Cleaned carbs - now runs like crap and revs very slowly

[MrZig]

Thanks basscliff. I use cmsnl all the time for diagrams and OEM part numbers. Super handy to just get the OEM numbers for what I need and take them down to the zuki dealership!

Also I meant that I'm going to fabricate my own airbox-to-carb boots. The ones I have are pretty gross looking and I can't afford to buy the proper airbox, nor do I even know if it would fit in my frame.

Any tips for getting the phillup-head screws out of the intake boots to replace the O-rings? Two weeks ago I went to take them out to have a look see but I just managed to round them off a bit, even with my best fitting screwdriver.

Edit: Also that is definitely my engine.

 

[BassCliff]

Hi Mr. MrZig,

Those Japanese phillips head screws are different than ASE screws. There are special screwdrivers made for them. Or you could just use a decent impact driver. I read a thread recently where someone took a #3 screwdriver socket tip, pounded it into the screws, then used a ratchet to take them out. This is the thread:

Easy removal of intake head boots without a Jap screwdriver

It helps to soak the screws with PB Blaster or your favorite bolt loosening liquid. Once you get them out, it would be best to replace them with hex head screws. Mr. Robert Barr at http://cycleorings.com has the O-rings and screws for not a lot of money. He's a good guy.

Keep us informed.

Thank you for your indulgence,

BassCliff

 

[C.V.]

Any tips for getting the phillup-head screws out of the intake boots to replace the O-rings?

Impact driver works beautifully. Got mine for 5.99 at Harbor freight, you might want a better one if you want to use it more than a few times.

Once you get them out, it would be best to replace them with hex head screws.

+1. do yourself a favor!

 

[MrZig]

I think I'll order the stuff from Robert Barr's site. First I gotta find out if the o-rings fit..

 

[Guest]

i know this might sound weird but i just got my vise grips on them and broke them loose and then used the screwdriver. definatly get you some hex screw head screws to replace them.

 

[MrZig]

If I don't order them from Rob, could I simply replace them with normal bolts? Or does the location somehow make getting a wrench on them difficult?

 

[Big T]

Regular bolts will work, but stainless steel "allen" heads show you love your bike.

I get my odds and ends bolts, including ss Allens, at Ace Hardware. Just be sure and take an original one along because of thread pitch.

 

[tkent02]

Regular bolts will work, but stainless steel "allen" heads show you love your bike.

Anti-seize compound says love too.

 

[MrZig]

Instead of posting a new thread, I'll ask it here.

What would the valve clearances be on my GSX400? The only numbers I can find are for the GS400's, GS450's, and the later model inline fours.

The 400 & 450's wouldn't really apply because they're not the same head design, nor are they 4 valve per cylinder engines.

The numbers I did find for the 400/450 is 0.03-0.08 mm on a cold engine. Extremely tight but apparently they loosen up when it warms up. Is it the same thing for the GSX400?

 

[BassCliff]

Hi,

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


Thank you for your indulgence,

BassCliff

 

[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: