Temp. Gauge Placement

Mark Younggren /

So when conversing with an old Motörhead relative of mine. He exclaimed he would never attach his temp. gauge to the spark plug where it was intended, but would rig it to one of the close inside head fins or a head bolt. He said it would give a more accurate read of what's really go on temp wise. Although it might take a little modification I liked that idea rather than getting a spark plug temp reading which would give more spikes in temp. What do you all think......?

Re: Temp. Gauge Placement

I did mine to the head bolt, It stays in place so dont have to mess with it ever again.

Re: Temp. Gauge Placement

I think that would be more inaccurate. The stud would act like a heatsink pulling heat from the head screwing up the reading...then again after it's heatsoaked maybe not.

Re: Temp. Gauge Placement

The thing about putting it on the spark plug is that's the reference everyone uses. So it's easy to tell if you're running too hot compared to everyone else on here because that's their frame of reference too

Re: Temp. Gauge Placement

Overpriced Parts /

Plug hole is best, It’s designed for the plug and hole, Remove plug crush washer too. If a bit too tight on plug threads file it a little,

Re: Temp. Gauge Placement

Dirty30 Dillon /

As stated, their is a reason why it's meant to mount to the plug.

A) CHT is a standard measurement, and without it your numbers basically are useless in terms of using community gathered data to tune and avoid seizure.

B) CHT does show more spikes, which actively coincide with engine fluctuations. This is because the plug center is the closest to combustion, giving you readings that most accurately reflect actual cylinder temps.

The same goes for people trying to use an IR thermo to tune. It's unreliable and inaccurate.

Re: Temp. Gauge Placement

It takes a split second for a seizure to happen .

Once to the point of melting , it's done .

Wouldn't it be best to see that coming as soon as possible ?

Placing the thermocouple as close to the heat source as possible could easily mean a 'life' saved . ;)

Re: Temp. Gauge Placement

Mark Younggren /

I like where everyone’s head is at. Great points. So at the spark plug your going to get the hottest temp reads and spikes. Which I think we can all agree on that.

With that in mind if it’s running in the 300’s consistently you would have a almost zero chance of seizure due to heat, correct? Obviously, it’s can seize for many others reason but this is a temp discussion. If it jumps in the low to mid 400’s or above we are getting into the danger zone, correct? Is low 400’s for a few seconds ok, or should I be looking to tune for mid to high 300 no matter what?

Re: Temp. Gauge Placement

Overpriced Parts /

On a puch kit No 400’s°F range especially the cheap made kits nowadays, 360-385f is ok

Re: Temp. Gauge Placement

Run 2 temp gauges on the same bike at the different connection points and report back your findings

Re: Temp. Gauge Placement

Mark Younggren /

Also, is it worth the extra $100 plus for the vapor model trail tech that shows RPM, speed and extra features? I am guessing wiring and power/setup is a touch more intricate then the basic model.

Re: Temp. Gauge Placement

CHT is useless information for tuning, it’s actually kind of a dangerous distraction. Especially if you are on a new bike and are constantly worried about this or that on top of taking your eyes off the road every 5 seconds to look back at the tto. EGT and AFM at the header is the only accurate way to know what is happening, but basically no moped needs all that business. Leak down test before you run it, then get the biggest jet in the drawer and work down until it goes well.

Re: Temp. Gauge Placement

> Daniel '' Wrote:

> -------------------------------------------------------

> CHT is useless information for tuning, it’s actually kind of a dangerous

> distraction. Especially if you are on a new bike and are constantly

> worried about this or that on top of taking your eyes off the road every

> 5 seconds to look back at the tto. EGT and AFM at the header is the only

> accurate way to know what is happening, but basically no moped needs all

> that business. Leak down test before you run it, then get the biggest

> jet in the drawer and work down until it goes well.

I think RPM is nice for when you are in that last 10% of tuning phase. Getting that upper 40s bike to break 50 so to speak but yeah I noticed that I look at it too often

Re: Temp. Gauge Placement

I don't use it much anymore but when I was learning how to tune it did help a lot with trying to understand what changes do what.

After you've tuned a dozen or so bikes you can 'feel' them but until then I think it really is a nice way to understand what is happening with the changes you are making and catch a problem before it seizes.

Re: Temp. Gauge Placement

Overpriced Parts /

> Graham Motzing Wrote:

> -------------------------------------------------------

> I don't use it much anymore but when I was learning how to tune it did

> help a lot with trying to understand what changes do what.

>

> After you've tuned a dozen or so bikes you can 'feel' them but until

> then I think it really is a nice way to understand what is happening

> with the changes you are making and catch a problem before it seizes.

I have tuned dozens of mopeds and 2t motorcycles before I used a gauge but once I used them I won’t go back to not having one because they're a safeguard like a temperature gauge in a car, especially in performance car, a performance bike build needs the same temperature protection,

They helped me a few times. Once I had lower than normal temperature and loss of power, it turned out my timing was going retarded because point cam was wearing,

Another time the temperature was climbing higher than normal, it turned out filter fell off and I had it air leak too.

There was other instances to like when I put a brand new bing jet in of the same size to replace an old one but it turned out I read it wrong (82 vs 88) the bike ran pretty much almost the same but with a higher temperature,

Two cycle engines are funny, they run the best right before they explode so going by how good they run doesn't mean Doink,

To keep them alive you need a bit more rich jetting then perfect optimal and a little less aggressive timing to control temps and a way to monitor engine condition,

I run tachometers on some bike builds too, a little loss of rpm means performance is down from blocked pipe, brakes, bearings, chain binding/dragging, something worn etc. before you can feel it,

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