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Cr 125 jetting

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Okay so here daily soon I'm gonna be tearing part my linkage and rear end and stuff so I figured I'd might as well just go ahead and clean the carb and check jetting. I have an 02 cr125 and recently got a fatty for it and was curious if the FMF suggested jetting would be a good starting point for me? I live in ohio btw so not exactly sea level but not the mountains. Any help would be much appreciated!

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Okay so here daily soon I'm gonna be tearing part my linkage and rear end and stuff so I figured I'd might as well just go ahead and clean the carb and check jetting. I have an 02 cr125 and recently got a fatty for it and was curious if the FMF suggested jetting would be a good starting point for me? I live in ohio btw so not exactly sea level but not the mountains. Any help would be much appreciated!

I recently got a 04 CR 125 that I originally bought for my girlfriend to ride but I ended up using it more than her. Its served as a good back up bike for me so far. I have tried to play with the jetting a little so far but haven't found anything better than what it was already running other than air screw. 

I know that it is a different year but maybe this can help. 

 

Stock pilot was a 40, main was a 420 but now it has a 55 pilot and a 430 main with the stock needle and clip in the middle. I have a Fatty and V-Force 3 reed setup but the rest of the motor is stock displacement and compression. So the bike needed a lot more fuel to run just the pipe and reed set up effectively. So far I've learned that the 125's are a lot more sensitive to modifications in regards to jetting changes. I have done the same mods on 250's and got away with the stock jetting but they seemed to be jetted rich from the factory anyway. 

 

I would say starting with the recommended jetting from FMF would be a good place to start but I would recommend also buying a couple of extra jets so you can fine tune it later. Take the time to do a plug check before going on a long ride or ripping it up on the track just to be sure. 

I just bought an assortment of jets for mine to try different settings later and they are pretty cheap so you can set up a small jetting box to have with your spare parts kit when you feel like doing some testing, which is the only way to dial in the best jetting. 

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Ditch the mikuni. Get a pwk!

I've seen many people say that on this forum. I'm thinking maybe bout mid summer upgrade. What are the advantages over it over the stock? And how much and where can I get one from?

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I've seen many people say that on this forum. I'm thinking maybe bout mid summer upgrade. What are the advantages over it over the stock? And how much and where can I get one from?

Easiest is get a new one from JD Jetting, comes pre jetted with #7 slide, and both his Blue and Red needle.  There is an Alternate Red needle that is really good, but you must request it.  Or look for a 99 or 2000 CR250 carb on ebay.  99 comes with a 5.5 slide, 2000 comes #7 slide.  I've got a bunch of jetting notes for several needles and slides, and there are some good guys here on this forum with expert jetting advise.  I'm still experimenting with some different needles, and will post my results in due time.

 

http://www.thumpertalk.com/topic/1044850-cr125-needles-pwk/#!J5dCI

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