So I haven't been active on this board for a while. My GS was sick, I couldn't ride it any more, life got in the way and it's just taking up space on my patio. The bike needed work to be reliable, and mods to suit my purposes. After a drop in my driveway while I was trying to push start it, (key was snapped off in the seat so I couldn't jump it), I gave up for a while. I did rather drop of the radar, apologies to Adidasguy for that. We were going to swap some parts around the world if I could sort some Australian fork tops.
I'd like to get the bike running, but to be viable I need to firm up the suspension and get it stopping a bit better.
My first question in on carbs (isn't it always). The bike is a '95 model, but has a 2008 motor in it due an earlier case of goats in 2011. For simplicity I used the bike's original carbs when I swapped the motor. Those carbs nos leak fuel horribly when I crank it, so would need rebuilding. I do have a set of the triple jet carbs that came with the '08 donor engine, they came off a running bike a couple of years ago, but I'll probably still have to rebuild them.
The later carbs have a lot of extra vac lines and switches on them, none of which I want to bother with. I have heard it suggested that I swap the bottom caps off the earlier carb without the vac lines, and build myself a simpler version of the triple jet. Has anyone done this successfully?
I'll ask more dumb questions later, I've got a front suspension and twin disk swap in mind, but first I've got to know it still runs ok.
Step away from the carbs...
Ok now, vehicle manufactures work on on big numbers so even $1 makes a huge difference on a part. If it was passable to just to swap the bottom cap get rid of the vac lines etc and get the same, or even nearly the same performance it would come from the factory like that.
Secondly, most importantly i look through the threads and see how some people battle with carb issues. That is even with the help of the forum members (You guys are all awesome by the way).
Now you in essence make a "new" carb. Nobody else has one, trouble shooting just got 1000 x harder.
On the other hand it may work like a charm, but messing with the thought of messing with a vacuum carb makes my palms sweat.
You can get rid of all that junk and have a functioning carb set, I did it. The key is learning what each device does, and not to be contradictory to metatron, but suzuki did put alot of extra junk on those carbs for one reason; emissions law.
Dont make all your decisions based on what I write here, do more research. This is all from memory.
The white caps at the top of the carb are to vent vacuum (or allow ambient pressure in, how ever you want to look at it) when the throttle is opened quickly, since the slides rise faster than necessary, creating a rich condition for a very small amount of time.
The vacuum lines run from them, to that little electronic device at the bottom of the right carb, and a third line runs to the motor. This third line is the vacuum supply for the device.
On the right side of the right carb, by the throttle rod, is a variable resistor. As you open the throttle, the resistance changes. This signal goes to the cdi (I think) and if it determines the throttle has been opened very quickly, it signals that device at the bottom to open, allowing motor vacuum to open the white vents at the top of the carbs, venting vacuum, thus slowing the rise of the slides.
Apparently, all this engineering was worth it to get a few less hydrocarbons out of the pipe and pass emissions. It probably does improve throttle response, as it does solve a problem inherit to all CV carbs. But is it necessary? No.
Again, read some more about it, but if you want to give it a go, just block the white valves on each carb with a short piece of vacuum line with a screw in the end. Thats how mine is setup, and it runs fine. You can leave the electronics on the carb, it wont hurt a thing.
As I said in the original post, I'd been working on my bike a few years ago when the project got away from me and I dissapeared off the GStwins radar. I'd lined up some parts, including a set of '89 clipons, from the ever patient and generous Patrick Lajko. I meant to apologise for the lapse in contact, but since posting I've learnt of last year's tragedy. I can only offer my respect and sympathy to family and friends.
Thanks to W201028 and Metatron for getting back to me. Whilst I agree that Suzuki doesn't spend money engineering bits for no reason, their reasons may be different to mine, since they have a lot of regulations to comply with, whereas i just want my old bike to do something when I turn the throttle.
Quote from: W201028 on July 12, 2015, 05:32:29 PM
The white caps at the top of the carb are to vent vacuum (or allow ambient pressure in, how ever you want to look at it) when the throttle is opened quickly, since the slides rise faster than necessary, creating a rich condition for a very small amount of time.
