RM125 RM125 motors interchangeable?

C

cb750mike

i have a 98 and I can’t find anything. My motor needs crank and connecting rod bearings so I figured I would just get a new crankshaft but I can only find ones for 2001 or newer. Any idea if the 2001 crank will work in my 98? Or a whole 2001 motor will bolt up to my 98 frame?
 
Trfsrfr

Trfsrfr

Crank bearings in stock at RMATV;
BEARING (22X56X16) 09262-22025 $41.32
Big rod end bearing in stock at RMATV;
BEARING (22X28X16) 09263-22060 $46.17
Small rod end bearing in stock at RMATV;
BEARING, PISTON PIN 09263-15040 $12.00
 
Mihylo33

Mihylo33

cb750mike:
i have a 98 and I can’t find anything. My motor needs crank and connecting rod bearings so I figured I would just get a new crankshaft but I can only find ones for 2001 or newer. Any idea if the 2001 crank will work in my 98? Or a whole 2001 motor will bolt up to my 98 frame?
Click to expand...


No. You need to have the crank rebuilt or buy a new oem. There’s nothing wrong with the oem cranks so just have it rebuilt and balanced.
 
O

ossagp

Aligning them is something about any machine shop or bike shop can do. Actual BALANCING where metal is added or taken away to achieve reduced vibration in a given rev range etc is something that a few are better known for than others, such as Falicon and Phil's Crankworks. Lots of people and shops refer to alignment as "balance" because if it is out of alignment it will sure be out of balance.
 
C

cb750mike

Another thing I just measured the distance of my connecting rod side to side play and it measures .017. Is that too much? Thinking I may need to just replace the crank shaft seals and top end and I should be good until next top end rebuild am I right?
 
Mihylo33

Mihylo33

cb750mike:
Another thing I just measured the distance of my connecting rod side to side play and it measures .017. Is that too much? Thinking I may need to just replace the crank shaft seals and top end and I should be good until next top end rebuild am I right?
Click to expand...


Do you own a service manual?
 
C

cb750mike

Mihylo33:
Do you own a service manual?
Click to expand...
Not yet. I just got the bike a week ago. Honestly not sure how long I’m gonna keep the 125. I like my 4 strokes lol my last bike before my bad accident a year and a half ago was a 2006 kx450f. Does that sound like an acceptable amount of play side to side on the crankshaft pin? I see the assembled crankshafts all note they are as close as possible to .01 gap.
 
Mihylo33

Mihylo33

cb750mike:
Not yet. I just got the bike a week ago. Honestly not sure how long I’m gonna keep the 125. I like my 4 strokes lol my last bike before my bad accident a year and a half ago was a 2006 kx450f. Does that sound like an acceptable amount of play side to side on the crankshaft pin? I see the assembled crankshafts all note they are as close as possible to .01 gap.
Click to expand...

I honestly don’t know if that’s good.
I recommend a 125 to every MX guy I know that wants to improve their corners and their speed. 125’s are deadly on a track if you know how to carry speed. That knowledge will carry over to 250’s and 450’s
 
C

cb750mike

Mihylo33:
I honestly don’t know if that’s good.
I recommend a 125 to every MX guy I know that wants to improve their corners and their speed. 125’s are deadly on a track if you know how to carry speed. That knowledge will carry over to 250’s and 450’s
Click to expand...
That’s definitely something to think about. I’m sure I’ll have it for a while to get back into my groove because my last accident left a dent in my confidence and fearlessness. I get anxiety about jumping again lol but I want to get over that and get back out on the dirt. I looked over the motor today and everything looks brand new. Clutch plates, seals, and it’s dry on the stator side. So I’m thinking about just getting a top end kit for it and boring out the cylinder and going out to ride. Anyone recommend running on vp race fuel or just sticking to a gas/oil mix? If you recommend the race fuel what jetting was good for you?
 
C

cb750mike

Also what oil do you guys recommend for the premix and crankcase? The oil I took out of the motor had a sweet smell to it. Never smelt that before from an oil.
 
Top