1970s DT175 Twinshock old Barn Find

[Teflon-Mike]

duel plug holes was common on air-cooled era bikes., espciailly the larger displacement 350 & 350 singles, where one hole was often fitted with a de-compressor to aid finding TDC on start up.... a hang-over from the big banger four-strokes.
On 2T's was most often so that a softer grade plug could be used on start up, then the HT lead swapped over to a hotter grade plug when warm.
Or as many did, used the second plug if the engine started missing as the primary plug oiled up.
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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?'

[Teflon-Mike]

[nbuuifx]

I emailed Yamaha motor Europe. They said it is a 1969 ct1. They think it was meant for the Japanese market so they don't have any registration details.

[Suntan Sid]

1G1 clarification from this site:-

https://yamaha-enduros.com/index.php/uk-vin-information

[Easy-X]

Nice one! It certainly looked like a late '70s twin shock.

Thanks for the confirmation
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Fizzer Thou]

Lots of pictures on goggle images

https://www.google.com/search?q=DT175+CT1&hl=en&tbm=isch&tbs=rimg:CYl84oQZJap8IjgMPe6cS4tWtaPig1cJVbw0XQJTiZq2emb_1jbaOsTaBKaxeN2p1EC8KsxsO6KG0i6vm5F2HNhKaVyoSCQw97pxLi1a1EUS4r2HoD76MKhIJo-KDVwlVvDQRPO71G7_1xEp0qEgldAlOJmrZ6ZhHtp1JlG08UlCoSCf-Nto6xNoEpEf-Cvy1-lfLqKhIJrF43anUQLwoRr1_1Ed30TzO8qEgmzGw7oobSLqxG-OkjDVgQ6TioSCebkXYc2EppXEdL9RVpxOeKB&tbo=u&sa=X&ved=2ahUKEwiU-bK1_pXhAhUJnRoKHfKMD64Q9C96BAgBEBg&biw=1024&bih=667&dpr=1

As for Stevos comment...

"Your post comes across as looking for the best way to shift it off your hands.

You and I know it needs a full sympathetic original restoration at huge cost. It'll make a nice project for someone, but that person isn't you.

No one takes on a full resto unless they have a real interest or desire to own the particular type of bike, for reasons such as:

1, They had one when they were 17 and are trying to get that feeling back of their carefree first bike happy days.

2, Same as above but the bike is the actual machine that they once owned, or the bike that they aspired to own that got away.

3, The bike was left as an inherited sentimental item from a family member or friend that has died.

If none of those apply to you, then your best off rid of it. Its project status anyway and it won't appeal anymore to people loosely nailed back together in one lump than it will as a collection of parts in boxes.

You should be able to get an idea of value from adverts for similar spares and bike parts/projects. I wouldn't waste any of your time on it that you don't need to.

Someone out there will really like to get stuck into that bike as a classic trail bike resto and will enjoy the build too"

I bought a Yamaha DT125LCII for the only purpose of doing it up as a project and to sell it on.I had absolutely no interest at all of keeping it for any reason and had never owned one before.I paid £25 for it and sold it for a considerable amount more and spent as little as possible without skimping too much.But what it did teach me was where to look for spare parts before the internet.

It looks like a worthwhile project for someone who has the facilities and the knowledge of how to use a spanner so have a go and see how far you get OP.If all else fails,ask on BCF
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Just talk bikes.What else is there?

Always have a 'Plan B'

[Riejufixing]

[nbuuifx]

Had another play today. Wasted some more time on bits that don't matter but that's half the fun.

I'd really like to get the engine fired up just to make sure it will run.

Any tips on what to do with an engine that has been stood for so long?

My thoughts are...

Put fuel in the tank, swill it around and tip it back out to check for crap in the tank. The tank looks spotless inside from what I can see through the filler but that isn't a great deal.

Put some oil in the engine as it is empty.

Mix to stroke oil in the tank in case the auto lube doesn't work.

Fill the auto lube up as well to check if it works.

Anything else?

I can't get to far yet as there is no ignition coil!

There were two could in the box but they were both 12v and they both have two ht leads each. I take it they won't work?

Is there a way to bypass all the wiring and just have the spark plug wired up when I do get a suitable coil?

I've put the exhaust on for now.

