continued overheating

[Anonymous]

As stated in a previous post "overheating problem", my bike runs up to 265 degrees F when driven at highway speeds. Well it is at least a little lean, but I can detect no air leaks with WD40. I did wonder wfth my stock type K&N air filter if I needed to turn my mixture screws out more to richen the mixture. So I turned them out 3 1/4 turns as opposed to the 2 1/2+ turns they normally like. Well the temp guage seemed to actually show a higher reading of approximately 275+, and my spark plugs were at least as lean if not more so. There did seem to be a little more carbon build up on the inner side of the metal of the plug. Not the electrodes, but the portion that the arm of the outer electode attatchs to. The electrodes and the porcelain were mostly clean with a small bit of light gray. Is there a definitive test that I or a mechanic can run for air leaks. Or does someone have another suggestion or two? All of the carb boots (both sides) are new. I have new foam sealing the lid to the airbox. I know as was suggested in the previous thread that it gets hot here in Oklahoma. However, if it is normal for a GS to get to 265 degrees when it is only 85 to 95 degrees out maybe they are not as great as I thought.

If my temp sensor were faulty would it consistently reach a regular temperature always with approximately the same amount and style of riding? Of course, I don't think it is at fault since I had to change the oil after only about 300 miles of riding. Any help would be appreciated.


Thanks,

Billy Miles: AKA Very frustrated in Oklahoma.

[earlfor]

Re: continued overheating

Mixture screws adjust the idle range/rpm mixture. For a lean condition in midrange or higher, you may as well wax your headlight. It would help about the same amount. :-)

Your plugs are burning clean with a small amount of light gray. THAT is a definitive test of what your mixtures are. Your oil temp is high because youre running so lean, the engine is cooking itself. At least raise your needles, or if they only have one groove, go up a couple sizes on the main jets.

Earl






[quote="78gs550"]
I did wonder wfth my stock type K&N air filter if I needed to turn my mixture screws out more to richen the mixture. So I turned them out 3 1/4 turns as opposed to the 2 1/2+ turns they normally like.


The electrodes and the porcelain were mostly clean with a small bit of light gray. Is there a definitive test that I or a mechanic can run for air leaks.

[Anonymous]

lean

like earl said but jet it or beprepared to push it, you are blaming the bike for some one not tuning it right. lean is lean and it needs jets and needle adjustment, or if you have the stock air box put it back on

[Anonymous]

The air box is on, the K&N filter is the stock type repalcement as I said earlier. Also, I have a new stock replacement filter, (the same as came on the bike originally), I have tried it on the bike, and still had the same overheating problem. So Earl, are you saying I should try raising the needles first and then only change mains if that doesn't work? Also, would it still have power, and run and idle smoothly if it needed different mains?

Thanks for the replies guys,
Billy Miles

[earlfor]

Billy, it is a fact you are running way too lean. Its possible, there is an induction leak somewhere, but after all your searching, you have not found it. Its possible, the stock replacement air filter is actually less restrictive than the original stock air filter. BUT.......you cannot continue to run that lean. You WILL be walking and pushing if the situation continues.
Richening a lean mixture (to a point) will always increase power, not cause a loss of power. From your description of the plugs, I would raise the needles two notches for a start and then cruise 20 miles or so and take another plug read. At that point, I would make the decision of whether to increase jet sizes or not.

There isnt a huge difference in the 1100 and 1150, and if I was going to do
your mods to my 1150, I would install 135 mains as a starting point to see where I was. What size mains do you have in the bike?

Earl

The air box is on, the K&N filter is the stock type repalcement as I said earlier. Also, I have a new stock replacement filter, (the same as came on the bike originally), I have tried it on the bike, and still had the same overheating problem. So Earl, are you saying I should try raising the needles first and then only change mains if that doesn't work? Also, would it still have power, and run and idle smoothly if it needed different mains?

Thanks for the replies guys,
Billy Miles

[Anonymous]

The current mains are 115s which came with the rebuild kit along with the stock 107s. I posted as well as asked local mechanics if I should need to rejet after installing the K&N filter. Everyone including those that have done it say no. In case I am being misunderstood, this filter is the type that fits into the same spot as the original. Not pods, original exhaust, etc. This filter is the only modification to the bike.

Thanks Earl for the reply,
Billy Miles

[Anonymous]

Another question that may get me closer to my possible airl leak, if I have one and just have not found it. Since, all my plugs run virtually the same color wouldn't that indicate that the possible leak would be located before the airbox boots? Therefore having to be in the boot connecting the two boxes together, the lid to the airbox, or solely caused by the filter not being restrictive enough?

Thanks,
Billy Miles

[Detman101]

Just another reason we need a "GS-CARB Rejetting MATRIX"!!

Just a thought...
Dm of mD[/u]

[earlfor]

My mistake Billy, I thought you had a 4 into 1 and K&N pods.

Did you have the lean problem before installing the filter?

I have a running "emergency" spare 1980 1100E 16 valve engine on standby for my 1150. I just went to the shop, pulled the mains and checked sizes. Its set up for stock pipes and stock airbox with filter.
The mains are 117.5 (no mistake, I checked the size with good light and a magnifying glass) :-) The mains in my stock setup 1150 are 122.5
Considering you are quite lean, I would be inclined to replace your mains with the same size my 1150 uses. (122.5)

You may have an unfound air leak somewhere, but with being unable to locate it (if it exists), my view is it is more pressing to get the mixtures richened to a normal operating temp first. That will give you time to continue looking and you wont have to worry about cooking anything while you search. If you find a leak at a later date, you always have the option of reinstalling the previous jets.

