Picking up a TTR125 as a rehap / rebuild project

[eprovenzano]

Lately I'm been rebuilding more and more bikes for myself and my friends.  I'm a 2-stroke guy, but lately I seem to be rebuilding more thumpers. I rebuilt a Honda 400EX quad and a KTM 250SXF.  Both required complete top and bottom end rebuilds, and both had valve issues. I rebuilt my buddies YZ125, and am in the process of finishing a Honda XR100.  The XR was the definition of a basket case...  The owner took it apart and had no idea how to put it back together...  It needed a new piston / rings, exhaust valve replacement, timing chain... etc.  I rebuilt it which included lapping the valves, valve seal replacement, cleaning the 10 year old gas out of the carb, and other general maint. items...  It now starts on the 1st or 2nd kick.

 

So I decided to look for another project...  I found a 07 TTR 125L that needs a lot of love...  I haven't seen the bike in person yet, (the pics show a tired bike) but I've been told the engine is sound... the rear wheel has several broken spokes, the plastic looks like chit... What makes me go hmmmm is how much abuse did this little bike receive to break the spokes...  I made a low ball offer, which after some negotiation was accepted. My plans are to 1st ensure I'm starting with a sound foundation... if its trashed I'll walk away...  Once I know the motor is sound and most of the issues are cosmetic / external, I'll strip the bike to the frame.  I'll try to replace the broken spokes, (this will be my 1st attempt at fixing / lacing up a wheel).  If I cannot fix the wheel, a used one will be sourced. I'll replace any suspect bearings, and repack all others.  It will receive new tires and I'll attempt to rescue the plastic with a lot of elbow grease.  I'll probably replace the chain and sprockets, grips, and add bark busters.

 

My son's first bike was a TTR125, and I don't recall every having an issue with the bike.  I remember it being somewhat cold blooded.  Once it was warmed up, it would start on the 1st kick.  Is there anything in particular I should be looking for, listening for???  How long before it will require a top end?  Any difficultly with the valves?   

 

Most of my rehab projects are for me done as a hobby, but for this one I'm hoping the little woman will ride the bike. If she decides not to I'll sell it, make a few $$$ and look for another project.  

Edited June 10, 2014 by eprovenzano

[KC824]

I've had an 07 125L for 3-4 years and never had any engine problems or had to rebuild the top end. I raced it in a few cross country races while my RM100 was down, too. Still in excellent shape. The carb has gotten gunked up a little.

I'd be interested in seeing your rebuild project in progress! ?

[mikedabike]

I have and 07 that I routinely beat the crap out of.  I am 6'3" and 220.  The only issue I have ever had was the starter clutch for the e-start went bad.  You are correct about being cold blooded.

[eprovenzano]

I'll most likely be picking it up this weekend...  I drilled down into the pics that I have and yea its pretty beat up, mostly cosmetic...  and I'm trying to get an answer on a few missing items.  

 

Thanks for the responses..  I thought these little bikes were pretty bullet proof, but wanted to make sure...  mikedabike I was looking over some youtube vids where someone drilled out the choke opening in the carb bowl.  He claims that it helps to start the bike easier when cold, and to allow the bike to go off of the choke within 30 sec, vs. several minutes in stock form.  He states the opening in the bowl is too small and this is why the bike is so cold blooded.  I still need to do more research before I'll buy into that one...  I'd rather just rejet.

[mx4god]

I have a '00 and '03 125L. They are very reliable if you change oil and clean the filter regularly. I swapped carbs to the vm24 on both of them. I just need to dial in the jetting on them since they came off kx65's, but they already start and run better.

[FroggerXCF]

Im in the same boat. Just got a great deal and finding some usual stuff. Heres one of the probs ive encountered.

[Fix-it]

Is that a stainless steel header on your ttr 125?

[FroggerXCF]

Is that a stainless steel header on your ttr 125?

Bike came with a FMF Powercore4 on it.

[fst96se]

I just bought an 01 TTR125L that needs front wheel bearings, and may need a fork rebuild.  Any links to what I need to do for a fork rebuild?  :0)  I may have to follow your thread closely.

[bronc3]

I have a '00 and '03 125L. They are very reliable if you change oil and clean the filter regularly. I swapped carbs to the vm24 on both of them. I just need to dial in the jetting on them since they came off kx65's, but they already start and run better.

Is that a pretty straightforward swap? We have an '04, '05L and an '08LE. They are all really cold-natured and on the lean side when warm.

[mx4god]

Is that a pretty straightforward swap? We have an '04, '05L and an '08LE. They are all really cold-natured and on the lean side when warm.

Yeah it's fairly easy if you have mechanical abilities. I think jetting is the hardest part, depending on where you get the carb. Here's an article on the swap, and there's a video on YouTube of it as well...

http://motocrosshideout.com/ttr125-mikuni-vm24-carb-swap-best-bang-for-your-buck/

[XLR8RR]

I just did the VM24 swap. Works great! Starts first kick every time now. Feels like a new bike.

Got the carb from nichecycle.com. Throttle response is waay better now.

I'm @100' above sea level, air box mod and a ProCircuit pipe are the only upgrades to this bike.

Jetted with 27.5 pilot, & 170 main. Should've done this mod years ago.

Easy install, 19/64" (perfect size) drill bit for the carb cap, and a longer fuel line is all you need.

Edited July 2, 2014 by XLR8RR

[bronc3]

Thanks, good info.

[FroggerXCF]

Yeah it's fairly easy if you have mechanical abilities. I think jetting is the hardest part, depending on where you get the carb. Here's an article on the swap, and there's a video on YouTube of it as well...http://motocrosshideout.com/ttr125-mikuni-vm24-carb-swap-best-bang-for-your-buck/

Great article. Plan on doing that after fixing my header bolt issue. Any good ideas? Read lots on this and it seems 50/50 chance of getting the header bolts out. May start to look for another head.

[F250Marine]

For those of you guys have the cold blooded issues. Pick up a 17.5 pilot jet for the stock carb. This seems to be the cure for everyone. I just put them in my 01, and 03. Now they fire right up and you can close the choke in about 10 seconds. And ride in a minute. There are a ton of threads on this and I just added a post to the ttr jetting section detailing my findings.

[redhed]

My original 125 wouldn't start when we found it chained to a tree and bought it. The man who was trying to sell it for a buddy admitted it wasn't running. My husband turned the idle mixture screw out until it started and ran good. The seller was impressed and gave us a good deal on it. I traded the bike for a 125L that the previous owner had put the 17.5 jet in  but it still wouldn't start or run worth a darn. He had the mixture screw cranked in all the way and wasn't having any luck with it at all. Once again, my husband adjusted that idle mixture screw out and now the bike starts great, even when I use the kick starter over the electric start.

 

Are they cold blooded? A bit maybe but I think you can adjust most of their stubbornness out of them if you have the patience.

 

I hope your wife bonds with the bike. I've been riding my 2nd bike for 3 years now and you couldn't pry me off it with a crowbar. Great bike for a smaller lady rider. The previous owners daughter is actually 2 inches shorter than my 5'2" and was motocrossing with it on their homemade track so the bikes can take jumps if you are so inclined. I use mine for trail riding and running errands around our farm.