Posts
55
Joined
12/24/2016
Location
Lac du Bonnet
CA
Edited Date/Time
2/23/2021 1:26pm
On Friday April 19th, 2019 I picked up a 2007 CR125. The bike is 99% original, even down to the Honda grips. The only thing I can see that has been changed is the rear tire. It has leaking fork and shock seals and the front wheel bearings need to be replaced. Ignore the messy garage.
I was originally just going to replace the bearings and get the suspension rebuilt and just rip it but that plan lasted all of about 5 minutes. I began tearing it apart Monday afternoon. On Thursday or Friday I'm going to be dropping the engine off with a local engine guy for a little case work and porting. I'm hoping to get away with running 100LL as its about 1/6th the price of C12 here.
That is where we were at as of Monday night.
I was originally just going to replace the bearings and get the suspension rebuilt and just rip it but that plan lasted all of about 5 minutes. I began tearing it apart Monday afternoon. On Thursday or Friday I'm going to be dropping the engine off with a local engine guy for a little case work and porting. I'm hoping to get away with running 100LL as its about 1/6th the price of C12 here.
That is where we were at as of Monday night.
Came out pretty good.
Current parts: PC Ti-2 shorty
2016 Oem Crf250r clamps
Lightspeed pegs
KYB PSF1 forks with only a few rides on them since new.
Current shopping list:
OEM gasket set
Wiseco Racer Elite Piston (unless someone has a better option)
VForce reeds
PC works pipe
2018 Stadium plate, fender, and fork guards
I haven’t decided between a Lectron or a PWK AS.
Trying to find a nice OEM wheelset off a new CRF with brake rotors.
Yamaha Ti springs fit the cr shock so I’m going to see if I can find one that is my spring rate.
Over the winter I’m going to pick up a set of triple clamps. I’m hoping Luxon releases clamps for Hondas by then because they are so trick.
The Shop
I’ll be dropping the engine off after work tomorrow. I’m getting pretty excited to ride this thing.
Yes, the Wiseco Racer Elite piston is a great choice. I have one in my '05 with about 15 hours. DO drill the holes for the exhaust bridge cooling per the instructions.
Lectron? Hell yes. I have both the 34mm and 36mm HV. They now recommend the 36mm HV. I've run both on the '05... The 36mm pulls a tiny bit more on the low end, but mid-top they are about the same. I run 50/50 87 E0/LL100, which is about 96 octane (R+M/2) mixed with Maxima K2 at 32:1. You'll be fine-ola running straight 100LL. Just let Lectron know you will run 100LL when you order.
The choke knob location on the Lectron will drive you nuts, but it is worth the pain.
NOW THE BIG THING - You WILL need a custom Motion Pro throttle cable, unless Lectron has magically sorted this out since last year.. I learned the hard way, so I did proper measurements and my design is perfect. No binding, crazy bends, and easily routed OEM style with proper slack. Here is my exact customized cable in Motion Pro terms:
THROTTLE: 07-1366 HL +7" **ELIMINATE INLINE ADJUSTER**
Also, look into an "MX Bonz" (look on Ebay) air box kit to prevent sucking in crap to your CR125. Trust me on this one. The stock air box sealing arrangement is pathetic
My '07 build is languishing somewhere here on Vital... I just may resurrect it.
I am merely offering information based on my experience.
Keep up the good work! These are a F-ING blast to ride!
EDIT: And YES to OEM gaskets unless you mod... Cometic outer case gaskets were too thin. Finished a full engine rebuild, filled with oil, turned engine upside down and it leaked in the seam area around the fill plug. You'll see that the OEM case inner/outer gaskets have rubber applied to strategic areas on them...
Thanks for the dimensions for the throttle cable, I’ll definitely order one when I pick up a Lectron.
I ended up getting a new OEM air box seal just to be sure. I’ll probably end up getting the mxbonz in the future.
I accidentally forgot gaskets in my last parts order... drove down to the states to pick up my parcel and realized when I got home that something was missing. Not my brightest moment. So once those come in I can drop them off and have the engine finished.
You definitely should revive your build thread, the more the better!
If there was only one thing I could could do to an 05' - 07' Honda CR125, it would be:
The MX Bonz air box mod using "3M BLACK SUPER WEATHERSTRIP AND GASKET ADHESIVE" on the underside of the plastic/rubber beneath both the inner and outer aluminum securing plates. Seal sandwich. Tough stuff. Semi-flexible, and highly fuel/oil resistant. No, NO, NO to silicone based sealants...This stuff holds VW rear view mirror mounting plates to glass. Practice with it first.
Sorry for the "ALL CAPS" but that is what the 3M product label says verbatim.
The stock Honda arrangement is a floppy joke. The outer OEM seal under the thin stamped steel sealing ring is a wispy bit of white foam crap. The stupid "nubbies" inside the air box (used as anchoring points for the outer ring securing screws) actually prevent a good filter seal. Why get your motor rebuilt and subject it to that?
Here are a couple pics of a new OEM air box/boot I have as a spare with an MX Bonz kit installed. The benefit is obvious.
I'd never kick one over without it.
I
Picked up a 4.7 and a 4.9 rear Ti spring from a member on here. I’ll be running 4.9 for now but hopefully I can slim my way down to the 4.7.
