Originally Posted by grizz1 (Post 10667760)

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).

:)

Originally Posted by motomatt (Post 10667790)

Travis,
with the engine at operating temp and the glowplug out, check to see how much pinch it has. One of the first things to happen when the pinch is going is, the idle goes away. Then it will only idle with a large gap and rich bottom. I'm not saying that this is what's wrong, but it's worth checking.

I leak check engines by taking the engine out, adding a piece of fuel line to the carb fitting, then cover the carb and exhaust openings with a fingertip over each (glowplug still in place , of course). Submerge the engine in a sink of water and then blow into the fuel hose. The most common leaks I've seen are front bearing seal and low speed needle o-ring. If you manage to blow hard enough, you might see a small leak at the carb boot. If it isn't torn or have holes in it I wouldn't worry about it much. It's almost impossible to get a perfect seal at the slide.

Yes, bearings are the same GX5R and GXII5R-HO.

post with your results please.

Moto

Originally Posted by AZTman (Post 10667813)

Hey Matt you got any Go brand front steel bearings in stock still?

Originally Posted by Eivind E (Post 10666568)

I'd been breaking in the engine (GX-5R), and have probably ran 2.5-3 litres of fuel through it, and had it out of the car for other reasons, so I took the time to replace the conrod. When I looked at it, the upper hole in the conrod seemed slightly oval. I measured it at 4.08mm top to bottom, and 4mm side to side.
Was this conrod really in need of replacement or not?

I had bought a new conrod, but it is not exactly the same as the original one.
The original one had two oil holes in the top hole, one from the top and one from the bottom.
The new one only has a single top oil hole in the top. Does this matter? It is a genuine Go Engine part, I figure there are probably revisions of these.

Any ideas?

Next time I was thinking to use the slightly 2nd hand conrod I have now from the break in, for the next break in? would that be allright? Then I don't have to waste another rod?

Originally Posted by AZTman (Post 10667673)

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?

Originally Posted by AZTman (Post 10680404)

So far there's lots of worn seals. I'm swapping out the front bearing because it looked more wet than normal around that area. Both carb throat Orings were trash, one was actually broken and hanging on by pinch, the other was also worn out. The boot has a tear in it and blows bubbles in the water pressure test. I'm taking the motor to a local guy that has a bearing tool, so I may be racing again by Saturday. When it's heated, there is no much pinch


I'll let you know what it does with all the new seals.

Originally Posted by AZTman (Post 10682863)

No chugging, only screaming. Won a bunch of races in that span, too.
EPA is good right now. Over the last full year, who knows?
I may get the bearings done tonight, depending on work.

Originally Posted by d45 (Post 10687426)

Hello, Does anyone know where I can get the Go Engine 3 port R engine. I had one awhile back and liked it alot. Or have the stopped making them?

Originally Posted by motomatt (Post 10710727)

Travis,

Have any of your orders from me ever made it in two days?
I have a used GXII carb I could priority mail to you.
I'd have to know by 10 am (central).