Suzuki Katana 1100sz

[jellywrestler]

You could also drill the air hole for the slide as Dyno jet do, along with the springs
Whoops Greg bet me too it.

my bimota SB3 has cv's and pods, prior to that it was a steve roberts airbox which the guy didn't like and threw away.
when the bike came to nz it had thirstier carbs on it, it just so happened that suzuki new zealand had about 23 sets of brand new gsx1100 carbs sitting on their shelf, so a set was purloined and fitted, odd that there were 23 gsx1100 black piper wire wheelers with slide carbs 'arrived' in the country at about the same time.....

[husaberg]

my bimota SB3 has cv's and pods, prior to that it was a steve roberts airbox which the guy didn't like and threw away.
when the bike came to nz it had thirstier carbs on it, it just so happened that suzuki new zealand had about 23 sets of brand new gsx1100 carbs sitting on their shelf, so a set was purloined and fitted, odd that there were 23 gsx1100 black piper wire wheelers with slide carbs 'arrived' in the country at about the same time.....

yeah, a huge co-incidence that.
SB3 would be the days of kit only Bims. so anything goes.

[Arronduke]

Its not a slow or fast thing with the slide, its a position relative to load/ RPM
In standard form in absence of the airbox, the slide rises too far, I know that brings the needle further out of the jet & you would think that would cause rich situation, but in the absence of sufficient suction, insufficient fuel is drawn up the jet tube. Increasing the spring tension, while holding the slide & consequently the needle further down for a given load/RPM increases the suction at the jet tube to create a choking effect which draws more fuel up the jet tube than if the slide was left to rise freely.
Its not tricking the carb into doing anything it wouldn't normally do, its just balancing the suction to the metering.
Pretty much the same reason why people throw away the excellent Rochester Quadrajet & put cheap nasty Holley carbs on V8's

wow what great info. never thought of it that way. cheers

[Arronduke]

my bimota SB3 has cv's and pods, prior to that it was a steve roberts airbox which the guy didn't like and threw away.
when the bike came to nz it had thirstier carbs on it, it just so happened that suzuki new zealand had about 23 sets of brand new gsx1100 carbs sitting on their shelf, so a set was purloined and fitted, odd that there were 23 gsx1100 black piper wire wheelers with slide carbs 'arrived' in the country at about the same time.....

SB3 - you lucky bastard, I would love to own one. A true classic!
How do you find it today after all these years, the old GS1000 motor?

[sidecar bob]

Agree - because you can't change the slide cutaway on bike CV's you've got to match the rate of slide rise to the air requirements of the motor.
My experience has generally been that as i've had no alternative springs I've had to tailor the size of the vacuum hole in the slide to get the response i want.
Are you working from a collection of SU springs ?

Umm. . . . no, what I do is make spacers out of plastic tubing, that I put between the top cover & the spring, that I adjust the length of until the mid range is correct. Then I get a piece of cardboard & put a pen line on it on one end & another pen Line at the other end that is equal to the free length of the spring, plus the length of the plastic tubing, plus a tiny bit (very technical measurements at this point lol) to allow for the dead area that the tubing took up that the spring will later occupy. I then hold the spring by the ends & stretch it. You have to be extremely careful at this point because while it can easily be stretched, it can never be shrunk, so I carefully work the length up, until it matches the length marked on the piece of cardboard, usually good results are achieved first time. Then turn to the needle for fine mid range tuning (often raising it by one or two positions) & the main jet for top end,usually by having two sets of main jets & drilling one larger than the previous until I go too far, & then returning to the previous size (usually works out to be up by 10 to 15)
If it hadn't worked for me countless times over 25 years plus, I don't think I would have had the ball bag to post it up in such company.

