Posts
137
Joined
8/20/2021
Location
Okeechobee, FL
US
Edited Date/Time
7/24/2022 9:40am
Hey guys figured I'd post up a thread on rebuilding my 07' rm125, just recently got the bike and thought it had a motor failure but ended up being something bouncing around off the flywheel. Oh well, good excuse to build it lol. Will preface this by saying I'm 15 years old and am learning along the way. This is my first bike, used to ride quads but that was 6+ years ago. Only had 4 rides on it before tearing into it, was just riding flat ground at my family's land getting used to it all. The bike ripped, I'm sure that's partially cause I weigh 112 pounds so the bike barley even notices me. 
Here's what she looked like before ripping into it. Please ignore the mess, we are about to start moving so its quite messy around. The bike is entirely labeled though, so no worries there about mess.
Here's the stage the bike is currently at, frame is getting re powder coated.
biggest issue so far has been this kick starter, got the bolt off but it will not slide off under any amount of pressure. luckily got off the inner clutch cover without removing the kick starter. Though I'm not too sure how it'll go back on without removing the kick starter It moves in and out a very small amount but will not come off. Any tips or ideas would be greatly apricated.
Here's what the fly wheel looked like after the metal object was in there for a bit, should be runnable? Any insight from a more knowledgeable person would be greatly apricated here. Not quite sure what the metal thing even was, looked like a mangled piece of sheet metal. checked many times and nothing was missing in the ignition area. The weirdest part is it didn't cause any issues till 19 hours and a year and a half after the motor was built. Previous owner had the motor rebuilt in 2019. After tearing into it, looks to be around that hour mark. The head had some detonation damage and I am done dealing with the straight ass pump gas that south FL has to offer, so the motor got sent out to Tom Morgan to get ported, along with getting the head recut for vp c12, and some carb work. The bottom end feels in good condition, so my dad wants to leave it together. We already have a new balanced crank along with all seals and bearings to do the bottom end, but my dad doesn't wanna go though the hassle of a motor build. I'm torn on tearing into it or not, as it feels healthy but we already have everything. Any opinions here would be apricated
Here's what the stator looked like after dealing with that foreign object bouncing around inside. It was covered in metal shavings but after a ton of electro cleaner it looks to be in fine shape.
The wiring harness is in rough shape and has clearly been re wrapped at some point by someone who doesn't understand how heat shrink works and loves electrical tape. So my dad will be helping me re heat shrink the entire wiring harness while its out. Have some graphics that I designed in motocal so far but am not 100% sure on the exact design. I will say its keeping the 2012 gen rmz front end, and the rad shrouds are inspired by the TP look. Will also be getting a full wheelset from fasterUSA as my current wheels have quite a few seized spokes. The current wheels will be rebuilt at a later date as spares. Thinking about yellow hoops with the "burnt magnesium" hub color. For right now the suspension is being left how it is, it was valued by the previous owner for a 160 pound rider. So its definitely stiff for me but remembering when I rode friends bikes years ago. I much preferred super stiff suspension. We'll see if I keep thinking that way after casing a few jumps, my wrists may want softer suspension lol.
Here's what she looked like before ripping into it. Please ignore the mess, we are about to start moving so its quite messy around. The bike is entirely labeled though, so no worries there about mess.
Here's the stage the bike is currently at, frame is getting re powder coated.
biggest issue so far has been this kick starter, got the bolt off but it will not slide off under any amount of pressure. luckily got off the inner clutch cover without removing the kick starter. Though I'm not too sure how it'll go back on without removing the kick starter It moves in and out a very small amount but will not come off. Any tips or ideas would be greatly apricated.
Here's what the fly wheel looked like after the metal object was in there for a bit, should be runnable? Any insight from a more knowledgeable person would be greatly apricated here. Not quite sure what the metal thing even was, looked like a mangled piece of sheet metal. checked many times and nothing was missing in the ignition area. The weirdest part is it didn't cause any issues till 19 hours and a year and a half after the motor was built. Previous owner had the motor rebuilt in 2019. After tearing into it, looks to be around that hour mark. The head had some detonation damage and I am done dealing with the straight ass pump gas that south FL has to offer, so the motor got sent out to Tom Morgan to get ported, along with getting the head recut for vp c12, and some carb work. The bottom end feels in good condition, so my dad wants to leave it together. We already have a new balanced crank along with all seals and bearings to do the bottom end, but my dad doesn't wanna go though the hassle of a motor build. I'm torn on tearing into it or not, as it feels healthy but we already have everything. Any opinions here would be apricated
Here's what the stator looked like after dealing with that foreign object bouncing around inside. It was covered in metal shavings but after a ton of electro cleaner it looks to be in fine shape.
The wiring harness is in rough shape and has clearly been re wrapped at some point by someone who doesn't understand how heat shrink works and loves electrical tape. So my dad will be helping me re heat shrink the entire wiring harness while its out. Have some graphics that I designed in motocal so far but am not 100% sure on the exact design. I will say its keeping the 2012 gen rmz front end, and the rad shrouds are inspired by the TP look. Will also be getting a full wheelset from fasterUSA as my current wheels have quite a few seized spokes. The current wheels will be rebuilt at a later date as spares. Thinking about yellow hoops with the "burnt magnesium" hub color. For right now the suspension is being left how it is, it was valued by the previous owner for a 160 pound rider. So its definitely stiff for me but remembering when I rode friends bikes years ago. I much preferred super stiff suspension. We'll see if I keep thinking that way after casing a few jumps, my wrists may want softer suspension lol.
For what its worth here's what was bouncing around in the fly wheel/ignition area. Looks like the bent sheet metal piece that holds on the clutch cable. Checked everything 20X comparing parts to the parts diagram for OEM parts and nothing was missing in there. So it was left in there from the motor build. Stupid thing almost made me crash, I found out it was there when the bike acted like I dumped the clutch while trying to turn around. I was partial throttle slipping the clutch while turning around and suddenly it jumped forward. I was quite unprepared and almost came off, luckily it stalled before that happened. I had thought a crank bearing failed due to the sound it made. So did all my friends, though I was very confused by why it did the weird thing with the clutch
If the bike ran well I wouldn't worry to much about the flywheel and stator.
You should think seriously about putting some money into the suspension. You will be much more confident with a set up for your weight and abilities.
The Shop
for the flywheel, the pickup is what matters. show a pic of the pickup on the flywheel
the kick starter pivot is steel, and the shaft is also steel. So its steel on steel contact, I'd be super worried trying to press it out. May just leave it instead. Cutting it off would be sketchy, luckily its a 2007 so still a lot of new OEM parts are available. Because of that I am stock piling OEM parts, as its going to be my main seat time bike and get a few hundred hours a year. It would be super expensive to cut off and replace, would rather take it to a machine shop and see if they have any ideas.
I also decided to pull off the petcock and check how dirty it is, I quickly remembered why I hate pump gas and why I'm going to race gas lol. Will be cleaning that really well
Pit Row
i feel like you could get this thing running without detonation if you just got it rebuilt properly and jetted it. you could prob get away with mixing 50/50 pump gas and c12
on all my 125's ive been able to overcome bad suspension or chassis with less work than a motor thats too slow.
good handling doesnt mean shit when your in last place casing everything
Got a bit of carbon in, just because is it really a build without at least some carbon? Still figuring out what suspension company to go though, it’s a pain to find a company I like that’ll type 3 ano my uppers
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