1972 Honda CB175 Super Sport restoration

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911hillclimber
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Re: 1972 Honda CB175 Super Sport restoration

Post by 911hillclimber »

Put the new switch in and managed to eradicate one set of connectors to the loom. Electrics are better with as few connectors as possible I recon.

All works, key even opens the seat 'lock' but so does a small flat bladed screwdriver...

The carbs are still an irritant and a barrier to finishing the bike off and getting it on the road.

Was going to try dropping the needles one notch down to lean things out a tough, good idea but the needles are already at max depth!
Didn't expect that.

I'm not sure if weakening the mains will help with the high tick-over and reluctance to go to a lower tick over, I can't get it to hold below 1500 indicated.

The water content from the silencers and the engine vent tube:

Does this indicate rich running or not bad at all?

Any ideas what to do next?? I don't see any point to getting new Chinese carbs, now available in UK for about £70 the pair.
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911hillclimber
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Re: 1972 Honda CB175 Super Sport restoration

Post by 911hillclimber »

Happy to report considerable progress over the last 2 days, makes a change.

Tried a lot of float height and needle height positions on the stock carbs and concluded that I'll never get them to tune-in.
Could not get a low stable tick over and always rich.

So, off they came yet again and I fitted the cheap (£14 each) Chinese knock-offs that are not quite right for the sixe of the engine, but worth a go.

After some delicate (as in very) adjusting of the tick over and the pilot screw managed a super stable and sweet sounding 1400 rpm that can go to 1200, even 1100 (but not reliably) and the heat of the silencers is even and very cool running. The fuel consumption has halved.

It has NEVER run this well.

Going to leave it there for now. Have a permission to buy the new correct size Chinese carbs now on the market and selling big style (£71) which I think will help with the running on the road as the choke size is a bit small at the moment.

Will leave the bike on the bench until the carbs arrive. It is so easy to work on using the table.

Soon be spring time.

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coomo
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Re: 1972 Honda CB175 Super Sport restoration

Post by coomo »

Not sure of airfilter set up on this bike.I probably have mentioned this, so ignore it if i have.Is your air filter sealed into casing as in early CB350? if so it will never run right
without air box sealed properly and the use of CORRECT air filter which has the congruent foam/paper foam density.
911hillclimber
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Re: 1972 Honda CB175 Super Sport restoration

Post by 911hillclimber »

oem filters are unobtainable and no replicas either so forced to DIY.

I have used sheet filter foam used by many on these bikes (which generally have the same design just as you say, a complex construction og paper concertina and all glued/sealed to encapsulate the rubber tube (itself complex in shape and handed) so is one unit that seals to the black outer case top which is decorated by mega expensive side covers.

There are NOS in the USA, but the 1972 CB175 and about that year are different in some details, so easy to by the wrong ones and be £150 plus post out of pocket.

I have achieved a good compromise so far and these filters I have made are the same as my previous cb175 which was 1976.

Really does run well with my DIY filters, but have just ordered the correct throat size replica carbs from China.
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911hillclimber
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Re: 1972 Honda CB175 Super Sport restoration

Post by 911hillclimber »

After the false dawn, the carbs finally arrived from Ningbo China Monday last.

Cleared a few errands so to speak and found a few hours to spend on the CB 175.
These carbs look nice, good casting detail and all connected up ready to go.
Swopped them over from the small China carbs that i got going well and connected everything up. Battery a bit flat but tried to start it up. A few farts and grumbles, so charged the battery over lunch time.

Removed the plugs and washed, sanded and greased them and tried a start on full choke. Churn churn, no leaks and Verrrroooom!

Got the slide screws in tighter and warmed it up at 2K rpm, both sides even heat (!), choke off after a minute and left to run some more.

Eased the slide screws to find the sync and eased the tick over way way down such that the screws are almost not touching the slides at all.
Like Richard's carbs (different source remember) the pilot air screws are 1.25 turns out and they still are.

