Cylinder Head Temps

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cmouta
Posts: 72
Joined: Tue Aug 14, 2012 8:23 am
Location: West Haven, CT

Cylinder Head Temps

Postby cmouta » Fri Aug 19, 2016 8:10 am

Has anyone ever run a cylinder head temp gauge? The ones that go around the spark plugs? My bike has run reasonably well since I've tuned it up a few years ago, check plugs all the time, nice and gray, snappy throttle, 1100rpm idle, needs a couple of miles of choke before warmed up enough. Installed one of these gauges yesterday and cruising in 85 degree weather to work today, 65-75 mph, 5000-5500rpm, #4 cylinder head temp was 340-350 degrees Fahrenheit. 3500rpm it goes down to about 320.

I DO run a .005" clearance on my exhaust valves per an sohc4 post by "Hondaman":

"This extra clearance lets the valve sit on the seat slightly longer, transferring a bit more heat into the head. Yes, it loses some cam duration, but on the exhaust side this doesn't hurt you like it does on the intake side"

Seems awfully hot but there's no real spec so who knows. Wondering if anyone had any numbers to compare to.

Mounted it on top of my fusebox with double sided tape it came with, regrettably because I didn't read the instructions and there is a button on the back to switch between max capture modes that is now inaccessible.
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Chris

1982 Candy Flair Blue Honda CB650SC Nighthawk
2013 Fiat 500C Abarth
1998.5 Black Ford Contour SE V6 MTX
1988 Mono Rosso Red Merkur XR4Ti T5 MT

cb650
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Re: Cylinder Head Temps

Postby cb650 » Fri Aug 19, 2016 1:28 pm

I always thought about running one when I was drag racing. And a oil temp. Seemed the bike always ran better when warm.
Did you clean the tank out?!?!?!?!

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Volker_P
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Re: Cylinder Head Temps

Postby Volker_P » Tue Aug 23, 2016 2:58 am

cmouta wrote: Seems awfully hot but there's no real spec so who knows.

I am not aware of overheating problems reported for the CB 650. If you just ride on the road this should be no issue.
For a time I had a thermometer at my oil pump but it never exceeded 100°C. This is low compared e.g. to a Honda 650 RFVC single engine. So I won't worry for the CB.

One may go to a rich jetting to reduce head temperatures effectively but again this should be not required for road use.
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cmouta
Posts: 72
Joined: Tue Aug 14, 2012 8:23 am
Location: West Haven, CT

Re: Cylinder Head Temps

Postby cmouta » Tue Aug 23, 2016 9:09 am

Thanks for the replies! I had one incident a few years ago as a fairly new rider(and although a competent shadtree mechanic, a novice to motorcycles/carbs/tuning) where I was stuck in stop and go traffic on a highway in the summer for about 20-30 minutes and the bike started overheating to the point that it felt critical that I ride the breakdown lane to get some airflow. I didn't enjoy that so I've been hypersensitive to the notion since then. That's when I stumbled across that post about the larger exhaust valve clearance. I haven't had a problem since but I also go very much out of my way to avoid situations like that which tends to means less riding(which I don't like.) I think I may try the HEI/GM Coil upgrade which should hopefully allow me to lower my idle to around 900rpm and further reduce temps and increase confidence in my machine!
Chris

1982 Candy Flair Blue Honda CB650SC Nighthawk
2013 Fiat 500C Abarth
1998.5 Black Ford Contour SE V6 MTX
1988 Mono Rosso Red Merkur XR4Ti T5 MT

cb650
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Re: Cylinder Head Temps

Postby cb650 » Tue Aug 23, 2016 2:29 pm

A oil cooler will help too if you can find one. Even just the increase in capacity will help.
Did you clean the tank out?!?!?!?!

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Volker_P
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Re: Cylinder Head Temps

Postby Volker_P » Wed Aug 24, 2016 12:28 am

Stop and go in summer is the worst case for an airhead engine.
You can kill every airhead that way (or even by infinite idle on the side stand). No real criterion for engine modifications.
cmouta wrote: ... the bike started overheating to the point that it felt critical that I ride the breakdown lane to get some airflow.

