Engine temps - *Solved*

[aclaytonb]

What's a good good engine temp for a 79 GS550? Put my IR thermometer on it after a ride (in 35f) and the engine temp was reading about 220-240f on the head. Exhaust header was about 240f at the head.

I only ask because I feel like I may be running lean. Bike pulls through all RPM range without breaking up, sputtering, or popping. I have no rational reason for thinking this - just a sneaking suspicion. Stock airbox and jetting but it does have a 4-1 header (MAC). The header is blued around the exhaust ports for about 6-8"" or so.

 

[habsdoc]

What do your spark plugs look like. They will tell you the story if you are running rich or lean.

 

[aclaytonb]

All four look like this.

 

[aclaytonb]

The compression ring has some oil on it for some reason. Unclear how though. Maybe just residue? It may also be my thread anti-seize.

 

[Gorminrider]

that plug does look lean but there is lots of info online and Many shop manuals have pictures too-(is it the Clymers' have this? one of em anyways) the pipes tempering to blue seems an indicator too. You can richen up your idle-mix, double check the correct heat range of plug, etc etc. Maybe the pipes themselves have an effect?

As to the IR thermometer, they are fun but I don't exactly understand them when a few degrees is important... Different materials have different emisssivity..shiny exhaust pipes, alluminum and so forth
google search "IR thermometer and emisssivity"

 

[aclaytonb]

Well, solved this hot mess. Bought 95 mains and tossed the airbox lid per the vance & hines instructions for their 4-1. I have a MAC but figured it was similar. Also located a pinched gasket between the plastic airbox and air cleaner box.

Bike screams now. Hadn't realized how sluggish it was before. Almost pulls the front wheel up from a rolling start. Not sure what the fuel economy will look like but I'm liking the changes so far.

 

[posplayr]

Blue pipes is a definite indication you are running lean; longer the leaner

 

[Guest]

Blue pipes is a definite indication you are running lean; longer the leaner

I disagree; it's a indication that the pipe has got hot. Thinwall pipes get hot faster. Black exhaust pipes don't blue anywhere near as much. Ritchening the mixture will not remove the blue.....

There is no magic mixture that will avoid pipe blueing under all conditions. Yes, it's an indicator, but exhaust pipes get hot next to the head.

As far as plug readings go, I've found that with the new and improved gas we get around here the insulator is always white. Yesterday I checked the plugs on a GS450 which is getting about 75% of the mileage that my 450 gets. It's running the needles way too high. The rim of the plug shows black and there's soot in the exhaust outlet, but the insulator is bone white. My bike shows a grey rim.

I haven't seen the tan insulator of song and fable for maybe twenty years. It's the Techron era now.

 

[Wingsconsin]

Visual aids help - My 1983 GS850GL

Visual aids help - My 1983 GS850GL

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[posplayr]

I disagree; it's a indication that the pipe has got hot. Thinwall pipes get hot faster. Black exhaust pipes don't blue anywhere near as much. Ritchening the mixture will not remove the blue.....

There is no magic mixture that will avoid pipe blueing under all conditions. Yes, it's an indicator, but exhaust pipes get hot next to the head.

As far as plug readings go, I've found that with the new and improved gas we get around here the insulator is always white. Yesterday I checked the plugs on a GS450 which is getting about 75% of the mileage that my 450 gets. It's running the needles way too high. The rim of the plug shows black and there's soot in the exhaust outlet, but the insulator is bone white. My bike shows a grey rim.

I haven't seen the tan insulator of song and fable for maybe twenty years. It's the Techron era now.

i agree you are disagreeing with a semantic argument . However that argument is equivalent to saying the the ash is a fireplace is no indication the fireplace is hot.

 

[aclaytonb]

Going to pick up new plugs and work through the various plug chops to check it all out. I'm might have to rebuild the top end this winter anyway. 125psi on every cylinder with 5% leakdown. Compression tester and leakdown tester guages both agree with a 150psi compressor so I'm assuming they aren't just reading low.

I did a lot of reading on various forums and everyone with MACs complains of bluing....

 

[posplayr]

I did a lot of reading on various forums and everyone with MACs complains of bluing....

Ever consider the fact that many people just change from 4:2 to 4:1 pipes and never consider the jetting? You get blue pipes especially if you put on pods. Blue means TOO HOT.

 

[aclaytonb]

I don't disagree that blue means too hot. I'm just relaying what 5 hours of reading indicated. Internet wisdom being what it is, I expect 90% of that to be garbage. Even still, everyone agrees thats MAC are cheap thin walled turds that blue no matter what (except MAC). I have no personal experience with them besides these - and they showed slight rust around the collars the day I unboxed them. My confidence level in them is not...high.

 

[Guest]

i agree you are disagreeing with a semantic argument . However that argument is equivalent to saying the the ash is a fireplace is no indication the fireplace is hot.

No, I am disagreeing with your implication that the pipe is turning blue because the mixture is too lean; it may well be, or not. Some pipes are double walled - pipe inside a pipe. Others are thin to be light. Like the edge of a blade on a grinder, the thin ones blue more easily and you'll pour a lot of unburned gasoline through them to avoid that.

You would think that the heat being radiated from the surface would be the same regardless of thickness and the heat absorbed from the exhaust the same as well. But there's a time and thermal mass aspect to consider which allows a thick pipe to slow down the heating process. Given a long enough straightaway, thermal flywheel effect should neutralize.

Funny how we love the blueing on a gun but not on a motorcycle. I don't care what color they are as long as they're not rusty.

 

[Nessism]

How many miles are on this 550 and has it been sitting? Did you rejet for the pipe? Pods? Performed valve adjustment?

There is a member here that put over 125k on a first gen 550 so they are seriously durable bikes if treated half way decently.

 

[aclaytonb]

20k miles. Valves checked and within spec. Compression 125 across the board, leakdown at 5% across the board.
No pods. Per vance/hines pipes recommendations, rejetted mains to 95 and ditched airbox lid. Hasnt been sitting long since I've owned it - 1yr.

I suspect its had a rough life as it had pods when I got it, front tire was on backwards, dead battery, dead r/r, flat black rattlecan paint job.

Now has stock airbox, rejuvinated airbox boots, rebuilt carbs, new intake o-rings, new cables, new brakes lines and pads, new air filter foam, new OEM petcock, new fuel / vacuum lines, coil relay, new points, new tires, gs1000 wire rims, new bearings, LED bulbs, new cap resistors, new hydro clutch, new oem clutch plates, new chain, etc.

Tossed in new plugs to run some chops and found #4 is dead rich at idle. Going to repull the carbs and look at the idle jets.

Edit: Oh, yeah, will re-vacuum sync onced #4 rich issue is solved.