Since I last posted I got the bike running. I ported it and oval bored the carb to 36mm with a file. The jetting is afowl until 1/3 throttle wherein it clears out. I am going to try a smaller pilot jet and a jet needle that is leaner at those openings. The main then may need to go larger, so I will get a few pilots, a few mains, and needle tapers. Bike gets on the pipe as the carburetion clears out I believe. I am having a guy named Gary Brown build a pipe for my bike should add quite a bit of power even on a stock bike,oh and mine's a 78 so the pipe will only work on 77 and 78 probably dt250s too as well as a dt400s but it's going to take a while cuz it needs a rolling frame to build it and so it'll be a while. Thanks again for the showing me the build on the carburetor I felt like I was doing it as you were doing it.I have had my car off quite a few times now and it's getting pretty easy I want to recommendation is put a little grease on it inside of the intake manifolds or on the carburetor front and back so when you do pull it off and take it off it's so much easier I mean I know that 75 different than the 78 but for me the grease really helped so much because these manifolds are pretty stiff by now being 40 something years old.
Good advice my friend, I use 'red rubber' grease so as to not have any long term adverse effects on the rubber surfaces. Also soak in warm water for a while before fitting works for me.
@@brucepauley6718 do you think I should take down the video for such misleading information, or leave it up to help even more people than it already has. More than happy to send people to your video if you let me have the link
Thanks for the video - at 3:18 there is little plastic elbow that helps to stop the fuel from spilling out of the carb. Any idea what that piece is called, and where I could find one? Mine seems to be missing.
Hi, it's a 90 degree elbow that connects the carb (a VM32SS ) to a piece of tubing as a breather I believe (although have had a way flooded carb pass fuel through it). It's a part that is nearly always missing and they are like Unicorn crap to find, the engines seem to run fine without them though. I improvise the part by using an elbow connection intended to join aquarium pump tubing, I use the type with brass fittings with a plastic body, brass because petrol fumes pass through and could perhaps dissolve a 100% plastic type. Just about completed another 1975 DT400 B, just need to finish of the electrics; hopefully a running and riding video soon. Cheers Paul
Thanks for the info, Paul! It makes sense that they are usually missing because this is the first time I noticed it. My bike has been sitting for about the last year and when I went to start it today I turned the fuel on it just started pouring out of that hole where the fuel inlet goes. I’m guessing I need to get in there and take the carb apart and clean it really good. This 75 Dt400b is my first bike. I live in Vegas and it’s been fun to take up in the desert hills. Would you mind if I reached out with other questions? You definitely seem to be the expert! If so, is there a an email I could use or would you rather I just comment on the video?
@@justindewey953 you may have more luck with spares in the US then we do in the UK. Not a expert, more like a well meaning meddler. Contact me anytime, messenger or whatsapp. To give you some indication of costs, a fully restored US bike will sell for up to £5000 gbp / 6000 USD
No need to on this occasion, after ultrasonic cleaning and several blasts through with cleaner and air it was as clean as a whistle. As you can see in subsequent videos the engine ran like a champ. Cheers Paul
Since I last posted I got the bike running. I ported it and oval bored the carb to 36mm with a file. The jetting is afowl until 1/3 throttle wherein it clears out. I am going to try a smaller pilot jet and a jet needle that is leaner at those openings. The main then may need to go larger, so I will get a few pilots, a few mains, and needle tapers. Bike gets on the pipe as the carburetion clears out I believe. I am having a guy named Gary Brown build a pipe for my bike should add quite a bit of power even on a stock bike,oh and mine's a 78 so the pipe will only work on 77 and 78 probably dt250s too as well as a dt400s but it's going to take a while cuz it needs a rolling frame to build it and so it'll be a while. Thanks again for the showing me the build on the carburetor I felt like I was doing it as you were doing it.I have had my car off quite a few times now and it's getting pretty easy I want to recommendation is put a little grease on it inside of the intake manifolds or on the carburetor front and back so when you do pull it off and take it off it's so much easier I mean I know that 75 different than the 78 but for me the grease really helped so much because these manifolds are pretty stiff by now being 40 something years old.
Good advice my friend, I use 'red rubber' grease so as to not have any long term adverse effects on the rubber surfaces. Also soak in warm water for a while before fitting works for me.
Just got a 76 dt 250 mx, finally found out from your vid how to measure float height, cheers Paul
Great, thanks for commenting.
If you haven't already could you please subscribe.
Let me know how you get on with your bike.
Thanks for the video! Helpful as I'm getting my carb setup as well!!
Thanks for the comment, hope all goes well.
Safe miles
i just got a 75 dt400 and this will help me so much
Thanks for the comment David, much appreciated.
It's not a choke. Its an enrichment valve. Instead of "choking" off air, it opens a fuel jet
@@brucepauley6718 do you think I should take down the video for such misleading information, or leave it up to help even more people than it already has.
More than happy to send people to your video if you let me have the link
I’ve got a DT200R, love all the models of these bikes although parts are awful to find
Thanks for the video - at 3:18 there is little plastic elbow that helps to stop the fuel from spilling out of the carb. Any idea what that piece is called, and where I could find one? Mine seems to be missing.
Hi, it's a 90 degree elbow that connects the carb (a VM32SS ) to a piece of tubing as a breather I believe (although have had a way flooded carb pass fuel through it). It's a part that is nearly always missing and they are like Unicorn crap to find, the engines seem to run fine without them though.
I improvise the part by using an elbow connection intended to join aquarium pump tubing, I use the type with brass fittings with a plastic body, brass because petrol fumes pass through and could perhaps dissolve a 100% plastic type.
Just about completed another 1975 DT400 B, just need to finish of the electrics; hopefully a running and riding video soon.
Cheers
Paul
Thanks for the info, Paul! It makes sense that they are usually missing because this is the first time I noticed it. My bike has been sitting for about the last year and when I went to start it today I turned the fuel on it just started pouring out of that hole where the fuel inlet goes. I’m guessing I need to get in there and take the carb apart and clean it really good. This 75 Dt400b is my first bike. I live in Vegas and it’s been fun to take up in the desert hills. Would you mind if I reached out with other questions? You definitely seem to be the expert! If so, is there a an email I could use or would you rather I just comment on the video?
@@justindewey953 you may have more luck with spares in the US then we do in the UK.
Not a expert, more like a well meaning meddler. Contact me anytime, messenger or whatsapp.
To give you some indication of costs, a fully restored US bike will sell for up to £5000 gbp / 6000 USD
@@paulbell9025 such a great job on this . thanks i just bought a dt400 . im going to watch this when i do the rebuild myself.
@@araspa just send me a email paul@bellservices.co.uk if you need any pointers, got to say though I'm not a mechcanic, just a well meaning meddler 👍
Nice video bro. Some good tips. I have a 78 dt400.
Thanks Frank, lot of similarities with the models. Fun bikes to ride
The O ring on the choke mechanism doesn't seem to be in the right place? On my DT400B, the O ring sits in the recess in the carb body...
You didn't remove and clean the emulsion tube
No need to on this occasion, after ultrasonic cleaning and several blasts through with cleaner and air it was as clean as a whistle.
As you can see in subsequent videos the engine ran like a champ.
Cheers
Paul
Hard to understand with accent!
Could be your English isn't quite good enough.