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CB125 TDC worth boring to 142cc?? Or am i being silly?

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the95th
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PostPosted: 16:41 - 02 Dec 2011    Post subject: CB125 TDC worth boring to 142cc?? Or am i being silly? Reply with quote

Hay,
I was looking for things i could do with doing to the CB125 TDC 1982 to make it more reliable ( Its been sitting for a few months due to work commitments and driving) And last time i rode it, it was horrible. Ive re aligned the carbs and added new jets that match the haynes manual, cleaned out oil filter and given it an oil change, but none of this really helps it be more normal

Ive tossed the idea about giving it a full engine rebuild around a lot, as the spark plug holes are knackered so it needs heli coiling... and It could do with a new cam chain.

Anyone know were cheapish heli coil kits are as £50 seems a bit extreme?

I was browsing ebay, and spotted that for 75 quid you can get a new standard head with pistons and rings , or for 85 quid you can bore it out to 142 cc

Now I know the legal ramifications of a 142cc bike on L plates etc. But i dont know the mechanical side, would this just bolt in place the same as a normal sized head unit?
is this worth doing? As at the moment the bike is dreadful to ride, thus its place of shame at the back of the garage. It needs new exhausts and tires, as well as brake pads, and a could old clean

But i though for an extra tenner i might as well see if i could squeeze out a bit more juice, as atm it struggles to remain at 60 on the A roads, slow to accelerate and does about 30 MPG

Would the combination of new exhausts and a few more CC's make this bike more reliable.... or would it just equal a more tempremental B*tch of a bike? would it sort out the MPG to a more normal price range, 20 quid should do more then 100 miles on a bloody 125 ( Why i swapped to a car, it worked out the same money wise and i had a nice heater and stero going)

As ive wanted to take my bike test for months now, but just cant afford it withwith 125 that just doesnt like doing anything.
I could rent a 125 out and take my test and sell the flaming thing but i just cant do it, I feel the need to make this blo*dy thing work


All i really would like to know is, if im going to rebuild the head, is the bigger bore worth an extra 10? or does it involve a lot more work for little gain.

Will it make the bike go up hill at 5mph and explode going down?
Cheers guys, its all appreciated, even swearing at me for "Being a lazy cnut and not taking my test and wanting a 100mph cg"...

i do want a 100mph cg, i think it would be hilarious and scary.

But on a serious note. HELP my CB125 TDC is Shit
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Efes123
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PostPosted: 18:24 - 02 Dec 2011    Post subject: Reply with quote

To be honest, I'd add another £35 or so, and take your test. Then you can have what ever bike you want.

Theory £31
Mod 1 £15
Mod 2 £75

You don't need to go over 60 on your test, there's a lot of 125s that wont. Even if you managed to do all the work required to make it go 100mpg (and that'll cost a fair bit more than just your £80), the first time plod saw you you'd get pulled. Then you'd be
a) driving with no licence
b) driving without insurance
c) speeding

I don't think you'd be getting back on a bike for a long time after that.
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Teflon-Mike
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PostPosted: 18:57 - 02 Dec 2011    Post subject: Reply with quote

The UK CB125TD- Super-Dream is de-tuned to the old 13.5bhp learner limit.
Unless it runs readily off the end of the speedo, it probably isn't making that due to normal wear & tear and neglect.
Well fettled UK 'Reduced Effect' models will top a genuine 70, and put the speedo needle well past the last tick at 80.

The 142cc big-bore kit is the largest piston size you can get into the standard 125 barel's liner. The extra 17cc is fuck all.

They can be bored bigger; other variants of the engine have been stretched by the factory as far as 233cc for the CM250 or CB-Two-Fifty. But not without machining the crank-cases to fit bigger liner barels.

Head is good enough to flow the air needed to make almost double the power of the Reduced Effect UK Super-Dream; so you cant really gain anything by trying to hack the ports bigger with a dremel; and the valves are about as big as can possibly be crammed in the combustion chamber as it stands.

What limits the power on them is the cam-shaft. And unfortunately, there aren't very many options here by way of after-market hop-up profiles. Best we have is the factory;s 'Full-Power' cam which, on a well built engine, and with properly set up and sized carbs can, on the 125 bottom end achieve 17bhp. However these cams are rarer than rocking horse do-dah. The correct carbs to go with them even rarer.

