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1973 CT3 175 rebuild. Hopefully.......


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On a strange impulse I bought this a couple of weeks ago....

ct3-L.jpg

Its an American import, and to my reading of the frame and engine number (CT1 - 120315) it is a CT3 175, circa 1973.

It starts, runs and selects all gears.

But...(there's always a but, isnt there?)

The kickstart flops about and doesnt engage unless you lean the bike to the right. Not ideal.

Most of the bike seems to be in reasonable order, and there is some common parts to the TY's I'm used to working with (I have two that I trial regularly)

so I thought I'd investigate further.

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Pulling the side case off showed the problem to be a little more serious than I expected.

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Finding half of the broken spring clip was easy, but the other half needed some fishing with a magnet. I also dragged out a sizeable lump of casing...

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Ho hum. Time to get creative. I pulled the other side case off in readiness for taking the engine out, and found damage there as well.

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The U-shaped hole centre screen, above the clutch arm, is not how Mr Yamaha intended. And all the oil spread everywhere is from an ingenious chain oiling idea...

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Put the sprocket nut on the wrong way, and you get a constant stream of oil direct to your chain, ingenious!

Not to worry, so far, nothing completely fubar. Yet.

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Engine out. The pine needles are from "The big storm", blowing the buggers under my garage door.

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And here's the empty frame. Some cleaning up to do while I decide how best to sort out these little problems. Helps that I've just picked up an AT 125 engine, same crankcases, to compare and contrast, and possibly steal from.

Mark

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Good start mover" its a tidy wee bike, and your used to TY"s , Alloy front fender ? this not standard eh,, were low wern"t they,,?

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Hi Blackhat,

That's a genuine ally-lookalike plastic Preston Petty front fender! You're spot on though, the original was a low mounted metal affair, with a nice long cable keep to stop the front brake cable sticking out at the side like it does now. Jury is still out on just how much money I spend on this one, but I have seen replica ones on eBay.

Mark

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Looking very nice. (bar the in side of the motor ha ha)

Look forward to seeing how she turns out

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No idea on what you paid for it but a very nice piece to start with,is the paint original?

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Hi DT, how much is probably too much, but it keeps me off the streets.

Paint is original yes, faded badly on top and quite scuffed, probably due to being thrown into a container with as many other old trail bikes that a certain importer can source from your side of the pond. Then sold on to nostalgic mugs looking to resurrect an object of their youthful lust all those years ago.

Mark

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That would explain why thoes bikes are getting so hard to find this side,rarely do you ever see 1 in that nice of shape thats original.And by rarely I mean almost never.

Personaly I would weld up the original cases,find a proper fender(if possible aged as well) and leave it as per is. Faded paint and all.

Just something about walking up to a bike that you can tell it is unmolested original,but still ridden is a ultra cool factor,bikes are a work of art to some of us and as they say beauty is in the eye of the beholder. To me all a bike needs to be is clean and in good working order to be beautiful,faided paint just shows how good the paint was to last all thoes years.

Some bikes you have no choice but to start over to make them even ridable,but taking a bike thats almost as new and redoing it to be new is a shame IMO,letting it show it`s battel scares of victoy over the years is more impressive to me than any `restored`` bike.

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That would explain why thoes bikes are getting so hard to find this side,rarely do you ever see 1 in that nice of shape thats original.And by rarely I mean almost never.

Personaly I would weld up the original cases,find a proper fender(if possible aged as well) and leave it as per is. Faded paint and all.

Just something about walking up to a bike that you can tell it is unmolested original,but still ridden is a ultra cool factor,bikes are a work of art to some of us and as they say beauty is in the eye of the beholder. To me all a bike needs to be is clean and in good working order to be beautiful,faided paint just shows how good the paint was to last all thoes years.

Some bikes you have no choice but to start over to make them even ridable,but taking a bike thats almost as new and redoing it to be new is a shame IMO,letting it show it`s battel scares of victoy over the years is more impressive to me than any `restored`` bike.

Yes, agree wholeheartedly, it is my intention to return it to a useable state, not concours condition.

Mark

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Hello,

Those kickstart mechanisms are very similar to the kickstarts found on the Later 1989-2004 kickstarts.

