Is this "surge" scenario common?

[BassCliff]

Hi,

Your bike does not have intake boot O-rings, but the intake boots themselves can crack as the rubber ages, causing air leaks. Have you gone through the maintenance lists in your "mega-welcome"? Sometimes it's just a process of elimination. The airbox also has to be sealed up and the boots between the airbox and carbs must have no leaks. Is the snorkel still attached to your airbox? See the Air Intake Repair article on my website, it will be similar to your bike.


Thank you for your indulgence,

BassCliff

[Windsmile]

If you are referring to the connector hose between the air filter housing and the manifold to the carbs as the snorkel, it is attached. Once the the weather cools down I'll go through the intake system and begin to eliminate possible air and vacuum leaks.

[BassCliff]

Hi,

My left index finger is resting on the snorkel on the back of my airbox.




Some previous owners have been known to remove this to try and increase airflow through the intake system.

Thank you for your indulgence,

BassCliff

[Windsmile]

I believe the air induction system on the '82 GS750T that I have is a different design. There is a plenum that holds the filter which in turn connects to a distribution manifold via a short tube. That tube clamps to each of those two pieces.

[cowboyup3371]

How are the boots from the carbs to the engine? Have you properly dipped the carbs yet to rule them out?

[Windsmile]

I need to inspect the boots better then I have to safely say that they are ruled out as the cause. It has been very hot here, too hot to even think about working on anything that's outdoors.

I'll pick up some incense sticks that make smoke and move them from place to place where a vacuum leak could occur in order to see if there is something that my first inspection didn't pick up on.

As for the carbs, before I go so far as removing the rail and opening them up, etc., I'm going to run some Chevron Techron fuel system cleaner to see if that changes anything. The heat here won't subside for about a week so it's going to be a while before I do anything more.

[cowboyup3371]

As for the carbs, before I go so far as removing the rail and opening them up, etc., I'm going to run some Chevron Techron fuel system cleaner to see if that changes anything. The heat here won't subside for about a week so it's going to be a while before I do anything more.

This will not clean out the crap that is probably in there and is only doing the job half-a$$. You will be better off to get the can of Berryman's and dip each one properly following the carb tutorial Nessism just re-wrote. Trust us on this as we've seen this type of problem several times and every time someone says they'll try a half-a$$ approach they always end up doing it the way we suggest

[Windsmile]

I thought about your suggestion (From CowboyUp3371) concerning the routing of the carb vent tubes and decided to read the manual and see where they belonged. That proved to be the fix to the surging problem. Somewhere along the line a previous owner had the tubes pointed down instead of up and running parallel and under the seat.

[cowboyup3371]

I'm glad you figured it out but Dogma was the one who actually suggested it to you here in your thread. It just happened to come up for my issue as well

Someone should mention making sure the carb vent tubes are correctly routed. I'm not sure where they belong on a 750T, but if they're exposed to "dirty"air, they can cause surging. If the airbox has a snorkel, make sure that's correctly fitted, etc.

[Windsmile]

Someone should mention making sure the carb vent tubes are correctly routed. I'm not sure where they belong on a 750T, but if they're exposed to "dirty"air, they can cause surging. If the airbox has a snorkel, make sure that's correctly fitted, etc.

Thank you for your suggestion. I looked in the Clymer manual and they told how the vent tubes should be routed. A previous owner had them pointed down toward the ground instead of straight back and parallel with the seat. There were even holders in place to aid in doing that. So I changed the path and so far it seems that the problem is gone. All that remains to be seen is if the problem comes back on an extended ride. The test ride with the vent tubes re-routed was only about a ten miler.

Once again thank you. Even if the problem returns, the vent tubes have been eliminated as a possible cause.