

[Micahdogg]

[Micahdogg]

The fruits of our labor.  Pretty much $1050 total investment.  And a happy owner taking it out on the maiden voyage (yes I know the rear tire is low).



And the boys hanging out, talking a little sh*t.



The bike runs great.  It is WAY undergeared with like a 46T sprocket when factory calls for a 53T I think.  That and the jetting is pretty far off (on the fat side).  Fixing those two things should really make it snap to life.  Overall, I kinda like it though.  I had my doubts, but I think it turned out good.

[Coop]

I dig the last pic. I love hanging out in a garage full of bikes, and working/bench racing. Good stuff  .

[MyckMcClung]

it's a cool picture despite the YZf in the fore ground.

[TxTechRedRider]

congrats on the outcome,
good times ahead

[Micahdogg]

First ride report.  The bike did great going around the block, but once we hit the woods it peetered out in about 5 minutes and wouldn't refire.  A friend went and fetched a new plug for us and that fixed it up..........for another 5 minutes.  Same story.

Luckily I remember the carb had a #58 pilot and the a/s was out just .5 turns.  So had my friend go fetch a screw driver and we cranked that puppy out about 2.5 turns.  We didn't even have to pull this plug, it cranked right up and ran good all day.  

After riding, I got home and installed a #52 pilot at 1.5 turns out, then leaned the clip 1 more notch.  It is more crisp, but has an annoying bog when you grab the throttle too quickly.  I'm thinking it's just a hair too lean now because neither of us remembered it bogging like that earlier.  We'll probably put the clip back where it was, but keep the new pilot.

Overall, bike ran good though.

[JPond53]

Where'd you pick this bike up from it looks familiar for some reason...

[Micahdogg]

Chatham Illinois.

[motoman356]

if you want to change gearing for cheap switch the front sproket. i think renthal has a gear ratio chart

[Micahdogg]

I guess I have a ride report.  I hate 125's.  I think they are gutless and you have to rev em too much.  This one was no exception.  It had NO roll on power whatsoever and required considerable clutching.  I rode it a little and absolutely hated it. 

We have sorted the jetting out as close as can be and it still fouls plugs occasionally.  In the interest of not jetting around a mechanical problem, I suggested he just buy some Boyeson super stock reeds.  We pulled the reed cage hoping to see some fractures, chips, warpage, etc...nothing.  The dual stage reeds that were in there looked perfect and laid down nice and flat.  I was quite disappointed and confident that we were wasting our time, but because he had brand new reeds in hand, we put them in anyway (single stage).

O.........M............G!  I could not believe the dramatic difference in power that it made.  This bike is night and day different.  It has GOBS more roll on power than it ever had.  It went from a bike that I hated, to a bike that I could actually ride all day and maybe even enjoy a little. I just could not believe that reeds would make that big of a difference. 

It still wants to foul a plug though and it appears he's loosing some tranny oil, so we will replace the clutch side crank seal and hope that fixes her up for good.

[motoxr377]

Great bang for the buck! Awesome write-up, man.

[eprovenzano]

Excellent write up...  Its nice to see someone look at the mechanics while rejetting...  If your tranny seal is leaking, yes you will foul plugs.  To jet a bike correctly, several mechanical items things need to be considered.  How fresh is the top end, proper reeds, and is the combustion changer properly sealed.  You have checked and or corrected all of the above...  I'll bet with a little fiddling of the brass, you will no longer need to worry about fouling plugs. and that bike will put a large sinister smile on your face...