[A100man]

Clean the carb with proper cleaner. Blast out all the passages you can find.
If it's a 6V then you will need a new or known good coil of teh right spec (primary Ohms). It may earth trough itself to teh frame so make sure that's in order bare metal. Have a good look at the points, in fact buy a new set from yambits. You may need a puller for the magneto to get to them - I had a DT once but that was about 40 years ago. Set timing and points gap.. You can use the pencil down the plug hole trick to verify TDC (approx)and go from there
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Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

[Teflon-Mike]

Much as hearing engine noises is 1/2 the fun, its really the last thing you need tackle.......

As to first fire:- Get some clear PVC widscreen washer pipe from the motorfactors and re-plumb the auto-lube. Clean out the auto-lube reservoir with petrol. Then spin the motor up until you can see the auto-lube piping fill with oil to ensure it's primed.

The oil injector pump is lubricated by the oil it pumps. No oil no lube, they wear and seize and have habbit of stripping the pump gears.

Common problem of old from folk thinking that all they had to do was mix pre-mix and that was that.

As for the ignition; its a mag. Electric for sparks is made in the megneto when engine spins. When engine spins, magnet on rotor passes ignition winding on stator, makes volts. Volts get sent to the coil. Coil 'energises' as volts build, then the points open. Points switch 'off' electric to coil and the magnetric field in the coil colapses, to which the coil responds with a reverse voltage to oppose the speed of change, and that is what gives the 1000x amplification to turn 6v low-tension current, into 6000v High-Tension current that will jump a gap and make a spark....

And it does it every time that the magnet on rotor passes winding on stator and the cam on the rotor opens the points.

The condenser, is a capacitor, and its connected across the points. When points closed, there's equal volts on both sides, so no electric flows through it. When points open, theres volts one side, none the other; so as the coil starts amping the volts to make enough that will jump a gap... the condenser sees the voltage difference and starts to charge, so it 'soaks' the current and charges up, so the electric is less wont to jump accross the points gap, than it is the spark-plug electrodes.... saves arcing and pitting points... but also, when points close again, the electric it charged up with is dumped back into the coil to help energise it for the next spark...... cleaver hugh?

But.. make sure points are good, and replace the condenser.

They are like a little battery, and have two foil 'plates' wound around a bit of acid soaked tissue paper, that stops the plates touching.

Over time, the tissue drys out, and the condenser will fail, and erratically.

If the acid drys out and the tissue rots away, or is burned away by a spark jumping between the plates, they can touch, and the condenser can go closed circuit, and couples accross the points, it has the effect that the points never break the circuit so cause the coild's field collapse, so no sparks.

If the acid drys out and the plates never touch, it fails open circuit as though there was no condenser, and you get sparks... but as often as not accross the points not the plug, and the points pit and the timing gap goes erratic.

Annoyingly... they can do both, or neither, and pretty much similiteniousely, so you get an ignition problem, and have devils own job trying to fathom it....

So just swap out the condenser before you start... saves soooooo many stupid questions later, and much muggering about poking things through the rotor windows!

Asside:- Trick-of-Old, was to wire a condenser, usually for a Mini or Morris minor (Cos cheap and readily available at halfrauds etc) between the LT feed to the coil and the frame. Either in replacement for the one in the mag, or as aid to it.

Anyhow; ignition as far as sparks go is 'Self Exited'.. it works when the engine spins, and makes sparks as it spins.

Its turning the engine 'off' that's the tricky bit.....

The ignition 'switch' then doesn't 'make' or 'break' a circuit to let electric to the coil, it make or breaks a circuit that 'short circuits' the LT feed to the coil, and re-direct the electric to earth.

No switch, engine running, it will keep running, making electric and spark each time magnet passes winding.

Switch then T-s in to the LT feed to the coil, and kills the engine by directing electric to earth, so sparks stop jumping and engine dies....

If no switch?

Well, brings back memories of the consternation I caused when I was ten, and dragging and old pedal and pop moped out of the garage was told "If you can fix it, you can 'av it', in expectation it would keep me out the way for the afternoon... The problem that had seen pedal and pop shoved in the back of the garage though, was that it had a short circuit in the headl-lamp and the ignition was constantly 'earthed'... as precocious 10 year old, I looked at ped, looked at rats nest of wires every teen-ager and self proclaimed expert had prodded, poked and wrapped in insulation tape.... and ripped it all out! Doweneed-dat, do I? and low... ped fired up.... cos I had got rid of the short ciurcuit.... and any means of making another to 'Stop' the engine!

