Overheating

[MrZig]

1982 GS400 motor

Okay so I took it for my first test ride since the old engine blew in May. Yay! Got an issue though.

The engine is running SERIOUSLY hot. I can't even dream of touching the dipstick with bare fingers, and even wearing a leather glove it gets too hot to hold. All engine covers are extremely hot. What would cause this? I went from a 110 main jet to 117.5's, and every other jet is stock. It doesn't run lean at idle, and I set the mixture screws out 1.5 turns like the book says. Maybe I should turn them out more? The oil had a burning smell. I just don't see why it should be running that hot.

Clymers also mentioned that the jet needle clip should be the fourth from the top. If I remember right, mins is in the middle (third?) - would that make it run so hot?

Or maybe I have unknown holes in my exhaust making it run lean.

[Steve]

The 400 has a dipstick?? Never had one, so I don't know for sure.

Why did you feel you had to bump the main jets up three sizes? Generally not necessary, although some will go up one size just on principle.

Rather than set your mixture screws according to the book, set them where the bike works better. Most will agree that a good starting point is between two and three turns out from lightly seated. 1.5 turns is just not enough.

With your needle clip in the third groove, the mid-range will be running a bit lean, but I don't think it would be lean enough to make it run as hot as you are describing.

By the way, when the bike is up to operating temperature, I would not want to open the oil cap without gloves or pliers, so temperatures that are uncomfortable to human skin are rather normal. Burning oil smell, however is not.

I am also a bit surprised that carbs on an '82 GS have adjustable clips on the needles.

.

[MrZig]

The 400 has a dipstick?? Never had one, so I don't know for sure.

Why did you feel you had to bump the main jets up three sizes? Generally not necessary, although some will go up one size just on principle.

Rather than set your mixture screws according to the book, set them where the bike works better. Most will agree that a good starting point is between two and three turns out from lightly seated. 1.5 turns is just not enough.

With your needle clip in the third groove, the mid-range will be running a bit lean, but I don't think it would be lean enough to make it run as hot as you are describing.

By the way, when the bike is up to operating temperature, I would not want to open the oil cap without gloves or pliers, so temperatures that are uncomfortable to human skin are rather normal. Burning oil smell, however is not.

I am also a bit surprised that carbs on an '82 GS have adjustable clips on the needles.

.

The 400 from 1980+ had the same lower end as the 450/500 so it uses the same dipstick

Oops, I wish I explained that better. Stock main jet is 117.5, for some reason the PO had 110's in there before so I replaced them with stockers.

I'll try turning the mixture screws out another turn each and see if it makes a difference. I'll take a look at the plugs, too.

[MrZig]

One more thing - my rear wheel was really hot to touch and the chain itself was also hot. The tension is set correctly, could it be from a dragging rear brake?

[MrZig]

Also which is the proper way up for the jet needle holder?

Position A)




Or Position B)




Based on this diagram (part #8) http://www.cmsnl.com/suzuki-gsx400-1...st/FIG-12.html it looks like the proper way is position A).

[Steve]

I have never seen a retainer like that, and you are right; the diagram shows "A" as correct.

However, "B" shows conflicting evidence to the contrary. There are wear marks around the edge that appear to have been pushing down on the slide (in the "A" position), but there is also visible wear around the screw holes, showing that screws were used with the holder in the "B" position.

Hopefully someone with experience will chime in here.

.

[MrZig]

I have never seen a retainer like that, and you are right; the diagram shows "A" as correct.

However, "B" shows conflicting evidence to the contrary. There are wear marks around the edge that appear to have been pushing down on the slide (in the "A" position), but there is also visible wear around the screw holes, showing that screws were used with the holder in the "B" position.

Hopefully someone with experience will chime in here.

.

Yeah it was like Position B), but I had taken them apart half a year ago and can't remember if they were proper or not. Position A) is how I put them in now. B) would have them run leaner I think so I'll try it with A).