They are 2 x 36mm Mikuni BST B316 CV (Constant Velocity) Carburettors. The two have a combined diameter equal to a single 51mm carb.

You can even get a Dynojet kit for the BMW. Should work fine on the DS..

 

nice to know. thanks for all your input freez.

off topic subject for you freez: are you in South Africa? the only pretoria I can think of is there. if so, have you ever been to sossusvlei sand dunes in Namibia? they are the largest dunes in the world. I would love to roost some sand there.

 

The best advice I can give about the airbox lid is if you are going to run without it make sure you remove the rubber cap on bottom of the airbox so the sand can get out..[img]i/expressions/face-icon-small-wink.gif[/img]

 

ERBEDS650

no i didnt But i will next time

 

Freez

thanks for the input, i will get back with my results later

You should out up some pics on your page af where you ride Its alwasy nice to see pics of different countries

 

I stay in South Africa, so the only "dunes" we have here is mine dumps. They are similar to sand dunes and there are lots of fun to be had on them. Some are just as sand dunes, so we don’t miss out to much here.

Twice a year the guys line up to do the desert run. We start in South Africa and you ride you quad, 2 wheeler or anything else you like for hundreds of miles till you get to the desert in Namibia. It takes a good coupe of days and its like a whole event. The cops let you ride on the roads and it all ends at Dune 7. It's the tallest dune on the world. If you plan to get to the top on your quad, you hit it in 5th gear full throttle and change gears to the top. Very few quads make it.

I will try to get some pics to show you guys.

 

nice! I thought it was some kind of national park or something. (namibia dunes) I wondered if you could even ride them or not. deffently post some pics. what is the elevation at the bottom and top of dune 7? or should I say, how #$%*ing tall is it?

 

I did some searching and it seems the dunes are around 340 meters or 1115 ft tall from top to bottom. Now add a 30 to 40 degree angle to that straight up height and you have to travel about 1300 to 1500 ft before you can get to the top. It’s nearly a quarter mile. Nice distance to drag up a dune!

Here is a link to the dune.

click here to see the dune

 

Im gona revive this for a couple. Im not taking any jabs at any one just thought this would be a big help .
In the January 2005 Dirt Wheels it has a article on Carburators Explaned page 162 it talkes about 2 strokes and four strokes. it gets into detail about Vacume Slide carb tricks pg. 175. Four Stroke Tech ( a reputable builder for those that havent herd of them) goes into detal on these carbs.

they state this " One of the hardest carbs to jet is the vacume slide-style carb" ....." As you open up the airbox, you lessen the pressure that allows the slide to lift, so you need to richen the mid-range up with a thinner needle. A thinner neddle allows more fuel to pass into the intake tract. This can be a trial-and-error process of learning."

It also goes into detal about using duct tape to cover your lid and tear off one peace at a time till you get a happy medium between pressure to lift the slide and more air for power.

Its a good article if you dont have the mag go out and get it.
Sam

 

I just have to put in my $0.02.

I didn't get a chance to read the whole thread, but I wanted to clarify something that I saw on the first couple of posts.

If I remember correctly, Mr HP never claimed that running with the air the air cleaner lid on created more power. What he did claim, is with the stock carb, he got more power from running the stock air filter tube (between carb and filter) than a direct mount filter. If I remember correctly the tapered tube acts as a velocity stack speeding the air flow up as it approaches the carb. The stock carb relies on air velocity just as much as it does volume to work properly.

If I'm wrong, oh well, wouldn't be the first time.