Open Air Box And Carbs

Sounds to me with your current set-up, you should be considering either re-jetting or at least raising the needle one notch........

.............if you open up the airbox, it will definitely give a weak mixture, so why not consider a Dynojet kit?

 

Dynojet Stage 1 and Stage 2 are options............It all depends on how much has been done to the bike........

Mine has a DJ Stage 2..........the airbox trumpets aren't fitted and you can see right through my zorst cans.

I don't know if your zorsts restrict the gas flow with baffles etc..........stick a long rod down them and see if it hits anything................or someone else will hopefully come along and confirm zorst details.

There should be fitting instructions with the DJ kit, (but I have added them for you).............which will comprise of two needles, two springs, a pair of main jets in two sizes, four O rings and E clips plus a load of little washers.

The springs and needles are easy enough to fit without removing the carbs (although it would be better to take them off and clean them out) once you have taken the airbox and battery box off...........you get at them via the carb tops (black plastic caps with a screw at each corner.......don't lose the tiny O -ring under each one; and carefully lift the edges of the diaphragms away from the carb body).

The main jets are accessed by removing the float bowls...be careful of the float assembly because it might fall out............I'm afraid without proper equipment, choosing the right jet size is only a guess ...... I think most people would opt for the larger size.

NB......Out of curiosity is it a brand new DJ kit or did you get it secondhand?.....if so, are you sure it is a DJ kit?

Raising the needle means you will still have to lift the top cap off and you may be able to tweezer the needle out, then shift the clip, but most of the time you will have to lift the slide out with the diaphragm on it, then tip it upside down to drop the needle out.

 

If you want to check it is a genuine DJ kit, some of us here know what to look for...........if you post a pic of the needle, spring and one of the jets so we can see the number on it........

.......there shouldn't be a number on the needle and only a number and nothing else on the jet.

The pic below shows the main jet location, albeit it is upside down........

Also attached are a couple of exploded diagrams with the relevant part red dotted........Pic1 shows the main jet and the O ring; Pic2 shows the needle, clip, spring..........I also marked the little O ring (no.9) which is hidden under the top cover (because it normally gets stuck in there).

The small washers that come with the DJ kit are for 'half a notch adjustment' of the needle........but without specialist equipment, you probably aren't ever going to know if you need them or not.....

Just be bl**dy careful with what you are doing.........take photos as you strip it down, so you know which wires and which bolts go where etc............

.........don't go blundering in to it if you aren't sure.....ask the questions, someone will help.

 

Definitely a DJ kit........(unless someone is an extremely good engineer and forger) I can tell from needle shape, spring coils and the jets.

With the main jets, sorry, I can't really give good advice as to which size to use..........If it were me, I would fit the larger ones.

OK, take it easy............I would also take a photo of your spark plugs so we can see how they have performed (burn colour) with your current set-up.........

........when you do the pilot screw adjustment as per the DJ instructions, you will be looking for Items 14 and 17 in the lower diagram.........17 is a rubber plug which you pull out (if it isn't already missing) and then you can get a small screwdriver into the screw slot.......Warning! These can sometimes seize, so if it has don't force it.........you will need the carbs right off to free it without damage..........

If the pilot screws turn OK (I would give them a WD40 squirt before trying anyway) screw them in as far as they will go, but don't tighten them hard.........just enough to feel them stop.

 

I've had to drill heads out before and fit new bolts. Replace with something with a hex head .

 

I had to use a Mole wrench on some of mine, but I changed all mine for M5 socket head stainless........one was stripped completely so that had to be re-tapped and an M6 stuck in.....

Don't use the trick of knocking torx bit in; unless you can support the other side of the carb..............you do not want to break off any of the carb or float bowl body.

See if you have a tighter fitting bit....maybe an imperial size rather than metric???

Anyway, it seems as though your float bowls haven't been taken off for some time, so what you are doing is probably a good idea, so you can clean any cr*p out of them....

.......try not to dislodge the float assembly unless you are doing a full strip........It should hang there without falling out, but they are sometimes a bit loose where they push into the carb body.

 

Although a bit on the expensive side, Allens Performance should have the pilot screws (ask for Steve)...........change the little O ring on them as well.........and if you can afford to spend a bit more, change the spring and the tiny washer (the o ring and the washer usually get stuck in the carb body.........don't dig them out with anything metal.....)

Clean the threads in the carb body as well as you can...possibly use WD40 and run the old ones in and out.....

If you want to be really stingy, you can carefully file the pilot screw head down and cut a new slot........

 

Although I'm not completely sure about this and hopefully someone else will correct me if I'm wrong, but as far as I am aware, on the carbed SS'sss 600, 750 and 900 all have BDST38 Mikunis; however, the 600 has Type B156; the 750 has Type B70; and the 900 has a Type B67 or a B97...........Quite frankly I don't know the Type differences, but I suppose it could just be the jetting specs being different......However, which carbs are fitted to yours?

On the basis of the SS ones, as long as the jets are switched over to the correct sizes for the 600, I see no reason as to why 750 ones shouldn't be OK..........the choke (bore) of the carb must be the same as the 600 though.

Have a look through this ebay ad which suggests I might be right........Mikuni 38mm Carburetors Carbs Yamaha YZF TDM XTZ TRX FZR GSX1100 Keihin BDST38 | eBay

In the meantime which side carb is damaged? Left or Right? or, Horiz cylinder or Vertical cylinder?

I have a right side one which is stripped down but still with the butterfly and linkage in place which you can try if you wish....you would just have to add all the other parts from your b*ggered one.

 

See photo..........My spare is the one where it says RIGHT.............but that doesn't have a throttle cable adjuster, but it does have the balance adjuster...........

 

I bet someone on this forum will have what you want, even if they are from an SS...........

 

Standard DD fare is DJ2 kit, airbox lid either cut out or removed, stage 2 KN filter, dyno set up for AF, opeb slipons with std geaders

Gave mine 52rwhp over 44 on same dyno before the work