Hey guys, I have a 2003 cr125 I bought a couple weeks ago and I'm having a problem with it. The spark plugs die every about 15 minutes, with hotter plugs it will last about 45 minutes. I herd that if the timing is off it can over heat the plugs and burn out the the resistor. Is there any truth to that? The reason I thinks it's not fouling is because when the plug dies it gives no spark no matter how much you clean it, And it shorts out.
Well, I've gone and done it. I decided to pick up another neglected, orphan bike to restore and play with for at least a few seasons. I came across a very inexpensive (I'll leave that ambiguous) 1997 CR250R that was calling my name. I knew the top-end was toast, but as with any new project, I had no way to know how far gone things would be until I took it home and unbuttoned the mill.
So, I'll share the bad news, the good news and then ask a few questions while I wait for a manual to arrive.
Looks like the bottom ring decided to eat itself. About 1 inch of it broke off, caught on the main intake port, dug a HUGE scar in the piston, nicked the top of two ports, then spent time salt-and-peppering the top of the piston and the head before exiting the motor.
Here are the pictures of the damage...first, the scar from the ring tearing down the side of the piston...
Then what looks like a seize-point or serious scuff, with more shrapnel damage...
...Here's what the top of the piston ended up as...
...and the matching head "acne"...
Now, here are the pics of the cylinder. The first two are from the underside, looking up the bore. The nicks are obvious.
These two are looking from the top down the bore.
And now...the questions.
First, is the head salvageable? Can that be cleaned up well enough without machine work that will cost more than a new head?
Second, the Cylinder. I was glad to see that there was no scoring or damage to the cylinder walls themselves. However, the damage near those nicks has me fearing. I know I had old iron-bore cylinders with worse damage that were smoothed out by hand, but I''m not sure I can safely pull this off in this case. Is this garage-repairable, or am I going to be forced to weld up, re-plate and bore the cylinder? I know that "the best thing to do would be...", but I'm asking what I can do...not necessarily what I should. Will those damage points, if smoothed, result in rings prematurely hanging/breaking on the next top-end?
Thanks for any input you folks can provide.
By Ryan Turner
So I'm at a bit of a cross roads, I currently own a 06 rm250 and I love it. I also have a 02 kx250 which I'm selling with intent to buy a newer two stroke. I can't afford a newer ktm and the older ones aren't that great and kawasaki never impressed me. so I'm stuck between 06 yz250 and 05 cr250. I've heard the yz and rm after 06 are almost the same bike just the Suzuki handles better and the Yamaha has better suspension. So I'm not sure if I wanna buy carbon copy of my bike with slight differences. That's why I'm interested in a cr250 I heard the 02+ models RC valves are shit garbage but was mostly fixed in the 05-07 models. I ride at a track and at some bogs down the road from me. So from people who have owned both, what would you recommend. I know the cr is known for a hard hitting power band which I enjoy since im an aggressive rider. Should i just see which deal comes my way first.
Like the title says I've recently acquired an 07 CR250. Just got it into a safe state to operate it and the first ride out I realize the suspension is pogo-stick, jack-hammer hard.
My data: Height 6'3" Weight 215, or 225-230 with gear, Slow B rider, hare scramble racer only-NO MX/no jumping, Current springs Forks .46, shock 5.5. I'd like to soften the first 1/2 of the travel to soak up roots, rocks, and sharp edge hits but maintain some firmness with the mid-valve for the last 1/3 of travel.
Here is what I'm looking at right now:
30.1 X 11 shims
14.2 X 5 shims
11.2 X 4 shims
I have not measured the mid-valve stack yet as I was hoping to just be able to modify the base valve first and see how it goes. I don't want to make too many changes at once.
I was thinking about taking out the even numbered shims (28, 26, 24, 22, 18) and placing them under the 14's as a trial. So it would look like this;
30.1 X 11
14.2 X 5
If anyone could offer some assistance with this I would sincerely appreciate it. I have a place local to me that has all the shims in stock so I just need to settle on a corrected stack and then get these back together.
I realize the pivot is the 14.2 and debated on making this a 2 stage stack.