Rebuild of my English CB175K6, 1972

FINALLY, I think I can say it is FINISHED as much as any classic ever is.

Everything back together, everything works and now with fuel in the tank.
Typing this, can't think of anything that needs doing to the bike, just need to insure it and get some bravery pills to ride it.
Have a helmet, so with a few other robust bits of clothing can be protected from the elements.

I really would like to thank everyone so very much for all the help and patience afforded me on this forum, both in written form as well as bits (Richard!)

Much harder than I thought it would work out to be and about £3500 total cost, but have lost count tbh.

I've learnt a lot and am a lot wiser too.

Thank you all again, and esp AD for such a great forum.







 
Well, it looks fabulous and now that it performs correctly too, it's a job well done. What a transformation it was, looking back.

Thanks very much for the kind words, but the forum was a group effort that we set out to do for all the right reasons - our favorite bikes, the members, and the best information and assistance we could offer for both. Feels good to know we've done pretty well in trying to achieve it.
 
Thank you indeed. The gold one was nicer just because the paint was pro done and cost 8 times more! (and took 12 times longer to get back....)

These bikes look very different (to me only maybe) without the mirrors? Look much lower??

 
Regarding the charging, I just put my multimeter set to the 20 volts scale across the battery. If the voltage rises to just under 14v when the engine is revved, and doesn't rise beyond that, I'm happy that it's charging, and my cheapy Chinese reg/rec is doing its job.
 
Thanks as ever Richard, will check that next time I run the bike, have 2 classic cars to fix first!

Have sent these 'finished for the moment' pictures to the previous seller who was acting on behalf of the owner who died just before the sale. He and they are delighted to see it done, good feeling.
 
Thank you.

At the moment I just enjoy looking at it!

However, can't see a thing through those mirrors! Useless as they are so will try rotating the handle bar to get them at a better angle.

Can't help thinking the USA high riding position is better than the UK type?
 
Can't help thinking the USA high riding position is better than the UK type?
Click to expand...

I have the luxury of both types of bars.

The CL175 with its high bars is ideal for cruising around, looking over hedges and the roofs of cars, but you catch the wind like a sail, especially with a bulky textile jacket. It is comfortable, but hard to feel what the front end of the bike is doing. Mirrors work well.

The CB175 low and narrow bars put me into a wind dodging crouch. Need to tuck elbows in to see in mirrors. Good feel from the front end. Shoulder ache sets in after a while, and brake and clutch cables don't run freely, tight turn at handle bar centre.

Back in the day, I rode long distances on my CB without discomfort, but these days I have to say I prefer the CL.
 
Just when you all thought I had ridden off into the distant English countryside...
today, started the bike, as usual, bit of a splutter on choke, but warm and even silencer temps after 3 mins or so, ticking over steady.
Sat on the bike, clutch in and nudge to 1st. CLUNK and stall, as if theclutch was not working.

after checking the adjustments decided to pull the clutch out, silencer off etc and oil everywhere, but all apart.
noticed when pulling the lever in the clutch pack moved out of the basket by 3 mm but all as a solid lump...

Several of the steel and friction plates were tightly bonded to each other, some free.
The steel plates had witness of the friction plate pads around the perimeter, both sides ad too a lot of elbow grease and abrasive pads to remove the marks.

Reassembled dry and the same still happens, the stack moves as a pack but will clear , i.e. Disengage, when I move the rear wheel in gear and the lever pulled in.

Is this normal?
Worked and rode great 4 days ago, clutch nice and clear, dropped into 1st with almost silence.
 
don't know about normal, but it happens all the time to some of my bikes after sitting for longer than like a week. you can scuff the metal plates up a bit with high grit sandpaper if it bothers you.
 
This isn't particularly abnormal, the oil when cold acts like a glue sticking the frictions to the steels. Problem should go away after the engine is completely hot and ridden, only to reappear after parked for a week or so.
 
Reassuring to read, thank you all.
I've polished the steel discs and checked the friction discs and the stack height is to spec, so all should be good.

Expensive to replace the whole stack here in the UK, about 120$.

New brake lever arrived today, repro, and was a poor fit which need some coarse filing to get the lever to seat correctly and give the correct positioning, but all done.

Oddly got the hankering for a CL 72, but that might be ambitious!
 
Oddly enough, I've never experienced a sticking clutch on any of my 175 engines, even left standing for three months or more. All still on the original plates.

I admire your ambition to do a CL/CB 72 or 77. Parts availability looks like a problem, thinking back to the primary drive chain thread here a while back.

Off topic a bit, each week in Motorcycle News they ask a bike person what they'd buy, given £5k to spend. This week it was David Silver, he said that you could still buy a good CB 750 for £3k. Article then said that you'd need to budget for a pattern exhaust on top of that, though.
 