Can bore the thing as far as you like, really, even the whole hog, bored and stroked to 233cc, you wont easily better the power JUST that camshaft offers.

The biggest 'family' engine using the CB125's 41mm stroke, was the over-square screamer CB200 motor, whose barrels are inconveniently incompatible with the 125 bottom end, and which only just made same power as full-power 125.

The most powerful of the 233 engines was the CMX Rebel, that I think was rated at about 21bhp, running paired CV carbs, on a 360 bottom end. CB-two-fifty chucked out about 19 depending on who you ask, on a single carb, but crank-cases opened up, to take bigger barrels, long stroke 360 crank, these engines dont offer solutions to tune a 125 super-dream as micing bits between 360 crank and 180 crank engines will result in mashed valves the cam opening valves on an up-stroke when crank ought to be doing a down stroke.

So.... 142cc? For a tenner, it ent going to hurt; but any more power you may get is going to be mostly from new piston & rings and rebuild finding more compression, not the extra cubes!

But for a tenner?

Had three barel sets in the last twelve months and done as many rebuilds. I didn't bother with the 142 kit. Keeping the stock bore size keeps things a known quantity, and saves a few penies.
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Teflon-Mike
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PostPosted: 19:08 - 02 Dec 2011    Post subject: Reply with quote

Efes123 wrote:
To be honest, I'd add another £35 or so, and take your test. Then you can have what ever bike you want.


Its a sentiment I tend to agree with, but presumes he's not already taken it...

I have a Super-Dream 125 (or five!) and a DT125... doesn't mean I HAVE to be a learner....

CB125, in good order is a great little bike. They are cheap and cheeky.

Their little twin engine has four-stroke low down chuckability, with the smoothness of a twin, loosing the tractor-like jerkiness of the usual singles; yet, twin carbed and tuned, as a sports-bike, to offer the performance of its two stroke peers in the early eighties, let them rev, and the'll howl well past the, rather astounding, for an air-cooled, two-valve per pot little twin, 12,ooo rpm red-line, and make life 'interesting', while still offering a thing called 'mid-range'. Sophisticated suspension and brakes for the era; they can handle pretty well too. Great Learner-Bikes; but very capable little commuters, too. Light, nimble and far more 'fun' than a YBR or CG, and less seriouse or expensive than a CB500 or its ilk.

Anyway.....

But its not actually an extra £35.... bike needs overhaul, bilke needs an overhaul... whether he needs it for test or not.

So its still £121.50 for tests, over and above repair cost.
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Efes123
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PostPosted: 19:41 - 02 Dec 2011    Post subject: Re: CB125 TDC worth boring to 142cc?? Or am i being silly? Reply with quote

Teflon-Mike wrote:
Its a sentiment I tend to agree with, but presumes he's not already taken it...

I have a Super-Dream 125 (or five!) and a DT125... doesn't mean I HAVE to be a learner....


I presumed from this Wink

the95th wrote:


As ive wanted to take my bike test for months now, but just cant afford it withwith 125 that just doesnt like doing anything.

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Im-a-Ridah
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PostPosted: 22:08 - 02 Dec 2011    Post subject: Reply with quote

As the others have said, take your test, opens up more options for you! When I went on test I only did a very brief amount of national speed road, about 0.7 miles including speeding up and slowing down distance, and even then you can just sit in the inside line at 55/60.
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totalllama82
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PostPosted: 22:41 - 02 Dec 2011    Post subject: Reply with quote

Whats actually up with the bike? Its horrible to ride but we don't know why...

Does it cough and splutter? bog down? Not happy to rev?

I'm all for going for the test and moving up to the big bikes but then if the 125 suits your purposes then fixing it up is by far the most economical option.

100 miles from £20 on a 125? I get 150 miles from £15 in a 900!! Shocked
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Frost
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PostPosted: 23:42 - 02 Dec 2011    Post subject: Reply with quote

I'm dead against heli coiling spark plug threads now. A mate did so to his bike as "It's what NASA use!" However the heli coil came out with the spark plug! So research shows that NASA and other space contractors do use heli coils, but they only screw something into them the once, they don't ever get undone. There are so many spark plugs of various fitment that if you look online using the codes you can usually find an identical plug that has a fatter thread. The spark plug hole can then be drilled and tapped by someone who knows what they're doing and it will be good as new, possibly even better as a bigger thread is less likely to get damaged.

