Originally Posted by
AZTman
I'm going to tear down my GX5R in search of air leaks. The tune was all over the place last night, wouldn't idle for anything until it was too rich with an idle gap too large, then would run lean and hot on the track. I know it sounds like the average woman tune, but when I leaned out the bottom and tried to close the gap it died very quickly on the stand. It has been a great motor so I'm sure I have a leak somewhere. Maybe 6.5-7gallons.
So.... I'll start by checking fuel and pressure lines, tank, O-rings in the hsn, lsn, idle screw, pinch screw, carb throat, boot, and the front bearing.
For the Go veterans, are there specific Orings or spots that are the most common where I should give extra scrutiny? Are they the same bearings for GX5R and GXII5RHO?
Hi Travis,
The GO motors are pretty well sealed up, and the O Rings have great longevity.
At 6 - 7 gallons I would say the front bearing might be starting to call it a day. That would be your most common place for an air leak in the actual motor itself.
The bearings and all O rings are the same as the GX Series.
Front bearing 7 x 19 x 6
Rear bearing 14 x 25.4 x 6
When you pop the carb out, check the lower O Ring (OR-0004) that sits in the crankcase.
With the powerful servo's we use on the throttle these days it is possible to get some movement of the carb body when applying the brake hard. This can move the bottom of the carb throat around on this O Ring and chew it up a little.
If it looks a bit chewed or soft I would replace it, and the carb throat O Ring (OR-0014) just to be on the safe side.
The pinch bolt O Rings (OR-0032) are usually sweet, as is the back plate O Ring (OR-0003).