[IronPawz]

For my GS650 i literally lopped the triple tree in half and had a certified welder stick a big steel bar up the middle of it and welded it in when i used the nsr250 front end to make it tall enough to fit through the katana frame. the front did sit around 32mm down from stock mostly due to the fact i didnt respring the nsr shocks. Still rode well but i always intended to respring them... I sold the motor out of it years ago and the bike ended up lapsing so if you want to buy the NSR front end with twin tokico 4 pots and front wheel with tyre im happy to take a decent offer on it, then you can look into a drop knuckle triple and whats involved in fitting it. It's been done alot on various bikes over at www.customfighters.com if you are looking for more info/ try asking there.

So you still have the bike minus the motor? Want to sell that together maybe.. Just the front end I'd be keen but I'd want to have a proper chat just to understand it. I'll take a look at that link and perhaps get a chat going there. Also I decided I might as well get the tap measure out and start trying to understand what can go but first I'll hunt up someone who can run me through the basics which I am sure I can do through my circle there are some friends of friends I am sure that can tell me what to measure etc.

Right now that front end is still my ability to understand in terms of expense to fit to what I have verses say a good old GSXR750 1991-1993 which are known to be low stress and it might be I spend time calling the bigger breakers around the planet looking for that (for example).

Stocked to see a real option mind just need to get my learn on. If I can get to that point I'd be totally up for it.

[Grumph]

Umm. . . . no, what I do is make spacers out of plastic tubing, that I put between the top cover & the spring, that I adjust the length of until the mid range is correct. Then I get a piece of cardboard & put a pen line on it on one end & another pen Line at the other end that is equal to the free length of the spring, plus the length of the plastic tubing, plus a tiny bit (very technical measurements at this point lol) to allow for the dead area that the tubing took up that the spring will later occupy. I then hold the spring by the ends & stretch it. You have to be extremely careful at this point because while it can easily be stretched, it can never be shrunk, so I carefully work the length up, until it matches the length marked on the piece of cardboard, usually good results are achieved first time. Then turn to the needle for fine mid range tuning (often raising it by one or two positions) & the main jet for top end,usually by having two sets of main jets & drilling one larger than the previous until I go too far, & then returning to the previous size (usually works out to be up by 10 to 15)
If it hadn't worked for me countless times over 25 years plus, I don't think I would have had the ball bag to post it up in such company.

If it works, it works. Two ways of doing the same thing. As I see it you aren't changing the spring rate, just the force needed to overcome it by dialling in more preload.
Your way gives the motor more fuel at a point where slide movement has stalled - letting it continue to rise in the revs.
My way lets the slide get past it's stall point - and yes, I've often had to lift the needles too - and the drill one/keep one jet system is well proven for me.

There's some history with drilling the slides. I heard a story about Schwantz and the GSXR750J at Daytona. CV carbs of course...The guys were drilling slides to get better response and Kev was saying more, more...so they kept drilling. I'm told that at a vacuum hole size around 6mm they discovered that the vacuum at full noise wasn't enough to keep the slides up around the bankings...He had to put up with a less than optimum respone just to get full throttle.
Still won though. Grant Ramage ran a 750J here and Suzuki NZ passed the info on.

[IronPawz]

He could get the heads punched as well.

Not sure what that means but really I'm just into the suspension at the moment with no real thoughts to the motor. No turbo or charger is going to suite my 750km's per week commute. Later on I might well look at the motor but beyond carbies, decent pipes or possibly putting in something else it is so early I'll just ride it standard and see how it goes. To be fair fuel economy is still of interest (I fill my blade every second day as it is).

This will be no drag bike but that will not stop me taking it to the drags!

[IronPawz]

What can I say, a perfectly good thread, of which I was enjoying has been ruined.
Me, I like kat's and old Suzuki's and I hope the offenders will take a deep breath and get back on topic.

There is nothing better than building your own bike, what ever it is. Building a bike is an art form, something to enjoy and be proud of. At the end of the day most likely you will not recover the cost but it all about the hunt for parts, the enjoyment of receiving parcels in the post and seeing what you end up with. You will have something original.. and that's cool..My kat owes me lots, the wire rim alone were more than I paid for the bike.

