CT1 ?

[Dom660]

Hi, I'm wondering if any body could help, I've just bought what I thought was a 1977 DT 175, unfortuanatley there was no paperwork or documents as the guy used it as a feild bike. I've just checked engine and frame numbers which match and they read CT1-312***

Does anybody have any knowledge of the CT1 ?

Cheers

[Cynic]

Hi, I'm wondering if any body could help, I've just bought what I thought was a 1977 DT 175, unfortuanatley there was no paperwork or documents as the guy used it as a feild bike. I've just checked engine and frame numbers which match and they read CT1-312***

Does anybody have any knowledge of the CT1 ?

Cheers

Are you sure of the numbers, CT1 is a prefix that covers a few years.

[Todd25]

Hi as far as I know ct1 was made in 1969 1070 1971. good luck Todd

[Cynic]

Hi as far as I know ct1 was made in 1969 1070 1971. good luck Todd

Incorrect, the prefix code on the engine and frame number coverd the:

CT1

CT2

CT3C

CT3

These were produced from 68 through to 73/4. As i said the numbers don't tally at the moment there should be a zero up front for the CT1's. The AT1's started with those numbers which is what makes it confusing.

Confirmation of the number, and the number of numbers(?) as well as the colour (was year/model specific back then) would help no end.

Wonder if and when they will be back.......

[Dom660]

Hi,there are 6 numbers in the code, Ive double checked the numbers and there correct *CT1 - 3124~~*, the bike was basically stripped of all road gear, it had a 77 era tank fitted and a exhaust of a similair age. This was probably why the guy I got it from thought it was a late 77-ish DT, also it does have a twin spark plug head, smaller sized hinged seat.

Thanks for your help and info.

[Cynic]

Hi,there are 6 numbers in the code, Ive double checked the numbers and there correct *CT1 - 3124~~*, the bike was basically stripped of all road gear, it had a 77 era tank fitted and a exhaust of a similair age. This was probably why the guy I got it from thought it was a late 77-ish DT, also it does have a twin spark plug head, smaller sized hinged seat.

Thanks for your help and info.

Can't really help more, i'll keep at the numbers as i like to track the oddities down but you have the CT prefix with the AT number stream. By no means impossible but does complicate things.

Any chance of some pictures?

[Dom660]

Thanks for the info, though I'm confused now I've found some images of the an early 70's CT1 and the rear subframe area looks diferent to mine, mine looks more like a 73-74 DT rear end. I'll try and post a picture if I can figure out how to load images here.

Thanks

[Airhead]

I'll try and post a picture if I can figure out how to load images here.

Thanks

See FAQ's for pictures

[Cynic]

Thanks for the info, though I'm confused now I've found some images of the an early 70's CT1 and the rear subframe area looks diferent to mine, mine looks more like a 73-74 DT rear end. I'll try and post a picture if I can figure out how to load images here.

Thanks

A 72/73 DT is actually a CT. They changed it about to bring it in line with the success of the 250cc DT1 so the CT became the DT and the AT series was dropped. The only real difference between the AT and CT was the fact that the engines had different barrels and carbs. The AT had 5 ports and no reeds. The CT had 7 and reed controlled induction giving a little bit more power but a much more driveable engine.

Most confusingly they had CT1 prefixes up to 1974 early 75 in some cases.

I don't suppose any of that helped did it.

[Dom660]

Thanks for the extra info, I'm going to strip the bike down over the next few weeks, so I'll check the ports to clarify things.

I'm going to try and register it for road use again so all the information is very useful.

Thanks very much.

[Cynic]

Thanks for the extra info, I'm going to strip the bike down over the next few weeks, so I'll check the ports to clarify things.

I'm going to try and register it for road use again so all the information is very useful.

Thanks very much.

Glad to help, pictures may still help with the identification, there were local differences that went to the american market that we didnt see. Most notably in the gearbox area.

Good luck with it.

[Dom660]

Hi, I've stripped the head an barrel yesterday, I have a 5 port barrel with a reeds which doesnt seem to match with the specs, which seems just about right for this bike. I'm guessing this bike must be 73 or 74 model.

[Cynic]

Hi, I've stripped the head an barrel yesterday, I have a 5 port barrel with a reeds which doesnt seem to match with the specs, which seems just about right for this bike. I'm guessing this bike must be 73 or 74 model.

Unfortunately REED's were a simple and popular mod. It really would help if we had some pictures to work from here?

As you work through the motor look for part/casting numbers that may help on some of the bigger lumps , stuff thats tricky to change. A bike that is nearly 40 years old, especially a 2 stroke is very unlikely to have the original barrel in place, (unless owned by Oldgitonabike ) so i would not use that as a dating reference.

[Dom660]

Good point, the barrell and piston are in mint condition, so have probably recently been worked on, I'll keep an eye out for any other markings on casings and so on.

Another thing that interested me was that Yamaha used to sell piston and carb kits ect, to spec up your DT for off road use, I wonder exactly what parts they sold.

As on my bike I have a Dellorto carb and a 21" front wheel.

[Dom660]

I've contacted Yamaha service today, the guy was really helpful and informed me the bike was a 1975 bike, What I need to do now is try and find its original registration number, does anybody have an idea how to go about this?

[blackhat250]

I've contacted Yamaha service today, the guy was really helpful and informed me the bike was a 1975 bike, What I need to do now is try and find its original registration number, does anybody have an idea how to go about this?

Yip " join the V.J.M.C. . Give them the frame number, and they"l sort you out .

[Airhead]

Thats what I would do too.

[Dom660]

Thanks guys, I'll give it a try. Though my mission is a bit tricky, I've allready exported the bike from the UK to where I live in Guernsey, Channel Islands and need to apply for export documentation from the DVLA which was OK but without any idea of the original reg number its turning into a nightmare.

I'm keeping my fingers crossed the VJMC might be able to help.

Thanks