BST36SS Carb parts

[Tombola]

Seeking help and a warning NOT to buy pattern parts!

I have a very poorly 1200 bandit S that will not run right It runs like it has an air leak somewhere but I'm unable to find it.

I bought a complete kit from Eblag to overhaul the carbs, fitted everything and the bike ran worse than before.

It would be popping and spitting between 3-4k which I believe is when it crosses over from pilot to main jet.

I've stripped them down again and this is what the pilot screws looked like after fitting!! These all was installed with the greatest of care, I've removed them and reinstalled the old ones.

 

Can anyone think of any other places I could be leaking air from or something ive overlooked?

Im sure the boots are fine.

Float heights checked and double checked 14.6mm

Needle 4th clip

jets are correct size

Plugs are in good condition

Air filter is ok

Noisy zorst removed standard one back on

pilot screws are out to the book at 1 3/4 turns, (although I'm going to go out another 1/2 when I get home)

Anyone heard of the carb spindle shaft seals being a problem?

 

 

[Gixer1460]

It doesn't go straight from Pilots to mains - you have the whole needle period to go through!

Dunno what the pictured needle is supposed to look like so won't comment on that LOL!

Shaft seals could leak air but it's pretty rare - do the usual spray test to check?

[Tombola]

It’s hard to see in a picture but when you have them in your hand you can see that the taper is deformed, almost like the metal is too soft or the taper has been cut right. I’m not sure what seat into I assume it’s just a hole? 

 

[MeanBean49]

24 minutes ago, Tombola said:

It’s hard to see in a picture but when you have them in your hand you can see that the taper is deformed, almost like the metal is too soft or the taper has been cut right. I’m not sure what seat into I assume it’s just a hole? 

 

How does it ride? Quite common for bandits to pop and bang because of the join between downpipes and link pipe not sealing or cracking. If it rides ok I would look elsewhere from the carbs

[Tombola]

It’s not even rideable chap, it was problematic before but rideable used to surge when coming on the power, bit of research pointed to the emulsion tubes. These have all been changed along with everything else in the kit. Ill try and upload a video later Ron.

there’s a few threads already started on carb issues, none of them have came back and confirmed if they fixed/solved it though...

I promise I will come back and tell everyone

 

 

[Tombola]

I’m clutching at straws because I took it the next needle clip down anyway. Someone take a look at this photo of the needle assembly, theres a washer between the slide and needle bushy bit. I don’t have those washers... I know someone’s been at these carbs before as originally one carb had that top hat bit that applies spring pressure onto the needle missing!

if someone has a set of bst36ss handy to do a quick measurement on how thick that washer is I really would appreciate it.   

 

Edited September 21, 2020 by Tombola
Photos

[Tombola]

[MeanBean49]

1 hour ago, Tombola said:

I’m clutching at straws because I took it the next needle clip down anyway. Someone take a look at this photo of the needle assembly, theres a washer between the slide and needle bushy bit. I don’t have those washers... I know someone’s been at these carbs before as originally one carb had that top hat bit that applies spring pressure onto the needle missing!

if someone has a set of bst36ss handy to do a quick measurement on how thick that washer is I really would appreciate it.   

 

That washer wont make the difference between it running perfectly and an unrideable piece if crap, only makes a marginal difference, they are about half as thick as the gap between needle clips.

Could be worth comparing your new emulsion tubes to the old ones, theres 2 versions of 36mm carb, gsxr and bandit and iirc the emulsion tubes will fit either carb but are different and will mess with fueling if they are the wrong ones.

Wirth checking the link pipe too though for piece of mind

[Buzuki]

-That is correct order of the needle plastic shims , 

- also you have to check condition of the O-rings which is on underside of slider guide, usually those O-rings becomes hard and bad and than false fuel being sucked in the carbs throat ,

-and also check condition of the intake boots O-rings , those O-rings during the time becomes overheated and bad , than false air being sucked in the engine , but be very careful when remove intake  boots bolts , no excessive force to be used ! .

[Tombola]

1 hour ago, MeanBean49 said:

That washer wont make the difference between it running perfectly and an unrideable piece if crap, only makes a marginal difference, they are about half as thick as the gap between needle clips.