The weak point of these bikes is the top end, they don't like running low on oil. So compression check it and see where you stand.
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the95th
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PostPosted: 15:30 - 05 Dec 2011    Post subject: Reply with quote

I would take my test and move onto a bigger bike, but the problem is.

1 id pay £100+ for a piece of paper I dont need at the moment. A full bike licence wont fix me bike.

2. If I sold the 125 id only get a crap amount maybe 300 quid, which wont get me a decent bigger bike in reality that wont have similar issues as the 125.

So Id of sold my bike and have a piece of paper saying i can ride bikes real good, But no money for a decent bike and insurance. So id kinda be in the same position just with a bigger bike.

Plus i wouldnt want to take this bike on my test untill its 100% reliable. Who can feel comfortable on a bike if its exhausts are rusting through and it sounds fucking awful. And for the lessons or what ever that break bad habits from riding on L plates id have to do a 20 mile round trip on a bike at the begginingg of winter when it gets dark quickly on a bike that is un reliable... not really worth my time at the moment i feel.


No, I think what i want to do, is fix this bike up fully. Whats the point in spending money on a full licence, when ill still have a shit bike.

However I understand your points!
Ive had this argument in my head a lot recently, Just sell the bike, take your test and buy another bigger better one, just when i thought about it. The return on the 125 is gonna be shit, the bike test costs say 300 quid with some lessons thrown in, plus what ever they charge for renting a 125 so say 500 quid and then add on a new bike and insurance. were looking at 2000 quid to get me back on two wheels that way, at least with a bike i wouldnt moan about ( was thinking a gpz500s at around the grand mark, so it would be a pretty damn good one)

Or i could spend 400 quid fixing up a 125, which i will then use on my test.


SO effectively the bigger bored barrels n pistons will fit, but the power increase would be non existant due to the cam and cam chain not transfering anymore power then 13.5bhp.
so the extra tenner wouldnt increase power, nor speed.
But would it make the bike more reliable? in the sense would it be under less stress and strain or more. Would the cam chain be more likely to wear thin because of the added 17cc. Or would those 17ccs be more like a fart in a hurricane?
Just when you think 17cc's are about an 8th of the overall engine size it kinda makes it seem "Bigger".

Efes123' I really dont see a copper pulling me over for a 142cc bike that looks like a 125... especially as that 125 is a honda cb from 1982. and is trundling along at 60mph.

Im not trying to make it go 100 miles to the gallon, im trying to make it go more then 30 miles to the gallon.


Ok heres my issues with the bike,

The spark plug holes need helicoiling, the knackered spark plugs are causing missfires.
The gear box is very clunky? as in, people can hear me change gear through the "Clunk".
The Exhausts need replacing due to holes... have now taken out baffles due to it being "clogged up" with rust and rot.
Cam chain hasn't been replaced since 1982
and when i replaced the head gasket, the piston and rings didn't look healthy.
Needs new tires.
Led indicators are a bit odd? ( I replaced the standard ones) the back light doesn't light up when the indicators are on.
What type of Helicoil Insert will I need for the spark plugs, all the sizes are confusing me! ( far from mechanical minded) Its not ideal, but it needs to be done. Getting it professionally rethreaded would be too time consuming and expensive.

The bike revs okay, like Mike says they are happy to buzz around at 12k revs ( certainly a strange bike)
It just has no power, and the two cylinders dont seem to be doing the best they can.
I believe its just leaking horses somewere, and my bet is the pistons.
All i truly want to know is will the extra 17cc and new pistons and rings make the bike healthier and is it worth ten pounds more for the extra 17cc.

I personally feel it may well be worth it, as it might take some strain off the engine, despite them being designed to sit at 12k revs at 50/60 mark it still feels wrong.
The Bike doesn't like running in 5th gear much either, as it looses power and cant build those crucial revs.

Will it be a bit more economical with the exhausts being replaced and the engine rebuilt?

Im anticipating these costs.