Many thanks

The photo looking at the back looks great. What extend the swing arm? I thought that was more a drag thing or it is for ride or tires etc. Things like wire rims I might well go there over time. But I will start with the functional ride and break with a view to some looks (like USD if I can). I don't even plan to paint it or fix the minor dent in the tank before doing the suspension and breaks.

Like the comments on the joy of bike building. I can see to you build for yourself anything new will not be liked by all and there is no reason to expect it should be. I've seen cafe racer Katana's (just horrible, I love kat's and cafe racers but together I'm horrified by a short seat on a Kat). Still I'm all in for other people to do there thing.

[Crasherfromwayback]

I then hold the spring by the ends & stretch it.. Then turn to the needle for fine mid range tuning (often raising it by one or two positions) & the main jet for top end,usually by having two sets of main jets & drilling one larger than the previous until I go too far, & then returning to the previous size (usually works out to be up by 10 to 15)
y.

So you're not actually fitting heavier springs at all, and you're also fattening up the mid range and top end. And without an airbox, the slides don't flutter at all? I've got a feeling you increasing the preload on the initial opening of the slides is helping fight the flutter you say doesn't exist.

[sidecar bob]

So you're not actually fitting heavier springs at all, and you're also fattening up the mid range and top end. And without an airbox, the slides don't flutter at all? I've got a feeling you increasing the preload on the initial opening of the slides is helping fight the flutter you say doesn't exist.

I'm no expert, but increasing the preload makes the slide harder to lift, with desirable results.
Pull the air box off a cv carb bike, fire it up & whack the throttle open & see if you can see any flutter. Fucked if I know, but what I'm doing works for me. The short of it is that I can make cv carbs work with pods or no filters whatsoever, because I understand how the carbs operate.
This flutter thing is brand new to me & sounds like somebody's excuse for not knowing how things really work. Not yours nesacarily.

[sidecar bob]

Not sure what that means but really I'm just into the suspension at the moment with no real thoughts to the motor. No turbo or charger is going to suite my 750km's per week commute. Later on I might well look at the motor but beyond carbies, decent pipes or possibly putting in something else it is so early I'll just ride it standard and see how it goes. To be fair fuel economy is still of interest (I fill my blade every second day as it is).

This will be no drag bike but that will not stop me taking it to the drags!

For what it's worth, your thread kind of turned to shit in your absence when a couple of blokes had a bit of a disagreement. Fortunately a mod pulled out a few offensive posts, which were of absolutely no value whatsoever.

[Laava]

For what it's worth, your thread kind of turned to shit in your absence when a couple of blokes had a bit of a disagreement. Fortunately a mod pulled out a few offensive posts, which were of absolutely no value whatsoever.

It was actually highly amusing yet tragic at the same time! Inappropes for this thread tho.

[IronPawz]

my bimota SB3 has cv's and pods, prior to that it was a steve roberts airbox which the guy didn't like and threw away.
when the bike came to nz it had thirstier carbs on it, it just so happened that suzuki new zealand had about 23 sets of brand new gsx1100 carbs sitting on their shelf, so a set was purloined and fitted, odd that there were 23 gsx1100 black piper wire wheelers with slide carbs 'arrived' in the country at about the same time.....

I just looked up the bimota SB3 what an absolutely cool looking machine. Pretty decent stats for the day (bit lighter than the Kat somewhat less pony but all the style you could hope for). Good example of a bike you could not mess with the look of in any good way. Give me the same great feeling looking at a ducati paso does (no idea what they ride like but just love looking at them).

Coolies.

[husaberg]

I just looked up the bimota SB3 what an absolutely cool looking machine. Pretty decent stats for the day (bit lighter than the Kat somewhat less pony but all the style you could hope for). Good example of a bike you could not mess with the look of in any good way. Give me the same great feeling looking at a ducati paso does (no idea what they ride like but just love looking at them).

Coolies.

Paso that's just wrong.... on so many levels
If you had said F2 Ducati