Author Topic: CB125s "Big Blue" is UN-DONE! (Read 57386 times)

RAFster122s · « **Reply #200 on:** May 21, 2013, 06:45:34 PM »

Why not just pick up a 175, came stock with close to 20bhp out of the motor if I recall correctly. That should be enough to satisfy your need for power on a small nimble bike. If not, buy a bigger bike.

grcamna2 · « **Reply #201 on:** May 22, 2013, 09:23:52 AM »

Quote from: Flying J aka ffJMoore on May 21, 2013, 04:58:02 PM

Bought it on eBay. 3mm only. It's old stock.

ffJ,
I did see one on there not too long ago & didn't notice whether it came w/ rings as a kit or not.Do you think there may be other companies besides what used to be Powroll(I bought a 135cc piston kit from them once..,miss'em...)that will sell an overbopre piston kit ? I was reading on a café racers forum that folks have used a std. o.e. CB750 piston(& sleeve I think..)in the past w/ some machining work required.I believe they said that raised the engine up to between 145-150cc & one member said that many felt that 145-150cc was the sweet spot. Please give me your thoughts on that.
Bill

ffJ, I'm finished w/ my questions & didn't mean to try to hijack your thread,sorry.

grcamna2 · « **Reply #202 on:** May 22, 2013, 09:30:26 AM »

Quote from: RAFster122S on May 21, 2013, 06:45:34 PM

Why not just pick up a 175, came stock with close to 20bhp out of the motor if I recall correctly. That should be enough to satisfy your need for power on a small nimble bike. If not, buy a bigger bike.

David,
Do you mean the CB175 ? or an engine swap "from" an XL 175 single into the CB125S ? I was considering an engine swap into my CB125S from an XL185S...,only the XL is a more mid-range torque dirt bike engine w/ limited top end w/ it's longer stroke crank/rod.I think if I was to go over square(bigger bore than stroke) & do the bigger bore on the stock CB125S single engine it'd be enough;it's a 200lb bike & well able to respond to more power.
In this venture I'd like to keep the rest of the bike as stock "looking" as possible.

Flying J · « **Reply #203 on:** May 22, 2013, 10:55:07 AM »

No worries onthe highjack. I sold the bike. As for pistons, the 750 piston needs to be re-sleeved. Now the cb550 piston i the same diameter as the big bore i bought and almost the same height, it was a hair shorter i believe. I think with some measuring you could shave down the cylinder or deck the head to make up for the loss and be good. That i what i plan on doing if i build another 125. I have a XL125 frame to start with and most of a motor.
Here is the kit i used.
http://www.ebay.com/itm/NOS-New-Honda-Piston-59mm-SL125-Big-Bore-3mm-Oversize-Kit-/190840376700?pt=Motorcycles_Parts_Accessories&hash=item2c6ef90d7c&vxp=mtr

the advantage of using the 550 piston would be that it has a 3 piece oil ring where the 125 pistons only have a 1 piece

grcamna2 · « **Reply #204 on:** May 22, 2013, 11:13:32 AM »

Quote from: Flying J aka ffJMoore on May 22, 2013, 10:55:07 AM

No worries onthe highjack. I sold the bike. As for pistons, the 750 piston needs to be re-sleeved. Now the cb550 piston i the same diameter as the big bore i bought and almost the same height, it was a hair shorter i believe. I think with some measuring you could shave down the cylinder or deck the head to make up for the loss and be good. That i what i plan on doing if i build another 125. I have a XL125 frame to start with and most of a motor.
Here is the kit i used.
http://www.ebay.com/itm/NOS-New-Honda-Piston-59mm-SL125-Big-Bore-3mm-Oversize-Kit-/190840376700?pt=Motorcycles_Parts_Accessories&hash=item2c6ef90d7c&vxp=mtr

the advantage of using the 550 piston would be that it has a 3 piece oil ring where the 125 pistons only have a 1 piece

Maybe it would be possible for me to purchase a High Performance "type"(higher compression to maybe 10:1..?) CB550 piston(I Like the 3 piece oil ring

rather than deal w/ the machining work required to re-sleeve & possibly have to change the circumference of the squish area of the stock CB125 cyl. head if I was to use a CB750 stock piston.I imagine it'd be kind of trial & error to get the compression ratio to optimum(around 10:1)using the CB750 piston/sleeve system...

RAFster122s · « **Reply #205 on:** May 22, 2013, 04:28:03 PM »

The cb125 has a problematic mechanical caliper so, I was recommending the cb175 as a better solution with classic looks like the cb125.

Flying J · « **Reply #206 on:** May 22, 2013, 08:38:31 PM »

Yeah that caliper is crap. I swap them out for a funtional drum. My next one im pretty sure will either be a fork swap or modified setup to run a hydraulic caliper.

yangb554 · « **Reply #207 on:** March 20, 2014, 08:27:49 AM »

Hi! New here, just got a CB 125 and I'm looking to get a rear rack for it. Wondering if anyone here has one. Also looking for advice on 6V to 12V conversion.

