RM125 help please 04 rm 125

[SRAD97750]

Here's my piston and my cylinder going to get it honed soon. My friend told me my clutch might be screwed because I told him how when I'm in gear and have my clutch lever engaged the bike won't move forward or backwards?

I do not like the look of the bottom of the exhaust port in that image. Any chipping of the coating requires a replating. Any close ups of these pin holes in the piston? -BIG DAN

 

[noahman22]

We'll I'm changing everything back to stock with the exception of the fmf so do you know if I need to change the jetting up? The stock main is 390 and pilot is 42.5. Do you recommend any size for just the shorty

 

[Mihylo33]

We'll I'm changing everything back to stock with the exception of the fmf so do you know if I need to change the jetting up? The stock main is 390 and pilot is 42.5. Do you recommend any size for just the shorty

Go to the fmf website. They have baseline jet settings for every elevation. That will get you into the ballpark for jetting.

 

[noahman22]

Above the ring there slight small holes (bad picture)

 

[Emily]

Good to see you working on the bike! Get the top end back together with a replated cylinder then worry about the jetting. Jetting is kind of a trial and error kind of thing especially when you don't have much experience. If you haven't found a company to replate your cylinder I suggest Millennium Technologies. I sent them my 125 cylinder and they had it back to me in 2 weeks which is a quick turn around time and I felt the price was right.

 

[rmboy]

Well, In my opinion... The 04ish RM125's have the crappiest powervalve setups, They are always fully of junk. They do not drain like they should. I would pull the power valve apart and clean it. If you try hard you can do this without pulling the engine apart. You have to loosen the motor mounts and remove some of the motor mount bolts.. To pull the covers off, And clean it with brake or carb cleaner. Cycle the power valve by and.

yeah hes right our 02 rm125's popwervalves are better design i think....i like the dial so you can adjust spring tension.

 

[rmboy]

did everything except compression test which it seems a little low but not where I can easily push it down, it takes some muscle. just put a new plug in and still didn't feel right. my jets floats and everything seems fine but ill check it again. I just look at my piston and there's all these tiny holes in the side of it and like 2 descent scratches in the cylinder. but a friend thinks my power valve is gunked up.

yeah..the lower end may have a leak. you can spray wd40 behind the flywheel while its running with that red straw wd40 comes with and see if at a steady idle it dies or bogs severly...or it may be inside the clutch cover the seal on the right ....that is what happened to our 02 and the thing seized the crank after a while...bummer