Mikuni tuning. Thermal imaging ??

The yaki

The yaki

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When tuning in the garage, or shed, could you use thermal imagery to check if the engine is at normal running temperature? If so , what temp range would it be . I have an imager for house insulation purposes . Anyone have any technical info on this? Roy.
 
Normally you put a sensor up the exhaust pipe which senses O2 levels eg a wideband lambda sensor and then that will tell you the fuel/air ratio.
 
Unfortunately my shed is lacking that. Also, what temperature does the chrome downpipes blue ?
 
The temperature lag with an EGT sensor is worse than with an O2 sensor and so a thermal imager would be even worse.

Norton Commando pipes are single walled, a well used and well running engine will turn them blue. You can get them internally coated to reduce the bluing.
 
It was just for checking the engine was at running temperatures ? So as to set the mixture screw and idler with a bit of accuracy, not for final tweaks. I did use to set up stromebergs and twin 40's with an engine exaust analyser. Cheap ones still available? I had a Gunson " expensive at the time " one ,but it worked ! Roy.
 
For idle then a Gunson Colortune works best if you can't do it be ear, just adjust for the bunsen burner blue when looking into the combustion chamber.
 
Be careful with that kind of tuning… years ago a friend terminated his Ducati 860 trying to get the mixture spot on in his shed…
 
Just take the bike for 5-10 min ride to get it to full temp...then tweak away. No need to get all fancy with measuring stuff.
 
Its an air cooled engine, don't try to get it up to operating temps just sitting in the garage without a good fan blowing on the engine.
 
Have a fan. Mostly for ventilation when starting the yr5 yamaha ! Quicker death than hose from exaust through window !! Cheers, Roy.
 
Wasn't the theory in the 70's that bluing of the exhaust headers means too rich and maybe too hot? Or was it cheap pipes?

Far as I know you can't tune an engine reading the external engine temperature in the garage. Gotta develop and good seat of the pants dyno and ride it. You may end up chasing your tail using an O2 sensor in the garage without a dyno computer and a serious load on the engine.
 
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You are being silly. When you ride the bike the load on the drive chain alters the vacuum in the inlet port and the carburetor. You cannot tune it in a garage unless you have an oxygen meter and a dyno. There are two ways of tuning - with a dyno -get the mixture right with the oxygen meter, and move the ignition timing to get maximum torque, - OR - set the timing, and adjust the mixture by road testing. I suggest the latter way is the most realistic. If you have a well-tuned motor and ride through a forest, if the bike becomes quicker, you have had it too rich. Road conditions and the taper on the needles in the carbs can affect performance. It depends on how you use the bike. On a race track is different to being on public roads, - you need to be quick enough. Race bikes are always faster,
 
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Schwany said:
Wasn't the theory in the 70's that bluing of the exhaust headers means too rich and maybe too hot? Or was it cheap pipes?

Far as I know you can't tune an engine reading the external engine temperature in the garage. Gotta develop and good seat of the pants dyno and ride it. You may end up chasing your tail using an O2 sensor in the garage without a dyno computer and a serious load on the engine.
Click to expand...
Too lean = hot so I think maybe those 70s dudes were smokin' something. I know I was back then :cool:

I regularly check my N15's temps after a ride with a $20 infrared gun, which I've checked for accuracy using different methods. It's always been spot-on. Top of the barrel at combustion central - 325 F is typical. I usually ride in quite warm weather here in SoCal. Elsewhere on the top end, it varies, but > 250. No pipe blueing, no plug issues, no oil usage so it's happy and so, alas, am I.

I was given a Gunson. It was fun to play around with, but the bike ran better just doing it by the old tried and true tickover/ear method - a tad richer than the Gunson indicated prob 1/16 of a turn on the Mikuni VM.

I think blueing happens when the exhaust gets super hot, like 500 F.

When I sync my big Suzuki GS1100E carbs I use a box fan on max, maybe 5' away from the front of the engine, and check temps with the gun. It's really helpful to check the temps right at the exjaist pipe curve, it correlates well to the sync and carb mixture settings, but with a 4 cylinder you need to account for the inner 2 being hotter a bit.
 
gpzkat said:
Too lean = hot so I think maybe those 70s dudes were smokin' something. I know I was back then :cool:

I regularly check my N15's temps after a ride with a $20 infrared gun, which I've checked for accuracy using different methods. It's always been spot-on. Top of the barrel at combustion central - 325 F is typical. I usually ride in quite warm weather here in SoCal. Elsewhere on the top end, it varies, but > 250. No pipe blueing, no plug issues, no oil usage so it's happy and so, alas, am I.

I was given a Gunson. It was fun to play around with, but the bike ran better just doing it by the old tried and true tickover/ear method - a tad richer than the Gunson indicated prob 1/16 of a turn on the Mikuni VM.

I think blueing happens when the exhaust gets super hot, like 500 F.

When I sync my big Suzuki GS1100E carbs I use a box fan on max, maybe 5' away from the front of the engine, and check temps with the gun. It's really helpful to check the temps right at the exjaist pipe curve, it correlates well to the sync and carb mixture settings, but with a 4 cylinder you need to account for the inner 2 being hotter a bit.
Click to expand...
Dirt weed smoked by the bale.

I've got a harbor freight infrared gun and yep it was around $20. I don't use it for tuning though. I don't have to sync anything anymore with only 1 bike using dual carburetion with the throttles linked with a shaft, but when I did sync carbonators or fuel injection on my motorcycles I definitely used a fan.

Setup for me is pure throttle response based, and has been for decades. No sniffers or remote electronic tuning tools get used. I'm probably leaving a couple of HP on the table, but I doubt it is much more than a couple with a old Norton. ;)
 
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Lean is OK, but if the motor misses when riding the bike, stop and raise the needles one notch. Do not continue to ride for miles - you could burn a piston or a valve. Main jets are usually too rich, and the idle circuit has usually been adjusted to give smooth idle, but is not used when the bike is being ridden. Carburetors are adjusted to suit the exhaust system, so do not change the exhaust without checking the carburation afterwards.
 
Schwany said:
Dirt weed smoked by the bale.

I've got a harbor freight infrared gun and yep it was around $20. I don't use it for tuning though. I don't have to sync anything anymore with only 1 bike using dual carburetion with the throttles linked with a shaft, but when I did sync carbonators or fuel injection on my motorcycles I definitely used a fan.

Setup for me is pure throttle response based, and has been for decades. No sniffers or remote electronic tuning tools get used. I'm probably leaving a couple of HP on the table, but I doubt it is much more than a couple with a old Norton. ;)
Click to expand...
I suggest many people underestimate the potential of the Commando engine. When using petrol as fuel, carburetors cannot give fine enough adjustment to give true potential. The 961 probably has electronically controlled fuel injection.
 

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