Flying J · « **Reply #208 on:** March 21, 2014, 10:24:34 PM »

This place sells them for trail 70. Not sure if it will fit a 125

http://www.hondaminitrail.com/ct70.html

As for the 12v conversion I dont recomend it. Its a huge pain for almost no gain. If you do it you need a cb350 twin stator. And one of these.
http://www.ebay.com/itm/TRIUMPH-BSA-NORTON-NEW-TYMPANIUM-REGULATOR-RECTIFIER-BEST-PRICE-PN-TBS-4034-/351026124703?pt=Motorcycles_Parts_Accessories&hash=item51bac9979f&vxp=mtr

Good luck finding a 12v headlight to fit the 125 housing. I think i used one from a cb160. Was not a direct fit but it went in there. Also change out the blinkers and everry light in the speedo. Oh and buy a 12v coil or wire resistors inline or you will burn throgh your points much faster.

That is what mine had when i sold it and it ran and charged good. Prior to that i had used a separate rectifier and an old cb350 regulator and it never would charge well.

grcamna2 · « **Reply #209 on:** March 22, 2014, 09:52:28 AM »

Did "Big Blue" go to a Caring new owner ?

Flying J · « **Reply #210 on:** March 22, 2014, 03:40:22 PM »

No. Guy was a douche Bag and tried to stiff me $100 after i drove 4 hours to bring him the bike. Then wrote me a check for the last $100, that bounced. I got creative and he ended up paying the $100 plus the cost of my creativity. My other ideas were less creative but basically ended with the bike being destroyed,

grcamna2 · « **Reply #211 on:** March 22, 2014, 04:13:08 PM »

You still own it ?

Flying J · « **Reply #212 on:** March 23, 2014, 09:49:21 AM »

no Its gone.

grcamna2 · « **Reply #213 on:** March 23, 2014, 09:52:47 AM »

Did you sell it w/ all the improvements that you've installed during this complete thread ? if so,I hope the new owner Really appreciated that.

Flying J · « **Reply #214 on:** March 24, 2014, 05:52:14 PM »

Yes. I sold it. And no, i doubt the kid appreciated it. He was a douche bag as stated above. But thats the way it goes sometimes.

grcamna2 · « **Reply #215 on:** March 24, 2014, 06:14:12 PM »

'I' appreciate it.

Thank You very much for this thread.

FuZZie · « **Reply #216 on:** March 24, 2014, 07:52:44 PM »

That was some nice weaving and bobbing Flying J!

FillionJ · « **Reply #217 on:** August 25, 2014, 07:52:15 AM »

Quote from: Flying J on May 17, 2011, 10:29:34 AM

IT RUNS!! swaped out the coil and condenser from my parts bike and put in a new spark plug. Adjusted the cam chain now i need to do the vales and put a tube in the back tire and take it for a spin. Maybe today, we shall see how much time i have.

@Greggo, I do have plans for this one but i have to try and balance time and money between it and the 550. So stay tuned.

Hey flying J, i noticed u mention a parts bike for your cb 125, I'm desperately trying to find a bottom right hand control housing for my 77 cb 125s any chance u can help me ?

Sent from my iPhone using Tapatalk

Flying J · « **Reply #218 on:** August 25, 2014, 08:58:15 AM »

I think I know what your talking about but a picture is worth a thousand words.

grcamna2 · « **Reply #219 on:** August 25, 2014, 11:48:07 AM »

Flying J,
I'm going to be installing(after a bunch of research & custom parts mods.) a 1983 XL200R engine into my all black 81' CB125S,I've already got both the 125 & complete 83' XL200R donor bike,do you have any recommendations for me? will an XR200R camshaft give me more all-around power?
I'll be taking my stock 81' CB125S exhaust and cutting off my restrictive stock muffler and custom fitting an early CB450 twin HM319 stock right side muffler,fortunately the head pipe is the same diameter between both bikes.

let me know your thoughts on anything that you might help me with including the intake manifold mod that I'll have to do w/ high hopes of using the stock 125 airbox.

grcamna2 · « **Reply #220 on:** October 22, 2014, 08:06:03 PM »

Bump. any more CB125S action out there ?

Flying J · « **Reply #221 on:** October 26, 2014, 08:09:51 PM »

I have an SL100 Im dropping a 125 in. The motor has been torn down and rebuilt. All i have to do is bolt the cylinder and head back on. But i have little time. Have a baby now so my projects have become long term.

grcamna2 · « **Reply #222 on:** October 26, 2014, 08:22:11 PM »

Quote from: Flying J on October 26, 2014, 08:09:51 PM

I have an SL100 Im dropping a 125 in. The motor has been torn down and rebuilt. All i have to do is bolt the cylinder and head back on. But i have little time. Have a baby now so my projects have become long term.

A baby beats Big Blue ANY day

congrats !

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Author Topic: CB125s "Big Blue" is UN-DONE! (Read 57386 times)