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-   -   1974 yamaha dt360 carb (http://www.advrider.com/forums/showthread.php?t=647090)

Kevin 007 12-26-2010 11:18 AM

1974 yamaha dt360 carb
 
What Mikuni carb is on my 1974 Yamaha dt360a? Is it the 32mm?? Where can I find a rebuild kit for it? or a new carb for that matter...

Tosh Togo 12-26-2010 12:13 PM

Quote:

Originally Posted by Kevin 007 (Post 14785028)
What Mikuni carb is on my 1974 Yamaha dt360a? Is it the 32mm?? Where can I find a rebuild kit for it? or a new carb for that matter...

It's an RT, not a DT...the 'D' prefix in those days referred to a 250... as in TD and DT: all the 350-ish bikes were 'R's...as in TR, RD, RZ, etc.

Check here for parts- SUDCO

eric123 12-26-2010 12:22 PM

Quote:

Originally Posted by Tosh Togo (Post 14785280)
It's an RT, not a DT...the 'D' prefix in those days referred to a 250... as in TD and DT: all the 350-ish bikes were 'R's...as in TR, RD, RZ, etc.

Check here for parts- SUDCO

Then how come Yamaha refers to the 360 as a "DT"?

Tosh Togo 12-26-2010 01:42 PM

Quote:

Originally Posted by eric123 (Post 14785325)
Then how come Yamaha refers to the 360 as a "DT"?

Because things were changing at that time. I never said that the Yamaha model lettering system was cast in stone. Rules get bent, changed, or forgotten sometimes. In this case it may have been a marketing adjustment.

Even though I was there, I don't remember the 70's all that well, so don't press me for all the details. :evil

Medium-bore Yamahas were TD250's, TR350's, DT350's and RT360's until the watercooled engines arrived here in ~1974, and then they all became TZ's or DT's. There was even a DT400 for a while. :huh

Ask an old dirt rider what a DT-1 is. :D

jackd 12-26-2010 02:40 PM

Now you've started something! My brother bought a '73 DT360 and still has it sitting in his shed - yup the old two stroke with the bronze tank. I got a chance to ride it as a youngster. I still remember the similar 250 & I think the 175 from the same year - same style but different coloured tanks. I decided to go to Google and plunk down the 'DT' & 'RT' 360 in the search window and I got the same pictures of the bronze tanked bike both time - though the majority of results showed the 'DT' as being the bike my brother has. So you might be right in your claim of 'RT' as being the identifier for bikes in the 350 range, but I'm not sure.....

concours 12-26-2010 05:39 PM

Yup, for a few years they called ALL the enduro's "DT's", it was kinda lame. Really, the model designations are as follows... JT=60cc. AT=125cc, CT=175cc, DT=250cc, RT=360cc. They even called the street bikes by the same letter design for a couple years, all two strokes were RD's, and all four strokes were TX's. Then they woke up and dropped the designation after the TX750 was a steaming fizzle.

davevv 12-26-2010 08:03 PM

The '74 model is in fact a DT360A. This is mine.
http://davevv.smugmug.com/Other/Yama...78_BGQhf-M.jpg
Prior to '74 the the models were JT100, AT125, CT175, DT250, and RT360.

The '74 DT360A was a one year only bike. The engine is different from the earlier RTs but similar to the later DT400s. It was also the first year with CDI ignition instead of points. There was also a MX360 that was not street legal, and one other even rarer model that I can't remember the details on.

As far as the carb goes, it is a 30mm Mikuni, model VM30ss. I have not been able to find anyone that has a stock parts rebuild kit for them as set up for the DT360A. This is actually a very common carb and is still in production, but there is a world of different combinations of slides, needles and jets. You pretty much have to buy individual parts wherever you can find them. I also have not been able to find the original needle and needle jet (I don't recall their numbers offhand). There is someone on Ebay who advertises custom jet kits for them. I haven't tried them yet, but may be forced to eventually.
http://cgi.ebay.com/ebaymotors/Yamah...item35ae2bb05d

By the way, the best place for info on these bikes is YamahaEnduro.com. Kind of the advrider of old Yamaha ATs, CTs, DTs, and RTs. Great forum with lots of info.

advNZer? 12-26-2010 08:13 PM

actually it wasnt quite as straught forward as that.
this is a dt3 the 250 of about 73
http://motoprofi.com/bikephoto/2709/...250_1973_1.jpg

this is a dt250
http://motorbike-search-engine.co.uk...1973-dt250.jpg

the rt3 was the same as the dt3 but bronze and a 360
the dt 360 looked exactly the same as the dt250 but was of course a 360

Kevin 007 12-27-2010 08:19 AM

Mine is a DT360. Ok a 30mm eh? At least that gives me a starting point, thanks

AC Swank 12-27-2010 10:54 AM

Quote:

Originally Posted by Kevin 007 (Post 14785028)
What Mikuni carb is on my 1974 Yamaha dt360a? Is it the 32mm?? Where can I find a rebuild kit for it? or a new carb for that matter...

You don't say where your at but if you are serious about getting a new carb, visit Vintage Iron. They can set one up to run right out of the box.

concours 12-27-2010 01:04 PM

A new carb would be crazy expensive. The Chinese copies don't work at all. These people have all the parts for all the Mikuni's. No kidding. http://www.sudco.com/

AC Swank 12-27-2010 04:20 PM

Quote:

Originally Posted by concours (Post 14791380)
A new carb would be crazy expensive. The Chinese copies don't work at all. These people have all the parts for all the Mikuni's. No kidding. http://www.sudco.com/

189.95 from Vintage Iron, plug and play.

Riding and maintaining these old bikes is not an inexpensive sport/hobby. If you want cheap, buy the chinese clones.

jackd 12-28-2010 12:59 PM

Still not sure.....
 
I just got back from a visit to my Brother and we started chatting about his old Yamaha. He then pulls out the owner's manual and a period Clymer manual that he still has. The title on the Owner's manual said RT3 360 Yamaha, but he claims that the serial number on the case has RT1 stamped somewhere in the sequence. He was aware of all the confusion that exists with these bikes. It was too crappy/cold out to go out to the bike to give it my own eyeball, so I couldn't verify his claims. We then went to the Clymer book and had a look at the specification section. He was always using the RT3 references for his maintenance but then I flipped across to the DT360 part to compare. The DT360 had the 21 inch front wheel whereas the RT3 had something along the lines of an 18 inch. We go back to his owner's manual and there in the specs it said that his bike came with the 21 inch front wheel. Now he is scratching his head realizing that his bike is actually a DT360 instead of a RT3. I'm glad I've got my Beemer - at least I know what it is.

stainlesscycle 12-28-2010 06:09 PM

that's crazy for a 30mm mik vm. should be $89.95

and 30mm seems awful small to me for a 360. i generally put 32's on 200, and 34/36 on 250's...


Quote:

Originally Posted by Armchair (Post 14792588)
189.95 from Vintage Iron, plug and play.

Riding and maintaining these old bikes is not an inexpensive sport/hobby. If you want cheap, buy the chinese clones.


AC Swank 12-28-2010 11:20 PM

Quote:

Originally Posted by stainlesscycle (Post 14800108)
that's crazy for a 30mm mik vm. should be $89.95

and 30mm seems awful small to me for a 360. i generally put 32's on 200, and 34/36 on 250's...

So you have little to no experience with piston port and early reed valve 2 stroke motors?

BTW, the price is for a plug and play carb, no trial period of selecting the idle jet, main jet, slide, needle, etc. to get the bike to run correctly.


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