Conclusion of this, was watching uncle try and 'stall' a twist and go... not easy... every time he opened the throttle, it reved up and made more load... so he sort of lurched up the garden a lot trying to hold the brakes on, and fell off! Then tried reving it up with the front wheel held against the garden wall.. which just made a lot of smoke.... then Grandad turning up and telling him to get out the way, and saying, "where's the coil?" Which on a pedal and pop with pure magneto ignition, there wasnt one! The 'coil' was the ignition winding in the mag! So he started trying to short the HT feed with a big screw-driver... got a lot of jolts, cursed a lot, and eventually managed to get the plug-cap off with a pair of mole grips and a few more jolts..... I was NOT popular that day!

BUT... there's your issue, getting it to 'run' is not a big deal, just isolate the ignition circuit from anything else and get kicking....

How you STOP the thing after? Well, that could be fun.....

Hint; a wire from the LT feed to the coil, that you can earth against the frame to micmick what the ignition switch would do, is good enough. BUT you do need to put that bit of wire in place BEFORE you get the thing started.

Elsewise..... back to top.

Why mess? If its just for fun, then well, like warning on auto-lube, random poking and prodding, is as likely to kerbigger stuff as fix it, or even tell you wnat aught be fixed, and you can spend a lot of time and effort, that 'may' be fun and better wast of time than playing golf.... BUT it's not making the thing any more saleable, if you intend to get rid, and isn't making it any more useable if you intend to go ride, and it isn;t making it any closer to roadable if you want to go use.

Think long and hard what you are actually trying to achieve here.

IF you want to restore it... bite some bullets and get it down to the frame, and start sanding stuff.

IF you want to get rid.... just get rid.

Idle messing like this, may be more fulfilling than playing Golf, BUT, end of the day, aren't really doing anything particularly useful, just skinning knuckles and giving you frustration..

And Motor is only half the word Motor-Bike, there's a lot ore to one than the engine, and much of it is far more important.

Old addage, BEFORE you try 'go', make sure you can STOP!

Brakes, steering, suspension, all tend to figure slightly higher up the list than whether engine make peekie-peekie noises!

Its a pretty rudimentary air-cooled two-smoke, there's basically only three moving parts, the crank, con-rod and piston, in tear-down, you would probably get the thing re-bored and use a brand new piston, crank would probably be pressed apart and rebuilt with new bearings and con-rod.... youd sap out all them bits anyway!

So whether engine shows signs of life of not,k is pretty immeterial. If it does? Well, Oh-Kay... but how good is it? Even if it runs it possibly aught be re-conned anyway, so you aren't particularly discovering anything or fixing anything. Its a two-stroke, in the grander scheme run or not make little odds, if you want it to, it will. State of the wheels, state of the brakes, state of the suspension for WHEN it runs, is far more important. Remember, before making it go, make sure you can make it STOP!
____________________
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?'

[nbuuifx]

Brilliant - thank you - loads of information there!

I know what you're saying with thinking about what I want to do but I honestly don't know and I'm fairly laid back.

I'm having fun with it at the moment, it doesn't owe me anything so I just want to see what I can do.

I'm far from an expert with these things, but have done plenty of messing over my time. I've had a variety of Land Rovers and done the many hours of bashed knuckles with those. I've rebuilt a V8, rebuilt a series 3 gearbox. I've had various motorbikes in the past and completed the maintenance on them.

I'm very guides based, and need a good guide to follow but normally get good results! I like the simplicity of the Yamaha.

I might get to a point where I decide I don't want to do any more and I might sell it, or I might decide to keep going with it and get it to a point where I can ride it. I kind of like the fact that it doesn't matter. I'll try not to spend a fortune on it, but may well get to the point where I complete it and ride it, but then start to replace other parts to make it better.

I kind of like the fact that I was given it as a bit of a challenge which I kind of failed to finish but now actually might! When I started about 13 years ago there was minimal information on the internet regarding them, now there is much more.


In terms of the rest of the bike, the frame was stripped down and resprayed when I first got it as was the swinging arm. So they are in good nick.

