cr125 cdi on a 2001 cr setup

[pope59]

just wonted to see if any of you guys have heard of running a 2001 cr125 cdi on the 2001 cr ignition just wanted some more info thanks guys

[Honda 250r 001]

Why wold you want to do this? Is the timing curve better on the 125 than the 250?

[derby]

Originally posted by Honda 250r 001
Why wold you want to do this? Is the timing curve better on the 125 than the 250?

There is about 8-9 degrees of advance down low with the cr125 over the 250. There are a few guys doing this. It would work well on methanol motors. Some race gas motors could use it as well depending on the setup.

[Honda 250r 001]

Would this work on a motocross machine on pump fuel? or only with race fuel

[derby]

Originally posted by Honda 250r 001
Would this work on a motocross machine on pump fuel? or only with race fuel

I am not going to say it wont work but your comp ratio is probably pretty close to maxing out for pump gas as it is. By advancing the timing it will have the same effect as increasing your compression. So there is a risk of detonation.

I just started testing a e85 motor right now with a pump gas dome, I am running about the same advance you get from the cr125 ignition. It looks like it is going to work really well. Maybe an idea for you if you had access to e85. I would not be surprised if a cr125 box on a pump gas if the motor had detonation.

[woodsracer144]

Originally posted by derby
I am not going to say it wont work but your comp ratio is probably pretty close to maxing out for pump gas as it is. By advancing the timing it will have the same effect as increasing your compression. So there is a risk of detonation.

I just started testing a e85 motor right now with a pump gas dome, I am running about the same advance you get from the cr125 ignition. It looks like it is going to work really well. Maybe an idea for you if you had access to e85. I would not be surprised if a cr125 box on a pump gas if the motor had detonation.

what you running for a carb on your E85 set up for a carb? Im gonna do the same with a Lectron i just got my plate for my 02? CR set up so i'll tell you how it works out, I just need a few small small bolts. for it, i'll have it going to prolly try and get it going tonight.

[derby]

I am using a 38pwk airstryker with a few mods. I am still on the stock ignition but with a vortex cdi and rpm timing advance bracket. I have to say initially it has exceeded my expectations. This is on a stock cylinder stock stroke motor. I am buying e85 for 1.79/gallon which is a 1/4 what vp c12 is.

[morse250r]

here you go cr 125 sounds like the ticket quicker rev ing map
http://www.trx250r.net/trx250rforums/index.php?showtopic=5336

[derby]

Originally posted by morse250r
here you go cr 125 sounds like the ticket quicker rev ing map
http://www.trx250r.net/trx250rforums/index.php?showtopic=5336

If you just switched the cdi out on a motor it actually is a little slower reving especially on the low end. The advance puts out more torque at the expense of rpm's. But it can be optimized based on fuel and compression.

[pope59]

IM NOT A MEMBER ON THAT STIE BUT I HAVE SEEN THE TORK CURVE ON THE 125 VS 250. I HAVE A CT 330 PV WITH A HEAVY DUNE PORT BY k&t40.5 pwk, vforce 3 reeds coolhead ect HERE IN UTAH I HAVE 185 LBS COMP AND I CURNTLEY HAVE THE 01 CR 250 SET UP JUST WANTED TO KNOW IF THIS WOULD GIVE A FEW MORE HP climbing at the dunes

[derby]

Originally posted by pope59
IM NOT A MEMBER ON THAT STIE BUT I HAVE SEEN THE TORK CURVE ON THE 125 VS 250. I HAVE A CT 330 PV WITH A HEAVY DUNE PORT BY k&t40.5 pwk, vforce 3 reeds coolhead ect HERE IN UTAH I HAVE 185 LBS COMP AND I CURNTLEY HAVE THE 01 CR 250 SET UP JUST WANTED TO KNOW IF THIS WOULD GIVE A FEW MORE HP climbing at the dunes

As far as wot hp there is nothing to really gain by using the cr125 cdi. It should give better torque #'s especially from the crack of the throttle through mid range. But it will generate more heat and possible detonation. I run slightly more advance on my 431 than the cr125 curve to make good lowend power. I also have to use 116 octane to keep it from detonating at 15:1 compression ratio. Detonation was obvious, you can hear and see it. I could not keep a plug screwed into the head with vp C12.

[pope59]

thanks guys just seen it on a site a wile ago and just wanted to see just what it would do as a upgrade