Running Lean on 2 cylinders, and running hot

[Duro5341]

Hey Guys,

First off I'd like to say what a wonderful site......

I purchased an 82 GS750E from a reputable person on this site back in February, and I am starting to ride it more often and there are a few things I have noticed. Before everyone says SEARCH, I have searched for 3 weeks, and read almost every carb, over heating, oil temp artical there is to read.

The bike is stock from what I know, other than a 4-1 Mac pipe, with 37,000kms, PO picked it up with a weak spark problem....originally. The coil relay mod has been done....but thats it

First off the bike is running really hot, around 150 degrees Celcius on a 25 degree day when cruising at highway speeds 80-120km/h 5th gear, and cools off alittle bit when sitting at a light (140 or so). I have determained with an infared temp guage that the guage is approx 10-15 degrees off, taking into account the 20 degrees F, difference between sureface and core temp.

Second it smells extremely rich at idle, you have to rev it abit to clear the carb throught before taking off, blows black smoke. This I can deal with...but the running hot problem get me worried

Now the previous owner, cleaned the carbs, and put new o-rings, and intake boots, and adjusted the valve (it starts up cold no problem), new plugs, and wiring harness, air filter. Since I have had the carbs professinaly balanced and mentioned the running hot problem, and the shop told me not to worry about it, the guage is off.......not that much by my tests, and I have done an oil change with Amsoil 10w40, just incase the temp gets to hot.

The bike pulls hard, and smooth throughout the rev range, just running alittle hot. The exhaust isn't blueing, no back fireing, or popping, or ticking when turned off

I pulled the plugs on Tuesday, and it indicated that cylinder 1,3 are running lean (white electrode), where as 2,4 are a nice light brown colour. So I opened the air screw on 1,3 a 1/2 turn with little difference, in running temp.

So I was thinking that I should pull the top off the carbs, and shim the jet needle alittle to get it to run alittle richer when in mid range, and cool the engine abit more......during cruise.

Let me know what you think
I am an automobile mechanic by trade, but no very little about bikes....

Thanks
Duro

[ryonker]

I am sure you will have better responses than mine very soon.

One thought is to buy or borrow a colortune and check each cylinder. It's pretty simple. You screw the adaptor into your plug hole and look to see what the color is and adjust your air/fuel screw (assuming CV carbs) until the color is a nice blue.

It sounds like all the basics are done. Like you said, the issue could be because of the pipes and may be a jet needle issue.

I was worried about mine being a little too hot so I just put on an oil cooler to ease my mind.

Hope this helps a little.

Rick

[Duro5341]

I would love to have an oil cooler, but its not as simple as the 8-valve 750's, or I would have had one on it already

Duro

[chef1366]

On the lean plugs how many threads up do you have color? If more that 2-3 I would put in one step up on the main jet. EX 115-117.5

[Duro5341]

I had slight brown in the thread all the way up the threads, to the gasket on all plugs......maybe I need a different heat range in plugs?

Duro

[chef1366]

Run D8EA
You need to up the main or you have some blockage in the carbs.

[Duro5341]

Plug numbers are NGK R -DR8EA on all 4 cylinders, Should I replace them with non-resistor plugs?

Duro

[GSXXZRX]

Wrong plugs.

http://www.sparkplugs.com/results_fitment.asp?pid=D8EA

[chef1366]

Those will work. Pretty much the same plug.

[Duro5341]

I know there not correct they have an extra resistor built into them, but this won't cause the problem I am experiencing would it?.....they are the correct heat range still

Duro

[ryonker]

I know there not correct they have an extra resistor built into them, but this won't cause the problem I am experiencing would it?.....they are the correct heat range still

Duro

No. I am pretty sure that is just to keep it interfering with a radio on your bike or something like that .

[Duro5341]

The R reduces radio interfience only.....

Do you think I should raise the needles? or what

Duro

[chef1366]

Have a look and see what in there. If they are that lean and you're running stock you may have to clean the carbs anyhow.

[silverhorse47]

Sorry if this is a thick response...but I have never seen colour proceed up the threads of a plug to the gasket. To me this sounds like the plug has not been tightened properly.
S.

[Duro5341]

Just telling what I see, it was a light gold colour at the base of the threads, all the way to the top gasket surface.

I will be installing new plugs anyway, it seems to run god when it's around 20 degrees C outside, but when it hits 26-30 it runs hot. Especially when the throttle is kept constant. Maybe I can out some cooler plugs in, and it'll give me that edge to hold the heat off

I will try raising the needles 1/2 notch, and well see what happens.....when I get time, to work on the bike

What size are the brass washers, I can get them at the local hardware store. What is the inside, and outside diameter

Duro