Back tire £45 to 50 quid
Helicoil kit ( will be worth the investment) £40 ( some on ebay)
big bore head £90 with postage
Exhausts £90
Cigarettes and Energy drink and beer£15 ( it'll be a long fiddley cold job)
Gaskets £10
Camshaft £40
Cam chain? not sure how much these are

Ill probably start off with the exhausts and tire, and will move onto the head after christmas.

Thanks for the help.
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2004 Rieju Rs2 Matrix 50cc, 1982 Honda CG125, 1986 Honda Cm125, 1982 Honda Cb125..... I kill a lot of 125's


Last edited by the95th on 16:11 - 05 Dec 2011; edited 2 times in total
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Efes123
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PostPosted: 16:05 - 05 Dec 2011    Post subject: Reply with quote

the95th wrote:

However I understand your points!
Ive had this argument in my head a lot recently, Just sell the bike, take your test and buy another bigger better one, just when i thought about it. The return on the 125 is gonna be shit, the bike test costs say 300 quid with some lessons thrown in, plus what ever they charge for renting a 125 so say 500 quid and then add on a new bike and insurance. were looking at 2000 quid to get me back on two wheels that way

Or i could spend 400 quid fixing up a 125, which i will then use on my test.



OK, I understand your reasoning, but you're not quite comparing apple with apples. £400 fixing up your 125, plus another £300 for tests and lessons, plus insurance £500, and you're at £1,200.

Buy a 500cc for around £750, insure it for around £250, tests & lessons at £300 equals £1,300. Then you can sell your 125 for £300, and you're £200 better off. Trust me, bigger bikes can be cheaper to buy than 125s, and they are a damn site cheaper to insure.

I'm not saying don't do up your 125, just don't kid yourself on the economics. Basically spend £400 on the 125, or sell it and put another £300 to £400 towards it, and you're in the same place, but cheaper insurance.
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the95th
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PostPosted: 16:23 - 05 Dec 2011    Post subject: Reply with quote

my insurance at the moment is only £6 a month lol.
with 2 years no claims.

Im not attempting to kid myself with the economics. My point is, the tests and lessons seem important, but in reality they are not neccasary at the moment.
I would rather spend my money on items, and products then just spend it on lessons and tests. Odd i know but the problems with the lessons and tests are. You need a reliable 125 for it.

And id rather spend the cash fixing the 125 up to a reasonable standard, taking my test, and then selling the 125.
then spend money on renting a 125, taking my test, and then selling the dodgy 125 and getting a bigger bike. Admittadly my sums of 2000 are exaggerated, its true cost will be about 1500.

But i dont have 1500, what i do have, is enough to fix up the 125, about 400/500 quid. I can get that going this year, I cant get my bike licence this year.
Like I said, im happy with the L plates for now, Id rather have a bike that ran well, and was happy. Than a licence, a 125 that needed a lot of work, and more expense.

I think my main point is, the licence is an unneeded expense that will take a while to achieve despite it being maybe a bit cheaper overall it takes longer, and id still have a 125 that doesnt run well to use.

I dont mean to deny your advice, its good advice, I want to take my bike test, But i'd also want to secure a pass. And to do that I would want my bike to be in top condition. Plus it helps its re sale value.
And, Winter aint the best time to take your bike test! Id rather wait till spring, in that time i can have this bike running like clockwork. And have a better chance of getting the all important pass.
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Efes123
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PostPosted: 16:37 - 05 Dec 2011    Post subject: Reply with quote

the95th wrote:
my insurance at the moment is only £6 a month lol.
with 2 years no claims.


Bloody hell, that's cheap for a 125. You must live in a no crime area. Good luck on doing your 125 up Thumbs Up
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the95th
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PostPosted: 16:48 - 05 Dec 2011    Post subject: Reply with quote

yeah, my bike insurance is only 6 quid a month... £80 a year! ( didnt have 80 quid in the bank when i bought my 125, did have 20 quid... so 6 on insurance 14 on fuel hehe)

My car insurance is £300 a month.... £2600 a year!
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stinkwheel
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PostPosted: 17:22 - 05 Dec 2011    Post subject: Reply with quote

Regarding helicoils. You can often buy the relevant tap and spring inserts seperately off ebay if you know what size you want. Last ones I bought were a fiver for the tap and a couple of quid for the inserts (1/4 BSF rather than sparkplug sized though). How many insertion and tang breaking tools does one need?