Chap at work bought a 400-4 new way back. He was a real keen biker, wife also on pillion etc.

He loved it and it looked just out of this world.
Similarly, another had a passion for Goldwings, fully dressed with everything on it, almost a car. Again, wife in pillion.

Clutch all on this morning, but bike reluctant to start! It fires on choke but LHS is all cough and spit. Plugs black dry soot but same on both sides.
I guess this will be an endearing 'attribute' of this bike for ever!

Saw a 125 AJS Chinese bike in black/gold etc looking a million dollars, fuel injection, disc brakes etc. All for £2500.

I think it is when the battery gets a bit low when electric starting, but these Chinese carbs need 'catching' for a cold start then ok after 2 mins.Yet more fresh oil in this engine, had 5 oil changes already!
Oddly, have a custom lubrication blender across the road so using their classic bike oil.

Would like another Honda to do. However, the prices for starter complete bikes are really high, nothing south of £2500 before you start. Once done the cost would be £6000, so a bit silly.

Getting bored!
I hate bikes with one down pipe...

AJS%2BCadwell%2B125%2BReview%2B4.jpg
 
911hillclimber said:
Reassuring to read, thank you all.
I've polished the steel discs and checked the friction discs and the stack height is to spec, so all should be good.

Expensive to replace the whole stack here in the UK, about 120$.

New brake lever arrived today, repro, and was a poor fit which need some coarse filing to get the lever to seat correctly and give the correct positioning, but all done.

Oddly got the hankering for a CL 72, but that might be ambitious!
Click to expand...

“Polishing” is what can cause the plates to stick together. They need to be a tad rough.
 
So many positives in modern bikes, yet so many style aspects I don't care for (along with the Godforsaken electronics). The quality of certain parts is so much better than it used to be, big giant brake rotors and dual piston calipers that will wrinkle the pavement, nicely finished billet aluminum parts, very nice rims and modern tires... and then they mount the front fender as if they're worried about excess mud accumulation under it and put a bump seat on it as if it's a cafe racer yet with standard location footpegs. And even if you like dual mirrors, those look hideous IMO. But I'm sure it's just me....
 
Middletons said:
“Polishing” is what can cause the plates to stick together. They need to be a tad rough.
Click to expand...

Yeah, just make sure you're not aimed toward anything and click it into gear with the revs up slightly while holding the front brake, it will break loose. My 450 does it now and then as well, really a fairly common experience with wet clutches.
 
I learnt a very very long time ago on my Lambretta to have the front brake on when twisting to fist gear, did that yesterday, but the clutch held fast.
The steel plates were not mirror polished, lightly sanded until the shadow of the friction pads had gone and then rubbed over with a coarse fiber pad.

Will test tomorrow with lots of room in front of me...

Hope this will not be a persistent problem.

As to the AJS above, I like the look and love the build quality having examined one close up, not just nice pictures of show demo bikes.

A bike to ride in a care-free way, cruising country roads, down to the pub, and cruise back, much as I expect with the CB.

However, all that for £2500 on the road in the UK. A pro wheel build with new rims and spokes, a DS twin exhaust and some other bits and you are close to that on a CB rebuild.
I think the brakes are superb and with the balance of torque etc it would be a nice sedate ride with lots of confidence building qualities. I sounds like an AJS salesman, but it just looks that way to me.

To the CB; both down pipes are going straw, so lean I think, and considering the changes Richard has embarked on to his Chinese copies (jet swaps etc).
I'll wait to see if he is happy first!
 
Sometimes I really wonder what I have done to deserve this CB.
Thought Iwould raise the needles a notch as per Richards method and this was easy.
Tried to start it after, turns over well, but nothing.

seems there are no sparks at all, neither plug, nothing, just out of the blue, nothing.
Checked the points, all good, back plate tight as a duck thingy so noticing slip.
wires all bell through, 12.49 volts present with the ingnition on, neutral light on.

swopped the coil for another and same condition.

Any bright ideas please?
 
I don't see a "kill" in the pix, but all it would take is the Black power wire to the coil to have dislodged....
Check for battery voltage at the Blue wire to point assembly connection when points are open.....
 
Just tried that, meter on 20V DC from blue lead on coil pack to anywhere on the points, no volts with the ignition switch on.
This coil is 'new' or about 30 minutes running time on it.
Ignition switch new, condenser new etc etc. New battery, freshly charged.

I have 12.49V on the yellow wire to the coil with switch on, horn works, so I think that side is ok.
The 2 terminals (blue and yellow wires) give a continuity on the meter's buzzer.