A rich condition for a very small amount of time. What a beautiful understatement. We'll leave it at that suffice to say that tunnels were made for downshifts.
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The vacuum lines run from them, to that little electronic device at the bottom of the right carb, and a third line runs to the motor. This third line is the vacuum supply for the device.
On the right side of the right carb, by the throttle rod, is a variable resistor. As you open the throttle, the resistance changes. This signal goes to the cdi (I think) and if it determines the throttle has been opened very quickly, it signals that device at the bottom to open, allowing motor vacuum to open the white vents at the top of the carbs, venting vacuum, thus slowing the rise of the slides.
I re-used all my bike's original 1996 electricals. All I had to do was swap the earlier pulse sender into the late model motor and change a few connectors from the stator. In my case the additional sensors and vac lines would be redundant without the later CDI box to send to. There's nowhere for the throttle position sensor to go to, and the gear position switch in the trans is redundant.
Quote
Again, read some more about it, but if you want to give it a go, just block the white valves on each carb with a short piece of vacuum line with a screw in the end. Thats how mine is setup, and it runs fine. You can leave the electronics on the carb, it wont hurt a thing.
Once I sort out this rusty tank full of three year old stale fuel, I think "further research" is going to consist of seeing what happens if I put the spare set of carbs on my bike with the vac lines plugged.
For anyone curious why I swapped the motor, or unfamilar with the term Goats, here's my original engine swap thread from 2011. I did ride it on the new motor for about 6 months before a series of other failures sidelined the bike.
http://gstwins.com/gsboard/index.php?topic=58197.0
(http://i156.photobucket.com/albums/t23/Cosimo_Zaretti/20150724_123843_001.jpg)
You can see where I've cut back the bougainvillea to reveal a motorcycle. Horrible stuff, my landlord had it removed, but it keeps sprouting up again and taking over the patio. The bike is under shelter, so it hasn't been out in the rain the whole time.
(http://i156.photobucket.com/albums/t23/Cosimo_Zaretti/20150724_123907.jpg)
I discovered that if you turn the tap to prime, the leak is from a split in the line on the carbs. I might get away with re-using these carbs yet. I also found fuel leaking around the tap switch itself, so a new petcock is in order. I never used anything ethanol based in the bike, which may save the carbies.
I'm not proceeding any further until I get a new petcock and replace all the old lines. Gravity fed systems are a massive fire hazard with any leaks, especially with a hot air cooled motor. The fuel will just keep flowing.
(http://i156.photobucket.com/albums/t23/Cosimo_Zaretti/20150724_124017.jpg)
This is what originally sidelined the bike. The clipon is bent in towards the tank and it's not a rideable proposition. A generic 37mm clipon would be the cheapest solution, but would require me to lose the top plate, which I don't mind, and then lower the front end an inch or so, which I don't specially want to. For this low budget resurrection, I might just lower the triples and go with the cheapest clipons I can find. The wiki tells me there are interference issues withe the headlight bracket if I wanted to put them under the top triple.
(http://i156.photobucket.com/albums/t23/Cosimo_Zaretti/20150724_124104.jpg)
Looking at this picture, you can see the headlight bracket takes up all the real estate between triples. There are plenty of slimmer and nicer looking headlight clamps on ebay, but for now the priority is to get this bike moving under its own power as quickly and cheaply as possible.
You can also see in this picture that right hand fork is leaking badly, and the legs of both forks have spots of surface rust. Not shown in the pic is that at least one leg has gouges where some gorilla has changed a fork seal with a screwdriver.
Too long didn't read?
Skip to the questions.
What size fuel lines to replace everything? Can I make 5/16 clamp onto all the fuel lines? What size is the petcock vacc line?
What can I use to clean the rust spots off the fork legs without further damaging the chrome? Should I even waste fork oil and seals, or just replace the forks?
What's the best way to clean out the inside of a rusty tank? I was planning on giving it the vinegar and bolts treatment then just filling it up with fuel. Full tanks don't rust.
Does anyone have a set of '89 clipons or low rise euros they might consider selling me?