What size Temp Sensor from the Trail Tech Vapor would fit our GS500?

[utgunslinger13]

I'm trying to figure out which model Air Temp Sensor I need (since I just found out I originally ordered the wrong model) but there are two options.  Which one do I need for my 1991 GS500?

10 MM Model:
http://trailtech.net/7500-3010.html

12 MM Model:
http://trailtech.net/7500-3012.html

These sensors go around the Spark Plug near the crush washer. Installation instructions can be found here:
http://www.trailtech.net/media/instructions/computers/vapor/010-ELV-07.pdf


Thanks,

Nick

[ke7syv]

If there are only two and you've already ordered a wrong one, wouldn't that make the other one the correct one? 

[Danny500]

The base on the spark plugs is 10mm I think, but even if it's 10 or 12 it won't matter by much... why not be safe and just order the 12mm. (The measurement is simply the diameter of the hole in that copper loop.)

Or, get a set of calipers and measure the thread width of the plug.

I always wondered how they got the temp off an air-cooled bike. Kinda neat.

Dan

[utgunslinger13]

If there are only two and you've already ordered a wrong one, wouldn't that make the other one the correct one? 

Unfortunately I ordered a 3rd option (there are a total of 5 I think) without realizing it.  There are 2 sizes for air cooled engines, and 3 sizes for water/coolant cooled and I got one for coolant!  So now I'm working with them to see about exchanging it for one of the air cooled models.

Anyone know 100% the size I would need?  I don't want to get the wrong one AGAIN! 

Thanks,

Nick

[Danny500]

That's the thing... get the 12mm because there's nothing to get "wrong"...

If it's a little big, who cares, it'll fit and work fine. Better that then getting the 10mm and not being able to use it.

Dan

[utgunslinger13]

Ok so even if the 12mm is to big it will still fit good enough for it to read correctly?

[Danny500]

Of course! The point of that loop is to get hot... that's it. The sparkplug is simply the "hottest" part of the motor's exterior  because it's directly connected to the combustion chamber. Theoretically you could just duct-tape the thing to a fin on the cylinder and get a +/- 10degree reading of the heat of the motor. It's not a uber-critical install, you know? Just as long as it's making connection to the spark plug base it'll be accurate.

When you get it, and install it, and get it to read properly (I think the directions say it won't actually recognize the sensor until it reads a 100 degree temp.) take it off and stick it under your tongue... Lol. If it reads at least 95 degrees I'd say it's pretty accurate.

Dan

[utgunslinger13]

lol, thanks for the advice.  Think I'll pass on putting it on my tongue tho!

I'll be contacting the company to see about an exchange.  If it comes down to it I can buy that sensor seperate but would rather exchange if its cheaper than the 25+shipping from Trail Tech.

Thanks again,

Nick

[coll0412]

Order the 12mm as that is the diameter of the GS spark plug.

The GS uses a DPR8EA-9, and according to NGK this represents as following

D=12mm
P=Projected Insulator Tip
R=Resistor Type
8= Heat Index Rating
E=19mm Thread Reach
A=Special Design
9=0.9mm gap

http://www.ngksparkplugs.com/docs/tech/design_symbols_plugs.pdf

[utgunslinger13]

I knew someone would be able to verify exactly.  Dan's logic made sense but I can rest easy knowing the science behind the madness!

Thanks,

Nick

[coll0412]

That's the thing... get the 12mm because there's nothing to get "wrong"...

If it's a little big, who cares, it'll fit and work fine. Better that then getting the 10mm and not being able to use it.

Dan

Not true  in this case, they use the washer that the thermocouple is attached to act as a sealing body(crush washer) between the spark plug and the cylinder head. The wrong size would result in it not fitting proper and then not getting a good seal on spark plug.

[Danny500]

That's the thing... get the 12mm because there's nothing to get "wrong"...

If it's a little big, who cares, it'll fit and work fine. Better that then getting the 10mm and not being able to use it.

Dan

Not true  in this case, they use the washer that the thermocouple is attached to act as a sealing body(crush washer) between the spark plug and the cylinder head. The wrong size would result in it not fitting proper and then not getting a good seal on spark plug.

OH! I didn't read that part. Yeah, good thing someone checked then, lol. I was thinking of that too, because if you had the coupler and the crush washer wouldn't you pull the spark out of the chamber a little... hah. Makes sense.

Dan