Do you have a clean, recently installed oil filter in the bike?

Earl

The current mains are 115s which came with the rebuild kit along with the stock 107s. I posted as well as asked local mechanics if I should need to rejet after installing the K&N filter. Everyone including those that have done it say no. In case I am being misunderstood, this filter is the type that fits into the same spot as the original. Not pods, original exhaust, etc. This filter is the only modification to the bike.

Thanks Earl for the reply,
Billy Miles

[Anonymous]

Yes, I change the oil filter everytime I change the oil, and I have never gone more than 600 miles without changing the oil. As for the air filter; it needed a new one when I bought the bike at which time I rebuilt the carbs as well as installed the K&N. However, according to the previous (and only other) owner it always ran great. The bike only has a little over 14,000 miles.

What would be the best source for just the 4 jets I need?

Also, something I have not mentioned mainly because I cannot afford to spend much more on the bike (we found out my wife is pregnant with our second child 2 weeks ago) is that I usually find small particles of aluminum in the oil. I found them in the first oil change I did and a few following. Then I started shifting at lower revs to save the clutch until I could afford to rebuild it, and I didn't see the metal anymore. I had the heavy duty hub assembly installed by APE and started shifting higher and the metal is back. Could this have something to do with the overheating, and therefore was occurring before I got the bike and the seller either knew or didn't? I don't think the metal is from the clutch basket though, the tech at APE said it was in better shape than almost all he had seen.

Thanks Earl,
Billy

[earlfor]

That would be my very most favorite supplier :-) :-)

http://www.crc2onlinecatalog.com/misc_carb_parts.htm#Main%20Jets

Mikuni mains cost $3.25 each.


I wish I had a clue where the aluminum particles are coming from. I dont think that could be the cause of overheating.

Earl


[quote="78gs550"]
What would be the best source for just the 4 jets I need?

[Wingnut]

I don't know what's in the pumps where you live but here in Ct. the gas pumps are clearly marked "10% Methanol". Methanol, which is a form of alchohol, workes great in dragsters but it needs to be delivered to the engine in 2" fuel lines because it burns so lean you need a much greater volume to maintaine the same mixture ratio. My GS 850 had all stock everything and it was running lean. I tried to pick up the needles a notch or two only to find out it did not have adjustable needles. So I moved the plastic needle spacer from the bottom to the top of the slide, (?) effectiviely raising the need about 3/32 of an inch and now the bike is so much better it's hard to believe. We all need to pay attention to the gas pumps to see how much alchohol is in the gas because our bikes are going to suffer from running lean if we don't adjust for the changes. Remember fuel cools!

bob

[Mysuzyq]

Earl,
Just curious, how hot does the 1150 run typically these days, at a sustained 70-90 m.p.h. (or higher ) in Fl. ? My '82 1100E reaches 100C (212F) on the temp guage under prolonged highway riding at the above speed....in stop/go traffic on ahot day it will sometimes climb to 110C (222-230F?). I have an 1150 oil cooler that I will be throwing on sometime this season & wonder how much (if any) temp. drop I can expect.
The Ontario summers are not as hot as your neck of the woods (for the most part), which could be why I have not yet seen 265F. Incidentally, the Suzuki shop manual has a test procedure I believe, to check that the guage is working properly.

Tony.

[earlfor]

In constant running in the 75-90 mph range on a hot day (about 95-100F), the 1150 usually shows an oil temp of 195 F. Stopped in traffic for a little while, it might reach 210F if I have just come off the freeway. If in town and I have to sit a bit in traffic, it takes probably 15-20 minutes for it to get over 200F. At 220F, I would shut it down regardless.

At 60-70 mph, oil temp is around 170-175F on the same day. When just cruising, I can stop anytime and put my bare hand on the cylinderhead. Not too long mind you, but its not scorching hot either. :-)

Earl

Earl,
Just curious, how hot does the 1150 run typically these days, at a sustained 70-90 m.p.h. (or higher ) in Fl. ? My '82 1100E reaches 100C (212F) on the temp guage under prolonged highway riding at the above speed....in stop/go traffic on ahot day it will sometimes climb to 110C (222-230F?). I have an 1150 oil cooler that I will be throwing on sometime this season & wonder how much (if any) temp. drop I can expect.
The Ontario summers are not as hot as your neck of the woods (for the most part), which could be why I have not yet seen 265F. Incidentally, the Suzuki shop manual has a test procedure I believe, to check that the guage is working properly.

Tony.

[crc1214]

Before re-jetting, try this........

Turn those screws IN not OUT to richen the mixture. These are air-screws. I know, on some of the later GS's they are indeed fuel screws, but on our 78 550's, they control the AIR flow.

Spec is 2 turns out from the seated position. I have mine at about 3/4 turn out, because I had a lean condition, even though my boots weren't leaky. Could be that the o-rings are cracking on yours and mine causing leaks.

With the air screws turned in she runs better, the throttle is more responsive, and my legs aren't burning up when riding!

Turn those things in my man!

Chad
Columbus, OH 1978 GS550E.