I managed a just about reliable tick over of 1000 to 1100 rpm, snappy throttle response, even temperature. After 5 mins and almost no fuel used i switched it off.

Still grinning, thought i will try again tomorrow and see where we are.

REALLY PLEASED.

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Hugo 356
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Re: 1972 Honda CB175 Super Sport restoration

Post by Hugo 356 »

True Grit! :cheers:
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911hillclimber
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Re: 1972 Honda CB175 Super Sport restoration

Post by 911hillclimber »

He looks as I feel!

Amongst several car related errands and fights, as relaxation decided to cold start the Honda just as I left it last evening.

Fuel in.
Choke on...
Ignition switch: click.......
Press button...........................

Vrooom the thing started first stab.

Delicate running while coming off choke and then a steady 1300/1200/1100/1200 tick over for ever and ever.

Blips of the throttle, 1200 rpm for ever and ever.

It works.

Tank on tomorrow, cut fresh fuel lines (very noticeable how quickly modern fuel lines harden with all this petrol change), pet--**** connect and get the bike to the ground.

Registration Log Book (UK description of the US Title) came today listing the bike as 'Historic Vehicle', so no tech inspection (our MoT) and no road tax to pay.
Will the wife let me ride it, a $1,000,000 question.

Quite fancy a 125 twin.
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neilbardsley
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Re: 1972 Honda CB175 Super Sport restoration

Post by neilbardsley »

Nice work Graham. Another super bike for someone to enjoy

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911hillclimber
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Re: 1972 Honda CB175 Super Sport restoration

Post by 911hillclimber »

Bit of a significant moment today, getting this Labour of Love (?) off the assembly table, first time in 8 months.
Forgotten how small they are and of course how aesthetically appealing they are too.

Used my trusty engine hoist to lift it off, always a nail biting moment and detached the support cradle from the front peg mountings.
The cross arm of the front pegs was a fiddle to fit, but a few spacers got it clear of the exhaust both sides and all is well.

Next is the side stand which needs a tweak. Not sure what it is off, but not this bike!

Tank on and cross pipe in place, petrol tap tubes next and ready to start on a tank of fuel.

A few more jobs to do on it but need to fix a road car this weekend as an Urgency, so hope to RIDE it out front next week which promises to be dry.

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Darren65
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Re: 1972 Honda CB175 Super Sport restoration

Post by Darren65 »

Looks great Graham 8) :thumbright:
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Re: 1972 Honda CB175 Super Sport restoration

Post by Kirklands 904 »

Graham,

I have just come across your rebuild topic as for some reason I had not been on DDK for a couple of years.

My last project to do is my Honda CB175 RTG516M which I have had from new in 1974. It was provided by my employer and replaced my company car in the midst of the petrol rationing situation. All might be revealed in due course!
Bill

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911hillclimber
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Re: 1972 Honda CB175 Super Sport restoration

Post by 911hillclimber »

Hope you get stuck-in soon Billy, it will save me from doing another Honda (or even another Lamberetta.)

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coomo
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Re: 1972 Honda CB175 Super Sport restoration

Post by coomo »

Great job.Finally all the frustration and effort has paid off.Bike looks fabulous.Build quality wise, nothing beats a 70s Honda.
911hillclimber
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Re: 1972 Honda CB175 Super Sport restoration

Post by 911hillclimber »

It was the build and design that drew me back to do another Honda. That French bike and in some part the Lambretta are quite crude.

Now off the stand I have to move the CB by hand, feels very heavy!
Forgot to get/make a grab handle to assist in heaving it up onto the centre stand, job to be done, maybe tomorrow if I can.

£30 to buy used but most in the USA.
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Re: 1972 Honda CB175 Super Sport restoration

Post by Ashley James »

Lambrettas and Vespas are utterly reliable and durable, nice to work on too, but Brit and French economy two strokes are dreadful.
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