Could be worth comparing your new emulsion tubes to the old ones, theres 2 versions of 36mm carb, gsxr and bandit and iirc the emulsion tubes will fit either carb but are different and will mess with fueling if they are the wrong ones.

Wirth checking the link pipe too though for piece of mind

I didn't think it would because moving the needle didn't make a difference but I will replace them.

When you say link pipe you are referring to the exhaust right?

 

[MeanBean49]

2 hours ago, Tombola said:

I didn't think it would because moving the needle didn't make a difference but I will replace them.

When you say link pipe you are referring to the exhaust right?

 

Yeah exhaust where link pipe goes into the colletor

[Tombola]

Thats lean right? 
@MeanBean49
@Gixer1460

[Gixer1460]

Not a Scooby Doo - i've never had CV carbs fall flat on their face like that - that is very flatslide like !

Will they rev out properly with a slowly opened throttle?

[Tombola]

Nope, when you roll the throttle on it’ll spit between 3-4K get to 5k then the revs will die back to 3k then rev out!

Speaking to the selling he’s refunded most of my money for the kit. 
 

I’m going to have to take it to someone with more experience, but it’s so annoying having an issue you can’t repair no matter how many times I’ve taken those carbs on and off checked double checked etc...

[MeanBean49]

34 minutes ago, Tombola said:

Thats lean right? 
@MeanBean49
@Gixer1460

Could be lean, ive just been helping a mate sort his out, was doing the same thing, we ended up with his needles on the bottom clip and with 4 washers as well as the plastic doughnut to get it running well.

He had done the same, all new everything, could be from the same supplier, possibly an issue with the parts

[Tombola]

That’s interesting, it was a keyster kit I had. 
 

[bluedog59]

Hmmm, If you suspect somebody has been dicking around with the carbs, have you checked they've not drilled out any air passages in the slide ? Are all your diaphragms in good condition and seated properly ? When you're running it without the tank, have you blanked off the vacuum feed for the tap ?

[MeanBean49]

1 hour ago, MeanBean49 said:

Could be lean, ive just been helping a mate sort his out, was doing the same thing, we ended up with his needles on the bottom clip and with 4 washers as well as the plastic doughnut to get it running well.

He had done the same, all new everything, could be from the same supplier, possibly an issue with the parts

Worth a go, i ordered a bag of 2.5mm washers so i could shim it lots easily. 

[Tombola]

On 9/22/2020 at 6:47 PM, bluedog59 said:

Hmmm, If you suspect somebody has been dicking around with the carbs, have you checked they've not drilled out any air passages in the slide ? Are all your diaphragms in good condition and seated properly ? When you're running it without the tank, have you blanked off the vacuum feed for the tap ?

As far as I can make out they are kosher.. apart from these brass parts from Eblag!! 
 

checking the valve clearances and the inlet are pretty nipped up I can’t get a .1 under but can get a .05 feeler under... 

[OzyChris]

I also have a Mk 1 bandit with carb issues. I managed to ride it home gently just short shifting the torque, but it wont pull at all, just bogs down. Tried gently rolling past it to see if it comes back but nope. It has twin K&N open filters and delivic system. Apparently previous owner sent it to a local shop who cleaned the carbs, but didnt nothing more. He told me they looked OK and opened and closed cleanly. 

Im guessing stage 3 jets needed, but want to go through and replace everything especially emulsion tubes. Can anyone recommend a rebuild good kit? None seem to be branded so I dont know if they chinesium or ok. Gonna be a learning experience but got a mate whose more patient and we have youtube! (by next week the earth will be flat and well all be zapped by 5G covid rays) 

Other question, K&N twin pods, or return to the air box?. I have the box and it seams like the K&N's may just be a PITA, especially if I ever ride it away and hit rain. Whats you thoughts?

 

[Tombola]

Ha I was just about to update this..

I can’t help you with your problems, accept check check valve clearances, plugs, compression, any air leaks

Right I’ve gone and adjusted all valve clearances, 0.2 exhaust and 0.15 inlet.

Started up, and I THINK it’s cured!! 
 

I think my vision got narrowed in on them carbs, because of the parts I found missing but you live and learn!
 

I can highly recommend the SMC24 from squealy made the job a doddle!