I recently purchased a 1974 DT250 which is in pretty good condition.  I took it out for my first ride and found it was 'blubbering' at pretty much any RPM over idle.   I took a look at the carb and found that the engine inlet spigot was wrapped with electrical tape, probably not making the best seal.   I also saw that the air cleaner boot barely reached back side of the carb.  Doing some research, I found that the carb I have is for a 1977 DT250 (Mikuni 1M1/00).  The O.D. on the carb I have is 35mm, but the I.D. of the intake boot is 40mm.   The electrical tape was used to fill in the gap.   The carb I have also has a spigot for oil injection, where the 1974 was still injecting oil into the cylinder.  The carb I am supposed to have is a Mikuni 438/60 (VM28SS).

I have attached a picture I found on the forum that shows the 40mm O.D. inlet on the 1974 Mikuni 438/60 compared to the 35mm O.D. inlet on most VM28 mikuni carbs

So here's my questions:

- Does anyone have a 1974 DT250 carb for sale in good condition?  (Mikuni 438/60)
- Does anyone know of an adapter to change a 35mm O.D. inlet spigot to 40mm O.D.?
- Does anyone know of an adapter to add to the overall length of the carburetor so it will reach the rubber carb boot? It only needs about 3/8".  (I tried pulling the rubber boot).  Maybe the spigot adapter could also add to the length?
- Has anyone successfully adapted a new Mikuni VM28/49 to a 1974 DT250?

Any assistance would be greatly appreciated.





 

There is this one in the UK.

YAMAHA DT250 DT250A 1974 CARBURETOR CARB | eBay

If you were interested, I would suggest checking with the seller that 438 is stamped on it.

Thanks, that was a great find.  It didn't show up in any of my searches.    It appears the seller is in the UK and ebay mentioned he may not be willing to ship to the US.   I sent him a message to check.

It did mention that it was stamped 438.

I'd be surprised if he didn't ship to the US. He's quite a large and respected UK ebay seller and should be able to use their Global Shipping Programme - this means that he only has to post to a UK collection address and doesn't have to complete any customs forms.

Anyway, if he says no, then I am happy to buy it for you and then post it on to you - I am in the UK and have done this for a couple of other forum members in the US.

I'm logging off for the night now, so won't see any further replies until tomorrow morning.

Thanks for your help with this.  I sent you a PM.

If I could get to my parts, I have a 74 DT250 that I should sell off parts too.

Thanks Sneezles.

I have bought the carb in the UK for Yamdog, but you shouldn't have any problem selling your DT250A spares, should you part it out. Talking of which, do you have petrol and oil tanks in good condition...........?!

Tank is on the RT2… but the oil tank…hhhmmmm.
Perhaps tomorrow I can find it.

"Tank is on the RT2… but the oil tank…hhhmmmm.
Perhaps tomorrow I can find it."

Thanks Sneezles, but I'd be wanting both tanks!

I have a DT360A which now runs, sort of, but both tanks will need attention. I prefer the 250 colour to the 360 (the best colour is the Euro market black, but I was too slow spotting some on leboncoin in France), hence my post regarding yours.