That said, I'd try pretty hard to fix the thread you have with a thread chaser if it is in any way fixable.

EDIT: You have a CR8HS plug size in NGK which means it is a 10mm thread diameter, 12.7mm deep.

So you need M10x1.0mm inserts.

You need a 10.3mm drill.

You need an appropriate (and slightly odd sized) tap, they tend to keep the tap size pretty close to their chest but they have them on ebay for sale as "Suitable for M10x1.0 inserts".
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Teflon-Mike
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PostPosted: 18:13 - 05 Dec 2011    Post subject: Reply with quote

the95th wrote:

Im anticipating these costs.

Back tire £45 to 50 quid - Ball-Park, possibly a tad less.
Helicoil kit ( will be worth the investment) £40 ( some on ebay) - Get it done pro, poss £10 at local M/C shop (If you want 'reliability)
big bore head £90 with postage - Its a barel & piston kit. Head will need seperate attension .
Exhausts £90 - OEM replacements try £140, & be sure to get Super-Dream pipes not CB125T pipes; lots and lots for the older T-shock bike on e-bay but they dont fit. also prices are each, one per side, NOT for a pair. Brand New Motad or Micron 2-1 system will set you back about £200. "nd hand systems, around £60 for one worth having.
Cigarettes and Energy drink and beer£15 ( it'll be a long fiddley cold job) - [img]Top end Rebuild is for me a two day job. Thats £15 woth of fags alone![/img]
Gaskets £10 - Make that £25 for full gasket set. £10 gets you a head & base gasket only. You will also want seals for output & gear shaft becouse I suspect you are going to be doing 'Full' engine build sliptting bottom end cases to look at that clunky box, & fit cam-chain
Camshaft £40 - That will be the Riders 'Lifan' cam, & bearing kit I presume. Not bad value, but its the later 'J' spec cam, and slightly softer than the earlier Super-Dream item; re-optimised to work with CV Carbs. Will work pretty good though and better than what you got, as like.
Cam chain? not sure how much these are - £20-£30 and you need to split the crank cases and draw the crank to fit.

You are talking a full engine rebuild.
Budget around £200 minimum, for gaskets, cam-chain & barel kit. You are advised to swap case seals too. And worthwhile new cam-chain tensioner blades. While you have it apart you can get seriouse and start spending seriouse money; roughlt £200 to get crank presed apart and re-assembled with new bearings and then re-balenced. Then theres the oil pump, clutch (worth douing, new plates & springs less than £20), gearbox bearings, etc. All mounts up, and if you skimp 'too' much you as like have to do it all again!

TBH with that list you are on a break-point.

Its not worth £300 as a dire runner, though you might get it, if you are lucky. If it has tax and test, its worth £250 to a nieve optimist (or a not so nieve, but ever hopeful dissolusionist optimist, like me!)

Top end rebuild it, you WILL be spending £120, and its a bastard if they go together nice and easy... because if it goes together easy, means cam-chain is stretched and it WILL snap!

Add £50 for decent second hand exhaust, you are up to £200 region.

Value bike at £250 and you are nudging over the £400 'value' and you still haven't sorted tyres, or the bottom end, or I suspect a host of other bits its likely to need sorting, like brakes and steering bearings and fork-seals.

These things are worth around £750 top book, for a 'good' example.

You can get Taxed, Tested Runners for around £500... though possibly not THAT much better than what you have.

SO... chucking the sort of meney this bikes likely to 'need' chucking at it to make it 'reliable'...

Will you get the value out of it, becouse you are going to HAVE to get the value out of it by using it, you are unlikely to get it selling...

Skimp to keep it serviceable and make it up to scratch, yes, £200-£250, you are just about on tipping point.

If you want to do it justice and get reliability, you are looking more like £500 order to get that bottom end tended to and new cam-chain in there.

Either way, head will need stripping; guides, & valves checking. Valve stem seals renewing; valves ground; & valve seats ground.

Now I wouldn't necesserily be put off by all this; but I know the bikes, and have heap of ready spares. And my threshold would be £250 buy price + £500 'work' = top book bike... I might just break even on, and get some proffit in the use and playing with it.

NOW: bikes come and go and with 55 weeks to no more testing for full A licence on a 125..... I would be looking on any £500 I might scrape together to fix bike very hard and pondering.