The seat is usable as is.
The tank and autolube tank look good enough to use as is and tidy up later.
The kick stand and foot pegs are usable as is.
The exhaust has surface rust but is solid.
The rear suspension seems good, and acts as it should according to the service manual.
The front forks are a bit pitted on the chrome, not ideal but operate correctly.
The wheels have some corrosion but are sound, will hopefully clean up.
Brake shoes look serviceable but will probably change if I get it running.
Airbox looks complete.


Only problems I can see right now are...

I haven't found the clutch lever yet.
The hi low switch is broken.
The ignition coil is missing.
Headlamp is missing the glass lens.
The rubber is missing for behind the rev counter.
I'm missing one of the rubber tank mounts.
I need to find the two bolts that hold the foot pegs / kick stand on.
I haven't identified the bits that make up the rear axle. I've got the main parts but need to work out which bits are the collars etc.


I've put most of the bike together now.

I found the three bolts that hold the engine in place.
I put the bearings into the races in the headset and found all the bits to bolt all of that together. I need to find the clamp bolts for the upper and lower yoke.
I found all the bits for the seat - the clip was rusted, so have cleaned it all up and repainted it.
I found the bash guard and have bolted that in place.
I found all the bits for the mudguards but they need a bit of cleaning up as they both have substantial surface rust.

My next jobs are:

Put the handle bars on and put all the relevant bits on.
All the electrics need doing.
Find the bits for the rear axle.
Fill up transmission oil.
Get the engine running.
Clean up the mudguards and repaint.
Clean up the exhaust and paint with high temperature paint.
Apply for registration documents.

As I say I'm quite enjoying spending the odd hour on it now and again at the moment. I don't mind spending a few quid here and there but don't want to spend a fortune.

I'll order a 6v coil and a condenser to make a start.

Thanks again.

[nbuuifx]

I've ordered a 6v coil.

However I'm struggling to find a condenser without spending silly money.

Are they specific to the model or are they fairly generic?

I've seen bosch ones for sale etc. but doesn't say what they are for.

I think I've found the old one in the box of bits but it looks beat up, looks like a previous owner has taken it apart in the past.

[Teflon-Mike]

Try Yambits and cough-up..... they aren't a generic part, they are common to many models of mag or dizzy, but not universal.

Think the ones on the air-cooled early Yams are mostly the same part-no across a lot of similar era Yams, like YB100's, air-cooled RD Twins, pretty certain they are the same as the XS500, and variouse others, but they aren't a universal or generic part.

In days of yore when points were almost universal, they 'were' a penny part, now? They dont have the mass-market ecconomies of scale to ce so 'cheap'.. as comment in earlier post, price of points and condenser for my DT175 were a little eye-brow raising... but if you are afriad of spending £20 of so now... get rid of the lot..... you could easily chuck a couple of grand at this bike and STILL not tackle everything....

As warned earlier, you could chuck as much money away catching a cold on a canal bank or ruining a good walk in the country and have as little to show for it.... but... few restos are particularly 'cheap' and even less result in something worth the money, let alone blood sweat and tears they take.

Again, stop playing at it with naive optimism... grasp the nettle, and either do it, and do it justice, or get rid.

See profile: there's links in there to 3 or 4 of my restos of recent years, including the DT175 I tackled, as a 'pocket money project'.... y-e-r-s..... almost two grand later..... without having tackled an engine rebuild, or re-spoking rusty wheels, or or or ..... I had a rather prettily painted pile of old scrap... that did run.... and it had brakes that worked and and and... BUT....Took a heck of a lot of work, it took a heck of a lot of money, and it took a heck of a lot of time.... and there was a lot of blood sweat and tears along the way.

The Austin series condenser trick? Did look on my webby, pretty sure I wrote up a how to, cos the old Cota engine with Motoplat mag was renown for short lived condensers 'cos of thier location on the back-plate in a hot spot on the crank-case... but photo-explanation seems to have gone awol. Use of generic Lucas condenser tagged in accross the coil, was convenient mostly because you could pick one up in any motor-factors, as much as it may be any cheaper... it probably still is... but again, you are fretting over a couple of quid, on something likely to cost you hundreds!

If that small difference has you clutching at mods and bodges, to try save a pittance? REALLY go re-evaluate the whole plan here!!!
____________________
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?'

[A100man]

https://yambits.co.uk/dt1b-condenser-p-46069.html
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Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600