Suzuki GSXR Forum banner
1 - 20 of 27 Posts

·
Registered
Joined
·
14 Posts
Discussion Starter · #1 ·
Good day to all
So I have Bandit mk1 600 that has upper part of the engine from r705 engine (gsxr 750 86). Now he is running on 32mm carbs that originaly came from bandit but I have bought bst36ss carbs that I asume came from gsxr 1100 because main jets are 122.5 in them. My question is can someone pls tell me what would be a good starting point setup for those carbs I'm planing to run them on ramair dual pods with carb to airbox rubbers.
Thank you all
 

·
Mod of the North
Joined
·
29,802 Posts
The BSTs are not gonna be real happy with the pods. I tried it and it was terrible for me. It ran much better with the stock air box.

I am confused about the engine. Is it 600cc or 750 cc?
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #3 ·
The BSTs are not gonna be real happy with the pods. I tried it and it was terrible for me. It ran much better with the stock air box.

I am confused about the engine. Is it 600cc or 750 cc?
Lower part of the engine is from 600cc ,pistons cilinders cams from 750,so it is 750cc , and I'am planing to put bst36ss carbs on it. So now I need a ball park for main jets, air screw,and
needles.....yes thats what I have heard of ,but I read someone used this ramair foam filters with carbs to airbox rubbers and it was running good,so here I am :D
 

·
Mod of the North
Joined
·
29,802 Posts
@Spyder13 is who we want in here. He is our resident carb guru. I am guessing you would be baselining the GSXR750 settings. The only thing I am wondering about is if the throw of the 600 crank is the same as the 750. If it is shorter it will mean you are less than 750cc. The air volume is going to determine the fuel settings.
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #5 ·
@Spyder13 is who we want in here. He is our resident carb guru. I am guessing you would be baselining the GSXR750 settings. The only thing I am wondering about is if the throw of the 600 crank is the same as the 750. If it is shorter it will mean you are less than 750cc. The air volume is going to determine the fuel settings.
Cranks are the same number,on both engines and according to sheath,it is the same stroke ,only different bore. Yes I have seen some of the spyders wisdom here and was hoping to get his thoughts on this .....
 

·
Super Moderator
1995 GSX-R 750
Joined
·
2,101 Posts
Pod filters of ANY kind, are a tuning nightmare. You have been warned...
BST36's came stock on the '95 750's.
With basically open air, I personally would probably start with 125's and needles raised 2 notches from center. You should at least be able to get it to fire from there, and see where you need to go from there.
Follow these guide lines, and you should be able to get it to run decent enough.

 

·
Super Moderator
1995 GSX-R 750
Joined
·
2,101 Posts
I forgot to ask. Does it run NOW? Still have the stock 600 carbs on it, or the 750 carbs?
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #8 ·
Now I'm running 32mm original bandit 600 mk1 carbs with stock air box and 130 main jets but it runs good only on first 1/3 of trotle,but this is just so I can ride it untill I manage to put 36 on there. I wanted to keep original air box duo to problems with tuning of the carbs with pods but to do that I would have to bore out this 600 air box to fit airbox to carb rubbers for 36s or buy 1200 mk1 air box. I couldn't find mk1 1200 airbox here in croatia ,and I don't know if it fits to mk1 600 frame ,so I decided to go this way with 36s ram air pods and carbs to airbox rubbers. Here I am now trying to find out what would be a good starting point with that set up (36s ,ramairs and carbs to airbox rubbers) to start with.
 

·
Super Moderator
1995 GSX-R 750
Joined
·
2,101 Posts
If it were mine? I would just get the 32's jetted and tuned correctly. It will still peal your scalp back under acceleration if you get it right. Clean them out really good, and jet them properly.
 
  • Like
Reactions: Tinsnips

·
Registered
Joined
·
14 Posts
Discussion Starter · #10 ·
If it were mine? I would just get the 32's jetted and tuned correctly. It will still peal your scalp back under acceleration if you get it right. Clean them out really good, and jet them properly.
So you think I will feel increse in power with 32s if jetted right and all with stock filter, compared to 600cc, because 600 has 78bhp and 750 around 100 with 36s .....it may sound dumb but It is what it is 🤣🤦‍♂️
 

·
Mod of the North
Joined
·
29,802 Posts
My understanding (Spyder correct me) is that you are now going to pull more air through that carb. 150cc’s more air per carb. Jetting larger for higher fuel flow and maybe raising the needles will add the additional fuel you need to keep the right air fuel ratio.

It might even be a slight advantage to have the 32’s on there. They will create a bigger vacuum differential across the carb and the BSTs may like that a lot.

Again, listen to Spyder and learn from my mistakes…
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #12 ·
My understanding (Spyder correct me) is that you are now going to pull more air through that carb. 150cc’s more air per carb. Jetting larger for higher fuel flow and maybe raising the needles will add the additional fuel you need to keep the right air fuel ratio.

It might even be a slight advantage to have the 32’s on there. They will create a bigger vacuum differential across the carb and the BSTs may like that a lot.

Again, listen to Spyder and learn from my mistakes…
Maybe,thats why I'm here, because some of the members here have experience that I can only dream of :D
 

·
Mod of the North
Joined
·
29,802 Posts
Well, Spyder has experience. Like I said, you can only learn from my mistakes. I have 40mm BSTs on my '89 1100 and had a heck of a time getting them to behave. I tried the pods and did not use the velocity stacks that are part of the air box. With out those velocity stacks (the tapered bell shaped inlet tubes) the air tumbled in and caused turbulence & poor performance.

