The 550 Project

[Molino]

Okay, so i got the carbs back from the shop, had them install the new Orings, and that kept them from leaking. Now i'm having the problem of the bike not starting without the help of starting fluid. I think when I brought the carbs back the mech may have messed with the float levels again, this is what its doing.

The first time I got the carbs back, the bike started right up just fine, just idled really high because I didn't have the carbs fully into the intake boots. With the help of some silicone spray, I solved that problem, but now it seems I'm at the complete opposite extreme.

Bike wont start up without the help of starter fluid. When it does start, the choke is fully engaged.
When I disengage the choke, it idles even higher. If I try and open the throttle, it dies.

Seems to me like he messed with the floats to the point where now they're closing off and not sending enough gas to the engine. Mostly just air with a little bit of gas. That would explain why it idles so high, and when I cut the choke off, it dies?

Its the same symptoms of an Air Leak, but insted the engine getting more air than gas because of the way the floats are set now?

Any thoughts my friends?

 

[cowboyup3371]

Take the carbs off the bike, remove your bowls, and measure the floats. Also, do another bench synch on the carbs since you really shouldn't trust the shop for that.

Edited to Add: It won't take much time to remove each of your jets while you are doing that so why not just give them a look see as well to check if they cleaned them properly.

 

[Molino]

Okay so removed the jets & got everything in between the Jets and the carb bodies themselves, squeaky clean. But I noticed something weird. On one side of each of the carbs they're running different Jets.

On the Right and outer side, its a 97.5 jet.
On the Left and inside, Its a 90 Jet.

It's like this for both of the Siamese carb bodies. Anyone know what the actual jet sizes are that are suppose to be in there?

 

[cowboyup3371]

Go here http://www.mediafire.com/?sharekey=3a0ab726f6117e564012e8015643d9c85717b31bfbde8fc1

and look at the bottom of his page for the database. If your carbs are like the 83 then you should be having 95s in 1 and 4 and 102.5s in 2 and 3

 

[Molino]

So the two middle cylinders are getting more fuel than the two outer cylinders? What's Suzuki possibly going on about here?

 

[7981GS]

So the two middle cylinders are getting more fuel than the two outer cylinders? What's Suzuki possibly going on about here?

Cylinder cooling on an in-line 4 cylinder engine where the center cylinders run much hotter perhaps?

Daniel

 

[Molino]

Finally got it running, took it for a spin, It's absolutely brilliant! And really f&$king scary!! I'm still a little jumpy from all the adrenalin .

Now the weird thing is, I cant get it to idle without providing a little bit of choke. If I give it full choke, it dies. Where's the A/F mixture screws on these Mikuni carbs?

And a photo for your personal enjoyment:

:dancing: Sweet.

 

[cowboyup3371]

Your idle mixture screws are on the top at the front of each carb (engine intake side). Use the highest idle method to set it.

 

[bietau85]

Okay, so i got the carbs back from the shop, had them install the new Orings, and that kept them from leaking. Now i'm having the problem of the bike not starting without the help of starting fluid.
Any thoughts my friends?

Are you trying to ruin your carbs?

 

[Molino]

Yes, thats exactly what I was going for..... completely irrelevant but okay. I don't know about you but I don't baby this stuff. When I'm trying to get it to run, I'm trying to get it to run. If I had not done that, I wouldn't have found out my carbs were still dirty and there was a piece of gunk still caught up in them. Jeeze, whats with the hostility....

Cowboy, are those the small-ish flathead screws? It's the siamese carb setup, so It may be a little different from your traditional single-barrel, four carb setup. Cheers

 

[bietau85]

Yes, thats exactly what I was going for..... completely irrelevant but okay. I don't know about you but I don't baby this stuff. When I'm trying to get it to run, I'm trying to get it to run. If I had not done that, I wouldn't have found out my carbs were still dirty and there was a piece of gunk still caught up in them. Jeeze, whats with the hostility....

Cowboy, are those the small-ish flathead screws? It's the siamese carb setup, so It may be a little different from your traditional single-barrel, four carb setup. Cheers

I dont know how you took my question as hostile, but yea obviously they didnt start without ether for a reason as you found out...just saying only cause i did that for awhile b4 i fixed my carbs right and had pinholes in my diaphragms that cost alot. so much is it was just worth buying a spare junk set of carbs for the damage I did. I was just trying to give good advice and help save you money since you just paid someone to work on em.

And yes if you back those flat head screws out all the way they should be needle screws. make sure they arent broken, and when dont tighten them too much because then you will be in a whole heap of trouble like i got my self into a few weeks back when I was doing my highest RPM method run.

 

[oohsam]

Molino -
It would be really helpfull instead of just saying "i got the bike running" to state what you did to get it running...your post doesn't have much info on what you actually did..

I as because I'm going to be possibly going through the same thing as you are now and it would be great to see your methods of madness, as it may save me some madness times! ha!

 

[Molino]

Well it took alot of trial and error, and it's going to drive you mad... that part's inevitable lol.

I'd say about three times I brought the carbs back to be cleaned. The second time is when I had to use starter fluid to get the bike to run. That's when I brought them back to the carb shop & the guy found a little peice of gunk behind some of the needle jets.

So I mean now it runs, but sorta janky. It will rev out to 4k unless I engage the choke partially. So with the choke engaged I have gotten it to have some sort of stable Idle around 1750... good enough to ride a little bit around the parking lot.

