Differences Between Bdst38 Carbs

The differences in the float chamber/bowl are almost certainly interchangeable, The reason I can’t say hundred percent interchangeable is because there were some versions intended for Yamaha/etc that are not, usual clue with these is that they have two bowl fixing screws instead of four. The electrical solenoids on each carb are a different matter though and I personally wouldn’t buy just because I’m not at home with them, and don’t know how they would affect the main circuits, hopefully somebody on here will be. I bought a brand-new pair at the beginning of the summer from Italy, can try and find a link if you would like.

 

I'm with Chris on this - at least try to get a pair of carbs with a known origin which is of similar specs to your own.

BDST38s may look all the same which in general, they may well be; but I have found that apart from jets which can be removed and changed for a different size, I am fairly certain there is a jet which cannot be removed and I think it governs the flow of air through the pilot circuit.

If you look at the air inlet side of the carb, you will see there are two holes at the bottom edge - one has a removable jet, other other appears to be fixed.

However, it it was me I would do a damn good job of cleaning and renovating the current ones off your bike. The most expensive things you might need are diaphragms and float assemblies. As long as you make sure you clean / keep crap out of the pilot circuits, there isn't much with a stock pair that can go wrong. It is usually incorrect setting up of them where problems eminate.

Even if you take Chris up on the link he mentions, you will still have to check / change jets etc and then set them up to suit.

Apologies to Chris if the OP decides he doesn't take up the link.

 

P.m.’d him Al, they had none left. I was lucky to buy mine when I did as it seems that they are not turning up any more, only the ones with the electrical devices on them. From memory there are a few “factory fitted” jets it’s easy to work out as you can look with a torch and if you don’t see a screwdriver slot then leave well alone.

 

Mr thick here. What exactly are the electrical things on the side of the carbs??

 

as said, was hoping someone with specific knowledge might step in - just had a long search to discover more but without luck and no point in me guessing. I feel sure that someone like Brad Black or Allens Performance at Bingham will know.

 

Some form of electric choke?

 

The mechanically operated choke is still in place if you look at the picture Mick.

 

They look to me a bit like small hose stubs for say, a vacuum tube - I wonder if they replace the small air cut-off diaphragm units.

 

Ask the man down under, he:ll know.

 

Ask the man down under, he'll know.

 

OP...these are p/n 134.4.032.1A carb heater elements used on 2000 750 Monster, for example

 

I have them on my 99 900, but no wiring for them that i've ever seen, but then I have he heated bowls

 

Oh, you mean Wipeout, I guess.

 

I'm looking at them upside own - of course they don't relate to the air cut-off diaphragm locations.

Twit isn't I.

 

With the 40 pilot jet you may just get away with not changing it by not turning out the pilot screws as much as you would normally for the earlier 600.