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need help, CR125.

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i have an 02 cr 125, ive been riding my whole life im 23 now. but ive never really modded anything past the exhaust handlebars and graphics.. lol. i mean i can work on an engine, ive done it before, im a very mechanically sound guy. i just dont really know what to do when it comes to modding. I cant really explain it well, i guess what im asking is, i need someone to give me advice on all the things i can do to help my bike run better, stay running longer, and get a little more performance out of it. i have an fmf gold series fatty and shorty silencer, and thats about it. my old CR had a budds creek cool head on it, evo suspension, and wiesco piston and rings, and same exhaust setup... it was sick. i loved that bike, too bad i was in an accident riding on the road, hit a car head on doing 50mph in 4th gear and almost lost my  leg and my finger. but anyway i fixed it up sold that and got a car. i just bought this bike, same year, 02 CR125. with FMF GOLD SERIES FATTY, SHORTY SILENCER, AND IT CAME WITH A TURBINE CORE Q2 ALSO.. 

 

SO MY QUESTION. WHAT WOULD BE THE BEST? TURBINE CORE OR SHORTY? I THINK SHORTY.. AND HOW SHOULD I GO ABOUT JETTING IT, AND WHAT ABOUT THE REEDS... CAN SOMEONE PLEASE SIT DOWN AND TALK WITH ME SO I CAN TAKE SOME NOTES. IM NEW TO THIS SITE SO IDK IF THERES A CHAT OPTION.. IF SO MESSEGE ME, U CAN EMAIL ME AT LANDSCAPER135@YAHOO.COM OR JPANTAGES@ECDRIVERS.COM

 

THANKS ANYONE WHO HELPS!

 

JOEY P

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Joey,

 

We have two of these same bikes and here's what we've done with wery good results.

- installed a 7mm power valve stopper (stock is 4mm)

- Phat head with H13 combustion chamber, the other bike has a VHM head. You can also mill the stock head. We did that first with 0,95mm squish but it wasn't as good as the Phat head or the VHM.

- V-Force 3 reeds. Some will say that the Boyesen rad valve would be better. I can't say. I only know that the engineering on V-Force makes sense to me.

- HGS exahaust with shorty. Shorty is little bit snappier on the bottom end

- case match the cylinder and exhaust flange

- polished transfer ports after matching them

- air boot from -05 or newer CR125

- 38 mm carb from an -03 CR 125. I've been told that the Keihin airstryker would be really good. You can get one from JD-jetting.

With the stock 36mm carb we ran 32,5 pilot, 390 - 410 main, needle 2nd or 3rd. The air screw we basically have to adjust everytine when at the track. Now with the 38mm carb we're running 37,5 pj, 390 - 410 mj and the needle on the 2dn or 3rd. The other bike has a cylinder from a Dutch tuner Riwa and with that one we're running much bigger 450 - 460 mj.

            The suspension is stock except we're runnin the forks with lighter W 2,5 oil and oil height is 87 mm (air space). With the stock W5 oil my sons were complaining that it hits hard on their hands.

            When it comes to the piston, we'd never use forged piston (Wiseco)  on a 2 stroke.I know now lot of people will dis-agree with me on this. Check out Vertex web page (http://www.vertexpistons.com/) and they'll explain you why. Personally we've been using Vertex and Prox and those have been working really well. In my opinion it's still a hell of a bike but it needs some modifications like this to run with others.

 

Br,

 

Kai

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Nice, I understand most of what u said. I just never really knew the exact ins and outs of all the intricate engine tuning. Like I grew up poor so I like had shitty bikes n parts n just learned what I could on the spot maintenance. So if I could maybe contact u if I have questions that would be pretty cool. Where u guys from ?

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Joey,

We have two of these same bikes and here's what we've done with wery good results.

- installed a 7mm power valve stopper (stock is 4mm)

- Phat head with H13 combustion chamber, the other bike has a VHM head. You can also mill the stock head. We did that first with 0,95mm squish but it wasn't as good as the Phat head or the VHM.

- V-Force 3 reeds. Some will say that the Boyesen rad valve would be better. I can't say. I only know that the engineering on V-Force makes sense to me.

- HGS exahaust with shorty. Shorty is little bit snappier on the bottom end

- case match the cylinder and exhaust flange

- polished transfer ports after matching them

- air boot from -05 or newer CR125

- 38 mm carb from an -03 CR 125. I've been told that the Keihin airstryker would be really good. You can get one from JD-jetting.

With the stock 36mm carb we ran 32,5 pilot, 390 - 410 main, needle 2nd or 3rd. The air screw we basically have to adjust everytine when at the track. Now with the 38mm carb we're running 37,5 pj, 390 - 410 mj and the needle on the 2dn or 3rd. The other bike has a cylinder from a Dutch tuner Riwa and with that one we're running much bigger 450 - 460 mj.

The suspension is stock except we're runnin the forks with lighter W 2,5 oil and oil height is 87 mm (air space). With the stock W5 oil my sons were complaining that it hits hard on their hands.

When it comes to the piston, we'd never use forged piston (Wiseco) on a 2 stroke.I know now lot of people will dis-agree with me on this. Check out Vertex web page (http://www.vertexpistons.com/) and they'll explain you why. Personally we've been using Vertex and Prox and those have been working really well. In my opinion it's still a hell of a bike but it needs some modifications like this to run with others.

Br,

Kai

Sorry im new to forums man. My reply is in comments

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1st, What kind of riding do you do?

I trail ride. Ride in open feilds. I been riding for like 15 years im 23 .. I like to air jumps and hillclimb. Freeride stuff. Im into the old crusty demons vids I grew up on em lol

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I trail ride. Ride in open feilds. I been riding for like 15 years im 23 .. I like to air jumps and hillclimb. Freeride stuff. Im into the old crusty demons vids I grew up on em lol

You need to shorten the gearing. We're running 13 - 53 on MX tracks and on supercross tracks 12 - 53. On trails, maybe 12 - 53 would be good. You also want to have softer damping on trails than on MX tracks.

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You need to shorten the gearing. We're running 13 - 53 on MX tracks and on supercross tracks 12 - 53. On trails, maybe 12 - 53 would be good. You also want to have softer damping on trails than on MX tracks.

How do u soften the dampening?

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