Yes, and almost identical to TY 175's. The problem I have is that the "stop" in the crankcase has smashed off, but dont worry, I have a cunning plan.......

Mark

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Oh I do love a cunning plan !!! What a pretty little bike, you must be quite chuffed with it. Will keep watching with baited breath (WHAT does that mean?) also like the idea of not messing with it to much, good luck.

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, but dont worry, I have a cunning plan.......

Mark

Really baldrick? a cunning and suttle one? as cunning as a fox thats just been apointed professor of cunning at Oxford university?

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So after taking the clutch and kickstart mechanism of, and a thourough clean up, we have this.

IMG_9234-L.jpg

The scars and gouges are a result of the broken spring being forced around with the kickstart gear by the previous owner, but they aren't going to be a problem. First thought was to drill and put a nut and bolt through in place of the missing stop, but there are webs at the back of the crankcase which put paid to that idea. There is enough meat to drill and tap it though, so that's what I did. I'm not that good with a camera and unfortunately the shot of the drilled and tapped hole was blurred. An M6 allen bolt was carefully screwed in, et voila!

IMG_9236-L.jpg

Some liquid gasket to seal the threads seemed like a good idea.

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But when I tried the kickstart mechanism there was a slight problem. I hadn't realised the importance of the hole in the casting just to the right of the allen screw. It's where the tang of the kickstart spring clip fits, and without the hole to locate it, it can rotate on the shaft and force the starter gear into the idler gear all the time. So out with the JB weld. I first undid the screw and picked off the liquid gasket, then re- applied it only to the threads in the hole. As I now have a good solid "stop" for the kickstart to return to, I don't have to worry about the shearing force, so I just need to replicate the shape in the casing. As it happens I have a example to work from lying at my feet.......

IMG_9239-L.jpg

I carefully pressed a blob of JB weld in place with a screwdriver and built it up to what you can see here. With the idler gear in place, I was able to drop the kickstart in to check I hadn't overfilled, which I had, and carefully remove any excess with a Dremmel. I took a picture, but again it came out blurry. Too concerned about getting dirty paw prints on my Girlfriend's Canon.

Back on with the clutch, fitted the seal holder from the AT engine which had been missing, new gasket and bolted it back together. Poured some fresh oil in, and then stood it on end overnight to test the integrity of the seal. No leaks, result!

Replaced the engine in the frame.

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Notice it's a lot cleaner now? Not pristine, but cleaner. The shift drum cover was missing, so another piece robbed off the AT. Two of the three bolt holes are damaged, but I was able to get enough purchase on two of them to hold it.

Whilst the carb has been off I've checked that through and cleaned it, then refitted with an NOS connector boot and a new oil pump cable courtesy of Venhill. Switched the clutch actuator arm from the original cover to the AT one and fitted that, along with the magneto cover. Oil tank, petrol tank and seat back on, bled the oil pump through, chucked some fuel in and wheeled her outside.....

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After a couple of wary prods on the kickstart, which went without hitch, I switched the fuel on, pulled the choke and crossed my fingers. Second kick was a splutter, third kick and she sprang to life!

Need some daylight and a quiet stretch of road now to see if my theory about the clutch is correct, then I can start on the little things which will probably take months to get done.....

Mark

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Result !!! Well done nice job that man. looks ok for an old bike and can only get better. :jossun:

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Yeh mark , plenty time,,, salt on roads now,, so be march before the weather gets better. restoration time,, :jossun:

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earthmover,

Your bike is very similar to the AG175 frame #428. AG has a plastic front guard, racks front and rear, rear brake rod goes over the swing arm,two spark plugs in the head, 11litre fuel tank. Mine also has the broken case on the lefthand side.

Your bike has had a very pamperd life, nice find.

wassie

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  • 2 weeks later...

Quick update.

Saturday afternoon saw me visiting a local farmer friend, who is also a keen off-road rider, and happens to have a long concrete driveway!

With the gearing as it is at the moment, I can get all 5 gears within 100 yards, but at least it proves they all select. With fresh oil the clutch is a lot better, but it still slips at higher revs? Not entirely sure about why that would be. The kick start works ok though, so back into the garage, and I think we'll start with the back end first........

Mark

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