So:
Removed the new coil
Resistance across the Primary terminals is 5.2 ohms. Resistance across the secondary plug leads, no caps, 17.8K ohms
Other coil I have spare, (near new) shows 4.5 ohms and 17.4 K ohms.

Thus I think these coils are good.

PLUGS!
Changed the plugs to 2 old ones I thought were naff and the bike started instantaneously, ran clean, warmed evenly and after 2 mins ticks over at 1600 rpm sounding like it would all day, all week long.

I'm pleased and irritated. They were fresh 30 minutes of running ago albeit at tick over, so "fouled plugs" syndrome.

Will buy some more, in bulk. (NGK 7112 D8HA), 2 in the engine, 2 in the toolbox.
 
I'm with Sprint on this one, a wire dislodged whilst taking the tops off the carbs. I'd check for12v at the black wire to the coil, ignition switch on.
 
Crossed posts, but see in bold above. The old plugs I changed as one stopped working having been flooded so much.
That was 2 months ago so dried out?
Checked all the wires to and from the ignition sides and all tight.

The richer needle setting sounds much better Richard and the exhausts smoke just a little, like on a cold day in England!

While the battery was charging for the 3rd time today, re-routed my throttle cable yet again and now the twist action is super smooth and really light, very comfortable. The cable run is reminiscent of a French Curve. (showing my age)

My friends are telling me to sell it. Wife is silent.
 
911hillclimber said:
My friends are telling me to sell it. Wife is silent.
Click to expand...

What do friends know? After all the work you've put into it, I couldn't imagine selling it if it were my situation. A little caution while getting back into the saddle will go a long way toward some confidence so you can actually enjoy your efforts.
 
Friends are probably just jealous ! Maybe they'd like a bike again but their spouses veto the idea, certainly true of someone I know ...

Even if you don't ride it very often, nice to have tucked away in the garage. It can only appreciate in value.
 
Sorry, I'm back...
Still have not ridden the CB, still start it to hot every week, still have a sticky clutch.
Firstly, riding it. Not confident with the clutch (later) so just polish the dust off it and admire the perfect proportions of this bike's design.
Secondly, starting:
Sometimes fights to start from cold, but once going heats evenly on both sides and when warm ticks over at 1200 all day long. Crisp throttle response too. Those Chinese carbs are great.
Thirdly, that sticky clutch.

The plate stack is so tight the engine stalls dropping the 1st to pull away. Hard rocking eventually cracks the bond of the friction/steel stack and all is well.
Leave it got a day, stuck again.
Can't have this, so going to change the clutch, and hence this post.

Planning to fit EBC friction rings but keep the steel plates. Do you all think this will fix the pack jamming up?
 
Do you mean the steel ones?
With so many parts stacking up i imagine only a few will give the problem. After 3 hours today and after freeing it off with a hot engine then, cold, the stack is stuck again.
Steel and friction plates stack-up a price too!
 
Nothing useful to add from here, except to say that I've got three 175 engines here, all on the original clutches, and I've not experienced a sticking or slipping clutch. Often left for months on end without being used.

As an aside, as a silly teenager, it used to amuse me to sit at the lights in first gear, clutch in, when the lights change rev the engine to 10k then drop the clutch. Only way I've ever managed to wheelie a 175. Haven't yet plucked up courage to repeat experiment on current bikes.
 
I have 3 old clutches in the shed somehow, so will check the steel plates for flatness and rust, new, Wemoto full kit would be about £60 with the gasket, best to fit new...
 
I'm back!
Still fiddling with the bike.
Changed the whole clutch pack yesterday and the difference is totally ...different.
The clutch does not seize up and is very very smooth on engagement.
The new steel plates had a slight stipple surface pressed into each face, somewhere oil could sit.

5th oil change and it has not yet been on the road.

The front forks though do not compress when moving and putting the front brake on or even pressing my body weight onto the bars.
The forks should give under those conditions and re-bound.

Took the forks out and each one compresses well holding the fork assembly upright in a vice and plunging the stanchion down. I have 200mL of fork oil in each (190 ran out of the bottom drain screw port), too much, should be 140cc but doubt that is the reason for the lock-up.


So each stanchion will compress and rebound freely but will not in the bike.

Worried that the head set is damaged or mis-aligned.

Any thoughts before I go deeper?
The manual suggests if the fork action is tight (mine was none-moving) then to tighten the wheel spindle first, then the pinch bolt then the top nut which is wrong.
I would have thought the opposite, tighten from the top going down and make sure the brake assembly will 'just' pass into the forks.

 
If the forks won't compress when fitted to the bike, something is obviously binding.

