Need help on jetting from a real mechanic!

[Rockstar2323]

I have a 2003 CR125 and I think the jetting might be off. Every time I drop the clutch like out of the holeshot or come out of a corner there in no power. But when I get going it seems pretty good. Does this sound like the jetting is off? Is there anyway I can check if it is? Thanks!

[Pedroski]

I know the answer, but I'm not qualified as a mechanic. Sorry.

[SRAD97750]

I know the answer, but I'm not qualified as a mechanic. Sorry.

?

-BIG DAN:thumbsup:

[clrwatrtom]

it's a 125 2 stroke. if you don't keep the motor on the pipe it's gonna seem like there is no power. these motors are designed to rev, so keep your revs up and learn how to feather your clutch on launches and corner exits. you'll be doing LOTS of shifting. Have fun! By the way, i'm also not a qualified mechanic.

[Wayward Son]

how much compression does it have? when is the last time it had a top end? reeds? powervalve serviced? current jetting?

[motoxmann]

Many people mistake needing a new top end with carboration or jetting problems.

I see this every day.

When I tell people this I usually hear, "We just put a new piston and rings in it".

Sometimes you can put a new piston and ring in a bike and it's fine.

If your bike is more than a few years old a piston and ring job is not usually enough.

A cylinder can look great and even pass a quick mic job.

However, unless you have experience with a mic and unless you have a decent set of mics that are properly calibrated you are better off letting someone mic your cylinder who has the proper experience.

A measurement of .0005 (4-6 times smaller than a hair off your head) or less can be the difference it a cylinder that can seal with a new set of rings and one that wont.

If your cylinder does not pass a careful inspection, then it will need to be repaired and re-plated or sleeved.

Once your top end is correctly repaired, do a compression check.

If it is not at or better then factory specs, no amount of jetting will help, really.