I NEED HELP WITH VELOCITY STACK CARBS SETTINGS. CHEERS!

[crazypj]

Your welcome.
If anyone comes to me with a question and asks for an answer, they get the reply they deserve
Sometimes it may be more abrasive than you would like, but, if your, 'in the trade' you'll get used to it (or leave for something more PC)
Getting it running OK is not he same as getting it running right.
It's not narcissism, just the facts.
If you have the electronics available, why don't you use them? (basic 5 gas EGA or is it manufacturer specific computer interface?)
If you have access to a dyno with 5 gas or even just O2 it's pretty simple (but time consuming)

 

[Rocker]

Hi again, and cheers for the more civilized reply ;D Much appreciated. At the point I had posted the 2nd last comment I was just acknowledging those that had given me advice in the past and was just letting them know that I was past that point. I have both access to dyno and electronics. There is a guy locally to me that builds 9 second race cars and customs.. he has the whole kit and kaboodle... so I will prob get him to help me dial it in I worked in the industry as a parts interpreteur for a major Australain importor and distributor for S&S and all the other hardcore custom aftermarket components like Baker and RevTech, Spyke, Meanstreet, custom chrome.. etc. My whole client database consisted of hardcore chopper builders and presidents of so-called "clubs" I spent everyday on the phone solving their build and fitment issues and tracking down difficult parts. I have partaken and represented at bike shows, and for me, I have always approached everyone with due respect and politeness. That's my style, and I have always had people show me the same in return out of professional courtesy. So, please excuse my reaction to your "abrasiveness" earlier. I appreciate the input, that's not the problem. It just seems that on forums these days, due to the high level of anonymity, people tend to be either short or rude with one another, and I just think if we are all in this together, and we all share the same obsession and passion, then we should treat each other with mutual respect and empathy.. and that first starts with the way we speak to each other Thanks again though for your input. I have taken it onboard. I do know that running velostacks on the cv will be tough, but apart from the cash at the mo... the other side of the coin is the challenge of getting the cv's to run the stacks

 

[crazypj]

Cool, I'm not good at sales, wrong attitude
As your probably aware there are an awful lot of people who think it's so easy you don't need a professional to sort things out (see the Bryan Fuller CB750 or any of the 'how big a tyre can I fit' threads : )
If you had given some info on your bio, I would have treated answer totally different, challenge I understand, it's probably why I still mess with CB360's ;D
From your initial post (which I didn't check date on) I assumed you were another 'whooooo shiny'
Obviously, you've dealt with them so you know where I'm at ;D

 

[teazer]

Pity you're up there in BrisVegas. I need a good dyno guy to run my race bikes through some cycles when I'm down in Melbourne next. One is a 2 smoke and runs shell 100 or VP race gas if I can get it and the other sucks metho, so the local Hoggly Doggly store is probably not where I'm headed.

What are you doing about filtering out dirt and dust and small dogs?

BTW, we should have talked about the fact that a larger engine breathing through the same sized carbs will result in much higher gas velocity through the carbs and higher velocity = bigger pressure drop. My guess is that you will end up with much smaller jets than stock on a 400.

 

[Rocker]

Pity you're up there in BrisVegas. I need a good dyno guy to run my race bikes through some cycles when I'm down in Melbourne next. One is a 2 smoke and runs shell 100 or VP race gas if I can get it and the other sucks metho, so the local Hoggly Doggly store is probably not where I'm headed.

What are you doing about filtering out dirt and dust and small dogs?

BTW, we should have talked about the fact that a larger engine breathing through the same sized carbs will result in much higher gas velocity through the carbs and higher velocity = bigger pressure drop. My guess is that you will end up with much smaller jets than stock on a 400.

Hey man dude... "same sized carbs will result in much higher gas velocity through the carbs and higher velocity = bigger pressure drop"... good point and that totally didn't even cross my mind! I was so concerned with getting enough fuel to supply the bigger pistons and extra air.. I totally forgot to include the higher velocity air flow as factor on pressure.... I have tons of jets here.. so if need be can always jet down thanks for the reminder. Mmmmmm VP race gas.... where you get that down there? That sounds like porn to me ;D mmmm... race gas.... as for filtering out small dogs... hahaha... love that.... not too worried about that.. will prob just pull the carbs down every so often and give em a clean... or possibly just run some stack socks on them... but I will have to make some since I can't find any around these days.