£121.50 is the test-fees. £65 per session to hire a school bike to do them.

Flogging the Super-Dream as a scrapper/project would cover that.

Leaving you in hand by repair costs, to go look for something elce, that, need not be a 125.

I bought my CB750 T&T'd for six months for only £450; if you dont look glamourouse there are a lot of big bikes out there for that kind of money; and, yes, I agree they may not be any better than your Super-Dream, but you are in the bargain basement; and its beggers and choosers.

And ecconomically, unless you are very daft and or unlucky, you WOULD get a useable 'big-bike' with a bit more life in it than your 125 currently has, that IS more likely to prove more reliable than doing cheap-skate top end rebuild.

Super-Dream, if you want to percevere with it; you will have to do the job thoroughly; and do full engine build, even if you dont go too farf rebuilding cranks and stuff. Doing the rest of the bike, you will be looking at having to chuck in the order of £500+ to do engine, zorsts, tyres, and a few mechanical bits, like greasing rear suspension (If that needs overhaul, has any siezed links SCRAP, it really isn't worth fixing!) renewing steering bearings, reconditioning forks and possibly servicing brakes.

They are a fantastic Learner-Legal, and a very good budget commuter, BUT big investment to make one 'good' and only ecconomicval IF you run life out of it as people will not pay what these bikes are worth for a 'good' one, when they can for same money have brand new Chinky or second hand YBR.

From your extended list of works.... THINK HARD
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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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Teflon-Mike
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PostPosted: 18:47 - 05 Dec 2011    Post subject: Reply with quote

Oh, 142 Big Bore.
Performance difference will be a gnats fart in a gale.
Reliability?
It sure as fuck wont give the bike an easier time, thats for sure.
Same power = Same forces.
Piston will be carrying teh same load, so will con rod, so will crank.
Only major change will be piston might carry a couple of psi less pressure, but your bigger piston will have bigger rings, so there will be more metal rubbing metal and any 'slap' will be magnified by added leverage.
But assembly and parts quality will have bigger influence, AND since it ent the weak link in the engine, crank mains and cam-chain are...
Its not worth a heck of a lot either which way.
As said; for sake of a tenner, I've not bothered.
Its £10's worth of cheeky 'I'm a bit naughty" factor, and some plascebo effect!
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the95th
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Joined: 15 Dec 2010
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PostPosted: 18:01 - 08 Dec 2011    Post subject: Reply with quote

SO in reality i may as well sell the bike and find another 125?

I would take my test but, it would be impossible at the moment with work. All i want is a 125 that runs well enough to take me to work every now and then and be there when i need it for my test.
next spring/summer when i can afford it.

However, £500 on fixing the bike up in my opinion is worth it considering cg's are selling for a grand on ebay, despite the inflated price. gum tree isnt much better in my area.

If i just rebuilt the head, replaced gaskets, and new exhausts ( swear i saw a set for 90 quid on ebay) as well as back tire. It should be improved. Ill probably go for the standard barrel as it poses less issues and a tenner saved.

were can i get a new cam chain?
And were abouts would a place likely helicoil? last person i asked if they did it said it would take 3 months ( i guess the wnker didnt want my bike in his garage)
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Teflon-Mike
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Joined: 01 Jun 2010
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PostPosted: 02:33 - 09 Dec 2011    Post subject: Reply with quote

The accountant in me says cut your losses.
The Biker in me says 'just do it!'
Engineer in me says lets look at the problems!

We dont just have a bike; we have your transport needs to consider; we also have test requirements to think about.

Lets deal with that one first. Its December 2011; we have 55 weeks until 3rd directive hits, and later you leave it into next year, harder its going to be to get test dates, and less room for 'slippage' if things don't go to plan....

I'm going to stick that one at the top of the list; I know you have put it at the bottom; you want reliable transport more; but...

£121.50 + £130 to hire a decent bike to do it on. You'd have to spend the £121.50 at some point anyway, if not on tests, repeat CBT, or testing for 125 only licence.

IF there's not enough money knocking about to get this bike how you want it; SHORT TERM, £130 for a School bike, is a lot more do-able, and gets that one OFF the books; clear.....

If that happened; would you STILL want a 125 commuter? Would you still want THIS 125 commuter?

