Cleaned carbs - now runs like crap and revs very slowly

[MrZig]

Hi,

The 4-valve per cylinder motors have a spec of .08mm - .13mm for the valve clearances.


Thank you for your indulgence,

BassCliff

Awesome, thanks for the quick reply. Going to have to write that down..

You wouldn't believe how hard it is to find ANY sort of information on my engine. Was it made in Canada, or just Japan? I wonder if it was imported. I don't know any history on the bike or what any previous owners did to it, heh.

Also what would be the best type of flexible rubber to use for custom airbox-to-carb boots? I was thinking of using radiator hose, but I was also thinking of using the type of rubber people use on turbocharger pipe setups to join pipes together. Any other ideas?

[reddirtrider]

Awesome, thanks for the quick reply. Going to have to write that down..

You wouldn't believe how hard it is to find ANY sort of information on my engine. Was it made in Canada, or just Japan? I wonder if it was imported. I don't know any history on the bike or what any previous owners did to it, heh.

Also what would be the best type of flexible rubber to use for custom airbox-to-carb boots? I was thinking of using radiator hose, but I was also thinking of using the type of rubber people use on turbocharger pipe setups to join pipes together. Any other ideas?

The rubber Suzuki uses is pretty flexible so that you can get the cabs off easier. Well, it was flexible when new anyway.

[Larry D]

I didn't mess at all with any mixture screws. To clean the carbs I used the baking soda & compressed air method then soaked them in hot water for a couple hours, and then blew out the passages with compressed air.

I didn't replace any o-rings, and I eye-balled the bench sync as best I could (comparing the plate positions against the pilot hole in the carb body).

If you didn't remove the mixture screws you didn't blow out ALL the passages with compressed air. How do you know the PO didn't break the tip of one the mixture screws off ? Which would certainly cause idling issues. How about the needle jets and seats did you remove them and clean them out ?
It is highly recommended to completely diassemble the carbs and dip them. Replace the orings. The ones in there are +-20 years old, hard and brittle. Secondly, if the bike is difficult to start a valve adjustment is in order, that is a tell tale sign.
Doing these basic maintenance items will help establish a clean base to work from when tuning the bike. The carbs must be cleaner than clean and the valves must be in specs or the bike will never run right, regardless of what else you do.

[MrZig]

The rubber Suzuki uses is pretty flexible so that you can get the cabs off easier. Well, it was flexible when new anyway.

Yeah it would be flexible and correct if it was made for my carbs, but because it isn't, I need custom ones. I'll try and take a picture tomorrow describing exactly what I mean. Basically it just doesn't line up, and forcing it to line up breaks the seal. New boots wouldn't fix this.

If you didn't remove the mixture screws you didn't blow out ALL the passages with compressed air. How do you know the PO didn't break the tip of one the mixture screws off ? Which would certainly cause idling issues. How about the needle jets and seats did you remove them and clean them out ?
It is highly recommended to completely diassemble the carbs and dip them. Replace the orings. The ones in there are +-20 years old, hard and brittle. Secondly, if the bike is difficult to start a valve adjustment is in order, that is a tell tale sign.
Doing these basic maintenance items will help establish a clean base to work from when tuning the bike. The carbs must be cleaner than clean and the valves must be in specs or the bike will never run right, regardless of what else you do.

I took out all the jets and the jet needle and cleaned them extremely well. Also the bike started very easily before I cleaned the carbs, and I don't think my valves got out of spec between then and now. However I will adjust them this weekend now that I know the specs.

[Nessism]

A lot of the Suzuki bikes shared the intake pipe O-rings, if you have part number information handy you could compare the part numbers between different models to see if any of Robert's intake O-rings will fit.

[MrZig]

A lot of the Suzuki bikes shared the intake pipe O-rings, if you have part number information handy you could compare the part numbers between different models to see if any of Robert's intake O-rings will fit.

I meant the carburetor o-ring set. I'm going to grab some intake O-rings from the dealer tomorrow.

[MrZig]

This is why I need custom intake boots.



The left side is 100% lined up. Notice how the right one is off by quite a bit..

[BassCliff]

Thanks for the picture Mr. MrZig.

Did you say those are different carbs (from a different bike)? It looks like the carb rack is narrower. Do you have the original carb rack? It looks as if you'll be fabbing up some airbox-to-carb boots after all. Please keep the pictures coming. I'd like to see your final solution. Thanks for sharing.


Thank you for your indulgence,

BassCliff

[MrZig]

Thanks for the picture Mr. MrZig.

Did you say those are different carbs (from a different bike)? It looks like the carb rack is narrower. Do you have the original carb rack? It looks as if you'll be fabbing up some airbox-to-carb boots after all. Please keep the pictures coming. I'd like to see your final solution. Thanks for sharing.

It's an entirely different engine. GSX400 engine in a '78 GS400 frame. However it uses the GS400 airbox.

A new carb rack wouldn't work because all the linkages and such wouldn't work anymore, plus they wouldn't align with the cylinder head.

I'm not sure what I'm going to do as far as custom boots, yet. But when I do I'll definitely post what I end up making.

[MrZig]

The boots are gross, yes, but this is the unsealable angle with them on:

[MrZig]

I was told that I should cut it in half, then cut out however much I need and find someone to plastic-weld it back together.

Thoughts? Also I don't think I should worry about changing volume becaue I mean, I am using the entirely wrong box for the carbs in the first place.

Edit: Meanwhile I have the carbs out, is there anything I can spray onto the diaphrams to preserve them?

[BassCliff]

I was told that I should cut it in half, then cut out however much I need and find someone to plastic-weld it back together.

Now why didn't I think of that? It should work, as long as the air filter still fits.


Thank you for your indulgence,

BassCliff

[MrZig]

Pretty big update:

I took the pilot screws out and what dy'a know, the o-rings and washers are missing.

That's right, they're not even in there. New o-rings are already on the way, and I'll try and find a couple washers of suitable size. Also the tip of the needles had a tiny bit of buildup on them.

Could missing o-rings cause some bad running? I'd say yes but I'm no expert. Also, one needle was turned out about 3 & 1/2 turns, the other one 2 & 1/2. Should I set them both to 2, or to 2 and a half for re-tuning?

[Stefnwolf]

Warning

Often the O rings and washers do not stay on the needle when its pulled.
They can be pretty hard to see in that tiny hole, but its possible they ARE STILL IN THERE.

Have a real good look, and dig around in the hole with a piece of soft wire to see if you can hook anything out.

[MrZig]

Often the O rings and washers do not stay on the needle when its pulled.
They can be pretty hard to see in that tiny hole, but its possible they ARE STILL IN THERE.

Have a real good look, and dig around in the hole with a piece of soft wire to see if you can hook anything out.

No, trust me, they aren't in there. Using a flashlight I can follow the inner wall down. I mean, it's not a single diameter all the way down, it shortens up a bit (see picture) but that isn't a washer.

I used some wire to try and fish out whatever was in there to no dice. I managed to scratch the walls up a bit too, that shouldn't cause an issue should it?

Also the fact that the caps have been drilled out, and that one of the screws was turned out 3.5 turns tells me that someone has mucked with it before.



(Isn't a washer, just the change in diameter of the cylinder. I think? I'm sure..)