I assume that both fork stanchions are straight. Next thing to check is that top and bottom jokes are aligned with one another, and that they are not twisted or bent.

I would slacken all the fixings, especially the pinch bolts in the bottom yoke, then see if the forks compress when you roll the bike forwards and apply the front brake. Also, put the front wheel between your knees and give the handlebars a good tug in either direction. If that frees things up, retighten the yoke bolts and see if it still works OK.

EDIT another assumption - front axle spacers present and correct, ditto wheel bearings and internal spacer ?
 
Thanks Richard, I had the first 'slacken everything' bit but I don't recall any spacers/shims in the front hub assembly, but the bike was a bit of a poor rebuild before I had it.
Thought I had done all this on the initial rebuild, but as it all slipped together maybe I got complacent/impatient.
I think I had everything finger-tight, set the head ball bearings to the right tightness and slackened off the top nut so allowing the top yoke to be free. Slid the stanchions in past all the headlamp parts and did the top nuts up over finger tight (where the oil is poured) then tightened the lower yoke pinch bolts tight. Filled the oil on both sides and tightened the top blanking bolts after.
Did the main nut up tight, checked for steering freedom.
Fitted the front wheel BUT did not check the stanchion compression, assumed it would be good.
Will take care tomorrow!

IIRC my gold CB compressed freely and seemed well damped on rebound.
Hope to refit everything tomorrow afternoon.

Wife actually said i should ride it. Need to find a reasonable helmet and gloves, have a leather jacket.

Have you seen the drop in CB prices on ebay recently?!
 
Not sure!
The container just states race weight, nothing else.
With the oil in the stanchion and at the right angle in the vice i can quite easily compress the unit against the oil and it return quite quickly, about 1.5 seconds to recover about 75mm.
 
All back together and working great.
The forks compress when I push down on the handlebars and rebound nicely, almost mimicking the action of the rear suspension when I sit on the bike, so I think that is about right.

So, how come it works?
No real idea except I re-filled the stanchions with 140cc and not 200cc.

Tightened the top/fill bolts first, then the pinch bolts and was able to compress with some effort each stanchion by hand. Fitted the front guard, action the same.
Re-installed the front wheel with the spindle loose, same action.
Tightened the castle head nut nice and tight and aligned the hole with the nearest tighter slot, pin dropped in.

Checked the action, all good.

Bit of a mystery, but the bike is now ready to ride....
 
I hope this is the last glitch before I ride it.

The front brake drum is obviously oval. The previous owner had new stainless spokes and rims fitted by a pro shop well known to many in England.
The front rim is dead true, the drum is not.
New front brake shoes so some bedding-in needed on the road, but that won't correct ovality.

What are my choices?
1
Take the wheel back and tell them the issue and see if they can get the drum and rim true (tricky i would think esp if the drum is permanently bent).
2
Have the drum skimmed as it is currently laced. Is that a reasonable approach, never read about people doing this.
3
Buy a 'new' drum and check for ovality, machine if requred and have the rim re-laced to the 'new' drum and check for ovality after/correct as required
4
Accept this condition and get on with it.

Doubt the factory let these out oval.

Guidance please.
 
Had this same prob on my 550. I just bought a new hub and relaced it to the existing rim. I think the braking surface is a steel insert. I doubt that it would machine correctly without problems.
 
On holiday, posting from my mobile, forgotten password, what fun ...

Anyway, my CB175 has a slightly oval front drum. Advisory at MOT. Brake judders a bit at low speeds, but stops me OK when travelling faster, so I'm really not bothered. Hoping it'll wear itself back round again. But I thought these drums COULD be lightly skimmed?
 
There are a few videos on YouTube of such skimming, one company in Staffordshire (!) but I can't find their details...
Not unknown, so will remove the wheel and try to quantify the ovality.
If more than 10 though i may be in trouble and have to strip the wheel and relace unless the hub has been pulled so hard by the lacing it is permanently oval.
Irritating!
 
I find it hard to believe that spoke tension would be sufficient to pull the wheel hub / brake drum out of true. More likely due to corrosion and wear.
 
I agree Richard, I'd imagine spokes would break or the nipples would strip before they could cause that much tension.
 
Not too much of a stretch, I’ve seen rebuilt wheels with the heavier spokes pull the Aluminum away from the cast-in brake liner. Especially if the new spokes are the original “cross 2” lacing pattern. The best is light spokes in a “cross 4” pattern.
 
I've only read a few times of this level of distortion, but will drop the wheel tomorrow and try to measure the drum ID and check for ovality.
If it is and not more than a few thou then will try to find a shop who will skim the drum.

Could modify my DIY wheel lacing stand so i can rig up a dti gauge which could be better.
 
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