Cr125 Build - Other Cars Forum

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Cr125 Build
Friday, June 08, 2012 11:38 AM
I'm bored to tears at work, so I figured I'd make a mini build thread about my Cr125 for something to do.

Bike is a 02' Cr125R, bought it 2 months ago and it looked like this...



Some new plastics, graphics and a seat cover later...it looked like this...



Hated the stock clutch lever, so I ordered one from Righteous Stunt Metal, this thing is awesome...



Then the bottom end blew, big end connecting rod bearing...so now it looks like this






I have on order:

- Hot Rods Crank Kit
-Wiesco Top End Kit
-FMF Fatty Expansion Pipe (mine was @!#$ when I bought the bike)
-05' CR125 Intake tube (helps with the top end power)
-A bunch of miscellaneous @!#$ that was broken or worn out after I tore it apart.

Might do the power valve mod as well to help out the non-existent bottom end power of the Honda 125.


Anyways, parts should be in early next week, gonna give the bike a good cleaning and then put it all back together.

Hmmm...I was hoping it would of taken longer to create this thread, now I'm still bored....dammit! LOL






Re: Cr125 Build
Friday, June 08, 2012 12:24 PM
I dig all things on 2 wheels.

Especially some hondas



Re: Cr125 Build
Friday, June 08, 2012 1:11 PM
Hahaha I wish I would of known that the Honda 125's where the slowest 125's in the early 2000's but oh well.

Its my first bike, so it was a good starter....although I have already outgrown it, it will be good for the rest of the season.





Re: Cr125 Build
Friday, June 08, 2012 5:08 PM
the 2001 250 was the best 250 2 stroke.

Swap that in and call it done

When i put a cr500af motor into my cr250r i have a motor for you



Re: Cr125 Build
Friday, June 08, 2012 5:35 PM
Riding the 125 will make you a much better rider in the end. Hopping on a 250 sure you'll get up the hill or whatever but learn to push the 125 and you'll be killing it on the 250 in no time.

Whatever you do don't get a 03(iirc) and up 250 cr.......read alot of bad about when Honda tried to re invent the 2 stroke lol.
Re: Cr125 Build
Saturday, June 09, 2012 7:07 PM
agreed.

I had to give it some power.

The power band is kinda weak. I put reeds, a spacer, procircuit pipe, and a pwk air striker. Still slow.


the cr125 with some upgrades is probably the best woods bike for a smaller rider



Re: Cr125 Build
Saturday, June 09, 2012 7:45 PM
Could always make it a 144... Eric Gorr









Re: Cr125 Build
Saturday, June 09, 2012 8:00 PM
jfire wrote:

agreed.

I had to give it some power.

The power band is kinda weak. I put reeds, a spacer, procircuit pipe, and a pwk air striker. Still slow.


the cr125 with some upgrades is probably the best woods bike for a smaller rider


Add a flywheel weight as well to that list to improve traction.
Re: Cr125 Build
Monday, June 11, 2012 11:24 AM
Ya I hear you on the better rider part, I hopped on my buddies CRF450 and after riding my bike in the sand pits all day, his bike seemed way easier to ride...the power is just insane, it turned the mountains I was trying to get my 125 up into mole hills....LOL

If I do upgrade next year it will be for a 450F of some sort. Nice thing is, they seem to go for less than 250's used, as I think they are in much less demand.


That 144 conversion is very interesting as well tho, I might have to look into that.

Just got a call all my parts are in





Re: Cr125 Build
Thursday, June 14, 2012 7:38 AM
Well all my parts are in, no pictures of that yet tho.

Finally got the stupid swing arm bolt out (it was seized in there solid) so I was able to pull off the rear swing arm and pull the motor out.

Motor is off to get the bottom end rebuilt, I was gonna tackle this myself but didn't have a case splitter nor a crank puller. It worked out to only an extra $100 to have it professionally done over what it would of cost me to buy all the tools....so screw it.

Here is were I am now...



Still need to pull the front forks off to get the seals changed out (seals should be in by the end of the week, hopefully).

Also got my new upper and lower shock bearings done last night, and started working on the top end, pulled the power valve assembly out for a good clean up.

Its getting there...slowly....lol





Re: Cr125 Build
Friday, June 15, 2012 12:59 PM
Just picked up my bottom end, gonna put the rest of the motor together tonight, and re-assemble the bike tomorrow.

With any luck, and provided I haven't lost and bolts or break anything, it should fire up tomorrow or Sunday and I can start breaking the engine in.


Btw, 2-stroke engine break in tips?

Guy that rebuilt the motor recommended that I start it, let it get to full temp, take it out for a 5min ride (only 2/3 throttle at the most), bring it back and let it cool completely down.

Repeat 2 more times adding like 5mins each time to the ride.

Then don't beat the piss out of it for the first 10hrs or so.


I'm gonna go ahead with that.....he seems to know what he is doing....LOL

Pictures will be posted....as no one cares what I'm writing and just wants to look at pictures....hahahahaha





Re: Cr125 Build
Friday, June 15, 2012 2:23 PM
This comes to mind.

http://www.mototuneusa.com/break_in_secrets.htm


- Your not-so-local, untrained, uncertified, backyard mechanic. But my @!#$ runs
Re: Cr125 Build
Saturday, June 16, 2012 4:51 PM
/\ good stuff that's my break-in technique

Funny thing. I'm in the same boat as you. Spun a rod bearing and put a nasty hole in the piston on my cr250r today.