And obviously you found a reasonable solution. :lol:
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

cmouta
Posts: 72
Joined: Tue Aug 14, 2012 8:23 am
Location: West Haven, CT

Re: Cylinder Head Temps

Postby cmouta » Wed Aug 24, 2016 8:32 am

Its illegal but I guess if your bike is ABOUT to break down there's an argument to be had! Even the "cagers" around me were asking me what the heck I was doing sitting in traffic like them :lol:

I've looked into oil coolers and spin on filter adapters and all that. I would hope that a bike would handle what it was designed to do although I understand 34 years of age may make things a little different. Despite the millions of online horror stories, I think my next move will be to switch to amsoil 10w-40 synthetic metric motorcycle oil. I already run amsoil in my contour(ford mondeo for you Volker_P) and XR4Ti(Ford Sierra for you Volker_P) so adding to my yearly order will be a nice convenience. If it "produces" leaks then I'll just do the headgasket and anything else this winter anyway.

I'm doing everything I can to convince myself I don't need a shaft drive/water cooled/fuel injected bmw k75S when I already have a mostly perfectly fine running machine!
Chris

1982 Candy Flair Blue Honda CB650SC Nighthawk
2013 Fiat 500C Abarth
1998.5 Black Ford Contour SE V6 MTX
1988 Mono Rosso Red Merkur XR4Ti T5 MT

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Volker_P
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Location: southern Germany

Re: Cylinder Head Temps

Postby Volker_P » Thu Aug 25, 2016 1:47 am

cmouta wrote: Despite the millions of online horror stories, I think my next move will be to switch to amsoil 10w-40 synthetic metric motorcycle oil.

If you know your engine is clean inside (e.g. after you did a complete rebuild) no real problem.
But synthetic oil may dissolve all the stuff from decades more or less at once at the first real heat up. This may cause trouble. In particular I worry about the calibrated nozzle to the camshaft at the cylinder bottom gasket level.
Also expect an increased oil consumption above 5000rpm.

cmouta wrote: ... and XR4Ti(Ford Sierra for you Volker_P)

Thanks, in the 1980's we had colorful Ford Fiestas, Escorts and Sierras XR2/3/4 models with rallye stripes here, too. :lol:

cmouta wrote: I'm doing everything I can to convince myself I don't need a shaft drive/water cooled/fuel injected bmw k75S when I already have a mostly perfectly fine running machine!

Sure you have. And everything in your list is expensive stuff in case of failure. Your 650 will not cause that kind of trouble because it does not have either of these things. You probably get a good, complete CB650 for the cost of a K75S shaft drive replacement. :wink:

BTW, in the early years of my CB650 I worried a bit if a CX500 could have been the better choice. This changed as in some 1990s summer a friend had to wait until fall for the ship with the plastic sprocket from Japan (I think it was for the coolant pump or is there a plastic sprocket in the CX500 transmission?).

Everything you don't have won't fail! :D
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

cmouta
Posts: 72
Joined: Tue Aug 14, 2012 8:23 am
Location: West Haven, CT

Re: Cylinder Head Temps

Postby cmouta » Thu Aug 25, 2016 9:51 am

I haven't done a full rebuild but I've done the oil pan seal and cleaned the pan and the oil pickup in the process. Since then, my oil has come out pretty immaculate but I also ride less than 800 miles a year, if that. It's not the worst idea to do one of those engine treatment cleaners before switching to synthetic and cleaning the oil pan/pickup again to make sure.

I tend have a tendency to make up problems that need fixing when I should really be riding more often! Same problem with my XR4Ti...drove through a heavy rain storm last fall and my electrical started acting up(even though it was fine the next day). I've spent all summer slowly moving the alternator from a lower engine mounting to the original high engine mounting that no longer fits because I converted to a serpentine system using a mustang 2.3 power steering bracket so i need to move it back down. No racing all summer because I'm slow acting and a worrier :(
Chris

1982 Candy Flair Blue Honda CB650SC Nighthawk
2013 Fiat 500C Abarth
1998.5 Black Ford Contour SE V6 MTX
1988 Mono Rosso Red Merkur XR4Ti T5 MT


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