Another issue I had was the pods were much freer flowing. That is great for getting air through the engine but the lack of restriction meant the engine got air TOO easily and didn't produce enough vacuum to open my slides fully. There is a mod for that but I didn't want to mess with my only set of original carbs.

If I were you I would clean the 32's and jet them. Set them up and see where you are. If you tune to the point you can't add anymore fuel and are still running lean THEN go to the 36's. The bright side is that if you do end up switching later you have a freshly rebuilt set of 32's you can sell.
 

·
Super Moderator
1995 GSX-R 750
Joined
·
2,101 Posts
I'm just saying that it will be MUCH easier to tune the 32's with the airbox, than it will be to tune ANY of them with pods. If you were building a track bike to take to the dragstrip, then I would recommend the pods, because you won't care about low-end rideability. But you're not... You want good smooth throttle response across the board. You won't get that with pod filters.
You will be leaving a couple (single digits here) HP's on the table using the 32's, but it's not enough to make a noticeable difference.
This is JUST my opinion based on experience with trying to tune CV carbs with pods.
I am by no means saying you can't tune them, I am saying you can't tune them to be perfect throughout the whole throttle range.
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #15 ·
I'm just saying that it will be MUCH easier to tune the 32's with the airbox, than it will be to tune ANY of them with pods. If you were building a track bike to take to the dragstrip, then I would recommend the pods, because you won't care about low-end rideability. But you're not... You want good smooth throttle response across the board. You won't get that with pod filters.
You will be leaving a couple (single digits here) HP's on the table using the 32's, but it's not enough to make a noticeable difference.
This is JUST my opinion based on experience with trying to tune CV carbs with pods.
I am by no means saying you can't tune them, I am saying you can't tune them to be perfect throughout the whole throttle range.
Understood,thank you Spyder,this is yesterdays update, went for a ride but took off air filter because I assumed it ran really rich with 130 main on 32s, and this time it ran really good after 7k rpm and before it didn't even want to go past 7k rpm.....it would ran and take throttle only on first 1/3 of throttle. So now next step is to find a good size main jet to ran it with standard filter in . I'm guessing 110 would be good starting point , maybe even 105.....and now I'm 3 turns out on air/fuel screw but that is too much so will go with 2.5 and see how it goes
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #16 ·
Well, Spyder has experience. Like I said, you can only learn from my mistakes. I have 40mm BSTs on my '89 1100 and had a heck of a time getting them to behave. I tried the pods and did not use the velocity stacks that are part of the air box. With out those velocity stacks (the tapered bell shaped inlet tubes) the air tumbled in and caused turbulence & poor performance.

Another issue I had was the pods were much freer flowing. That is great for getting air through the engine but the lack of restriction meant the engine got air TOO easily and didn't produce enough vacuum to open my slides fully. There is a mod for that but I didn't want to mess with my only set of original carbs.

If I were you I would clean the 32's and jet them. Set them up and see where you are. If you tune to the point you can't add anymore fuel and are still running lean THEN go to the 36's. The bright side is that if you do end up switching later you have a freshly rebuilt set of 32's you can sell.
I did plan to use velocity stacks on 36s because thats how ram air pods work they go over the velocity stacks (I called them in my post carb to airbox rubbers because I couldn't remeber that th3y are called velocity stacks,sry this is not my native language :D) I have read that they behave better than k&n pods because u keep the velocity stacks and they are quite restrictive with air ......so mybe i'll give them a shoot but for now I'll go with 32s properly jetted . Thx Tinsnips :D
Btw these are the carbs ,and bike:
 

Attachments

·
Super Moderator
1995 GSX-R 750
Joined
·
2,101 Posts
If you are at 130's and it runs really rich with the correct filter, I might drop to 115's to start with. Also order a set of 112.5's, and 110's (they are stupid cheap, so...).
This way you aren't waiting for shipments instead of riding. Start with the 115's, and the needles 1 notch higher than center. (so technically below center) so they are raised one over center. This should give you a good starting point to evaluate which direction you need to go with which circuits.
 

·
Mod of the North
Joined
·
29,802 Posts
Great looking bike. To be honest I was using K&Ns and there was no velocity stack. It ran terrible. Yours may give better results.
 
  • Like
Reactions: Mario750-86

·
Super Moderator
1995 GSX-R 750
Joined
·
2,101 Posts
Velocity stacks will help, but not cure. The problem isn't just the air flow quality. It's the transition between fueling circuits. I.E. pilot to needle to main. too much air, and turbulence makes these transitions really rough. Again, if you were building it for the drag strip, then this would be the way to go, because all you care about is WOT. On the street you want all of these transitions to be smooth. So smooth you don't even know it's happening. That is the ideal tune...
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #20 ·
If you are at 130's and it runs really rich with the correct filter, I might drop to 115's to start with. Also order a set of 112.5's, and 110's (they are stupid cheap, so...).
This way you aren't waiting for shipments instead of riding. Start with the 115's, and the needles 1 notch higher than center. (so technically below center) so they are raised one over center. This should give you a good starting point to evaluate which direction you need to go with which circuits.
No,with correct filter it would not go past 7k Rpm, with no filter at all in airbox it runs past 7k rpm but still rich with 130 main,thats why I said I would try to go with normal filter with 105 mains. :D
Pls can you give me link for the jets or something it seems that I have found only the expensive ones 😂 . Thanks
 
1 - 20 of 27 Posts
Top