Big bore kits for 125cc - Yes or No?

[Teflon-Mike]

The seals are about £7 a pair.
The oil to refill the fork legs is about £30 a liter.
Its cheaper to swap the fork seals than loose a leg full of bludy oil!
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My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

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[MarJay]

I have to say I noticed Tef said that and thought it ridiculous, but my tef filter is too attuned these days.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[Teflon-Mike]

Last bottle of fork-oil I bought, was probably three or four years ago, and Alzheimer is probably kicking in, but I was sure it cost me about £10-£15 and was only half a liter.

Either way, cost of oil, is at least as if not more significant than seals, so why waste oil to find out of seal shot, just swap the seal, and be done!
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My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

[Pigeon]

I is confused (more than normal)

What has fork oil got to do with big bore kits?

[ThatDippyTwat]

[Rogerborg]

[bladerunner]

[bikenut]

Many many many moons ago ( 1970's ) when cb125s 's where everywhere, in the monthly mags there was a big bore kit advert usualy in the back of the mags, a small black and white box add with real cool artwork of an oversized cb125s engine, would anyone have the mag with the advert in please ??????
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nuts about bikes

[stevo as b4]

Oh the good old back in the day tuning ads in magazines!

I remember the TTS ads, Stan, Bob, and uncle Frank's adverts too.

Point being almost anything could be or was being tuned in them days. People used to use and mess with whatever bike they had. None of this save your money for a scabby old superbike instead.

Turbocharged superdreams and all that for the fun of it.

[bikenut]

anyone have old monthly bike mags with that advert in it please, been searching for it for ages now, years in fact.....anyone ??
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nuts about bikes

[1198]

[dydey90]

[1198]

[kemeng]

Late reply, but Im just in this process. I cannot say yes or no, it is depends:


If you upgrade:
- get proper kit which has good reputation, trusted. Price wont tell you so much: Got Takegawa kit (139cc) made for my bike (xtz125 - almost same engine with ybr or xt) was nice, runs smoother than original set till 1700km-s. Even I broke in slowly and with soft wrist (1500kms, 5x oil change, built up from short rides low end till extended top end). Means when it got the same grade syntetic oil and cooler brisk spark (used to use before) made only 200km.
- got 144cc (57.4) kit then from UK seller with higher lift cam (half price than Takegawa). Piston is heavy or cam is too much (and/or bad timing) heats up like hell, cannot go over 6-6500rpm or riding more than 30min (and used to use make 270-300kms in one run). Definitely the quality of materials are good otherwise it supposed to be blow up already. We will take out the cam, and see how is without.
- as I ride in jungle/rural area 2-600kms daily (do motorbike tour) I need thrust at this moment I cannot use that bike.

- may you need bigger carb or set original properly (lean=heat) , more airflow (open the airbox), thicker front pipe, better muffler and lots of patience, time, cash and pray.

- you wont get more top speed btw (max 1-5km/h), you will have better accelation. If you want more speed change sprockets

- found now a Nikasil coated, forged piston set (airseal brand), will go with that with all everything else stock. I would chose that kit first, If I could see it before. (So spend lots of time, money etc for nothing).

- C plan if you want little more braap and thrust is Wiesco forged piston (original 54mm size or oversized) made for YFM125 RAPTOR (as it has same piston, engine as mine and definitely ybr or xt)

- there are kits for 180cc but you have to open, make bigger everything and you cannot use the bike for cruise anymore that sure. I would even change that many chinise bearings from engine to quality C3 clearence ones (done btw as balancer bearing blow up too sometime)

- If you find the perfect kit and settings (hope the nikasil will be fine) than you can save money over the original cylinder/piston/ring/pin/gasket price (50% cheaper at a least). If not, just read back what I've written above.



If you remain at stock:

- got a Honda 125 too, it has 77000km's and still running (almost:) like new (next to this tropical, seaside weather conditions). I am strictly use original engine parts with (never rebore even - change whole kit as cost 50USD only:) . It has never stopped, never left me somewhere middle of jungle or nowhere.

[BusterGonads]

Waste of time obviously, but I thought this wheelying turbo charged CG125 was quite funny.

https://www.youtube.com/watch?v=yLxxipyMCsw

Most of these turbo cg125 films show some saddo pointing a camera phone at a cobbled together lash up in a dark Pakistani garage and have the motor ticking over roughly. This one is hurtling down the street and going up on its back wheel in second or maybe third gear.

Doubt it does a lot for the engine reliability. Probably like those early Nazi jet planes that had a new engine every two or three quick flights.
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2016 Triumph Street Twin; 2000 Honda CG125; 1997 Honda Nighthawk CB250