Posts
4467
Joined
8/1/2013
Location
Avondale, PA
US
Edited Date/Time
8/18/2022 10:08am
Anyone have some good info on these bikes?
Should I look for 08 crf450r forks to swap on the front?
Any go to set up or mods? I saw boyesen makes replacement stock style reeds to replace the stock or should I just get Oem?
Any piston worth getting or just go with stock?
I just got a low hour bike but want to go thru it lightly and have it ready to rip.
A lot of the info I’ve come across is to make the 02-04s run decent but it seems the 05-07s make relatively decent power.
Should I look for 08 crf450r forks to swap on the front?
Any go to set up or mods? I saw boyesen makes replacement stock style reeds to replace the stock or should I just get Oem?
Any piston worth getting or just go with stock?
I just got a low hour bike but want to go thru it lightly and have it ready to rip.
A lot of the info I’ve come across is to make the 02-04s run decent but it seems the 05-07s make relatively decent power.
Profeshenal has no problem landing tons of chicks with those bikes so you should be golden with it as is....
Boyesen rad valve over vforce
Fmf is broader power band the pc is more top end.
It's power band is mostly mid
This bike vs my 06 yz125 it really favors an aggressive riding style.
The Shop
Mostly a midrange focused engine, they do fall a little flat on top. It will never have the power spread or run quite as cleanly as a YZ. Jetting is quite a bit off from the factory so there is some rideability to be gained be spending some time sorting that out.
Get a PWK and a 134cc kit. If I remember correctly, they really benefited from the 134.
Revalve forks and shock with springs to suit my son's weight. Front and back are both very plush.
Pro Circuit Works pipe and Shorty silencer; stock motor.
JD Jetting kit on the stock Mikuni. Runs perfectly, tan plug, never fouls.
That's it. Ride the hell out of it. Reliable as a rock.
Got to admire the guys who know that but still choose to build pure passion projects and still go and wring them out on the weekend.
Pit Row
I dropped the disc guards on mine and updated the 240mm front rotor/hanger; 240 was good at the time and on such a light bike, but there are better options with 04-14’ fitment that are direct fits. Also, that hybrid steel/aluminum rear sprocket lasts, but at the expense of pulling power. All aluminum is noticeable on the small-bore CR’s!
MXA was pretty on-point with their assessment:
https://motocrossactionmag.com/amp/on-the-record-complete-test-of-the-2…
BTW, I find it PIA to work on pwk carb in situ, lack of space as its a tight fit and usually end up swinging the sub frame out the way
I have the vortex ignition switch fitted and tbh it's not night and day difference, it may need setting up (if you can) properly, but for me I wouldn't miss it if wasn't there
These bikes still turn heads at tracks and ritely so, they was well a head of their time in the looks department
@profeshenal125 what's you're story, I must of mist it, did you have a prang on you'res, do you have a build thread
Where you guys picking up bits for it, I did have some original stuff sent over from the states, partzillia I think
def a good bike to teach you how to go fast!
is bolting on the showas off the cr250 worth it? i hear the kyb stuff stock is just as good.
or the real question is...is putting the kyb stuff on a cr250 an upgrade? the TC showas of this era had midstroke harshness
a hot rod stock bore cr125 prob made 35 hp perfectly jetted
i know the shifter cart cr125 guys made big hp but those engines were all top end
Gonna change the fluids, change the top end, and the other parts and see what she’s got next weekend!
I owned a pretty good running 07' cr125 for a while, and it was by no means fast. It was super fun to ride though. I felt like a hero on that bike, but the race results didn't show it.
I never really like the stock KYB forks. I just could never get them to work the way I wanted them to, so I swapped them out for a set of Showas from an 08' crf250, along with the rear shock as well. I was able to get the Showa stuff to work soooo much better than the oem KYB components. After I made those changes, it was the best handling bike I have ever been on. I couldn't do anything wrong, handling wise, probably because the engine was so weak, but what a fun bike to ride.
I have an 05 CR250 with the TC Showas. My son's CR125 with revalved KYBs is plusher and transmits less chop to the rider. I think my bike handles big hits better.
Unless you're a top level pro, I'd leave the KYBs on and just revalve/respring for your weight. They are light and work amazingly well.
So i started going through some old threads about the last generation engine and saw that Derek Harris? Claimed that the 05-07 cylinder were more or less a YZ clone when it comes to the port design.
So what is the problem then on the last generation? Still to much crank case volume or what?.
I told my self to keep this bike stock, but i saw that the nicasil are starting to show some wear and will soon need a re-plating and that got my head spinning.
It’s rare to see a full blown build when it comes to the engine on the last generation.
Post a reply to: 05-07 cr125 talk