Slabby 11 on 36 carbs won’t run

[Zixxer]

Hello lads - I have an 87 Slabby 1100 and swopped over her original BST34 carbs to a set of BST36SS from the GSX750F teapot 

Spotless carbs all new internals with floats set to standard height - she will fire up, run on choke for a few secs but then dies. Will run with throttle almost wide open but dies as soon as let off - just can’t get an idle at all

Getting plenty of juice to all 4 carbs and loads of spark. Using foam Ramair pods 

What am I missing? Needle clip in the middle, 120 mains, 37.5 pilots, screws 2.5 turns out

Thanks for any advice

 

 

[wraith]

Pilot jets, the 37.5 are for the 750 engine, put your pilot screws to 3 1/2 turns out and see how that goes 

[Zixxer]

40 minutes ago, wraith said:

Pilot jets, the 37.5 are for the 750 engine, put your pilot screws to 3 1/2 turns out and see how that goes 

Just tried that now and a little closer definitely - now she’ll stay running as long as there’s a little choke 

Soon as I try applying throttle she starts to bog down and dies - winding in the idle screw kills it

Idle screw out all the way and a little choke she keeps running 

[Zixxer]

I put the 42.5 pilots from her original 34mm carbs in and now she won’t start at all 

it’s now on those pilots and middle slot on needles and back at 2.5 turns but nothing 

Edited July 8, 2022 by Zixxer

[wraith]

Are you using the standard gsxr1052 carb inlet rubbers?

If so they will be to small and they may not be giving a good seal, and you could be getting air leaks.

You say you're using Ramair filters, what exhaust are you using?

Just for info 

Gsxr1100 (1127cc) 36mm carbs run 40 pilot jets 2 turns out.

 

 

[Zixxer]

Wraith I’m sorry I took so long to reply but this is what happened in the end 

 got pissed off trying to get the 36s working so went back to trying to get her original 34s rebuilt and dialled in and had some success

she is now on 2.75 turns out on pilot screws and bottom clip on needles on rebuilt internals and going strong 

I suspect the 130 main jets might be too lean so intend trying out a set of 135 jets which I need to order

i found a set of 155 Keihin jets in a box of jets I have from years ago which I believe equate to 135 mikuni size and might try using them but not sure if they’re compatible with the new emulsion tubes and needles from the Keyster kit I rebuilt the carbs with?

anyway I’m very pleased she’s alive and pulling surprisingly well

[Gixer1460]

Not sure Keihin jet threads are same as Mikuni as I seem to remember they used to bind up ! A 2mm difference in bore shouldn't mean carbs won't work - the 1127 engine went from 36's to 40's and worked well, although i'm sure the Suzuki & Mikuni development tech's spent MANY hours on a dyno getting the jetting correct! There is a moral there - 'If you don't understand what to do to correct it - don't fuck with it in the 1st place' LOL!

BTW that test track is far to empty to be real !