Balancing carburetor and tuning

[Guest]

Hello all! I am new to my dream bike, a 1979 GS1000L and new to tuning four carbs. I could use some advice for tuning.

I pulled the carbs out to replace leaking fuel joints, fuel/vacum lines, cleaned them well, and replaced carb boot O-rings that seat against engine block and installed inline fuel filter.

My question is, how important is Balancing the carbs after taking them apart for cleaning?

I have it all back together, air box with filter installed and the Bike fires right up without the choke and will idle fine once warmed up after about 30 secounds. It runs good up to about 5000 rpm and then start to sputter, lose power and back fire when slowing down. I did not balance the carbs, could this be the issue? Thank you for any help!

[JTGS850GL]

Yes you need to sync the carbs, but my bet is you haven't cleaned them properly yet. Once cleaned you'll still have a few other things to work on with your dream bike before it's really road worthy. Valve clearances need to be check and adjusted, carbs synced, brake fluids changed just to name a few. Go here to get a copy of your manual and a links to other maintenance items. Here's a mega welcome that will help as well: Welcome

[Steve]

Balancing the carbs will be more of an issue at idle than at 5000 rpm.

After doing virtually ANYTHING to your carbs, they will need to be balanced.

However, don't bother doing that until after you have adjusted the valves (unless you have already done that).

When you "cleaned the carbs well", did you replace all the o-rings inside the carbs and set/verify the float level? Until some of these basics are resolved, there is no point in telling you how to fix problems at 5000 RPM.

.

[DanielGS1000]

Thank you for the helpful link with the basic info, thats good stuff!

I have not checked or set the floats yet but will be doing so now that it has been brought to my attention.

I have not adjusted the valves yet. I guess i need to learn how to do that.

When I cleaned the carbs I did not replace any o-rings, the o-rings and gaskets on the carbs were in good shape. o-rings and gaskets were soft which lead me to belive they were rebuilt in the last 5 or 10 years. They appered to be in great shape just clogged from bad gas. I used carb cleaner and compressed air to clean them and removed every piece I could and spryed out all ports with carb cleaner. What else could be done to clean carbs?

[JTGS850GL]

Go to the carb rebuild tutorial on the website I gave you a link to for a very detailed rebuild that NEEDS to be done. Carbs need to go through a complete dis-assembly and dip in carburetor/parts cleaner.

O-rings can be purchased through cycleorings.com. and must be replaced as well. Don't forget the O-rings behind the intake boots that seal the boots to the head.

[DanielGS1000]

Thanks again! That carb rebuild guide is AWESOME!

I did replace the o-rings that seal the boots to the head. Also, I feel I cleaned the carbs. good. I sprayed and dipped every part in good carb cleaner and got them really clean.

I am going to check the floats for proper positioning and then check/adjust the valves as said to do so.

From there I will see how she runs and see if I need to pull the carbs again and clean them.

Also I read that to much filter oil is bad as well, and I do admit I drenched that sucker with UNI filter oil so i will wipe it off with paper towels and see if that helps!

[OldVet66]

If you didn't soak them dissembled in carburetor dip for 24hrs, especially VM carburetors, you will be amazed at the crud that boils out of them when you put them in the dip. Carburetor cleaner and compressed air is useless until all the hardened up residue in the tiny passages is softened up so your carburetor cleaner and compressed air can actually be of use. You need to trust us on this one, and do the job right.

[DanielGS1000]

You guys are right! I just ordered the O-ring kit for the carbs and will be doing the 24 hour soak in carb cleaner!

Then we will see how she runs!