@ crazypj.. cheers man. Yeah, I prob should put more in my bio... I just tend to be too modest for my own good some days and i tend to be a bit reclusive... hence my limited info LOL... I'm working on it though. Cheers again... oh yeah, I love those old cb360's... I have an original early CB frame here.... was looking to do an old skool cafe with it eventually... but since i've picked up the 84 Suzuki GSX750...(which will become a salt-lake land speed racer), I'm thinking I may just hoik this cb frame.. but love the smaller cb's... so light and nimble... easy to work with and even easier to ride.... fantastic old bikes! I love working with XS models.. especially the 250-400's... mainly coz they have sh*t brakes, sh*t handling, and sh*t styling... might as well ride around on a damp dish sponge LOL ;D BUT, i love the challenge of taking something mediocre and making them look, go, and handle bad-ass it's all about making something live up to it's potential... the potential the factory should ovf given it, but never did... that's what making custom cafe's is all about i guess! 8)

 

[crazypj]

... or possibly just run some stack socks on them... but I will have to make some since I can't find any around these days.

but since i've picked up the 84 Suzuki GSX750...(which will become a salt-lake land speed racer), I'm thinking I may just hoik this cb frame.. but love the smaller cb's... so light and nimble... easy to work with and even easier to ride.... fantastic old bikes! I love working with XS models.. especially the 250-400's... mainly coz they have sh*t brakes, sh*t handling, and sh*t styling... might as well ride around on a damp dish sponge LOL ;D BUT, i love the challenge of taking something mediocre and making them look, go, and handle bad-ass it's all about making something live up to it's potential... the potential the factory should ovf given it, but never did... that's what making custom cafe's is all about i guess! 8)

First off, damn good laugh first thing in the morning, wife wondered what the hell I was doing ;D ;D
I worked for Honda/ Yamaha dealer then Suzuki/BMW/Vespa dealer who 'dropped' Vespa and BMW to take on Yamaha so I worked on the XS250/400 from new and everything you said is right ;D
Saying that, the XS and Suzuki GS/GSX 250/400 'square' tanks are now looked at as 'cafe'

GSX motors are fantastic, massively overbuilt, engines, particularly the 750 (1425kit?, 1750 kit? turbo? 1750 turbo ;D )
BTW, for 'murricuns', GSX was a GS over here, it was designation for 4 valve per cyl motors everywhere else in the world

As for filters, you probably don't remember speedway/'scrambles' in the 50's~60's, use a nylon stockings tied over bell-mouth then tied to rear of bike, it was a common 'mod' on dusty tracks with virtually zero restriction when done right
All you need to do is find a woman in stockings and persuade her to remove them (not that I remeber 50's but I seen pictures 8) )
Looks a bit strange but I doubt anyone has seen it done for last 40+ yrs, plus it is really 'vintage filter'

 

[Rocker]

First off, damn good laugh first thing in the morning, wife wondered what the hell I was doing ;D ;D
I worked for Honda/ Yamaha dealer then Suzuki/BMW/Vespa dealer who 'dropped' Vespa and BMW to take on Yamaha so I worked on the XS250/400 from new and everything you said is right ;D
Saying that, the XS and Suzuki GS/GSX 250/400 'square' tanks are now looked at as 'cafe'

GSX motors are fantastic, massively overbuilt, engines, particularly the 750 (1425kit?, 1750 kit? turbo? 1750 turbo ;D )
BTW, for 'murricuns', GSX was a GS over here, it was designation for 4 valve per cyl motors everywhere else in the world

As for filters, you probably don't remember speedway/'scrambles' in the 50's~60's, use a nylon stockings tied over bell-mouth then tied to rear of bike, it was a common 'mod' on dusty tracks with virtually zero restriction when done right
All you need to do is find a woman in stockings and persuade her to remove them (not that I remeber 50's but I seen pictures 8) )
Looks a bit strange but I doubt anyone has seen it done for last 40+ yrs, plus it is really 'vintage filter'

LOL... ;D yah... i seen pics of those stocking filters somewhere too! I just thought it might look a bit funny on the streets... but if I run this thing on a track at any time, will be going the stocking option. Perhaps I can sew some smaller permanent stylesocks from some stocking material..? Hmmm *ponders*

