05 cr125

[hammy56]

I fouled a few plugs in my 05 cr125 the first few rides...I ended up running a hotter plug and leaning it out quite a bit, 45 pilot and raised clip, I was just wondering if anyone else was using a hotter plug in their cr? And whats the deal with the Mikuni jets? The older Mikuni jets I had werent the same as the new ones, so I had to order some. Stock is a 55 so I ordered a 50 and a 45.....p.s. Im located in Florida (sea level?)-Hammy

 

[bikepilot]

Honda claims that their jets are bike specific, ie a 45 mikuni jet from a KX125 may be totally different than a 45 for a CR125 or even an 01 may be different than an 05. I don't know how true this is, but its what honda claims (its even in the owners manual).

Most bikes are jetted way too rich from the factory, don't be surprised if you have to lean it out quite a bit. Don't forget the main jet too.

I've run an 8 heat range on 125's that were going to be ridden slowly at low rpm, but wouldn't use one for MX or fast riding.

good luck

 

[DIRT-RIDER]

Hammy, same problem happened to my 2002 CR125. And well frankly chance are your bike had a bad oil seal on the clutch side and is letting your tranny oil into the cylinder. Right now i have my engine in peices fixing this problem. I was fouling plugs every 1 hour. i leaned out my bike too, but the plug still ran grey instead of tan. And my silencer has lots of black oil comming out of it, If u have the same characteristic in your bike, then i would look into splitting the cases and replacing the crank. oil seals.

 

[DIRT-RIDER]

Your plugs start fouling all of a sudden, it goes from running perfect to running too rich a fuel mixture. if u dont want to split ur cases any time soon, try running 70wt tranny oil, it will work for a while till the oil thins out. I went from running a BR9EG when it ran good to running a BR8EG when the oil was getting in my cylinder, and it did not foul any more plugs, but it still ran kinda badly.

 

[hammy56]

thanks for the replies...I just got back from riding at Durhamtown Plantation in Georgia...great place, 4th time there in 4 years!.....ended up with 410 main, 42 pilot, 2.5 turns on the a.s., stock needle and went back to 3rd clip, is ran pretty good but I think I need the next leaner needle(raising the clip seemed a little too lean?)....and after leaning it out this much I went back to a br9eg plug....and as far as the Mikuni jets, I should have specified that the mains are the same but they changed the pilots :coocoo: ...now they use the same numbers as a Keihin, 42, 45, 50, etc.....-Hammy

 

[oldfrt613]

I just gave up on jetting my '05 CR250 and ordered a JD Jetting kit. About $60. Oh what a difference. The bottom half of the needle is substantialy leaner than your stock one. I resorted to this because not even my local Honda dealer could get me the optional needles listed in my manual.