[split4161]

1997 suzuki rf 900 carb problems

ive got a 1997 suzuki rf900. when the bike ran it would idle low or it would idle high. when i got on the throttle it would bog down. This was about 6 months ago. when i decided that it would probably need some money to get running i drained the full tank and plug the lines going from the fuel tank to the motor, this was the beggining of its six months of none running storage. someone mentioned that the carbs may have needed to be synced, but that doesnt make any sense to me because there preset from the factory and unless you take the bike apart they should be fine. i tried to start it yesterday, i connected the lines and filled it with fresh gas and all it does is crank, its got compression, but it doesnt start. what should i do?

 

[enos]

Did you drain the carbs when you drained the tank? If not, they're varnished up and need to come out for a clean.

 

[LovemyKawiZX6R]

Just take the carbs out and clean the hell out of them.

 

[split4161]

If i take the carbs out will that mess up anything? will they be out of sync when i put them back in?

 

[15dollar]

Try running some SeaFoam through the system first. It's cheap and easy and may fix your problem. If you fully remove the carbs they will need to be synced again. Do you have a service manual?

 

[enos]

In his case the only option other than taking them off is to drain the carbs, rinse them with some fresh gas, then pour full strength seafoam directly into the fuel line. Let it sit at least overnight, drain and try to start it. The floats will keep the seafoam from getting everywhere but it might get it clean enough to start. Then keep putting seafoam in the gas and let it finish the job.



Carbs gradually come out of sync anyway. The service manual says to sync them every dozen thousand miles or so. The sync is for the main butterfly plates and the big thing that might disturb the sync is separating the carb bodies. Even that won't affect it by much. At each junction there is a sync screw and turning that adjusts the butterfly with respect to its neighbor. So don't turn it.

I've never noticed a difference in the sync before and after taking the rack apart as long as I didn't mess with the screws. You might if you had perfect sync before you start, but I bet yours is far from perfect as it is.

A bad sync shows up as vibration in the engine and that's pretty much it. It's pretty easy to make yourself a $5 manometer with some clear tubing and do the sync yourself. You'll be amazed how much smoother the bike will feel.

 

[LovemyKawiZX6R]

Try running some SeaFoam through the system first. It's cheap and easy and may fix your problem. If you fully remove the carbs they will need to be synced again. Do you have a service manual?

No u don't. If u take them off and don't touch the sync screws, then it stays the same and u don't have to sync it but it doesnt hurt to sync it anyways.

 

[Veefer97]

No u don't. If u take them off and don't touch the sync screws, then it stays the same and u don't have to sync it but it doesnt hurt to sync it anyways.

And how would you know that they were synced properly to begin with? After a carb clean I would certainly take 20 minutes to properly adjust the carbs.

 

[chinmay]

one Q from me. what if he only drain the fuel from float chamber by removing drain screw which is in the bottom? so after that fresh gas will come in the chamber.
second thing how about cleaning the plugs. coz the bad fuel and liquid fuel might screw up the conductivity??? because bad fuel will not burn for sure but it might stick to plugs. After that just incase if the bikes starts and later on he can use carb cleaning liquid so that won't hamper synch...

 

[LovemyKawiZX6R]

And how would you know that they were synced properly to begin with? After a carb clean I would certainly take 20 minutes to properly adjust the carbs.

Yes u should sync them but taking the carbs off doesnt mess up the sync.

 

[Gee]

I'd drain the carbs while on the bike (try to catch what comes out with a piece of hose and a container looking for rust, water, trash, etc). Once drained, put Seafoam in as mentioned above and let it sit at least over night. If its ridable after that, I'd put some Chevron "tectron" in the tank as well. It works very well at cleaning out the entire system...

If that doesn't work, remove the entire carb rack WITHOUT unbolting -(KEEP THE 4 CARBS TOGETHER AS A UNIT), it should come out all 4 carbs. Remove the float bowls and clean out the jets using carb cleaner and an air compressor. As long as you don't adjust the sync screws it shouldn't make the sync any worse/better. Once running correctly, you can do a sync. As stated above, the sync helps more with rough running/ vibrations.

I suspect the carbs will be very gummed up...

 

[enos]

one Q from me. what if he only drain the fuel from float chamber by removing drain screw which is in the bottom? so after that fresh gas will come in the chamber.
second thing how about cleaning the plugs. coz the bad fuel and liquid fuel might screw up the conductivity??? because bad fuel will not burn for sure but it might stick to plugs. After that just incase if the bikes starts and later on he can use carb cleaning liquid so that won't hamper synch...

Old gas forms varnish and solid deposits inside the small passages and jet orifices of a carb. Draining the old gas won't remove those deposits.

The plugs may well be fouled, but instead of cleaning them it's best to get new ones.

 

[Veefer97]

I seriously doubt that Seafoam will clean out gunked up carbs. It is a good product but not a miracle product. Take the carbs off and clean them properly.

 

[chinmay]

Old gas forms varnish and solid deposits inside the small passages and jet orifices of a carb. Draining the old gas won't remove those deposits.

The plugs may well be fouled, but instead of cleaning them it's best to get new ones.

ahhhh! ok i got it...