Lets start by floating that idea?

£250... full licence....

Cutting losses, thats what you would get for the Super-Dream'...

Leaves you the £500 fix-fund to go look for a 33bhp restrict 'big-bike', and they are out there at that kind of money, and IF you want to fix up a bike, and a bike you are going to keep, then something like my CB750, may be more worthy a 'project'....

PONDER and tell me your thoughts on that...

Meanwhile; without burrying too deep into this ere Super-Dream.

WHY don't you want to take tests on it? You said exhausts...
You said it was running rough, but with shagged exhausts, would run rough.

COULD we get this bike scrubbed up to something a bit 'more' serviceable, without a major renovation?

I have big pile of ready spares; some of them not so 'wonderful', but serviceable.

IF we could get a replacement pip on the thing, and do some carb fiddling... do you think it could be made 'tidy' enough to do tests on?

If so... back to the top; tested; licence in your pocket, would you still want to chuck money and effort at it?

Tackling a Super-Dream 125, head on, and making something worth the effort; well, have a look at Snowies 'Top End' renovation blog on S&T... Build bill topped £2K and she has a borrowed engine at the moment; waiting on me finding funds and bits to build a top end, and tuned benley motor. Doing one that you would REALLY want to keep hold of, costs.

My Blog on the Corporal's renovation, is more doable. I did that one as an 'every-day' practical classic, and I tried (and failed) to bring it in for less than I sold it to Smiler (£750). With the advantage of that big pile of ready spares from the bikes I have broken. Realistically to 'do' a Super-Dream from a £250 'base', including an engine rebuild, you are looking at, £750-£1000, all in.

Your notional £500 budget to get your bike scrubbed up and make nice, is realistic, and you could do a lot; but you wont have a lot in the pot to pretty it up; that will just about tackle the main mechanicals, and ONLY if there are no 'biggies'. Biggies on these bikes:
1/ Engine
2/ Rear Suspension
3/ Front Brake

Rear suspension is £200+s worth if its utterly shot and needs major overhaul with new bushes and shock.

Front brake; its twin piston floating caliper. those two pistons double the overhaul cost, compared to most lightweights brakes. If you need to overhaul the master cylinder; replace the brake hose; replace the pistoins and seals; and pads, and disc,; this one sub-assembly alone CAN cost £200ish.

Engine; prices already mentioned; to 'do' the bare minimum from the cases up, £200 up.

Your budget, doesn't give you much room for niceties; like powder coating the frame, or nicely painting the shiney bits, or making it look 'factory' with decals.

You have all the pottentials I had with the Corporal, and the known starts that above what I did with the Corporal, you need tyres; £60 for hard cheapo's; £90 for nice grippy M45's. And exhaust. I had to find exhaust on the Corp, but uncosted; I took it off one of the scrappers. Front brake I wasn't happy with; again, I circumvented that with bits from a scrapper, and I was 'lucky' with the rear suspension; it coming up with clean and grease and again, shocker from a scrapper.....

THAT is what you are faced with. So back to break-point.

IF you want a CB125 Super-Dream, you have built, with all the satisfaction that offers, and rides really nicely, like they should, and is a joy to own, AND looks good, and LOOKS like its worth all the money and effort.... you are going to have to up the budget, to do some of the niceties, AND cover any maledies like brake or suspension...

So... to do your bike justice.... with a full licence in your pocket....

Is your Super-Dream, worth £1200 to YOU?

I can tell you now, that it wont be worth that to very many people who actually have that money, if you sold it, no matter how 'nice' it was when done.

If so; then yoru £500 budget would get things moving, but realistically, its the old 'double the money' tripple the time' addage. Doing it justice, you need to be prepared to spend up to a grand, over what is sitting infront of you here and now.

And, plenty of scope, if you get carried away, for those costs to escalate, unless you hold the purse strings tightly;

You look at the frame and see add for powder coating £45. Do a quick reckon, and tally up big can of smoothrite and some thinners, plus a couple of brushes and conclude its 'only' and extra £20 for a 'forever' finish.... so, while you are at it, you chuck the swing arm, suspension drop links, head-lamp bracket, steering yokes, indicator brackets, bar clamps, and a few other odds and sods like the centre stand, the brake pedal... and your powder coating bill, goes from £45 for just a frame, to £145, for everything else you COULD have painted out of that £15 can of smoothrite....

You look at second hand exhausts, and ponder similarly, when T-Shock pipes are only £50 a side, and again, brand new pipes; twice the price but more than twice the life.... but your £40 second hand exhuats suddenly becomes a £130, when you get the correct 'pattern' replacements for a super-dream.... but hey-ho, at least they are as shiney as the paint and decals, that has gone from 'a couple of £8 Halfords Rattle-Cans, to two £8 cans of primer, one £10 can of hi-build, two cans of £12 colour coat, two cans of £10 clear coat; one can of £15 petrol-proof laquer, AND £30's worth of vynal decals.....

And YES, 'Done' it ought to be a really nice bike to ride; something a lot more 'special' than a three year old YBR125 that costs the same money, and ought to have a lot more life in it; and be rather more exiting to ride than that or a CG125.....

But it will only be worth the money, let alone the effort to YOU.

It will NOT be a bargain; you will not make money on it; you WILL get a nice bike..... BUT, being realistic, you HAVE to be sure that you will get two to three years use out of it, to get any real value back from it all, before the sell price you might get isn't so gauling. And realistically, it needs to be a bike that when you do decide you want to move up; gets stuck in the garage as a souvineer of your efforts, and early exploits, you can afford to litterally 'write off' and not need to justify against travel.

I cant tell you what to do, and I have laid it out pretty hard, and made it look a non-starter.

Its NOT a complete non-starter. I do these bikes for fun. I would not be put off. BUT I do have some advantages. One is that big pile of ready spares. Other is I have done a few bikes before, including a couple of Super-Dreams. And while the Corporal cost me more to renovate than I sold it for; it was 'within limits' and I had eight months use of the bike, and learned a lot about super-dream foibles in the process, and well... you win some, you loose some, and I have another five bikes to 'do'.

In your shoes; more risk of budget over-run and problem magnifiers; but also better chance you COULD get the value from any excess expendature from use.

BUT, we are up into three year old YBR territoty, you really need to think about the real 'worth' beyoind the numbers and whether its worth it to you, AND nieve optimism dampened IF you can deal with a project of this order.

Helicoiling spark-plug holes?

Remove the Cylinder head; take the head, on its own to an engine re conditioners; and see what they say. If they dont do many motorbike engines, they may refer you to some-one that does, becouse Super-Dream has small plugs, they may not have drill, taps and coils to do; BUT they will tell you who does.

Fall-Back; if you end up heding down to me to root through ready-spares; I have a very helpful engine reconditioners on my door-step; and if they cant do it; can probably find a replacement head in the pile of spares! (I have clocked a rather scruffy Micron 2-1 system, that's been plated and pin-hole puddle welded, in a couple of places, but is serviceable, and may be some use to you!)
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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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WD Forte
World Chat Champion



Joined: 17 Jun 2010
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PostPosted: 19:12 - 23 Sep 2018    Post subject: Reply with quote

I'll do it for you mate
If moneys no object we can start tomorrow
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Evil Hans
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Joined: 08 Nov 2015
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PostPosted: 20:08 - 23 Sep 2018    Post subject: Reply with quote

Martin125tdc wrote:
Has anyone been able to be successful in doing a rear disc brakes conversion??
I’d love to know that this is achievable.

Cheers



Two things I hate: Dragging up years-old unrelated posts, and double posting the same stupid question. FFS.
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bikenut
World Chat Champion



Joined: 21 Nov 2011
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PostPosted: 15:00 - 24 Sep 2018    Post subject: cb125t Reply with quote

It ain't worth it. A good cb125t is quite a goer....in fact a mates cb125t which laid down much more blue smoke than very over oiled rd left me for standing on my 750, he was thrashing the 125 and i did not want to do his speeds to try and catch him up. I only court him up when he had been home for some minutes !
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Evil Hans
World Chat Champion



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PostPosted: 16:34 - 24 Sep 2018    Post subject: Reply with quote

... and that, Martin125tdc, is why you don't drag up old threads. Bikenut has just wasted his time answering a seven year old question, which is different to your question, which you already asked in another thread.
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The last post was made 5 years, 207 days ago. Instead of replying here, would creating a new thread be more useful?
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