Looks like it's the weisco kit for me



Re: Cr125 Build
Monday, June 18, 2012 8:44 AM
Hahaha what are the odds! At least top ends are cheap!

Bit more of an update here,

Got the top end put back on the bottom end Friday night.



Unfortunately my buddy was cleaning my carb up for me and managed to fumble the throttle plate and it landed needle first on the ground, needless to say it bent and so far the earliest I can get one is 2.5 weeks.

I'm on the hunt at lunch today for someone who can get it earlier.

So spent the day on saturday anyways putting the bike back together and now I'm here.



Just need that needle and then she will be good to go.





Re: Cr125 Build
Tuesday, June 19, 2012 10:43 AM
Well managed to find a needle and it will be here on Thursday.

Got a bit bored last night and with the bike just sitting there and me all horny to get it running I decided to repair the best I could the needle and toss it together.


Fired it up and runs like a boss, let it get fully warmed up and took it out for a break in ride, it however unfortunately runs a bit crappy....lots of hesitation.....noticeably more powerful tho despite running like a bag.

Pulled the plug and it was a ting white...so its running a bit lean, hoping this has something to do with the needle still being the slightest bit bent.


FMF suggests I run a 390 main jet and a 32.5 slow jet.

Currently running the bikes stock 400 main jet and 32.5 slow jet.....so I don't imagine it is a jetting issue.

Mixing a 40:1.

Thoughts?

Also, forgive me here for being a bit of a noob on carb tuning, but if I drop the clip on the needle a notch this make the needle sit higher and will allow more fuel in from the main jet correct?







Re: Cr125 Build
Wednesday, July 04, 2012 11:53 AM
Carb needle is finally in!!!!!!!!, picking it up tonight on my way to the gun range.

Toss it in the bike tonight and hopefully it runs better than it did with the bent one.


So freaking pumped that I can ride this thing again





Re: Cr125 Build
Wednesday, July 04, 2012 7:12 PM
newt wrote:


Mixing a 40:1.

Thoughts?

Also, forgive me here for being a bit of a noob on carb tuning, but if I drop the clip on the needle a notch this make the needle sit higher and will allow more fuel in from the main jet correct?

32:1 with honda synthetic race oil ONLY it will pamper your glass top end and keep it tip top little smokey but it's the best ratio for these hondas

Yes, the carb needle moved up will allow more gas in at any given position of the throttle. However it focuses on the function of 1/4-full throttle position





Re: Cr125 Build
Thursday, July 05, 2012 8:05 AM
I haven't heard of people having issues with the Honda 125 top ends, from what I've read they are pretty solid, seems most everyone runs 40:1. Only problem I've read about seem to be from people forgetting about the oiling holes in the piston for the exhaust bridge.

I've been mixing with Amsoil Synthetic, well and I used one bottle of Ipone since I was out of oil once and my buddy had some spare.

Then again, you seem to know what you are talking about, so maybe I'll trust ya..haha


Bike runs great now with the new needle, a bit of a lower RPM bog it would seem, I'll try tightening the air screw and see if I can lean it out a bit.

It sounds wicked with the FMF pipe and my custom shorty silencer.





Re: Cr125 Build
Tuesday, July 10, 2012 10:21 AM
Well she is all done, running great.

Having some plug fouling issues, but I seemed to get that straightened out now.

Last few pics of it all done.









Re: Cr125 Build
Tuesday, July 10, 2012 12:19 PM
I like this thread. Bike looks good!



Re: Cr125 Build
Tuesday, July 10, 2012 1:35 PM
Thanks man!

Looks much better than when I bought it lol

The FMF pipe made a noticeable difference, picked up alot of mid-range and much less lag before the bike gets on the pipe, great for the really tight trails where staying on the pipe is harder.

Need a new back tire since its pretty slippery now in the back end since it hits harder on the pipe.

I was thinking of selling it and grabing a 250F, but I might just keep it now and do that 144 big bore kit over the winter.






Re: Cr125 Build
Wednesday, July 11, 2012 7:08 AM
Hell, sell it to me and buy a 250 haha



Re: Cr125 Build
Wednesday, July 11, 2012 11:58 AM
hahaha

Unless you want a bike for tight woods trails, a 125cc will disappoint you, and even then there is a lot to be said about the low end snap of a 4-stroke for getting out of the corners.

I wanted a 125 since it was my first bike, but out grew it within the first few rides. It still scares me from time to time, but in all those cases I was doing something incredibly stupid...LOL


If it hadn't been for all the money I've put into it, it would for sure have a for sale sign next spring....but since I'll take a huge loss on what I put into it, I might as well keep it and get some enjoyment for my money.





Re: Cr125 Build
Wednesday, July 11, 2012 11:59 AM
Also, I'm going to try and borrow my buddies gopro and get some vids up of some of the sweet woods riding around where I live

Everyone loves videos.





Re: Cr125 Build
Wednesday, July 11, 2012 12:14 PM
I got quite a few vids of the honda down the trails, Tons of tight twisty trails by me. I have owned plenty other bikes in the past, My first bike was a '79 suzuki RM80. Nasty, nasty bike for an 11 year old and unpredictable as hell when you are only 90something lbs I'm most comfortable on 2 stroke 125's. I love 250's but its too much for the type of riding I do

I eagerly await more videos, I love these things



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