Got my engine back from the builder. Should rip pretty good. Set up for 100LL. Only problem is i have it to him assembled and I got it back assembled so I didn’t have a chance to vapor hone it. I also don’t feel like splitting the cases and removing the bearings just to clean it up so vapor honing will have to wait until the winter.
Got the light speed pegs mounted on 2016 CRF mounts. I’ll definitely have to sharpen these up a bit.
It’s slowly coming together. Got a few more things to button up before I can take it out.
BRAKES
-Front and rear rotors from a newer CRF
-Front brake Assy from a newer CRF(M/C, brake line, caliper, and hanger)
SUSPENSION
-I’ve thought about sending it away to get valved but living where I live it’s not really ideal. If I’m not happy with it or I want some small changes I have to send it back and that’s approx 200$ in shipping and I’m out my suspension for 10 days. There is one local guy (80 miles away) who I may look into getting it done by.
-My other option is to buy a ton of shock and fork oil and spend some time on the Thumpertalk forums. For the cost of my last revalve I could build myself a nice suspension table with a sink, vice, nitrogen set up and a bunch of supplies. This is the route I’m thinking of going.
WHEELS/TIRES
-Going to go for as light of a set up as I can.
-Fat bike tubes.
-Got myself a set of motion pro lightweight rimlocks.
-probably going to run Hoosiers (I’ve messaged them asking if they will be coming out with a 100 rear tire but i didn’t receive an answer). Or I may just end up running Pirelli MX32 MidSofts which is what I’ve been running on my 250f.
CARB
-still leaning towards a Lectron just gotta bite the bullet and order one.
My last 38mm HV Carb is serial # 1433F4. Dave & crew will share the base settings. Buy that puppy if in good condition and priced right with correct air boot cut./fitment for Honda 2007 CR125. 3-2 is what I run.
Nail them on #1433F4. 50/50 E087/100LL, 32:1 . They WILL help you out. If not, I'll pull and measure for you this weekend. Made a few slight adjustments, but also can likely find OG paperwork. Best you make friends with them.
To be certain I am not losing my mind...
https://www.vitalmx.com/forums/Moto-Related,20/Lectron-Carb-YZ250-2-str…
"I also got another Lectron for my 07' CR125 build (HV 38mm), but got a lot of work to do to finish it. Lectron is recommending the HV 38mm for CR/YZ 125's now for improved bottom and all-around better performance."
It’s good to know that the 3-2 that comes with this one is the right rod, or at least close enough to test with.
Thanks for the help man! I really appreciate it.
EDIT Lectron just got back to me suggesting a 5-1 metering rod. They said the dimensions of the carb should be the same. I’m going to message the guy to see if I can pick it up tonight after work. I’ll measure the intake bell and engine side, just to verify.
Pit Row
Great that Lectron got back to you so quickly! They are good folks.
Definitely roll with what Lectron tells you ... They do seem to update based on their testing. Does the carb you are pursuing come with the adjuster tool? If not, pick one up when you order the new metering rod. Just make it easier. Also advise to get a couple-three spare slide cover gaskets.
It'll be a tight fit. Be patient fitting it. I also find it easier to remove the seat, fuel tank, and cylinder head stays when adjusting the rod. Pain in the ass. Thankfully all I had to do was lean 1/4 turn on both and been GTG..
Yeah, best going new on a sweet CR like yours. Get what you WANT.
Guess you'll be ordering the full kit with cable, right?
Let me know how the Lectron supplied cable works out. I was not happy. I hope they have it well sorted by now..
If you aren't thrilled with the Lectron supplied cable, I have 3 of my custom made units in hand as spares. I can send you one to try. That will save you waiting 2-4 weeks at Motion Pro and get you riding before snow hits, LOL!. If you like it, you can have it for cost. You seem an honest chap.
I got a chance to clean up a few more parts in my small vapor hone. They came out pretty good.
It sounds pretty crisp on the stand so I’m pretty excited to take it out and get some laps in.
I’ll be picking up new chain and sprockets after I get some time on it. I’d hate to buy new and then decide I don’t like the gearing.
I have a bit of a plan for this winter.
-I’ll go through the engine and clean it up inside and out (clean up all imperfections and casting flaws), vapor hone. I’m going to pick up a few pistons and do the Cerakote low friction coating on the piston skirts and use their piston coat on the piston tops and the head.
-For the wheel set I’m going to clean up the stock hubs and maybe cerakote them. Still haven’t decided on rims. More than likely black, but I have a thing for gold rims on Honda’s so that’s a possibility.
I’m currently running the stock Honda tubes which are fairly light but I may switch to MTB tubes to shave a bit more weight.
-For suspension that’s going to be completely dependent on how the first few rides go. I’m going to be getting a nitrogen set up so I will for sure do my own rebuilds over the winter. Might try and mess around with valving myself aswell.
-Still looking for a used Motostuff front rotor or even a OEM crf 260mm. As well as a CRF rear rotor.
-I’ll clean up the chassis a bit more too. In particular I want to strip the ano off the swing arm.
-Now wiring is something I’ve always wanted to try my hand at. I will probably order a harness off EBay and chop it up for the connectors and keep the stock one intact. I don’t like the cheap plastic covering and electrical tape that the OEMs use. I’ll also be able to completely remove the TPS portion of the harness as I don’t need it with the Lectron. If it goes well I will probably give it a go on my Yz250f.
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Post a reply to: '07 CR125 From up North. First stage done!