Before I was a parts interpreter, I wrenched at my local Honda dealership... like you LOL... they couldn't organize a root in a brothel, which is when I decided to get the custom parts job currently trying to land a job at my local Yamaha dealership.. hopefully in the parts and services dept Mmmm... four valves per cylinder... yeah.. those GS motors are bombproof.. but the boxes get a little "clunky" as they get on... bit sticky... but they don't chew oil as badly as a yami does in older years I'm going for a standard .5 overbore wiseco low compression set-up on the 750, with possibly a turbo... OR a high comp piston set-up and run nitrous injection into a custom intake manifold with a single big ass Webber side draught or similar... stretch the rear out and make it rigid with a jack-shaft set-up (15 => 17 front pulleys & 33 => 42 rear pulleys) which acording to my calculator factoring in internal gear ratios, should give me approx 220mph by the fifth mile marker, which, coincidently, should be about the time I'm hitting 5th gear (top gear).. which allows me a whole mil stillto get some more from her. Only going for partial streamlining... so should be interesting ride LOL

 

[Rocker]

p.s. for you and anyone else that is interested... here is the link that helps you work out final drive speeds

http://www.rbracing-rsr.com/gearspeed.html

 

[Rocker]

final drive ratios for my '84 GS750 salt flat racer... as per drive ratio calculator

 

[crazypj]

19t is a far more efficient size for front sprocket, it's why 'OLD' bikes ranged from 19t~21t, the chain doesn't have to 'bend' as far.
Not sure it will fit on GSX cases though, 18 is probably as big as you can go?
It's easier to change rear sprocket to get required top gear
18>18 and 28~27>33 should be close
I'm guessing your going to need about 190~210bhp (or more), thats a lot for GSX750, usually they are tuned to about 110bhp before nitrous (although I did see a heavily worked over 1100 making 318bhp with a turbo and NOs)

 

[Rocker]

hey mate... sure that all sounds great cheers for the advice. On the GSX750.. I'm thinking of running 4 30mm flat slides and running CRY02 kit with them.... But, to be honest, I know how to set up the Vm style carbs for synch... and adjust ment... but I'm not sure how to go about connecting the throttle cable or jet sizes... I've used a 2-into-1 vm cable set up before on two 28mm vms... but how to connect 4 pwk flat slide styles..? 2-1 + 2-1 both into a third 2-1 then onto single throttle? Or is there a 4-1 vm cable adapter out there somewhere? Then, I'm going to run the 813 big bore Wiseco high comp piston set... how will I find the correct jet sizes to fuel this motor with the pwk flat slides? I'm mostly familiar with CV carbs... :-\ As for the nitrous/turbo options.. I'm definitely going for naturally aspirated I think... sure, the extra power oxygen from turbo or nos is great.. but it makes the chamber hotter... and it's oil cooled... I'm thinking more like the other way and using co2 injection to cool the intake mixture, so it's similar to cold air induction.... bigger bang still, but less heat being produced in chamber... since there is like 5+ miles of run out for a salt lake speed lap... I'm mostly going to rely on getting the jackshaft gear ratio right... but i'm hoping the pistons and flat slide/cooler increased mix will help acceleration through the tall gear ratios... hopefully will be enough to move me thru to 200mp+ within the 5 mile distance whilst still keeping in naturally aspirated

Also, was set on tuning the XS400 with the CV's... I have modified the slide and jetted correctly for velocity stacks... intheory should run okay... but I'm aware there may be issues in lower gears with vacuum... that doesn bother me just yet.. BUT, if i find it bothers me too much, I will swap them out to 2 x 28mm PWk flat slide style carbs.. with a 2-1 throttle set-up... my concern again is this though.. I have no idea about jettting for these types of carbs.... anyone able to help with some info please? I will be running velo stacks on the flat slides, and the head is flowed and polished... what size pwk jets should i be running please...? Any takers?

 

[crazypj]

You may be able to find a throttle cable for a Honda CB750 K0 (it had cable operated slide carbs)
They are a total pain to set up though which is why later models had linkages with single cable.
The best you can expect is 'close' for an hour or so until cables stretch/compress into position.
First 3 months will drive you nuts ;D

 

[Rocker]

You may be able to find a throttle cable for a Honda CB750 K0 (it had cable operated slide carbs)
They are a total pain to set up though which is why later models had linkages with single cable.
The best you can expect is 'close' for an hour or so until cables stretch/compress into position.
First 3 months will drive you nuts ;D

LOL ;D Cheers mate.. yeah.. that sounds like a nuisance! Hmmm *ponders* think I might do a 4-1 intake manifold and a big fat Dellorto