The Idle control screw sort of has an effect, I was able to tweak it to just the right point where, with the choke partially engaged, it'll sort of idle. Now when I disengage the choke, and it revs out to 4k, messing with the idle screw doesn't bring the idle down, only takes it up... (If I bring the idle up that is.)

And now it's suppose to rain for the next three days... just my luck haha. So I wont be toying with it as much as I wanted too.

 

[bietau85]

What color are your plugs? all of em....

Also Do you have all of the intake sealed? I can never get mine to idle correctly if anything is loose fitting, even the the airfilter has to be in and clamped up/screwed on...
Also have you backed the actual idle screw out all the way so the butterflies are all closed? Possibly see if it will run with a slight turn in to see the rpms there. I am assuming you know that that is the big grooved know under your gang rail.

 

[spyug]

The Idle control screw sort of has an effect, I was able to tweak it to just the right point where, with the choke partially engaged, it'll sort of idle. Now when I disengage the choke, and it revs out to 4k, messing with the idle screw doesn't bring the idle down, only takes it up... (If I bring the idle up that is.)

/QUOTE]

Now if you have to use enricher (choke) to get it to idle the carbs are not properly cleaned and or the o-rings were not replaced. Period. I suspect the o-rings. This happened to me recentley and it was my own fault.

On my 550 project I was told by the PO that the carbs had been rebuilt. Being sceptical and as it had been done over a year ago I thought I'd take a peak inside before firing up. They did look clean and the o-rings looked new.

I tried to start the bike and had a devil of a time. Finally got it running but running like snot. I tore them down and resoaked everything. I was about to put it all back together using the o-rings already in it when something made me look closer at them. When "relaxed" they looked good but when slightly stretched, they were all torn and obviously leaking....all of them.
I replaced them, bench synched (also extremely important) and fired up the bike. With a wee bit of dialling on the idle screw and she ran flawlessly.

I should also mention, that the bike runs fine without an airbox, pods or filters of any kind. While they are designed to run with an airbox or pods, when clean and freshly rebuilt they will run and idle properly without them. All of my Zuks have (550, 750 and Katana).On mine, as the airbox was out of the frame when I got it (and tough to get back in) so I fabbed up some pods with Unifoam filters.

Redo your carbs and do them yourself. This is not the first time I've heard of carbs being "professionally" cleaned and not working thereafter.

Good luck with it.

cheers,
Spyug

 

[Molino]

Nono, all the orings were replaced, I had the carb guys replace them the second time around with the Oring kit. Now the plugs, I haven't gotten around to checking yet (rain sucks), but I suspect it's running lean... atleast that's what the harley mechanic I work with said.

Also he thinks the jets are still clogged somewhere. I don't know how this is possible considering it's been through an ultrasonic machine twice, but I suppose stranger things have happened.

Also I noticed air coming from somewhere around the Carbs. I couldn't tell if it was heat comming off the engine, or if one of my intake boots are cracked, which he suspects could also be the problem.

So next order of action is to pull the plugs, see what they look like. I think I'm going to replace the boots either way, just to be able to rule that out. Then the Harley mechanic wants me to take the Carbs back off cause he wants a look at them.

Gettin' closer... But boy was that thing a blast to ride!

 

[spyug]

I had the carb guys replace them the second time around with the Oring kit.

Sorry but I wouldn't take that as gospel. You need to check yourself. There are lots of mechanics that are sloppy or rushed and I've seen o-rings come out of the package that were bad. They do break down over time. Running lean, as you suggest is a result of air infiltration and erratic or high idle is usually air infiltration in side the carb itself, especially if you can't dial down the idle.

There are o-rings between the carb boots and the head too and that is often another area that air gets in. Were they changed? If there are cracks in the boots they too will need changing as you suggest.

These carb issues can be a PITA to sort out but if you can't get it to idle without choke you definitely have an air infiltration issue.

Just as an aside: I realise that being new to bike wrenching can be intimidating and working on carbs seems like rocket science but it is really not difficult. When you farm out the job to an "expert" you are at their mercy. The majority of guys are honest and above board but mistakes and oversights can happen and there are lots of folks that are not beyond a bit of larceny. The only way you know the job is done right is if you do it yourself. Owning an old bike it becomes important to learn to work on it yourself. If you don't it will get costly in terms of cash and or frustration.

Good luck sorting it out.
Cheers,
Spyug

 

[Molino]

Yea I know what you mean, which is why i'm going to end up taking the carbs apart again. It's not so much daunting as it just get's annoying taking the carbs in and out over & over again, as well as not having a shed or something to work on it when I want to! I'm a Vespa mechanic, so It's nothing new.... well Siamese carbs are pretty new lol.

But I'm going to check the whole intake boots & intake boot orings though. The boots were never changed as far as I know, but I never noticed any cracks in the boots. Well you never know. If only I could work on it at night, things would get done alot quicker, ha.
Cheers.

 

[oohsam]

Hey Molino.
These are boot rings you need to check. A crack in these are going to cause you alot of issues.

Like I said I have not done my carbs yet, but before i tore my bike down, it was running just fine and idling really nice as is. Before I tear them down I will try and run the bike before I replace them all. I bought the O-ring kit. and although it seems like a daunting job, I will be doing it myself. You can never rely on anyone...

Make sure you clean out the jets with a small piece of wire man....if there is gunk in it, you will know about it.

 

[Molino]

Ya, I was actually just reading about it. The more and more I think of it, running lean (have to check sparkplugs), engine running hot, erratic idle; I bet it's just the orings in the intake boots have to be changed like the orings were in the carb.

Ha, getting the screws off those boots will be fun.