Leaks in Airbox

[Guest]

Hey friends, I have an '82 GS850GL. I've been trying to narrow down an issue I have where the throttle response is weak when getting up to speed from a stop. After throttle is turned there seems to be minimal response and after holding it in the same position, it races up. Better when choke is engaged and slightly better when warmed up. Obviously seems to be a lean situation early in the throttle twist. Currently I'm looking at the airbox as the culprit.

When I got the bike the seal between the filter cage(?) and the top of the airbox was completely gone so I made one using weather stripping. I also replaced the old beat up filter with a UNI filter. After cleaning carbs, replacing old leaking boots, and replacing a dripping petcock the issue began to show itself. To test I have jetted up one notch on the mains and pilots (117.5 and 42.5 respectively) to accommodate for more airflow from the UNI filter, this seemed to help, but primarily in the top end. I'm thinking the weather stripping may not be doing quite a good enough job, or perhaps it is receiving to much airflow elsewhere into the airbox.

In short, my main question is: How critical would a small leak be if it was coming from the chrome endcaps? The whole airbox seems so cheap and unstable I've toyed with the idea of pod filters. Anyone else have similar issues or can direct me to another thread where this has been taken up?

[Sam 78 GS750]

I'll beat everyone else to the punch here... What I don't see on the list is a valve adjustment. You'll drive yourself crazy chasing down demons if the valves are out of spec. There's a nice write up of the procedure over here: http://members.dslextreme.com/users/bikecliff/images/gs850valve_adjust.pdf

To answer one of your questions...Yes, air getting in through the end caps could cause an issue if the rubber there is shot (or missing). Using weather stripping like you did elsewhere is a good way to prevent that...

[fastbysuzuki]

One thing you need to avoid is putting pods on you will spend forever rejetting trying to get it to run correctly.
make sure your airbox is sealed look here http://members.dslextreme.com/users/...ox-sealing.pdf
and as said in other post check the valve clearances.
the bike should run ok on standard jetting with the standard airbox assuming the carb to head rubbers and carb to airbox are all ok no cracks, splits, or leaks.

[maerchkque]

Thanks! That’s a great breakdown of what to look for in the airbox.

[maerchkque]

Thanks! I have done a valve clearance check and I had to change out one shin. But at the time I wasn’t aware that it is suggested to recheck after 500 miles. I will recheck again in the cold months. Thanks again!

[jdvorchak]

Just for a sanity check are you sure it's idling and running on all 4? What you're describing could very well be running on only 3 cylinders. From a cold start and at idle make sure each pipe is heating up about evenly. They get very hot very quick so careful. You could also use water dribbled on the pipes or even better ice cubes if you don't have a non-contact thermometer.