KDX 200 / KDX 220 Coolant Temperature Sensor Installation

Discussion specific to the 1995 - 2006 KDX200 (H Series) and 1995 - 2005 KDX220R (A Series) models sold in the USA
Post Reply
User avatar
billie_morini
Gold Member
Gold Member
Posts: 187
Joined: 04:31 pm Aug 02 2020
Country: Central Coast California

KDX 200 / KDX 220 Coolant Temperature Sensor Installation

Post by billie_morini »

My 1999 KDX 220 is used. I’ve owned it nearly 1 year. The previous owner installed a Trail Tech Vapor Speedometer/Tachometer part number 752-113. This package comes with two different in-line coolant temperature thermocouples (“sensors”). Both thermocouples are 19mm in length. One is installed in a 25mm outer diameter (O.D.) piping boss (“adapter,” “bushing” [part number 7500-3076]) and an M6 x 1.0 mm pitch thermocouple with smaller hex nut (part number V300-003). The previous owner installed the 25mm bossed coolant thermocouple (“sensor”) between and at the top of the left and right radiator.

This worked fine with the OEM fuel tank. It did not work with the larger capacity fuel tank purchased by me. The front bottom portion of the Clarke tank directly contacted the tubing and thermocouple boss and could not rest against the circular rubber bushing installed in the frame above the radiators. The larger capacity tank I bought is a Clarke Racing KDX 200/220 (1997-2007) 3.6 gallon tank. Part #11483 in translucent “color” so it is possible to see fuel level.
User avatar
billie_morini
Gold Member
Gold Member
Posts: 187
Joined: 04:31 pm Aug 02 2020
Country: Central Coast California

Re: KDX 200 / KDX 220 Coolant Temperature Sensor Installation

Post by billie_morini »

Photo 1 shows view of lower portion of left radiator. The 19mm inner diameter (I.D) black tubing comes from the cylinder head. The coolant is hottest when exiting the cylinder head. Inboard of the 19mm tubing nipple is a threaded coolant system drain. The OEM plug is a black ferrous bolt with a flat head requiring a 5mm allen wrench to remove/install. I modified this plug.
Attachments
KDX_thermo-1.jpg
KDX_thermo-1.jpg (3.05 MiB) Viewed 1783 times
User avatar
billie_morini
Gold Member
Gold Member
Posts: 187
Joined: 04:31 pm Aug 02 2020
Country: Central Coast California

Re: KDX 200 / KDX 220 Coolant Temperature Sensor Installation

Post by billie_morini »

Photo 2 shows the modified radiator drain plug. I drilled the plug through its center resulting in an 13/64-inch hole. This hole was threaded with M6 x 1.0 mm tap. I also filed 6 flat surfaces on the originally circular plug head to accommodate a 16mm wrench. This photo also shows the thermocouple V300-003 that will be installed through the modified drain plug. Before it was possible to use the thermocouple, it was necessary to significantly increase the wire length. Thermocouples are not sensitive to wire length and are not calibrated to a specific wire length (like other temperature sensors). I actually transplanted the relatively long wire from the thermocouple installed in the 25mm boss. CAUTION: these stranded wires are very fine! It’s easy to damage them and/or accidently cut them when stripping insulation from them. After soldering the wire from one thermocouple to the other, shrink wrap was installed onto wire splices for a professionally looking job.
Attachments
KDX_thermo-2.jpg
KDX_thermo-2.jpg (2.39 MiB) Viewed 1783 times
User avatar
billie_morini
Gold Member
Gold Member
Posts: 187
Joined: 04:31 pm Aug 02 2020
Country: Central Coast California

Re: KDX 200 / KDX 220 Coolant Temperature Sensor Installation

Post by billie_morini »

Photo 3 shows the modified radiator drain plug installed. The plug was installed with ThreeBond 1184 (gray) liquid gasket on the threads. A minimal amount was used to assure excess did not get into the radiator. You can use Yamabond, Hondabond, if you like.
Attachments
KDX_thermo-3.jpg
KDX_thermo-3.jpg (2.96 MiB) Viewed 1783 times
User avatar
billie_morini
Gold Member
Gold Member
Posts: 187
Joined: 04:31 pm Aug 02 2020
Country: Central Coast California

Re: KDX 200 / KDX 220 Coolant Temperature Sensor Installation

Post by billie_morini »

Photo 4 shows the thermocouple installed. The white nylon washer came with it. I placed a crush washer like those used for brake lines between the hex head and white nylon washer. Three bond 1184 was applied onto the thermocouple threads prior to install. It is necessary to not overtighten the thermocouple because too much force will break it. I went with “just enough” knowing it would be leak tested at temperature. If it is necessary to drain the cooling system from the bottom of the left radiator then I will simply remove the 19mm black tubing. Benefit: draining will be much faster than from the sacrificed radiator drain plug.
Attachments
KDX_thermo-4.jpg
KDX_thermo-4.jpg (3.06 MiB) Viewed 1783 times
User avatar
billie_morini
Gold Member
Gold Member
Posts: 187
Joined: 04:31 pm Aug 02 2020
Country: Central Coast California

Re: KDX 200 / KDX 220 Coolant Temperature Sensor Installation

Post by billie_morini »

A new piece of 19mm I.D. black tubing was installed to connect the two nipples at the top of the radiators. I thought about replacing all coolant houses with colored silicon tubing, but it the out-of-pocket cost was considerably higher. The only tubing that was truly needed was about 7 inches of tubing to connect the radiator tops together. I got that from an automobile parts store for $1.50 to $2.00.
User avatar
billie_morini
Gold Member
Gold Member
Posts: 187
Joined: 04:31 pm Aug 02 2020
Country: Central Coast California

Re: KDX 200 / KDX 220 Coolant Temperature Sensor Installation

Post by billie_morini »

Results/Conclusions
1) Larger capacity tank fits correctly
2) Coolant thermocouple works as good as the original owner’s installation
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Re: KDX 200 / KDX 220 Coolant Temperature Sensor Installation

Post by KDXGarage »

Very nice! Great work and documentation of your process. Thank you for sharing with us.
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
Post Reply