Low end

[YZ_Rider...Only]

Hey fellow riders, i have a 1999 yz 125 and i ride a lot of trail and hills for practice when im not racing, i was wondering if any of you could help me with low end, i have a pro circuit pipe and a few people said that it's good for top end, but i need more low end power, I have to play with the clutch a lot. It would be a lot of help if anyone could clue me in on low end, and possibly how to get more of it.

Thanks.

[04whyzee]

Add a tooth or two to the rear sprocket and you will gain some bottom end. However you will sacrifice some top speed to gain that low end power.

[YZ_Rider...Only]

are you on a 125 if so, what size sproket are you running

[SirFallsALot243]

FMF Gnarly Pipe.

[Blitz393]

ineeda, i dont think they make the Gnarly for 125's. i know i havent seen any.

04whyzee has a 04 YZ125 and i have a 92... i believe Psyklone has a 99 125. anyway, just add two teeth to the size of your rear sprocket size, it essentially doesn't really give your motor more bottom, but where you used to be lugging a gear you can be up in the RPMs a bit more.

a shorty silencer helps the bottom end punch, and proper jetting also.

hope that helps! and Welcome to ATM

Rob

[Aus_Rider_22]

I went from 49-13 gearing to 50-12 and it shifted the power down alot! Worth a shot at trying different sprocket sizes, though!

[YZ_Rider...Only]

Thanks rob i think ill try adding some more teeth on the sproket

[psyklone393]

good call blitz.

yup, i've got a '99 yz125 and had pretty much the same question you did back here:

yz125 gearing

if you still have the 13 tooth counter sprocket, move up to a 50 tooth sprocket from the stock 48 tooth and see what you think.

cheers!

-Z

[YzRacer#53]

Do you have reeds?

[YzRacer#53]

I also have a yz I own a 2002 YZ125... It's currently stock but im tuning it to put out it's full potential until I get the money to upgrade it.

[SirFallsALot243]

I was pretty sure they made the gnarly for 125's... thought they had it in my rockymountainmc catalog... : Oh well...

[Woody_YZF]

Get a YZ 250F, that will give you a little more low end.

[Blitz393]

lol woody

ineeda, i cant be sure but i THINK they dont have one. either way, i'd rather pay $50 for a larger rear sprocket than $200 for a pipe! lol.

good call, though.

Rob

[Jaybird]

I also have the '99 yz125.
It has better bottom end stock than any of the late model 125's.

Gearing change is the cheapest most effective modification you can make to increase the bottom end torque.

A 125 is NOT going to do what you want it to. It is a high rev type motor. If you are feathering the clutch all the time to make it perform, then GOOD...that's what you are supposed to do.

[ossagp]

Low end doesnt come as easily as high end sometimes. If you are considering a pipe, Dynoport is the only one I would consider other than a stock pipe from a 95. You can add 3/16" to 1/4" to your header if you want, that about does as much for low end. (the DynoPort won't hurt the top as much though, and that would only be slight anyway.)

A thinner base gasket will work well with that mod. You spend very little really. Wiseco is making a 2 ring piston for my 139cc kitted YZ. You can tell a small difference in low end with that.

If you want to do some machining, start with .020 off the base of the cylinder. That will retard your port timing and improve the low end, as well as raising the compression.

Most all of that requires jetting changes, likely towards the leaner side of things. The pipe mod and the basegasket are cheap or free really. the piston when one is needed if available.

FYI I used procircuit and FMF as well as the Dynoport on my son's 95 cr125. None really did anything but the Dyno, and it did just what it said, increased lowend. I also have a procircuit and a fatty for my yz125 (rpm kitted 139 now). Neither of them are worth buying unless you have broken your stock one, where lowend is concerned.

For trail consider going a heat range hotter to increase your lowend response a little. (Just remeber how your are "plugged" and jetted when it comes to wide open running though.)

Gear for what you do as is suggested.

[ossagp]

Nix the 95 pipe, your mount at the cylinder is different unless you want to weld a lot. Somehow I read your post as a 97. The added header lengthy by spacer or welding is not too tough though.